- Email: [email protected]
Biatrial electrograms during coarse atrial fibrillation and flutter-fibrillation
Biatrial electrograms during coarse fibrillation and flutter-fibrillation
atrial
Carl V. Leier, M.D.,* Stephen F. Schaal, M.D.** Columbus, Ohio
Atria1 flutter was first determined to be a significant dysrhythmia in man by MacWilliam’ in 1887. It is recognized on the scalar ECG as a rapid (220 to 350 beats per minute) regular undulation of the baseline with identical broad atria1 deflections (F waves). The undulation in the inferior limb leads most often resembles a “sawtooth” pattern. Atria1 fibrillation is a form of disorganized atria1 activation, whose scalar ECG features consist of rapid irregular undulation of the baseline with smaller chaotic atria1 deflections (f waves). In 1899, Cushney’ brought atria1 fibrillation to the attention of the medical world as an important rhythm disturbance in man. Coarse atria1 fibrillation (CAF) and flutterfibrillation (Fl-Fib, impure flutter) are disorders of atria1 activation with scalar ECG features of both atria1 fibrillation and atria1 flutter. The ECG characteristics of CAF are those of fibrillation with superimposed larger, but still irregular f waves. The scalar ECG of Fl-Fib generally shows the superimposition of rapid regular F waves upon a fibrillation baseline or mild variation of the amplitude and/or regularity of a flutter baseFrom the Division Medicine, Columbus, Supported Chapter
of Cardiology, Ohio.
Ohio
State
by Grants 7533 and 7631 from of the American Heart Association.
Received
for publication
Dec.
Accepted
for publication
March
University the
Central
College Ohio
of
Heart
21, 1978. 6, 1979.
Reprint requests: Carl V. Leier, State University Hospitals, 653 Cglumbus, Ohio 43210.
M.D., Means
*Assistant Professor of Medicine Cardiology, Ohio State University for the Central Ohio Heart Chapter
Division of Cardiology, Hall, 466 West Tenth
and Pharmacology, College of Medicine; of the American
Ohio Ave.,
Division of Investigator Heart Asaocia-
Table
I. Cardiac diagnoses of the study popula-
tion Number of patients 12 9
Rheumatic heart disease Primary conduction system disease Hypertensive heart disease Arteriosclerotic heart disease Congenital heart disease Congestive cardiomyopathy Mitral valve prolapse Valvular disease (non-rheumatic) Others* Unknown *l amyloid heart Wolff-Parkinson-White
disease,
8 5 3 3 3 2 4 8
1 pericardiectomy for calcific syndrome, 1 Lawn-Ganong-Levine
pericarditis, syndrome.
1
line. While the intracardiac atria1 electrograms of atria1 flutter and fibrillation have been described, little information is available concerning the atria1 electrical events of CAF and Fl-Fib. Irregular high right atria1 activity concurrent with regular low right and left atria1 activity were noted by Puech and colleagues3in a patient with Fl-Fib. Zipes and DeJoseph’ reported that three of ten patients with dissimilar atria1 rhythms (documented by intracardiac recordings) had simultaneous scalar ECG patterns of Fl-Fib or CAF. This study was designed to investigate the electrical events of the atria which occurred during the scalar ECG patterns of CAF and Fl-Fib. Methods
tiOIl.
**Associate University
Professor of Medicine, College of Medicine.
0002-8703/80/030331
+ 11$01.10/O
Division
of Cardiology,
0 1980
The
Ohio
Patients. The presence of CAF and/or Fl-Fib on the scalar ECG was the sole criterion for
State
C. V. Mosby
Co.
American
Heart
Journal
331
Leier
Table
and Schaal
II. Atria1 electrical activity
recorded in the patient population Surfuce ECG
I. II.
III.
Biatrial fibrillation with periodic Dissimilar interatrial rhythms Right atrium*
V.
VI.
Left
Dissimilar
Fast
Fibrillation Flutter (FF Flutter (FF Flutter (FF Fibrillation Flutter Fibrillation
atria1 flutter rates Interatrial (right # left) Right intra-atria1 (high right
> 160) 5 160)
Left > 160) 5 160) > 160)
# low right)
flutter-biatrial FF = 150-170 msec. FF < 150 msec.
Fragmented
CAF
Fl-Fib
24
24
0
11 4 7 4 2 1 1 1
0 4 1 3 0 1 1 0
11 0 6 1 2 0 0 1
2 1 1 2 1 1 1
2 0 1 0 0 0 0
0 1 0 2 1 1 1
4 3
1t 0
3 3
12 4
0
12 1
5 4
0
atrium
Flutter (FF > 160) Fibrillation Flutter (FF 5 160) Fibrillation Fibrillation Flutter (FF Fibrillation Flutter (FF Flutter (FF > 160) Quiescence Flutter (FF 5 160) Quiescence Fibrillation-reg. Quiescence Atria1 tachycardia Flutter Dissimilar right intra-atria1 rhythms High right Low right Flutter (FF > 160) Fibrillation Fibrillation Fibrillation Flutter (FF > 160) Atria1 tachycardia Atria1 tachycardia
IV.
regularity
showing
No of events
F deflection FF > 160 msec. FF 5 160 msec.
atrium
Fibrillation Fibrillation Fibrillation Flutter Flutter ? ?
3t
5 2
23
*Rhythms of high right and low right atrium were the same. tone patient demonstrated both features CAF and Fl-Fib. $Both patients showed features of CAF and Fl-Fib.
inclusion in the study. CAF was defined as fibrillation (fine undulation) of the scalar ECG baseline with superimposed larger f waves (1 1 mm.)s of unequal amplitude and unequal f-f intervals. ECG recordings showing a fibrillation baseline with varying periods of rapid regular waves of uniform amplitude were designated Fl-Fib. These dysrhythmias either occurred spontaneously or were induced by rapid atria1 pacing of atria1 flutter, paroxysmal atria1 tachycardia, or sinus rhythm. Fifty-seven patients were studied. The mean age of the patient population was 57 years (range 21 to 81) with 25 females and 32 males. Various cardiac disease states were represented (Table I) and the diagnoses were substantiated with cardiac catheterization in 43 of the patients. Thirtyeight (67%) of the patients had roentgenographic
332
cardiomegaly; 27 (47%) had clinical and/or radiologic evidence of congestive heart failure; and six had moderate to severe chronic obstructive pulmonary disease. Right and/or left atria1 enlargement was noted on cardiac fluoroscopy and/or the echocardiogram in 32 (56%) patients. Atria1 conduction studie@ were performed in 19 patients within one year of this study and 18 were found to have atria1 conduction disease. Thirty patients were receiving a cardioactive drug at the time of study (20 patients on digitalis, five on quinidine sulfate, two on propranolol, and three on propranolol and quinidine sulfate). All patients were clinically euthyroid; two of the patients were taking a thyroid preparation. Atrial recording studies. Written informed consent was obtained from each patient prior to each study. No premeditation was administered. In 56
March,
1980,
Vol.
99,
NO. 3
Biatrial
Fig. 1. Electrograms from the high right atrium (HRA) and left atrium (LA) showing slowing and regularity (reg). A similar pattern was present in the low right atria1 region. was present in aVF and V,.
Fig. 2. Biatrial electrograms during dissimilar atria1 rhythms (LRA) atria1 recordings showing flutter (FF = 190 msec.) and impure flutter and flutter-fibrillation were noted on the scalar coarse atria1 fibrillation with high right atria1 (HRA) fibrillation Separate low right atria1 recordings also showed fibrillation
patients, right and left atria1 electrograms were recorded from bipolar electrode (interpole distance of 1 cm.) catheters placed respectively within the right atrium and esophagus (posterior to the left atrium) and/or coronary sinus. A
American Heart Journal
electrograms
fibrillation with periodic Coarse atria1 fibrillation
in two patients. A, High right (HRA) and low right left atria1 recording (LA) showing fibrillation while ECG (50 mm./sec. paper speed). B, Surface ECG of and left atria1 (LA) fast flutter (FF = 140 msec.). (25 mm./sec. paper speed).
minimum of two catheters were placed in the right atrium, one for recording the high right atria1 electrogram and the other for recording the low right atria1 electrogram. Left atria1 electrograms were not recorded in one patient. In 36
333
Leier
and
Schaal
Fig. 3. Right atria1 and flutter-fibrillation
flutter (HRA and pattern present
LRA, FF = 240 msec.) and left atria1 (LA) quiescence on the scalar
patients, a six-pole catheter was also placed across the tricuspid valve for the simultaneous recording of low right atrial, bundle of His, and the ventricular depolarizations.’ High right atria1 (HRA), low right atria1 (LRA), and left atria1 (LA) electrograms, and three scalar ECG leads (usually I, aV,, and V,) were recorded simultaneously on an Electronics for Medicine DR-12 recorder at paper speeds of 25, 50 and 100 mm./ sec. Intracardiac and esophageal electrode signals were amplified in a frequency range of 30 to 500 Hz. Atria1 pacing was performed with a Grass Instrument S88 stimulator and isolation unit. An atria1 electrogram showing an irregular depolarization pattern (at atria1 rates > 360/ minute) was defined as fibrillation; a regular depolarization pattern at atria1 rates in the range of 220 to 4OO/minute was defined as flutter. Results The electrical events of each atrium occurring during CAF and Fl-Fib of the patient population are presented in Table II. Fibrillation with periodic regularity. Twentyfour of the patients had atria1 electrograms showing biatrial fibrillation with periodic slowing and
334
with
impure
flutter
ECG
regularity (Fig. l), and the scalar ECG of each of these patients revealed CAF. Dissimilar atrial rhythms. Transient (> 1 and < 5 minute duration) or persistent (> 5 minute duration) dissimilar right and left atria1 rhythms were observed in 31 patients. Flutter of one atrium and fibrillation of the other was the most common form of dissimilar atria1 rhythms noted (Fig. 2, A and B). When the electrograms demonstrated flutter of one atrium and fibrillation of the other atrium, the scalar ECG showed CAF in seven of eight patients whose flutter FF interval was 5 160‘msec. and showed Fl-Fib in 17 of 18 patients with FF intervals > 160 msec. Four patients demonstrated dissimilar atria1 rhythms with left atria1 quiescence. Two of these patients had right atria1 flutter at FF intervals of 240 and 250 msec. with low amplitude flutter and Fl-Fib on the scalar ECG (Fig. 3); another patient had rapid right atria1 flutter (FF = 160 msec.) with the scalar ECG of CAF; the last patient had right atria1 fibrillation (with periodic regularity) with fibrillation and infrequent. coarsenesson the scalar ECG. A patient previously reported’ had scalar ECG patterns of Fl-Fib and “impure” flutter during right atria1 tachycardia and left atria1
March,
1980, Vol. 99, No. 3
Biatrial
4. Dissimilar right intra-atria1 rhythms. A, High right atrium (HRA) shows fibrillation while and left atrium (LA) demonstrate flutter with an FF interval of 180 msec. Flutter-fibrillation the surface ECG. B, Another patient with low right atria1 (LRA) fibrillation occurring simultaneously right atria1 (HRA) and left atria1 (LA) flutter (FF = 200 msec.). Fig.
(LRA)
flutter and Fl-Fib and CAF interatrial Wenckebach.
during
periods
of
Dissimilar right intra-atrial rhythms. Dissimilar rhythms within the right atrium itself were observed in nine patients. Seven instances involved flutter of either the high or low right atrium and fibrillation of the remaining portion of the right atrium (Fig. 4). The simultaneous left atria1 recording showed either flutter or fibril-
American Heart Journal
electrograms
the low right was noted on with high
lation and again, the scalar ECG demonstrated Fl-Fib if the FF interval exceeded 160 msec. and CAF if the FF 5 160 msec. A patient with high right atria1 tachycardia (AA = 440 msec.) had transient episodes of low right atria1 flutter (FF = 220 msec.) interchanging with periods of low right atria1 fibrillation (Fig. 5). No left atria1 recordings were obtained on this patient and the scalar ECG showed Fl-Fib.
335
Leier
and
Schaal
AVF
Y --u--v-d +fSECW
+IsEc*
Fig. 5. Two different forms of dissimilar right intra-atria1 rhythms in the same patient. A. High right atria1 recording (HRA) showing a regular atria1 tachycardia with an AA of 440 msec. A simultaneous low right atria1 recording (LRA) demonstrates a regular faster atria1 tachysystole (flutter, FF = 220 msec.). Flutter-fibrillation and impure flutter patterns are present on the scalhr ECG. Placement of a premature atria1 depolarization (extrastimulus) in the low right atria1 region changed the LRA to fibrillation as noted in punel B. The HRA remained in regular tachycardia at AA = 440/minute. Left atria1 recordings are not available.
III. Atria1 electrical events noted during the scalar ECG recordings of coarse atria1 fibrillation (n = 39)
Table
Atria1
electrical
events
Biatrial fibrillation with periodic regularity Dissimilar atria1 rhythms FF > 160 msec. RA-Fib LA-F1 FF 5 160 msec. RA-Fl LA-Fib RA-Fib LA-F1 RA-Fl LA-quiet RA-Fib LA-quiet Dissimilar right intra-atria1 rhythms FF > 160 msec. HRA-Fl, LRA-Fib, LA-Fib FF 5 160 msec. HRA-Fl, LRA-Fib, LA-Fib Fast flutter-biatrial FF 2 150 msec. FF < 150 msec. Abbreviations: PAT = atria1
336
FF = flutter FF interval; Fib = fibrillation; Fl = flutter; tachycardia; quiet = quiescence; RA = right atrium (high
No
9;
34 10
62 25
1 4 3 1 I 3
8
‘2
5
2 1
0 2 HRA = high and low).
right
atrium;
LA
= left
artium;
March,
LRA = lOW right atrium;
1980,
Vol.
99, No.
3
Biatrial
Dissimilar atrial flutter rates. Transient unequal flutter rates of each atrium occurred in four patients. Three of these patients had scalar ECG recordings of Fl-Fib with right/left atria1 FF intervals of 200/270, l&5/170, and 230/170 msec. (Fig. 6). Features of both CAF and Fl-Fib were observed on the scalar ECG tracing of a patient with a right flutter interval of FF = 190 msec. and left atria1 flutter interval of 170 msec. A patient with Fl-Fib had transient episodes of dissimilar flutter rates within the right atrium itself; this patient had flutter (FF = 240 msec.) of the left and low right atrium with a slower somewhat irregular high right atria1 rhythm secondary to right intra-atria1 and interatrial Wenckebach (Fig. 7). Another patient had two different episodes of Fl-Fib with unequal flutter rates within the right atrium itself; the left and high right atria1 flutter was faster than the low right atria1 flutter on one occasion with FF intervals of 180 and 200 msec., respectively, and the other episode consisted of left atria1 fibrillation, high right atria1 flutter with an FF interval of 200 msec. and low right atria1 flutter with an FF interval of 230 msec. (Fig. 8). Fast and fragmented flutter. The remainder of the patients with CAF or Fl-Fib had either biatrial rapid (FF I 170 msec.) flutter and/or fragmented (duration of F deflection > 80 msec.) flutter (Fig. 9). In biatrial rapid flutter alone, FF intervals L 150 msec. were usually manifested as Fl-Fib on scalar ECG and FF intervals < 150 msec. as CAF or CAF with episodic Fl-Fib. Discussion
This study shows that the scalar electrocardiographic manifestations of CAF and Fl-Fib may be secondary to a variety of atria1 electrical events. Tables III and IV summarize the atria1 electrical events recorded during these dysrhythmias. Transient or persistent CAF occurred 39 times and Fl-Fib 53 times in this study population. Coarse atrial fibrillation (Table Ill). The majority (62%) of CAF events were secondary to biatrial fibrillation with periodic slowing and regularization. In contrast to the regular frequency of flutter, the regularization of fibrillation showed f-f intervals which were still somewhat variable and usually quite short at < 140 msec. (atria1 rate > 430/minute). The periods of regularization noted on the atria1 recordings did not always
American
Heart
Journal
electrograms
Fig. 6. Transient unequal interatrial flutter rates recorded simultaneously with a flutter-fibrillation pattern on the surface ECG. A slower fragmented flutter (FF = 230 msec., arrows indicate measurement points of F deflections) occurred in the high right atrium (HRA) simultaneous with a faster left atria1 (LA) flutter (FF = 170 msec.). A very mild variation of the HRA FF interval is present. A separate recording from the low right atrium showed the same flutter rate as the HRA.
coincide with the periods of coarseness on the scalar ECG; this indicates that areas of the atria (e.g., anterior RA, lateral LA, etc.) not directly recorded by the three electrodes contributed significantly to the depolarization pattern of the atria and thereby modified the scalar ECG recordings. CAF was also associated with electrograms showing dissimilar right and left atria1 rhythms, dissimilar right intra-atria1 rhythms, and fast flutt,er. Most of the patients (nine of 10) with CAF and dissimilar atria1 rhythms had flutter rates 2 375/minute (FF I 160 msec.). Two patients with FF intervals > 160 msec, and the scalar ECG of CAF had dissimilar intra-atria1 rhythms with flutter only in the high right atrium and fibrillation in the low right and left atrium. Fragmentation of the F waves on the atria1 electrograms was generally not found to be a cause of CAF, although two patients with rapid fragmented F waves (FF intervals < 160 msec.) had scalar features of both dysrhythmias (CAF/ Fl-Fib, Table II). Rapid biatrial flutter alone (without dissimilar rhythms or fragmentation) was found during CAF when the flutter rate exceeded 4001minute (FF < 150 msec.); the pre-
337
Leier
and
Schaal
Fig. 7. Atria1 electrograms showing regular left and low right atria1 (LA, LRA) flutter (FF = 249 msec.) with Wenckebach periodicity occurring in the high right atria1 region (HRA). The time interval (msec.) between the LA and HRA deflections are indicated above the HRA recording. X = dropped HRA beat. A separate recording at 25 mm./sec. paper speed and at a slower ventricular rate showed Fl-Fib and impure flutter pattern on the scalar ECG.
Table IV. Atria1 electrical events observed during the scalar ECG recordings of flutter-fibrillation (n = 53) Atria1 electrical events Dissimilar
atria1
rhythms
FF > 160 msec. RA-Fl LA-Fib RA-Fib LA-F1 RA-Fl LA-quiet RA-PAT LA-F1 FF i 160 msec. RA-Fib LA-F1 Dissimilar right intra-atria1 FF > 160 msec. HRA-Fl, LRA-Fib, HRA-Fib, LRA-Fl, HRA-Fib, LRA-Fl, HRA-PAT, LRA-Fl, HRA-PAT, LRA-Fib, Dissimilar atria1 flutter Interatrial Right intra-atria1 Fast flutter-biatrial FF = 150-170 msec. FF < 150 msec. Fragmented F deflection FF > 160 msec. FF 5 160 msec. Abbreviations:
338
I
see Table
No
I
9
21
40
6
11
6
11
13
25
7
13
11 6 2 1 1 rhythms LA-F1 LA-F1 LA-Fib LA-? LA-? rates
1 2 1 1 1 3 3 12 1 5 2
III.
March,
1980, Vol. 99, NO. 3
Biatrial
sence of small areas of fibrillation in locations not directly recorded by the electrodes cannot be excluded in these patients. Flutter-fibrillation (Table IV). In contrast to CAF, Fl-Fib was never present on the scalar ECG when the electrograms demonstrated biatrial fibrillation with periodic regularity. Sixty-two per cent of the Fl-Fib events were associated with dissimilar right and left atria1 rhythms, dissimliar right intra-atria1 rhythms, or dissimilar flutter rates. The remainder of the Fl-Fib events were secondary to rapid flutter (FF I 170) or fragmentation of the F waves. It appears that regular activity must be present in at least one portion of the atria in order to have Fl-Fib represented on the scalar ECG. The remaining portions of the atria may demonstrate fibrillation, atria1 tachycardia, a different flutter rate, electrical quiescence, or a combination of these. In instances of biatrial flutter, the flutter must be rapid (FF = 150 to 170 msec.) or fragmented to produce a Fl-Fib appearance. Ninety-two per cent (37 of 40) of patients with scalar Fl-Fib tracings and atria1 electrograms showing dissimilar rhythms or rates or fragmentation had flutter FF intervals 2 160 msec.; and 92% (12 of 13) of patients with Fl-Fib and atria1 recordings of biatrial flutter (same rates and without fragmentation) had FF intervals L 150 msec. In general, a FF interval above 160 msec. tends to produce the scalar ECG tracing of Fl-Fib, and an interval below 150 msec. will usually show CAF on ECG. In the FF interval range of 150 to 160 msec., the scalar ECG pattern will depend on the atria1 electrical activity occurring at the time (pure biatrial flutter = Fl-Fib, dissimilar rhythms or rates or fragmentation = CAF or CAF/Fl-Fib). The incidence of dissimilar right and left atria1 rhythms was high in our study population, occurring in 40% of the Fl-Fib recordings. Dissimilar right intra-atria1 rhythms probably belong to the dissimilar atria1 rhythm family and differ only in that the boundary of the dissimilar rhythms is located between the two right atria1 electrodes instead of between the right and left atria1 recording electrodes. In most instances, the atria1 catheters were repositioned to look for variations in the atria1 electrogram or to identify boundaries of flutter or fibrillation. Intermediate areas were frequently identified which showed regularity with intermittent fragmentation or irregularity and were bounded by relatively pure flutter on one border and fibrillation on another. Overdrive American
Heart
Journal
electrograms
Fig. 8. Transientunequalright intra-atria1 flutter rates in a patient with dissimilar atria1 rhythms and flutter-fibrillation on the surface ECG (Lead V,). The right atrium (HRA and LRA) was in flutter and the left atrium (LA) was in fibrillation. The high right atrium flutter rate was 3OO/minute (FF = 200 msec.), while that of the low right atrium was 260/minute (FF = 230 msec.). The FF intervals of the slower flutter (LRA) were slightly irregular (5 10 msec. variation).
pacing applied to the region of flutter (while the remainder of the atria was in fibrillation) consistently converted the flutter region to fibrillation. While these observations suggest that the dissimilar atria1 rhythms of flutter and fibrillation are not independent, this study does not indicate which of the two dysrhythmias is dominant. The flutter zone may be dominant and rapid pacing of this region may move the disorganization of conduction (fibrillation zone) closer to the recording catheter. The studies of Zipes and DeJoseph” suggest that the fibrillation regions are dominant and that the rhythm and rate of the flutter zone are controlled by a longer and more uniform refractory period. During overdrive pacing, the refractory period of the flutter zone shortens and/or becomes non-uniform. allowing more of 339
Leier
and
Schaal
Fig. 9. A, Biatrial recordings of fast flutter (FF = 150 msec.) manifested on the scalar ECG as flutter-fibrillation. B, The right atrial F deflection is fragmented to a duration of 100 msec. during a flutter rate of 230/minute (FF = 260 msec.). The simultaneous surface ECG showed flutter-fibrillation and impure Rutter.
the fibrillatory impulses to enter the region. Overdrive pacing of right atria1 flutter during left atria1 quiescence did not alter the flutter rhythm and rate or converted the region into fibrillation. Although the electrical quiescence was explored with multiple catheter locations (full length esophageal and coronary sinus readings) at high gain and various recording frequencies, it is possible that very fine fibrillation was present in or around the quiescent region. The mechanism of different intra- or interatrial flutter rates (dissimilar atrial flutter rates) is not clear. The region with a slower flutter rate probably has a longer refractory period, and is depen-
340
dent upon conduction from the faster flutter region for its impulses. The activation of a passive region with a longer refractory period to the more rapid regular impulses of another region would be slightly irregular, as noted in Figs 6 and 8, or would show a set cond’uction pattern as observed in the patient with interatrial and right intraatria1 Wenckebach (Fig. 7) and in another patient with interatrial Wenckebach and 2:l interatrial conduction? The dissimilar atria1 flutter rate events were all transient (5 5 minutes duration), implying that this rhythm disturbance is unstable and will probably not persist as a chronic atria1 dysrhythmia.
March,
1980, Vol. 99, NO. 3
Biatrial
Most patients in this series had cardiac disease with cardiomegaly alone (20%) or cardiomegaly with clinical and/or roentgenographic congestive heart failure (47%). Fluoroscopic and/or echocardiographic data revealed that atria1 enlargement was present in 56% of the patients. Twenty-five of 29 (86%) patients who spontaneously developed CAF or Fl-Fib had cardiomegaly and/or atria1 enlargement and/or evidence of congestive heart failure. Thus, only four of 29 patients (14%) with spontaneous CAF or Fl-Fib did not have cardiomegaly, atria1 enlargement, or congestive failure. Two of these remaining four patients underwent atria1 conduction time measurements; both demonstrated prolonged atria1 conduction times indicative of atria1 conduction disease. Therefore, of 29 patients who had developed spontaneous FlFib or CAF, a cardiac-pathophysiologic etiology was not identified in only two patients. The patient prototype for CAF and Fl-Fib in our study was an individual with a form of cardiac disease accompanied by one or more of the following: (1) cardiomegaly, (2) atria1 enlargement, (3) congestive heart failure, or (4) atria1 conduction disease. This study does not provide direct information on the mechanisms of atria1 fibrillation or flutter, but it does illustrate some of the interactions of the two dysrhythmias. The scalar ECG recordings of the relatively common dysrhythmias, CAF and Fl-Fib, appear to be secondary to-an interesting spectrum of atria1 electrical events.
fibrillation or flutter-fibrillation on the scalar electrocardiogram. Atria1 electrograms in coarse atria1 fibrillation most often showed biatrial fibrillation with periodic slowing and regularity, while dissimilar interatrial or right intra-atria1 rhythms were noted less frequently. Flutterfibrillation on the scalar ECG required the presence of rapid regular tachysystole (flutter) somewhere in the atria and was usually associated with dissimilar interatrial or right intra-atria1 rhythms, dissimilar atria1 flutter rates, or fast or fragmented flutter. Coarse atria1 fibrillation and flutter-fibrillation may be secondary to a variety of atria1 electrical events. The authors would like to thank Mrs. Marlene Griffin, Ladd Snyder, Ms. Max Bather, Mrs. Margaret Chambers, Mr. Fred Davis for their technical assistance.
American Heart Journal
Ms. and
REFERENCES
5.
6.
7.
Summary
Right and left atria1 electrograms were recorded in 57 patients who demonstrated coarse atria1
electrograms
8.
MacWilliam, J. A.: Fibrillary contraction of the heart, J. Physiol. 8:296, 1887. Cushney, A. R.: On the interpretation of pulse tracings, J. Exp. Med. 4:327, 1899. Puech, P., Latour, H., and Grolleau, R.: Le flutter et ses limites, Arch. Mal. Coeur 61:116. 1970. Zipes, D. P., and DeJoseph, R. L.: Dissimilar atria1 rhythms in man and dogs, Am. J. Cardiol. 32:618, 1973. Peter, R. H., Morris, J. J., and McIntosh, H. D.: Relationship of fibrillatory waves and P waves in the electrocardiogram, Circulation 33:599, 1966. Leier, C. V., Meacham, J. A., and Schaal, S. F.: Prolonged atria1 conduction-a major predisposing factor in the development of atria1 flutter, Circulation 57:213, 1978. Scherlag, B. J., Lau, S. H., Helfant, R. H., Berkowitz, W. D., Stein, E., and Damato, A. N.: Catheter technique for recording His bundle activity in man, Circulation 39:13, 1969. Leier, C. V., and Schaal, S. F.: Dissimilar atria1 rhythms-a patient with interatrial block, Br. Heart J. 39:680, 1977.
341
atrial
Carl V. Leier, M.D.,* Stephen F. Schaal, M.D.** Columbus, Ohio
Atria1 flutter was first determined to be a significant dysrhythmia in man by MacWilliam’ in 1887. It is recognized on the scalar ECG as a rapid (220 to 350 beats per minute) regular undulation of the baseline with identical broad atria1 deflections (F waves). The undulation in the inferior limb leads most often resembles a “sawtooth” pattern. Atria1 fibrillation is a form of disorganized atria1 activation, whose scalar ECG features consist of rapid irregular undulation of the baseline with smaller chaotic atria1 deflections (f waves). In 1899, Cushney’ brought atria1 fibrillation to the attention of the medical world as an important rhythm disturbance in man. Coarse atria1 fibrillation (CAF) and flutterfibrillation (Fl-Fib, impure flutter) are disorders of atria1 activation with scalar ECG features of both atria1 fibrillation and atria1 flutter. The ECG characteristics of CAF are those of fibrillation with superimposed larger, but still irregular f waves. The scalar ECG of Fl-Fib generally shows the superimposition of rapid regular F waves upon a fibrillation baseline or mild variation of the amplitude and/or regularity of a flutter baseFrom the Division Medicine, Columbus, Supported Chapter
of Cardiology, Ohio.
Ohio
State
by Grants 7533 and 7631 from of the American Heart Association.
Received
for publication
Dec.
Accepted
for publication
March
University the
Central
College Ohio
of
Heart
21, 1978. 6, 1979.
Reprint requests: Carl V. Leier, State University Hospitals, 653 Cglumbus, Ohio 43210.
M.D., Means
*Assistant Professor of Medicine Cardiology, Ohio State University for the Central Ohio Heart Chapter
Division of Cardiology, Hall, 466 West Tenth
and Pharmacology, College of Medicine; of the American
Ohio Ave.,
Division of Investigator Heart Asaocia-
Table
I. Cardiac diagnoses of the study popula-
tion Number of patients 12 9
Rheumatic heart disease Primary conduction system disease Hypertensive heart disease Arteriosclerotic heart disease Congenital heart disease Congestive cardiomyopathy Mitral valve prolapse Valvular disease (non-rheumatic) Others* Unknown *l amyloid heart Wolff-Parkinson-White
disease,
8 5 3 3 3 2 4 8
1 pericardiectomy for calcific syndrome, 1 Lawn-Ganong-Levine
pericarditis, syndrome.
1
line. While the intracardiac atria1 electrograms of atria1 flutter and fibrillation have been described, little information is available concerning the atria1 electrical events of CAF and Fl-Fib. Irregular high right atria1 activity concurrent with regular low right and left atria1 activity were noted by Puech and colleagues3in a patient with Fl-Fib. Zipes and DeJoseph’ reported that three of ten patients with dissimilar atria1 rhythms (documented by intracardiac recordings) had simultaneous scalar ECG patterns of Fl-Fib or CAF. This study was designed to investigate the electrical events of the atria which occurred during the scalar ECG patterns of CAF and Fl-Fib. Methods
tiOIl.
**Associate University
Professor of Medicine, College of Medicine.
0002-8703/80/030331
+ 11$01.10/O
Division
of Cardiology,
0 1980
The
Ohio
Patients. The presence of CAF and/or Fl-Fib on the scalar ECG was the sole criterion for
State
C. V. Mosby
Co.
American
Heart
Journal
331
Leier
Table
and Schaal
II. Atria1 electrical activity
recorded in the patient population Surfuce ECG
I. II.
III.
Biatrial fibrillation with periodic Dissimilar interatrial rhythms Right atrium*
V.
VI.
Left
Dissimilar
Fast
Fibrillation Flutter (FF Flutter (FF Flutter (FF Fibrillation Flutter Fibrillation
atria1 flutter rates Interatrial (right # left) Right intra-atria1 (high right
> 160) 5 160)
Left > 160) 5 160) > 160)
# low right)
flutter-biatrial FF = 150-170 msec. FF < 150 msec.
Fragmented
CAF
Fl-Fib
24
24
0
11 4 7 4 2 1 1 1
0 4 1 3 0 1 1 0
11 0 6 1 2 0 0 1
2 1 1 2 1 1 1
2 0 1 0 0 0 0
0 1 0 2 1 1 1
4 3
1t 0
3 3
12 4
0
12 1
5 4
0
atrium
Flutter (FF > 160) Fibrillation Flutter (FF 5 160) Fibrillation Fibrillation Flutter (FF Fibrillation Flutter (FF Flutter (FF > 160) Quiescence Flutter (FF 5 160) Quiescence Fibrillation-reg. Quiescence Atria1 tachycardia Flutter Dissimilar right intra-atria1 rhythms High right Low right Flutter (FF > 160) Fibrillation Fibrillation Fibrillation Flutter (FF > 160) Atria1 tachycardia Atria1 tachycardia
IV.
regularity
showing
No of events
F deflection FF > 160 msec. FF 5 160 msec.
atrium
Fibrillation Fibrillation Fibrillation Flutter Flutter ? ?
3t
5 2
23
*Rhythms of high right and low right atrium were the same. tone patient demonstrated both features CAF and Fl-Fib. $Both patients showed features of CAF and Fl-Fib.
inclusion in the study. CAF was defined as fibrillation (fine undulation) of the scalar ECG baseline with superimposed larger f waves (1 1 mm.)s of unequal amplitude and unequal f-f intervals. ECG recordings showing a fibrillation baseline with varying periods of rapid regular waves of uniform amplitude were designated Fl-Fib. These dysrhythmias either occurred spontaneously or were induced by rapid atria1 pacing of atria1 flutter, paroxysmal atria1 tachycardia, or sinus rhythm. Fifty-seven patients were studied. The mean age of the patient population was 57 years (range 21 to 81) with 25 females and 32 males. Various cardiac disease states were represented (Table I) and the diagnoses were substantiated with cardiac catheterization in 43 of the patients. Thirtyeight (67%) of the patients had roentgenographic
332
cardiomegaly; 27 (47%) had clinical and/or radiologic evidence of congestive heart failure; and six had moderate to severe chronic obstructive pulmonary disease. Right and/or left atria1 enlargement was noted on cardiac fluoroscopy and/or the echocardiogram in 32 (56%) patients. Atria1 conduction studie@ were performed in 19 patients within one year of this study and 18 were found to have atria1 conduction disease. Thirty patients were receiving a cardioactive drug at the time of study (20 patients on digitalis, five on quinidine sulfate, two on propranolol, and three on propranolol and quinidine sulfate). All patients were clinically euthyroid; two of the patients were taking a thyroid preparation. Atrial recording studies. Written informed consent was obtained from each patient prior to each study. No premeditation was administered. In 56
March,
1980,
Vol.
99,
NO. 3
Biatrial
Fig. 1. Electrograms from the high right atrium (HRA) and left atrium (LA) showing slowing and regularity (reg). A similar pattern was present in the low right atria1 region. was present in aVF and V,.
Fig. 2. Biatrial electrograms during dissimilar atria1 rhythms (LRA) atria1 recordings showing flutter (FF = 190 msec.) and impure flutter and flutter-fibrillation were noted on the scalar coarse atria1 fibrillation with high right atria1 (HRA) fibrillation Separate low right atria1 recordings also showed fibrillation
patients, right and left atria1 electrograms were recorded from bipolar electrode (interpole distance of 1 cm.) catheters placed respectively within the right atrium and esophagus (posterior to the left atrium) and/or coronary sinus. A
American Heart Journal
electrograms
fibrillation with periodic Coarse atria1 fibrillation
in two patients. A, High right (HRA) and low right left atria1 recording (LA) showing fibrillation while ECG (50 mm./sec. paper speed). B, Surface ECG of and left atria1 (LA) fast flutter (FF = 140 msec.). (25 mm./sec. paper speed).
minimum of two catheters were placed in the right atrium, one for recording the high right atria1 electrogram and the other for recording the low right atria1 electrogram. Left atria1 electrograms were not recorded in one patient. In 36
333
Leier
and
Schaal
Fig. 3. Right atria1 and flutter-fibrillation
flutter (HRA and pattern present
LRA, FF = 240 msec.) and left atria1 (LA) quiescence on the scalar
patients, a six-pole catheter was also placed across the tricuspid valve for the simultaneous recording of low right atrial, bundle of His, and the ventricular depolarizations.’ High right atria1 (HRA), low right atria1 (LRA), and left atria1 (LA) electrograms, and three scalar ECG leads (usually I, aV,, and V,) were recorded simultaneously on an Electronics for Medicine DR-12 recorder at paper speeds of 25, 50 and 100 mm./ sec. Intracardiac and esophageal electrode signals were amplified in a frequency range of 30 to 500 Hz. Atria1 pacing was performed with a Grass Instrument S88 stimulator and isolation unit. An atria1 electrogram showing an irregular depolarization pattern (at atria1 rates > 360/ minute) was defined as fibrillation; a regular depolarization pattern at atria1 rates in the range of 220 to 4OO/minute was defined as flutter. Results The electrical events of each atrium occurring during CAF and Fl-Fib of the patient population are presented in Table II. Fibrillation with periodic regularity. Twentyfour of the patients had atria1 electrograms showing biatrial fibrillation with periodic slowing and
334
with
impure
flutter
ECG
regularity (Fig. l), and the scalar ECG of each of these patients revealed CAF. Dissimilar atrial rhythms. Transient (> 1 and < 5 minute duration) or persistent (> 5 minute duration) dissimilar right and left atria1 rhythms were observed in 31 patients. Flutter of one atrium and fibrillation of the other was the most common form of dissimilar atria1 rhythms noted (Fig. 2, A and B). When the electrograms demonstrated flutter of one atrium and fibrillation of the other atrium, the scalar ECG showed CAF in seven of eight patients whose flutter FF interval was 5 160‘msec. and showed Fl-Fib in 17 of 18 patients with FF intervals > 160 msec. Four patients demonstrated dissimilar atria1 rhythms with left atria1 quiescence. Two of these patients had right atria1 flutter at FF intervals of 240 and 250 msec. with low amplitude flutter and Fl-Fib on the scalar ECG (Fig. 3); another patient had rapid right atria1 flutter (FF = 160 msec.) with the scalar ECG of CAF; the last patient had right atria1 fibrillation (with periodic regularity) with fibrillation and infrequent. coarsenesson the scalar ECG. A patient previously reported’ had scalar ECG patterns of Fl-Fib and “impure” flutter during right atria1 tachycardia and left atria1
March,
1980, Vol. 99, No. 3
Biatrial
4. Dissimilar right intra-atria1 rhythms. A, High right atrium (HRA) shows fibrillation while and left atrium (LA) demonstrate flutter with an FF interval of 180 msec. Flutter-fibrillation the surface ECG. B, Another patient with low right atria1 (LRA) fibrillation occurring simultaneously right atria1 (HRA) and left atria1 (LA) flutter (FF = 200 msec.). Fig.
(LRA)
flutter and Fl-Fib and CAF interatrial Wenckebach.
during
periods
of
Dissimilar right intra-atrial rhythms. Dissimilar rhythms within the right atrium itself were observed in nine patients. Seven instances involved flutter of either the high or low right atrium and fibrillation of the remaining portion of the right atrium (Fig. 4). The simultaneous left atria1 recording showed either flutter or fibril-
American Heart Journal
electrograms
the low right was noted on with high
lation and again, the scalar ECG demonstrated Fl-Fib if the FF interval exceeded 160 msec. and CAF if the FF 5 160 msec. A patient with high right atria1 tachycardia (AA = 440 msec.) had transient episodes of low right atria1 flutter (FF = 220 msec.) interchanging with periods of low right atria1 fibrillation (Fig. 5). No left atria1 recordings were obtained on this patient and the scalar ECG showed Fl-Fib.
335
Leier
and
Schaal
AVF
Y --u--v-d +fSECW
+IsEc*
Fig. 5. Two different forms of dissimilar right intra-atria1 rhythms in the same patient. A. High right atria1 recording (HRA) showing a regular atria1 tachycardia with an AA of 440 msec. A simultaneous low right atria1 recording (LRA) demonstrates a regular faster atria1 tachysystole (flutter, FF = 220 msec.). Flutter-fibrillation and impure flutter patterns are present on the scalhr ECG. Placement of a premature atria1 depolarization (extrastimulus) in the low right atria1 region changed the LRA to fibrillation as noted in punel B. The HRA remained in regular tachycardia at AA = 440/minute. Left atria1 recordings are not available.
III. Atria1 electrical events noted during the scalar ECG recordings of coarse atria1 fibrillation (n = 39)
Table
Atria1
electrical
events
Biatrial fibrillation with periodic regularity Dissimilar atria1 rhythms FF > 160 msec. RA-Fib LA-F1 FF 5 160 msec. RA-Fl LA-Fib RA-Fib LA-F1 RA-Fl LA-quiet RA-Fib LA-quiet Dissimilar right intra-atria1 rhythms FF > 160 msec. HRA-Fl, LRA-Fib, LA-Fib FF 5 160 msec. HRA-Fl, LRA-Fib, LA-Fib Fast flutter-biatrial FF 2 150 msec. FF < 150 msec. Abbreviations: PAT = atria1
336
FF = flutter FF interval; Fib = fibrillation; Fl = flutter; tachycardia; quiet = quiescence; RA = right atrium (high
No
9;
34 10
62 25
1 4 3 1 I 3
8
‘2
5
2 1
0 2 HRA = high and low).
right
atrium;
LA
= left
artium;
March,
LRA = lOW right atrium;
1980,
Vol.
99, No.
3
Biatrial
Dissimilar atrial flutter rates. Transient unequal flutter rates of each atrium occurred in four patients. Three of these patients had scalar ECG recordings of Fl-Fib with right/left atria1 FF intervals of 200/270, l&5/170, and 230/170 msec. (Fig. 6). Features of both CAF and Fl-Fib were observed on the scalar ECG tracing of a patient with a right flutter interval of FF = 190 msec. and left atria1 flutter interval of 170 msec. A patient with Fl-Fib had transient episodes of dissimilar flutter rates within the right atrium itself; this patient had flutter (FF = 240 msec.) of the left and low right atrium with a slower somewhat irregular high right atria1 rhythm secondary to right intra-atria1 and interatrial Wenckebach (Fig. 7). Another patient had two different episodes of Fl-Fib with unequal flutter rates within the right atrium itself; the left and high right atria1 flutter was faster than the low right atria1 flutter on one occasion with FF intervals of 180 and 200 msec., respectively, and the other episode consisted of left atria1 fibrillation, high right atria1 flutter with an FF interval of 200 msec. and low right atria1 flutter with an FF interval of 230 msec. (Fig. 8). Fast and fragmented flutter. The remainder of the patients with CAF or Fl-Fib had either biatrial rapid (FF I 170 msec.) flutter and/or fragmented (duration of F deflection > 80 msec.) flutter (Fig. 9). In biatrial rapid flutter alone, FF intervals L 150 msec. were usually manifested as Fl-Fib on scalar ECG and FF intervals < 150 msec. as CAF or CAF with episodic Fl-Fib. Discussion
This study shows that the scalar electrocardiographic manifestations of CAF and Fl-Fib may be secondary to a variety of atria1 electrical events. Tables III and IV summarize the atria1 electrical events recorded during these dysrhythmias. Transient or persistent CAF occurred 39 times and Fl-Fib 53 times in this study population. Coarse atrial fibrillation (Table Ill). The majority (62%) of CAF events were secondary to biatrial fibrillation with periodic slowing and regularization. In contrast to the regular frequency of flutter, the regularization of fibrillation showed f-f intervals which were still somewhat variable and usually quite short at < 140 msec. (atria1 rate > 430/minute). The periods of regularization noted on the atria1 recordings did not always
American
Heart
Journal
electrograms
Fig. 6. Transient unequal interatrial flutter rates recorded simultaneously with a flutter-fibrillation pattern on the surface ECG. A slower fragmented flutter (FF = 230 msec., arrows indicate measurement points of F deflections) occurred in the high right atrium (HRA) simultaneous with a faster left atria1 (LA) flutter (FF = 170 msec.). A very mild variation of the HRA FF interval is present. A separate recording from the low right atrium showed the same flutter rate as the HRA.
coincide with the periods of coarseness on the scalar ECG; this indicates that areas of the atria (e.g., anterior RA, lateral LA, etc.) not directly recorded by the three electrodes contributed significantly to the depolarization pattern of the atria and thereby modified the scalar ECG recordings. CAF was also associated with electrograms showing dissimilar right and left atria1 rhythms, dissimilar right intra-atria1 rhythms, and fast flutt,er. Most of the patients (nine of 10) with CAF and dissimilar atria1 rhythms had flutter rates 2 375/minute (FF I 160 msec.). Two patients with FF intervals > 160 msec, and the scalar ECG of CAF had dissimilar intra-atria1 rhythms with flutter only in the high right atrium and fibrillation in the low right and left atrium. Fragmentation of the F waves on the atria1 electrograms was generally not found to be a cause of CAF, although two patients with rapid fragmented F waves (FF intervals < 160 msec.) had scalar features of both dysrhythmias (CAF/ Fl-Fib, Table II). Rapid biatrial flutter alone (without dissimilar rhythms or fragmentation) was found during CAF when the flutter rate exceeded 4001minute (FF < 150 msec.); the pre-
337
Leier
and
Schaal
Fig. 7. Atria1 electrograms showing regular left and low right atria1 (LA, LRA) flutter (FF = 249 msec.) with Wenckebach periodicity occurring in the high right atria1 region (HRA). The time interval (msec.) between the LA and HRA deflections are indicated above the HRA recording. X = dropped HRA beat. A separate recording at 25 mm./sec. paper speed and at a slower ventricular rate showed Fl-Fib and impure flutter pattern on the scalar ECG.
Table IV. Atria1 electrical events observed during the scalar ECG recordings of flutter-fibrillation (n = 53) Atria1 electrical events Dissimilar
atria1
rhythms
FF > 160 msec. RA-Fl LA-Fib RA-Fib LA-F1 RA-Fl LA-quiet RA-PAT LA-F1 FF i 160 msec. RA-Fib LA-F1 Dissimilar right intra-atria1 FF > 160 msec. HRA-Fl, LRA-Fib, HRA-Fib, LRA-Fl, HRA-Fib, LRA-Fl, HRA-PAT, LRA-Fl, HRA-PAT, LRA-Fib, Dissimilar atria1 flutter Interatrial Right intra-atria1 Fast flutter-biatrial FF = 150-170 msec. FF < 150 msec. Fragmented F deflection FF > 160 msec. FF 5 160 msec. Abbreviations:
338
I
see Table
No
I
9
21
40
6
11
6
11
13
25
7
13
11 6 2 1 1 rhythms LA-F1 LA-F1 LA-Fib LA-? LA-? rates
1 2 1 1 1 3 3 12 1 5 2
III.
March,
1980, Vol. 99, NO. 3
Biatrial
sence of small areas of fibrillation in locations not directly recorded by the electrodes cannot be excluded in these patients. Flutter-fibrillation (Table IV). In contrast to CAF, Fl-Fib was never present on the scalar ECG when the electrograms demonstrated biatrial fibrillation with periodic regularity. Sixty-two per cent of the Fl-Fib events were associated with dissimilar right and left atria1 rhythms, dissimliar right intra-atria1 rhythms, or dissimilar flutter rates. The remainder of the Fl-Fib events were secondary to rapid flutter (FF I 170) or fragmentation of the F waves. It appears that regular activity must be present in at least one portion of the atria in order to have Fl-Fib represented on the scalar ECG. The remaining portions of the atria may demonstrate fibrillation, atria1 tachycardia, a different flutter rate, electrical quiescence, or a combination of these. In instances of biatrial flutter, the flutter must be rapid (FF = 150 to 170 msec.) or fragmented to produce a Fl-Fib appearance. Ninety-two per cent (37 of 40) of patients with scalar Fl-Fib tracings and atria1 electrograms showing dissimilar rhythms or rates or fragmentation had flutter FF intervals 2 160 msec.; and 92% (12 of 13) of patients with Fl-Fib and atria1 recordings of biatrial flutter (same rates and without fragmentation) had FF intervals L 150 msec. In general, a FF interval above 160 msec. tends to produce the scalar ECG tracing of Fl-Fib, and an interval below 150 msec. will usually show CAF on ECG. In the FF interval range of 150 to 160 msec., the scalar ECG pattern will depend on the atria1 electrical activity occurring at the time (pure biatrial flutter = Fl-Fib, dissimilar rhythms or rates or fragmentation = CAF or CAF/Fl-Fib). The incidence of dissimilar right and left atria1 rhythms was high in our study population, occurring in 40% of the Fl-Fib recordings. Dissimilar right intra-atria1 rhythms probably belong to the dissimilar atria1 rhythm family and differ only in that the boundary of the dissimilar rhythms is located between the two right atria1 electrodes instead of between the right and left atria1 recording electrodes. In most instances, the atria1 catheters were repositioned to look for variations in the atria1 electrogram or to identify boundaries of flutter or fibrillation. Intermediate areas were frequently identified which showed regularity with intermittent fragmentation or irregularity and were bounded by relatively pure flutter on one border and fibrillation on another. Overdrive American
Heart
Journal
electrograms
Fig. 8. Transientunequalright intra-atria1 flutter rates in a patient with dissimilar atria1 rhythms and flutter-fibrillation on the surface ECG (Lead V,). The right atrium (HRA and LRA) was in flutter and the left atrium (LA) was in fibrillation. The high right atrium flutter rate was 3OO/minute (FF = 200 msec.), while that of the low right atrium was 260/minute (FF = 230 msec.). The FF intervals of the slower flutter (LRA) were slightly irregular (5 10 msec. variation).
pacing applied to the region of flutter (while the remainder of the atria was in fibrillation) consistently converted the flutter region to fibrillation. While these observations suggest that the dissimilar atria1 rhythms of flutter and fibrillation are not independent, this study does not indicate which of the two dysrhythmias is dominant. The flutter zone may be dominant and rapid pacing of this region may move the disorganization of conduction (fibrillation zone) closer to the recording catheter. The studies of Zipes and DeJoseph” suggest that the fibrillation regions are dominant and that the rhythm and rate of the flutter zone are controlled by a longer and more uniform refractory period. During overdrive pacing, the refractory period of the flutter zone shortens and/or becomes non-uniform. allowing more of 339
Leier
and
Schaal
Fig. 9. A, Biatrial recordings of fast flutter (FF = 150 msec.) manifested on the scalar ECG as flutter-fibrillation. B, The right atrial F deflection is fragmented to a duration of 100 msec. during a flutter rate of 230/minute (FF = 260 msec.). The simultaneous surface ECG showed flutter-fibrillation and impure Rutter.
the fibrillatory impulses to enter the region. Overdrive pacing of right atria1 flutter during left atria1 quiescence did not alter the flutter rhythm and rate or converted the region into fibrillation. Although the electrical quiescence was explored with multiple catheter locations (full length esophageal and coronary sinus readings) at high gain and various recording frequencies, it is possible that very fine fibrillation was present in or around the quiescent region. The mechanism of different intra- or interatrial flutter rates (dissimilar atrial flutter rates) is not clear. The region with a slower flutter rate probably has a longer refractory period, and is depen-
340
dent upon conduction from the faster flutter region for its impulses. The activation of a passive region with a longer refractory period to the more rapid regular impulses of another region would be slightly irregular, as noted in Figs 6 and 8, or would show a set cond’uction pattern as observed in the patient with interatrial and right intraatria1 Wenckebach (Fig. 7) and in another patient with interatrial Wenckebach and 2:l interatrial conduction? The dissimilar atria1 flutter rate events were all transient (5 5 minutes duration), implying that this rhythm disturbance is unstable and will probably not persist as a chronic atria1 dysrhythmia.
March,
1980, Vol. 99, NO. 3
Biatrial
Most patients in this series had cardiac disease with cardiomegaly alone (20%) or cardiomegaly with clinical and/or roentgenographic congestive heart failure (47%). Fluoroscopic and/or echocardiographic data revealed that atria1 enlargement was present in 56% of the patients. Twenty-five of 29 (86%) patients who spontaneously developed CAF or Fl-Fib had cardiomegaly and/or atria1 enlargement and/or evidence of congestive heart failure. Thus, only four of 29 patients (14%) with spontaneous CAF or Fl-Fib did not have cardiomegaly, atria1 enlargement, or congestive failure. Two of these remaining four patients underwent atria1 conduction time measurements; both demonstrated prolonged atria1 conduction times indicative of atria1 conduction disease. Therefore, of 29 patients who had developed spontaneous FlFib or CAF, a cardiac-pathophysiologic etiology was not identified in only two patients. The patient prototype for CAF and Fl-Fib in our study was an individual with a form of cardiac disease accompanied by one or more of the following: (1) cardiomegaly, (2) atria1 enlargement, (3) congestive heart failure, or (4) atria1 conduction disease. This study does not provide direct information on the mechanisms of atria1 fibrillation or flutter, but it does illustrate some of the interactions of the two dysrhythmias. The scalar ECG recordings of the relatively common dysrhythmias, CAF and Fl-Fib, appear to be secondary to-an interesting spectrum of atria1 electrical events.
fibrillation or flutter-fibrillation on the scalar electrocardiogram. Atria1 electrograms in coarse atria1 fibrillation most often showed biatrial fibrillation with periodic slowing and regularity, while dissimilar interatrial or right intra-atria1 rhythms were noted less frequently. Flutterfibrillation on the scalar ECG required the presence of rapid regular tachysystole (flutter) somewhere in the atria and was usually associated with dissimilar interatrial or right intra-atria1 rhythms, dissimilar atria1 flutter rates, or fast or fragmented flutter. Coarse atria1 fibrillation and flutter-fibrillation may be secondary to a variety of atria1 electrical events. The authors would like to thank Mrs. Marlene Griffin, Ladd Snyder, Ms. Max Bather, Mrs. Margaret Chambers, Mr. Fred Davis for their technical assistance.
American Heart Journal
Ms. and
REFERENCES
5.
6.
7.
Summary
Right and left atria1 electrograms were recorded in 57 patients who demonstrated coarse atria1
electrograms
8.
MacWilliam, J. A.: Fibrillary contraction of the heart, J. Physiol. 8:296, 1887. Cushney, A. R.: On the interpretation of pulse tracings, J. Exp. Med. 4:327, 1899. Puech, P., Latour, H., and Grolleau, R.: Le flutter et ses limites, Arch. Mal. Coeur 61:116. 1970. Zipes, D. P., and DeJoseph, R. L.: Dissimilar atria1 rhythms in man and dogs, Am. J. Cardiol. 32:618, 1973. Peter, R. H., Morris, J. J., and McIntosh, H. D.: Relationship of fibrillatory waves and P waves in the electrocardiogram, Circulation 33:599, 1966. Leier, C. V., Meacham, J. A., and Schaal, S. F.: Prolonged atria1 conduction-a major predisposing factor in the development of atria1 flutter, Circulation 57:213, 1978. Scherlag, B. J., Lau, S. H., Helfant, R. H., Berkowitz, W. D., Stein, E., and Damato, A. N.: Catheter technique for recording His bundle activity in man, Circulation 39:13, 1969. Leier, C. V., and Schaal, S. F.: Dissimilar atria1 rhythms-a patient with interatrial block, Br. Heart J. 39:680, 1977.
341