Atrioventricular Nodal Dysfunction in Patients with Atrial Septal Defect

Atrioventricular Nodal Dysfunction in Patients with Atrial Septal Defect* Abnormalities of Conduction and Reciprocal Rhythms Jose A. Sabrina, M.D.; Federico de Lombera, M.D.; Alejandro del Rio, M.D.; Ignacio Plaza, M.D.; Isabel Mate, M.D.; Jose L. Sotillo, M.D.; Cristina Hemdndez-Lanchas, M.D.; and Nicolas Sabrina, M.D.

Electrophysiologic studies were performed in 17 unselected patients (mean age, 20 years) with atrial septal defect (ASD) of the ostium secundum type. In nine (52.9 percent) signs were found of atrioventricular (A-V) nodal dysfunction, in seven (41.1 percent) prolonged A-H interval, and in three (17.6 percent) prolonged effective refractory period of A-V node and in five (29.4 percent) A-V nodal tachycardia and reentry. 1bree of the four cases showed anterograde conduction (Ae-H Interval) faster than retrograde conduction (H-A e in-

A trial septal defect (ASD) is associated in cer-

tain cases with supraventricular arrhythmias,

especially rhythmic tachycardia, and atrial fIbrillation. On the other hand, atrioventricular (A-V) conduction abnormalities have also been described in ASD. The combination of ASD (ostium secundum) with abnormalities of A-V conduction has been found in several members of the same family, suggesting that the association may result from an autosomal dominant pattern.!" To evaluate the incidence and mechanisms of arrhythmias and A-V conduction abnormalities in patients with ASD, electrophysiologic studies were performed in 17 unselected cases. A high incidence of A-V nodal dysfunction was found, often revealed by A-V nodal tachycardia with uncommon properties. The basis of these abnormalities is discussed. PATIENTS AND METHODS

Seventeen patients with ASD of ostium secundum type (mean age, 20 years) underwent cardiac catheterization to confirm the diagnosis and to quantitate the atrial shunt. Mter the routine catheterization, an electrophysiologic study was performed. No patient was taking medication. The diagnosis was confirmed at surgery in all of the cases. In only one patient were bouts of tachycardia demonstrated. °From the Cardiology and Hemodynamic Unit, Cardiovascular Surgery Service, La paz Hospital, Madrid, Spain. Reprint f'equest8: Dr. Sobrina, Hilarion Eslava 55, Madrid 15, Spain

CHEST, 81: 4, APRIL, 1982

terval) during the tachycardia. In one patient with reentry a similar phenomenon was observed. In the remaining patient the conduction time w. revened (Ae-H longer than H-Ae). In two patients infrahisian and intrahisian block (first and second degree) with penistence of the tachycardia was observed. Patent or latent abnormalities in A-V node function are a frequent finding In patients with ASD. In the siDus node, any kind of significant abnormality can be found.

Electrophysiologic Study With patients mildly sedated, having received 10 mg of diazepam, and before performing angiocardiograms, two electrode catheters were introduced through the femoral vein. The quadripolar catheter was placed in high lateral and middle aspects of the right atrium (HRA). The tripolar catheter was used to record the His bundle electrogram ( HBE ). Both catheters were passed to the left atrium (LA) through the septal defect to obtain recordings at this level. Given the character of the study, we did not use other veins to introduce more electrode catheters, nor was ventricular pacing performed. In all cases previous consent was requested. The recordings were obtained in a Mingograf-81 Elema at a paper speed of 100 mm/sec.

Protocol of the Electrophysiologic Study During the spontaneous rhythm of the patient recordings, the following intervals were measured: (1) between atrial ( A) potentials of HRA and LA; ( 2) between A potentials of HRA and HBE; ( 3) A-H interval measured from the beginning of A potential to the beginning of H deflection in HBE; and (4 ) H -V interval from the beginning of H to the beginning of ventriculogram (V) in HBE. During sustained tachycardias the catheters were placed in the sites mentioned, and retrograde atrial potential (A e) was recorded in HRA, HBE, and LA, therefore obtaining simultaneous recordings of HRA-HBE and HRA-LA. During the tachycardias the Ae -H and H-A e intervals in the HBE were measured according to Akhtar et al": The Ae-H interval from the end of Ae to the beginning of H and the H-A e interval from the end of H to the beginning of Ae. The Ae-H interval was also measured from the beginning of Ae to the beginning of H.

AV NODAL DYSFUNCTION 477

lationship between the magnitude of left-to-right shunt and the electrophysiologic abnormalities was found. According to that, the QP/QS in the patients with clear abnormalities was the same as in the patients without any kind of abnormality (mean, 2.61 and 2.87, respectively). In three patients (cases 6, 11, and 12), a mitral valve prolapse without mitral regurgitation was observed in the left ventriculogram. According to the data of Abella et al l O on children and young persons and Oarcia-Civera'! on a sample of a Spanish adult population, the A-H intervals were prolonged in seven cases (41.1 percent). In three patients (cases 1, 2, and 4) the AVNERPs were clearly prolonged. In eight cases the AVNERPs were not obtained because the AERPs were reached before. In two cases HBERPs were longer than the AVNERPs, and in both cases a gap phenomenon was seen. In 11 patients, the Wenckebach block was recorded, appearing with cycles abnormally long in

Programmed Electrical Stimulation A programmed digital stimulator (Medtronic 5325) was used. The stimuli (S) were delivered in HRA in a continuous fashion ( S-S ), observing the technique of abial extrastimulus delivering an extrastimuli with increasing prematurity. With these techniques the following parameters were determined: (1) the corrected sinus node recovery time (CSRT) by the method of Mandel et al;8 (2) refrac.. tory periods: the atrial effective refractory periods (AERP), A-V nodal effective refractory periods (AVNERP) and His- Purkinje effective refractory periods (HPERP ), were measured according to the method of Denes et al9 ; (3 ) the longest cycles in which Wenckebach block (WB) appeared measured in the S-S intervals of continuous atrial pacing; (4) existence of sudden increases of A-H interval during delivery of extrastimuli of increasing prematurity. When the tachycardias did not end spontaneously, rapid atrial pacing or extrastimuli were used to finish them.

REsuLTS Table 1 summarizes the electrophysiologic data and the interabial shunt, expressed in a relation of pulmonary flow to systemic How (QP/QS). No reTable

De.. 0,,17 Paden. . .itla Atrial SeplGl Defeet-

l-E~'ropla".aiolo.c

Atrial Stimulation A

Tachycardia Sudden HPERP, and Reentry A-H H-H msec Increase A.-H/H-A. 1 Block QP/QS

yr

A-H Interval, msec

eRST, msec

AERP, msec

AVNERP,

16

70

140

280

330

2

14

140

520

210

510

3

14

130

350

225

4

49

155

150

320

350

-1:70

No

2.20

5

18

130

120

245

280

400

Yes

2.30

6

14

90

220

200

210

400

No

3.20

7

35

105

250

240

250

300

No

2.91

8

11

70

ISO

225

230

325

Yes

9

:J7

80

240

230

270

No

2.80

10

13

140

500

250

No

2.80

11

22

140

130

250

Yes

12

19

110

510

250

.wo

13

13

95

170

ISO

270

14

14

70

150

190

15

17

65

100

210

220

16

15

40

50

ISO

200

17

19

60

460

280

20

105

249

230

Case No.

M~an

age, yr

Age,

msee

WB, msec

A

<1

Yes 600

Yes

2.25 2.53

No

Yes

3.61

>]

380

1.90

<1

Yes

3.00

2.78

Yes

2.60 Yes

<1

2.17

400

No

>]

2.90

375

No No

287

\

383

1.42

375

3.90 2.66

·Abbreviations: A-H interval; basal atrioventricular nodal conduction time; eRST, corrected sinus node recovery time; AERP, atrial effective refractory period; AVNERP, atrioventricular node effective refractory period; WB, Wenckebach block; Sudden A-H, sudden increase of A-H interval; HPERP, His-Purkinje effective refractory period; A., atrial echo; 1 block, intranodal block; A.•-H/H-A., ratio hetween anterograde nodal conduction during the tachycardia; QP IQS, pulmonary flow/systemic flow (LIm).

478 SOBRIIiO ET AL

CHEST, 81: 4, APRIL, 1982

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1. Onset of tachycardia in case 1. A-S interval of 320 msec lengthens A-H interval to 240 msec, eliciting atrial echo with H-A•. interval of 170 msec and A•.-H interval of 100 msec (from beginning of A. -H to beginning of H) that induces infrahisian block, 2 : I, with persistence of tachycardia. Ae-H/H-A•. ratio less than 1 during tachycardia; H not well defined . FIGURE

cases 2 and 4 and with cycles longer than usual according to age" in four patients (cases 5, 6, 12, and 15). Sudden increases of A-H interval were found in seven of 16 cases (43.7 percent) by the technique of the atrial extrastimulus. This finding is indicative of nodal dual pathway." No patient showed prolongation of eRST. All values were within the wide range found in normal cases, 110 to 525 msec according to Narula et al,14 with similar values in children.15 In case 15 two types of reentry were observed. First, with an A-S of 270 msec, the A-H interval was prolonged to 170 msec followed by an A ~ with H-A•. interval of 250 msec (A-H/H-A.
During the tachycardia, Ae-H measured 100 msec and H-A., 250 msec (Fig 1) . In case 3 the tachycardia began after prolongation of A-H interval to 460 msec and was followed by a first A~ with very short H-A ~ (A~ within V) . From the first ~, the A.-H interval shortened and the H-A. interval lengthened, but a ratio of A.H/H-A•. > 1 was maintained. In case 11 during the tachycardia two types of .f\...JVI' -rc."",..... "'!j)Jvo'--_

FIGURE 2. Sustained tachycardia in case 11. Recording of isolated H potential. Ap-H interval shorter than H-A e interval (A e-H 90 msec ; H-A•. 150 msec).

=

=

AV NODAL DYSFUNCTION 479

~=-=

==

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:=JiCiVi

In all cases A. appeared before in HBE but not in HRA. In cases 1, 11, and 14 with recordings in LA during the tachycardia. A. was recorded simultaneously in HRA and LA.

UVl"":

DISCUSSION

r---J-

I j

~

y

Given the experimental character of this study, performed at the end of a routine cardiac catheterization, the protocol used was limited to the recording of endocavitary potentials in the basal state and after different types of atrial pacing. If in this setting the rate of reciprocal nodal rhythms was 29 percent, the use of ventricular pacing probably would have increased this rate.!" since the type of nodal tachycardia observed in the majority of the cases was of the fast-slow form. Although the behavior of retrograde conduction was not observed with ventricular pacing, some of the data suggest a nodal mechanism rather than an accessory pathway with only retrograde conduction. First, there was initial retrograde depolarization in low atrium of HBE recording and simultaneous depolarization in HRA and LA 17 in cases 1, 11, and 14. Second, in cases 1, 11, and 14, the A.-H/HA. ratio was less than 1, a feature of nodal reentrant tachycardia of the fast-slow form . IS In cases 3 and 15 variations in retrograde conduction (H-A. interval) were not in accordance with retrograde conduction by an accessory pathway. The features mentioned, the changes in P wave polarity at the onset of tachycardia," the absence of the "warming" phenomenon," and the absence of intra-atrial conduction abnormalities," are not in

' y

FIGURE 3. Sustained tachycardia in case 11. Recording in two deflections (H and H') . A. is with in V potential in HBE . Abbreviations as in Figure 1.

conduction were observed: (1) conduction 1:1 with A.-H < H-A. (A .-H : 90 msec , H-A. : 150 msec, and HV : 75 msec, Fig 2); and (2) conduction 1:1 with the recording of two H potentials (intrahisian block, Fig 3) . In case 14 the interval A.-H and H-A. remained constant at 60 and 220 msec, respectively (Fig 4). Delivering two extrastimuli during the tachycardia, the second greatly increased the A-H and drastically shortened the time of appearance of the following A. (H-A., 60 msec) . This echo had prolonged anterograde conduction (A.-H, 260 msec), ending the tachycardia (Fig 5) .

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A, II V

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....

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FIGURE 4. Tachycardia in case 14. Induction of tachycardia with continuous atrial pacing (s-s 280 msec} , No increase of A-H interval during atrial stimulation. During tachycardia, A.-H interval 60 msec, H-A. interval 220 msec.

=

480 SOBRINO ET AL

CHEST, 81: 4, APRIL, 1982

A. H V

A. H V

Ao H V 1

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I

,

A. H V

H VA.

N V

I

'"-'\..... , A. I

A.

A.

A.

s ~ S~

V--

I

AI

~

' _ _J" ' : ~

A

~

!

FIGURE 5. Tachycardia in case 14. Atrial premature stimulation during the tachycardia. First extrastimulus with coupling interval (A.-S) of 230 msec induces no change of A-H interval; second extrastimulus (S-S 200 msec) elicits important lengthening of A-H interval. Following atrial echo evoked with short H-Ae interval (60 msec) , This A. induces long A.-H interval, ending tachycardia.

=

agreement with the existence of ectopic or reentrant atrial tachycardias. The presentation of intrahisian and infrahisian block is an unusual finding during tachycardias. Its presence implies that the area where it is produced has a refractory period longer than the transmission time through the reentry circuit." In our cases the A-V block was infrahisian in one, developing after a period of sustained tachycardias, and intrahisian in the other, developing when the anterograde infranodal conduction suddenly changed from slow to fast. These two cases and two others (cases 8 and 19), without tachycardia but with a His-Purkinje refractory period longer than that of the A-V node, suggest that in the population studied there was a high incidence (23.5 percent) of cases with HPERP longer than AVNERP. In this situation, the sudden changes in intranodal conduction, the increase in rate of the tachycardia, and its persistence with short cycles predispose to the production of infranodal A-V block during the tachycardia. During tachycardia changes in Ae-H and H-A. intervals could be explained in case 11 by a delay at the intrainfrahisian level. In cases 1, 3, 4, and 15 these changes were intranodal, in case 1 appearing before the infrahisian block. In cases 3, 14, and 15 abnormalities in infranodal conduction were not recorded. The functional dual A-V nodal pathways, with fast and slow conduction, and different refractory periods'" constitutes the most suitable factors for the developing of A-V nodal reentries. Both pathways, proved by electrophysiologic studies in

CHEST, 81: 4, APRIL, 1982

patients with supraventricular tachycardias.r' may induce two types of tachycardia depending on the pattern of anterograde and retrograde conduction, fast-slow or slow-fast forms . The reciprocal changes in A.-H and H-A. intervals observed in our patients suggest that both anterograde and retrograde pathways are intranodal, with a clear interdependence. These reciprocal changes may be explained if we accept that each pathway, anterograde or retrograde, has the capacity of dual conduction as previously shown.25 •26 In this situation certain phenomena, such as the influence of the autonomous nervous system, some drugs, and pacing could change the refractory periods of either pathway and reverse the velocity of conduction. If we consider that the basal lengthening of the A-H interval and AVNERP, the production of WB with slow cycles, and the existence of reentrant tach ycardias are signs of nodal dysfunction, we must infer that in our relatively older group of patients with ASD (mean age , 20 years) with moderate left to right shunts (QP/QS mean, 2.60), 52.9 percent showed one or several signs of nodal dysfunction. This number would increase if we were to take into account the sudden changes in A-H interval with the extrastimulus technique, suggesting dual pathway , but this phenomenon may also be a normal response to cardiac stimulation.Fv" The abnormalities cannot be explained by the hemodynamic effects of the ASD, since no relationship was found between the magnitude of the shunt and the electrophysiologic findings , because the QP/QS in nor-

AV NODAL DYSFUNCTION 481

mal subjects was the same as in those with obvious electrophysiologic abnormalities. In ASD secundum type, the conduction system is normal, unless the defect extends beyond the confines of the limbus, since in this situation the A-V node may be displaced posteriorly and distally.2I The frequent association of ASD with mitral valve prolapse.f apparent in only three of our cases, could also explain these abnormalities. However, in an analysis of Swartz et al3t on the arrhythmias in patients with mitral valve prolapse, the most frequent were premature atrial or ventricular contractions or both (55 percent), while supraventricular tachycardia was noted in only 6 percent. Only one of our three patients with mitral valve prolapse had tachycardia, and none showed premature atrial or ventricular contractions of a significant degree. The association of ASD and apparent or latent A-V node dysfunction is frequent and cannot be explained by the present state of knowledge. REFERENCES

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482 SOBRINO ET AL

lisis de la conducci6n cardiaca normal por el registro de

los potenciales de His. Med Esp 1974; 72:225 12 Roberts NK, Gillette PC. Clinical electrophysiologic data in the investigation of an arrythmia. A review of techniques and normal values. In: Roberts NK, Gelband H, eds. Cardiac arrhythmias in the neonate infant and child. New York: Appleton-Century Crofts, 1977 13 Rosen KM, Mehta A, Miller RA. Demonstration of dual atrioventricular nodal pathways in man. Am J Cardiol 1974; 33:291 14 Narula OS, Samet P, Javier RO. Significance of the sinus recovery time. Circulation 1972; 45: 14 15 Gutgesell HP, Gillette PC, McNamara DG. The response of the sinoabial node to rapid atrial stimulation. Pediatr Res 1974; 8:350 16 Sung RJ, Styperek JL, Myerburg RJ, Castellanos A. Initiation of two distinct forms of atrioventricular nodal reentrant tachycardia during programmed ventricular stimulation in man. Am J Cardiol 1978; 42:404 17 Wellens HJ, Durrer D. Pathway of tachycardia in Wolff.. Parkinson-White syndrome. Circulation 1974; 49:22 18 Akhtar M, Damato AN, Raskin IN, et ale Anterograde and retrograde conduction characteristics in three patterns of paroxysmal atrioventricular junctional reentrant tachycardia. Am Heart J 1978; 92:22 19 Goldreyer BN, Gallagher JJ, Damato AN. The electrophysiologic demonstration of atrial tachycardia in man. Am Heart J 1973; 85:205 20 Katz LM, Pick A. The arrhythmias. In: Clinical electrocardiography. Philadelphia: Lea & Febiger, 1959: 142 21 Akhtar M, Caracta AR, Lau SH, Gilbert GJ, Damato AN. Demonstration of intra-atrial conduction delay, block, gap and reentry: a report of two cases. Circulation 1978; 58:947 22 Wellens HJJ, Wesdorp JC, Lie KJ. Second-degree block during reciprocal atriovenbicular node tachycardia. Circulation 1976; 53 :595 23 Moe GK, Preston JB, Burlington H. Physiologic evidence for a dual A-V transmission system. Circ Res 1956; 4:357 24 Denes P, Wu D, Dhingra RC, Chuquimia R, Rosen KM. Demonstration of dual A-V nodal pathways in patients with paroxysmal supraventricular tachycardia. Circulation 1973; 48:549 25 Schuilemburg RM, Durrer D. Ventricular echo beats in the human heart elicited by induced ventricular premature beats. Circulation 1979; 40:337 26 Satake S, Heijima K, Sakamoto Y, Suzuki T. Demonstration of bidirectional dual A-V nodal pathways in the same patient. J Electrocardiol 1971; 10:71 27 Denes P, Wu D, Dhingra R, Amat y Leon F, Wyndhan C, Rosen KM. Dual atrioventricular nodal pathways: a common electrophysiological response. Br Heart J 1975; 37:1069 28 Thapar MK, Gillette PC. Dual atrioventricular nodal pathways: a common electrophysiologic response in children. Circulation 1979; 60: 1369 29 Lev B, Bharati S. Anatomy of the conduction system in normal and congenital abnormal hearts. In: Roberts NK, Gelband H, eds. Cardiac arrhythmias in the neonate and child. New York: Appleton-Century Crofts, 1977 30 Victorica BE, Elliot LP, Gessner IH. Ostium secundum atrial septal defect associated with balloon mitral valve in children. Am J Cardiol 1974; 33:668 31 Swart M, Teichholz LE, Donoso E. Mitral valve prolapse: a review of associated arrhythmias. Am J Med 1977; 62:377

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