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Diastolic Time during Static and Dynamic Exercise in Myocardial Infarction
Diastolic TIme during Static and Dynamic Exercise in Myocardial Infarction* Tadashi Hasegawa, M.D.; Tetsuro Sugiura, M.D., F.C.C.R; Masahide Matsutani, M.D.; Tsutomu Sumimoto, M.D.; Toshiji lwasaka, M.D., RC.C.R; and MitsuD Inada, M.D.
To evaluate the difference in the response of DT in the early phase of static (sustained weight load) and dynamic (treadmill) exercise, the relation of DT and UR was studied by ear densitography in 11 patients with myocardial infarction. None of the patients had an ischemic electrocardiographic response during exercise. Despite an increase in UR and the pressure-UR product with both types of exercise, the pressure-UR product was significantly higher at three minutes of dynamic exercise, which was associated with a significant lengthening of left ventricular ejection time. Diastolic blood pressure rose significantly during static exercise, but it remained unchanged with dynamic exercise. Electromechanical systole and UR had a linear
inverse relation at three minutes of exercise, and DT and UR had a nonlinear inverse relation (DT=e7.-.o.0158 )(HIl, and DT = e7.07-O.0142)( Hil for static and dynamic exercises, respectively). A significant prolongation of QS2 with a consequent shortening of DT (p
Diastolic time, an important determinant of myocardial oxygen supply, has a nonlinear relation to HR in various conditions, including exercise, 1-4 and a small increase in HR will produce a large decrease in DT, particularly in low-level exercise. Static and dynamic exercise must be performed numerous times in daily activities after discharge from the hospital of patients with acute myocardial infarction. Static exercise is known to induce less increase in HR but greater increase in blood pressure than dynamic exercise. The differences in hemodynamic responses to static and dynamic exercise in coronary artery disease have been evaluated; however, not many studies have focused on the difference in the hemodynamic response in the early phase of static and dynamic exercise. This study was designed to evaluate the difference in the response of DT in the early phase of static and dynamic exercise in patients with recent myocardial infarction.
had postinfarctional anJ,tina, valvular heart disease, atrial 6hrillatioll, intraventricular conduction defects, hypertension, or clinical (.'on~estive heart failure. An medications were dis<"ontinued for at least five half-lives, and no patient was receivinJ,t ~-adrenerwc hlockers or diwtalis before the wei~t load and the treadmill exercise.
MATERIALS AND METII()DS
Patients
The studied population was <.'omprised of 11 patients (mean SD, 51 ± 8 years) with a documented myocardial infarction three to four weeks before the study. All patients included in this study had had their first Q-wave myocardial infarction, and none
a~e ±
*From the Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan. Manuscript received January 2; revision accepted March 14. Reprint requests: Dr. Hasegawa, CCU, Kama; Medical University, 1 Fumizono-cho, Aloriguchi City, Osaka, Japan .570
DT = diastolic time; UR systole
=heart rate; QS. =electromechanical
Recordings
Data for systolic time intervals were re<..'orded from the ear pulse derivative and the electrocardi()~am.:"t.~ Ear densito~ramswere obtained with a photoelectric earpiece (HewlettPackard 780-10) modified and filtered throu~h a polYW-aph (Fukuda Denshi MIC 6600). Recordin~s were made on a thermal re<..'order (Fukuda Denshi RF-85) at a paper speed of 100 mm/s. densito~raph
Aleasurements
The methods employed for measurin~ HR, preejection period, and left ventricular ejection time were as described elsewhere. ~.H The DT was calculated as cardiac len~th minus QSz (QS2 = preejection period plus left ventricular ejection tirne). Measurements of HR and systolic time intervals \\'crt- aided hy a diJ,titizer (.'oupled to a eomputer (Fujitsu F~f-8) and were calculated fruln the avera~e of five consecutive beats for eadl of the recordin~s. Statk f:xercisl'
The static exercise test was dOll{- with tht> patit"uls in the postahsorptive state. The patit"nts continuously held a sa(·k w('i~hill~ 10 k~ (30 to 35 percent of maxilnal lift t'apacity) ,,'Hh one hand (ri~ht hand) in the standin~ position for six ruinutes.\J Lt.>ads aVF, V.. , and V!\ <.'ontilluously monitored, and full electr
667
free fronl it. silu.'e respiration was ohserv{ad shortly ~,fter the initiation of the wei~ht load ext-rdse.
Dynalllic
":xen:i.~u'
The trtAadlnill exerdsta test was done 30 Ininutes after the static exercise test. Tht" test was perfonlled on a stress systenl (Fukuda Denshi M L-H()()() and treadlnill (~1AT-2()()() without interruption fi)r two 3-minut{A sta~es at slopes of 50 and I()O at it constant speed of 1.7 rnph. Leads aVF, V., and V~ were (.·ontinuously Illonitored. and full electrocardio~rams were ohtained at restin~ ("ontrol and on tilt- tninute durin~ eXt"reise. lh tavaluate the rtasponses of systolic tilne intervals in the early phase of exercise, rec()rdin~s were Illude at standin~ ('ontrol and three Ininntes of cxereise. Blood pressure was recorded with an apparatus (Nippon Colin STBP-680) and was taken at ('ontrol and three ,ninntes of exereise. Raclionuclicl~? Angiogrllphy
Left ventri<.'ular end-diastolic and end-systolic vohnues "'ere determined hy the first-pass nlethod ,,'ith a ('omputerized Illulticrystal calnera (Baird-Atonlit' Systetn-77) in the anterior projection. The left ventrieular ejection fraetioll was detennined fronl the hack~round-('()rre-(·tedrepresentative eardia(' cycle as: (end-diastolic {.'()unts Ininus end-systolk ('()unts)/(end-diastolic counts x 1(0). Left ventrk'ular end-dhlstolic volunle was calculated hy the area-Ien~th Inethod of DcKl~e et aL ICI ,,'ith the ellipse of revolution IlHKlified froln the sin~le anterior plane projection as 0.85 X A2/L, where A is the area ohtained hy planinletry, and L is the lon~est dianleter measured frclIn the aorti<.' valve to the apex of the left ventricle. Stroke vohllne was dtarived fro III the measured ejection fraction and end-diastoli<.' vohllne by the f()llo\\'in~ equation: stroke vohnne = end-diastolic vohllne x eje-etion fraction. The reliability and reprodueihility of this ,nt"thcKI have heen reported. lI · ' :l After ()btainin~ the data at sittin~ control, the patients were exercised on the hieyde er~olneter in the sittin~ position. The \\'orkload was inereased hy 25-W increments every three minutes until 75\\~ and the dahl were ohtained at peak exercise (at 9 nlinutes). The radionuclide an~io ~raphit- studies were carried out ,,'ithill three days of the predisehar~e Inw-Ievelexereise test (statk and dynarnk t"xereise).
titne, and blood pressure). Nonlinear re~ression models were derived for the DT-HR relatioll, whereas linear re~ression models ,,'ere derived fi)r the QS2-HR relation and the left ventricular ejection tillle-IIR relatioll in each study (static and dynamic exercise). The two re~ression lines were then analyzed by analysis of (·ovariance. Statistical si~nificance was aceepted at the 95 pereent eonfidence level (p
All patients finished the sustained weight load exercise and dynamic exercise protocol (the treadmill and the bicycle ergometer exercise) without angina pectoris or ischemic electrocardio~raphic responses (less than 1 nlm of horizontal or downward-sloping STse~ment depression 60 ms after QRS complex in three consecutive beats).
Responses of HR and Blood Pressure There were no significant differences in HR, blood pressure, and pressure-HR product at control between static and dynamic exercise (Table 1). Although HR and pressure- HR product increased significantly in both types of exercise, the exercise values were significantly greater with dynamic exercise. Diastolic blood pressure rose significantly with static exercise (control to three minutes of exercise); however, the exercise values were not statistically different from each other. DT (msec)
0- -0 stat ic exercise
500
\
\
'0 \
?
Stati.~tic{l/ Aflalysis
The I-test f()r paired sarnples was used to ('()Jnpare an exercise value with ('()ntrol (HR. preeje<.-tion period. left ventrieular ejection
\ 0,0
\~
400
~
.\0
Table I-Heart Rate, Blood Pressure, and Pressure-HR Product at Control and Three Minutes of Exercise Data
Statk' Exereise
Dynamic Exercise
HR, heats per nlin Control 79± 10 81 ± 12 3 min of exereise 88± 12 98± 12 <0.001 P value <0.001 Blood pressure. mm H~ Systolic Control II5± 19 119± 17 3 min of exercise 133±31 136±31 pvalut" <0.00.'5 <0.05 Diastolic Control i4± 10 77±i 3 nlin of exercise 82± 13 i5± 16
668
p Value
.......-. dynamic exercise
\0 ~
\
300
\
\
~
\
~
•
NS
\
<0.005
NS
\
~\
•
\ \
200-
,
NS
NS
NS
L~--50
NS <0.05
100
150
HR
( beats/min)
FI<;lIHE 1. Diastolic tinle-IIR relations at three Ininutes of static and dynamic exercise. Re~Tession eurves are superimposed on data points. Diastolic lime during Exercise in MI (Hasegawa et all
DT-HR an([ QS2-HR Relations
LVET
The DT was 443 ± 82 ms and 426 ± 85 ms (static and dynalnic exercise, respectively), and QS2 was 328 ± 19 ms and 332 ± 26 ms (static and dynamic exercise, respectively) at control (Fig 1 and 2). There \vere no significant differences in DT and QS2 at control between static and dynamic exercise. 1b obtain the DT-HR and QS2-HR relations at three minutes of exercise, DT and QS2 were plotted against the corresponding HR during each type of exercise. The DT and HR had a nonlinear inverse relation, the equations for which were: DT = e7.29-0.0156X UR (r = - 0.99; p
There were no si~nificant differences in left ventricular ejection time and preejection period at control QS2
0- -0 static exercise
\
350
o.
',0,
,'<:>
'0
,
0,
..-. dynamic
exercise
•
,
••
',~
300
o 00'0 '
,,
"i,
,, ,
250
,,
\
0- -0 static exercise
e---e
,
\
250
,
,
\
,
,,
••
•
0
'",\ \
o
•
0', 0
o ,
0', •
200
\
\
o
,
0" 0 \
,,
\
50
100
150
HR
FIGURE 3. Left ventricular ejection time-IIR relation at three minutes of static and dynamic exercise. He~rt'ssion lines are superilnposed on data points. LVET, Left ventricular ejeetion titne.
between static and dynamic exercise (Fig 3; Table 2). The regression equations for the left ventricular ejection time- HR relation were: left ventricular ejection time=355-1.61 x HR (r= -0.70; p<0.05) at three minutes of static exercise; and left ventricular ejection time = 420 - 1.77 X HR (r = - 0.84; p
L~(50 - 150 100 HR
(beats/min) FIGURE
•
o
Data
200
dynamic exe rc i se
300
(beats/min)
l£jt Ventricular Ejection Time-HR and
(msec)
(msec)
2. Electronlechanical systole-HR relations at three nlinutes
of static and dynamie exercise. Regression lines are superimposed on data points.
Preejection period, ms Control 3 min of exercise p value Left ventricular ejection time, ms Control 3 min of exereise p value
Static Exercise
Dynanlie Exercise
110± 12 18
11O±9 76±8 <0.001
218±20 214±28
22.'3±26 246±24 <0.001
<0.05
1().'3 ±
NS
NS
pVahlt.',
CHEST I 98 I 3 I SEPTEMBER, 1990
NS
NS
669
Radionuclide Angiographic Studies Ejection fraction \\'as 47 ± 10 percent, left ventricular end-diastolic vohnne \vas 135 ± 30 Inl, and stroke volunle was 59 ± 10 Inl at control, \vhich increased significantly to 51 ± 13 percent, 164 ± 391nl, and 79 ± 9 ml at a peak HR of 105 ± 14 beats per Ininllte (ejection fraction, left ventricular end-diastolic volume, and stroke vollllne, respectively). DISCUSSI()N Cardiovascular responses to static and dynamic exercise in patients \vith coronary artery disease have been evaluated, and the nUlnber ofpatients developing myocardial ischelnia during static effort is reported to be less than observed during maxiJnal dynaJnic exercise, I:l·lh but Haissly et a1 13 reported that the duration of nlaxilnal stress to \\,hich the heart is exposed may be a factor, since this period is In uch shorter in static than in dynalnic exercise. In this study, therefore, DT and systolic tiIne intervals were obtained at three Ininutes of static and dynalnic exercise to evaluate the difference in the helllodynalllic response in the early phase of exercise. Both \veight load and dynanlic exercise \\'ere \veJl tolerated without clinical evidence of ischelnia, but a significantly higher HR and pressllre-HR product, as \vell as a disproportionate shortening of DT, \vere observed at three Ininutes of dynalnic exercise, compared \vith static exercise. The ear densito~raphicpulse derivative, because of the delnonstrated stability of the pulse transmission time, is a reliable pulse Illeasurelnent for determining all of the systolic time intervals and DT during exercise. 2,5-7 The duration of diastole is determined by HR (cardiac cycle) and the duration ofQS2' An increase in HR and a lengthening of QS2 \\'ill shorten DT. The two main components of QS2 are preejection period and left ventricular ejection tiIne. Although there \\'ere no significant differences in preejection period and left ventricular ejection tiJne frOlll control to three Ininutes of static exercise, preejection period shortened and left ventricular ejection tiIne lengthened si~nificant)y at three Inillutes of dynalnic exercise. Despite an increase in HR as a result, left ventricular ejection tilne and QS~ during dynulnic exercise \\'ere longer at any given H R ('onlpared to static exercise (Fi~ 1 and 2). The initial rise in left ventricular ejection titne observed in the early phase of dynalnic exercise \\'as paradoxic in relation to its cllstomary clinical correlate, HR, which sho\ved an expected increase. The t\\,O factors determining left ventricular ejection time are stroke vohnne, \vith a direct relation, and ejection rate, with an inverse relation.17,1~ The action of the contracting muscles on the nluscle veins returns the translocated blood (muscle venous pump) and restores the central blood flo\\' at the beginning of 670
exercise. 19 Although stroke volume was not Ineasured at three Ininutes of dynanlic exercise, our data from radionllclide study showed left ventricular end-diastolic volume and stroke volume increased significantly froin control to low-level upright ergometric exercise (at HR of 105± 14 beats per minute) in all patients. Thus, the explanation filr the prolongation of left ventricular ejection time and QS2 at three minutes of dynamic exercise, compared with static exercise, may be related to the increase in left ventricular enddiastolic volume and possible increase in stroke vollllne \\,hich overrode the effect of the increased ejection rate in the early phase of upright dynamic exercise. 20 Most coronary blood flow occurs in diastole, and coronary perfusion to the subendocardial layers is related not only to aortic diastolic pressure but also to left ventricular end-diastolic pressure and to DT.3.21 In addition to a decrease in subendocardial coronary blood flow as a result of increased HR, a disproportionate shortening of diastole at any given HR in dynamic exercise (Fi~ 3) permitted a further reduction of subendocardial blood flow compared ",ith that of static exercise. On the other hand, a higher pressure-HR product increases myocardial oxygen consumption. Thus, a larger increase in HR (righnvard movement along the DT-HR curve) and the disproportionate shortening of DT (downward shift of the DT-HR curve) with higher pressure-HR product in the early phase of dynamic exercise have a potential for initiating imbalance of Iuyocardial oxygen supply and demand. REFERENCES Boudoulas H, Ritt~ers SE, Ley/is R~ Leier C~ \Veissler AM. in diastolic time \\'ith various pharmaco)oJ,Fic agents. Circulation 1979; 60: 164-69 Su~iura T, Iwasaka T, Takahashi N, Matsntani M, Takayama Y, Inada M, et al. Effect of exercise on ventricular diastolic time in coronary artery disease. Am J Cardiol1987; 59:1089-92 rvfeiler SEL, Boudoulas I-I~ Unverferth D~ Leier CV: Diastolic time in c()n~estive heart failure. Am Heart J 1987; 114:1192-98 Hasegawa T, SUJ.,'iura T, lhkahashi N, Iwasaka T, Inada M. Diastolic tilne durin~ low-level exercise in the late hospital phase of acute Inyocardial infarction. Chest 1989; 96:601-05 Quarry-Pi~ot 'I, Chi rife R, Spodick DB. Ejection time hy ear densitogram and its derivative: dinical and physiologic applications. Circulation 1973; 48:239-46 Spodick DB, Lance VQ. Noninvasive stress testing: methodol()~. filr elimination of the phonocardiogram. Circulation 1976; 53:673-76 Lance VQ, Spodick DH. Systolic time intervals utilizing ear densitography: advantages and the reliahility filr stress testing. Arn Heart J 1977; 94:62-6 Chirife R, Spodick DB. A new method fclr evaluation of cardiac performance at rest and during exercise. Am Heart J 1972; 83: 493-503 \Vilke NA, Sheldahl LM, Levandoski SG, Hofflnall ~tD, Tristani FE. \Veight carrying versus handgrip exercise testing in men with coronary artery disease. Aln J Cardiol 1989; 64:736-40 Chan~es
2
3 4
5
6
7
8
9
Diastolic Time during Exercise in MI (Hasegawa et al)
10 D()d~e HT, Sandler II, Ballow D~ Lord JD Jr. The use of biplane an~iocardio~raphyfor the measurement of left ventricular volume in man. Am Heart J 1960; 60:762-76 11 Dyke D~ An~er D, Sullivan R~ Vetter \VR, Yano Y, Parker HC. Cardiac evaluation fronl radioisotope dynamics. J Nucl Med 1972; 13:583-92 12 Scholz PM, Rerych SK, Moran JF. Quantitative radionucJide angio~raphy. Cath Cardiovasc Diag 1980; 6:265-83 13 Haissly Je, Messin R, Der~e 5, Vandermoten ~ Delnaret B, Denolin H, Comparative response to isonletric (static) and dynamic exercise tests in (.'oronary disease. Aln J Cardiol 1974; 33:791-96 14 Lowe DK, Rothhaum DA, Mcllenry PL,Corya Be, Knoehel SB. Myocardial blood flow response to isometric (hand~rip) and treadmill exercise in coronary artery disease. Circulation 1975; 51:126-31 15 Kerber RE, Miller RA, Najjar SM. Myocardial ischenlia effects of is 01net ric, dynamic and (.'C)mbined exercise in (.'C)rouary artery disease. Chest 1975; 67:388-94
16 lIer~ ~fK, Bai JX, ~farin J. ChaJl~t"s in Ipft ,,("ntricular wall stress durin~ isolnetrit, and isotonic t~xercise in Ilt"althy .nen. Aln J Cardiol 1988; 62:794-98 17 Braunwald E, Sarnoff SJ, Stains),y \VN. Dt"tt"rrninailis of duration and mean rate of ventricular {"jet,tioll. (:ire Ht'S I H5k: 6:31 u2S 18 \Veissler AM, Peeler RG, Rot'hll \VII Jr. Relationships Iwh\'een left ventricular ejection titne, strokl' VOh'1l1t', and heart rate in nonnal individuals and patients with cardiovascular dist"ase. Aln Heart J 19tH; 62:369-7H 19 Shepherd]T. Circulatory response to exerl'ist" in health. Cir<:ulation 1987; 76(suppI6):VI-3-VI-I0 20 Stl~itlra T, Doi YL, Bishop RL, lIaffty B(;, Spo(lick I) II. Elucidation of physiol()~iclen~thenin~ofleft ventricular ejection tilne durin~ upri~ht exercise. Aln Heart J HJH1; 101:309-13 21 Ellis AK, Klocke F. Effects of preload on tht" transilltlral distrihution of perfusion and pressure-How relationships in tht' canine eoronary vascular hed. Circ Res IHH(); 46:68-77
Infectious Disease Update The University of Arizona Health Sciences Center will present this program October 6 at Loews Ventana Canyon Resort, Tucson. For more information, contact the University of Arizona Colle~e of Medicine, Continuing Medical Education, Tucson 85724 (602:626-7832),
CHEST I 98 I 3 I SEPTEMBER, 1990
671
To evaluate the difference in the response of DT in the early phase of static (sustained weight load) and dynamic (treadmill) exercise, the relation of DT and UR was studied by ear densitography in 11 patients with myocardial infarction. None of the patients had an ischemic electrocardiographic response during exercise. Despite an increase in UR and the pressure-UR product with both types of exercise, the pressure-UR product was significantly higher at three minutes of dynamic exercise, which was associated with a significant lengthening of left ventricular ejection time. Diastolic blood pressure rose significantly during static exercise, but it remained unchanged with dynamic exercise. Electromechanical systole and UR had a linear
inverse relation at three minutes of exercise, and DT and UR had a nonlinear inverse relation (DT=e7.-.o.0158 )(HIl, and DT = e7.07-O.0142)( Hil for static and dynamic exercises, respectively). A significant prolongation of QS2 with a consequent shortening of DT (p
Diastolic time, an important determinant of myocardial oxygen supply, has a nonlinear relation to HR in various conditions, including exercise, 1-4 and a small increase in HR will produce a large decrease in DT, particularly in low-level exercise. Static and dynamic exercise must be performed numerous times in daily activities after discharge from the hospital of patients with acute myocardial infarction. Static exercise is known to induce less increase in HR but greater increase in blood pressure than dynamic exercise. The differences in hemodynamic responses to static and dynamic exercise in coronary artery disease have been evaluated; however, not many studies have focused on the difference in the hemodynamic response in the early phase of static and dynamic exercise. This study was designed to evaluate the difference in the response of DT in the early phase of static and dynamic exercise in patients with recent myocardial infarction.
had postinfarctional anJ,tina, valvular heart disease, atrial 6hrillatioll, intraventricular conduction defects, hypertension, or clinical (.'on~estive heart failure. An medications were dis<"ontinued for at least five half-lives, and no patient was receivinJ,t ~-adrenerwc hlockers or diwtalis before the wei~t load and the treadmill exercise.
MATERIALS AND METII()DS
Patients
The studied population was <.'omprised of 11 patients (mean SD, 51 ± 8 years) with a documented myocardial infarction three to four weeks before the study. All patients included in this study had had their first Q-wave myocardial infarction, and none
a~e ±
*From the Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan. Manuscript received January 2; revision accepted March 14. Reprint requests: Dr. Hasegawa, CCU, Kama; Medical University, 1 Fumizono-cho, Aloriguchi City, Osaka, Japan .570
DT = diastolic time; UR systole
=heart rate; QS. =electromechanical
Recordings
Data for systolic time intervals were re<..'orded from the ear pulse derivative and the electrocardi()~am.:"t.~ Ear densito~ramswere obtained with a photoelectric earpiece (HewlettPackard 780-10) modified and filtered throu~h a polYW-aph (Fukuda Denshi MIC 6600). Recordin~s were made on a thermal re<..'order (Fukuda Denshi RF-85) at a paper speed of 100 mm/s. densito~raph
Aleasurements
The methods employed for measurin~ HR, preejection period, and left ventricular ejection time were as described elsewhere. ~.H The DT was calculated as cardiac len~th minus QSz (QS2 = preejection period plus left ventricular ejection tirne). Measurements of HR and systolic time intervals \\'crt- aided hy a diJ,titizer (.'oupled to a eomputer (Fujitsu F~f-8) and were calculated fruln the avera~e of five consecutive beats for eadl of the recordin~s. Statk f:xercisl'
The static exercise test was dOll{- with tht> patit"uls in the postahsorptive state. The patit"nts continuously held a sa(·k w('i~hill~ 10 k~ (30 to 35 percent of maxilnal lift t'apacity) ,,'Hh one hand (ri~ht hand) in the standin~ position for six ruinutes.\J Lt.>ads aVF, V.. , and V!\ <.'ontilluously monitored, and full electr
667
free fronl it. silu.'e respiration was ohserv{ad shortly ~,fter the initiation of the wei~ht load ext-rdse.
Dynalllic
":xen:i.~u'
The trtAadlnill exerdsta test was done 30 Ininutes after the static exercise test. Tht" test was perfonlled on a stress systenl (Fukuda Denshi M L-H()()() and treadlnill (~1AT-2()()() without interruption fi)r two 3-minut{A sta~es at slopes of 50 and I()O at it constant speed of 1.7 rnph. Leads aVF, V., and V~ were (.·ontinuously Illonitored. and full electrocardio~rams were ohtained at restin~ ("ontrol and on tilt- tninute durin~ eXt"reise. lh tavaluate the rtasponses of systolic tilne intervals in the early phase of exercise, rec()rdin~s were Illude at standin~ ('ontrol and three Ininntes of cxereise. Blood pressure was recorded with an apparatus (Nippon Colin STBP-680) and was taken at ('ontrol and three ,ninntes of exereise. Raclionuclicl~? Angiogrllphy
Left ventri<.'ular end-diastolic and end-systolic vohnues "'ere determined hy the first-pass nlethod ,,'ith a ('omputerized Illulticrystal calnera (Baird-Atonlit' Systetn-77) in the anterior projection. The left ventrieular ejection fraetioll was detennined fronl the hack~round-('()rre-(·tedrepresentative eardia(' cycle as: (end-diastolic {.'()unts Ininus end-systolk ('()unts)/(end-diastolic counts x 1(0). Left ventrk'ular end-dhlstolic volunle was calculated hy the area-Ien~th Inethod of DcKl~e et aL ICI ,,'ith the ellipse of revolution IlHKlified froln the sin~le anterior plane projection as 0.85 X A2/L, where A is the area ohtained hy planinletry, and L is the lon~est dianleter measured frclIn the aorti<.' valve to the apex of the left ventricle. Stroke vohllne was dtarived fro III the measured ejection fraction and end-diastoli<.' vohllne by the f()llo\\'in~ equation: stroke vohnne = end-diastolic vohllne x eje-etion fraction. The reliability and reprodueihility of this ,nt"thcKI have heen reported. lI · ' :l After ()btainin~ the data at sittin~ control, the patients were exercised on the hieyde er~olneter in the sittin~ position. The \\'orkload was inereased hy 25-W increments every three minutes until 75\\~ and the dahl were ohtained at peak exercise (at 9 nlinutes). The radionuclide an~io ~raphit- studies were carried out ,,'ithill three days of the predisehar~e Inw-Ievelexereise test (statk and dynarnk t"xereise).
titne, and blood pressure). Nonlinear re~ression models were derived for the DT-HR relatioll, whereas linear re~ression models ,,'ere derived fi)r the QS2-HR relation and the left ventricular ejection tillle-IIR relatioll in each study (static and dynamic exercise). The two re~ression lines were then analyzed by analysis of (·ovariance. Statistical si~nificance was aceepted at the 95 pereent eonfidence level (p
All patients finished the sustained weight load exercise and dynamic exercise protocol (the treadmill and the bicycle ergometer exercise) without angina pectoris or ischemic electrocardio~raphic responses (less than 1 nlm of horizontal or downward-sloping STse~ment depression 60 ms after QRS complex in three consecutive beats).
Responses of HR and Blood Pressure There were no significant differences in HR, blood pressure, and pressure-HR product at control between static and dynamic exercise (Table 1). Although HR and pressure- HR product increased significantly in both types of exercise, the exercise values were significantly greater with dynamic exercise. Diastolic blood pressure rose significantly with static exercise (control to three minutes of exercise); however, the exercise values were not statistically different from each other. DT (msec)
0- -0 stat ic exercise
500
\
\
'0 \
?
Stati.~tic{l/ Aflalysis
The I-test f()r paired sarnples was used to ('()Jnpare an exercise value with ('()ntrol (HR. preeje<.-tion period. left ventrieular ejection
\ 0,0
\~
400
~
.\0
Table I-Heart Rate, Blood Pressure, and Pressure-HR Product at Control and Three Minutes of Exercise Data
Statk' Exereise
Dynamic Exercise
HR, heats per nlin Control 79± 10 81 ± 12 3 min of exereise 88± 12 98± 12 <0.001 P value <0.001 Blood pressure. mm H~ Systolic Control II5± 19 119± 17 3 min of exercise 133±31 136±31 pvalut" <0.00.'5 <0.05 Diastolic Control i4± 10 77±i 3 nlin of exercise 82± 13 i5± 16
668
p Value
.......-. dynamic exercise
\0 ~
\
300
\
\
~
\
~
•
NS
\
<0.005
NS
\
~\
•
\ \
200-
,
NS
NS
NS
L~--50
NS <0.05
100
150
HR
( beats/min)
FI<;lIHE 1. Diastolic tinle-IIR relations at three Ininutes of static and dynamic exercise. Re~Tession eurves are superimposed on data points. Diastolic lime during Exercise in MI (Hasegawa et all
DT-HR an([ QS2-HR Relations
LVET
The DT was 443 ± 82 ms and 426 ± 85 ms (static and dynalnic exercise, respectively), and QS2 was 328 ± 19 ms and 332 ± 26 ms (static and dynamic exercise, respectively) at control (Fig 1 and 2). There \vere no significant differences in DT and QS2 at control between static and dynamic exercise. 1b obtain the DT-HR and QS2-HR relations at three minutes of exercise, DT and QS2 were plotted against the corresponding HR during each type of exercise. The DT and HR had a nonlinear inverse relation, the equations for which were: DT = e7.29-0.0156X UR (r = - 0.99; p
There were no si~nificant differences in left ventricular ejection time and preejection period at control QS2
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FIGURE 3. Left ventricular ejection time-IIR relation at three minutes of static and dynamic exercise. He~rt'ssion lines are superilnposed on data points. LVET, Left ventricular ejeetion titne.
between static and dynamic exercise (Fig 3; Table 2). The regression equations for the left ventricular ejection time- HR relation were: left ventricular ejection time=355-1.61 x HR (r= -0.70; p<0.05) at three minutes of static exercise; and left ventricular ejection time = 420 - 1.77 X HR (r = - 0.84; p
L~(50 - 150 100 HR
(beats/min) FIGURE
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Data
200
dynamic exe rc i se
300
(beats/min)
l£jt Ventricular Ejection Time-HR and
(msec)
(msec)
2. Electronlechanical systole-HR relations at three nlinutes
of static and dynamie exercise. Regression lines are superimposed on data points.
Preejection period, ms Control 3 min of exercise p value Left ventricular ejection time, ms Control 3 min of exereise p value
Static Exercise
Dynanlie Exercise
110± 12 18
11O±9 76±8 <0.001
218±20 214±28
22.'3±26 246±24 <0.001
<0.05
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CHEST I 98 I 3 I SEPTEMBER, 1990
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Radionuclide Angiographic Studies Ejection fraction \\'as 47 ± 10 percent, left ventricular end-diastolic vohnne \vas 135 ± 30 Inl, and stroke volunle was 59 ± 10 Inl at control, \vhich increased significantly to 51 ± 13 percent, 164 ± 391nl, and 79 ± 9 ml at a peak HR of 105 ± 14 beats per Ininllte (ejection fraction, left ventricular end-diastolic volume, and stroke vollllne, respectively). DISCUSSI()N Cardiovascular responses to static and dynamic exercise in patients \vith coronary artery disease have been evaluated, and the nUlnber ofpatients developing myocardial ischelnia during static effort is reported to be less than observed during maxiJnal dynaJnic exercise, I:l·lh but Haissly et a1 13 reported that the duration of nlaxilnal stress to \\,hich the heart is exposed may be a factor, since this period is In uch shorter in static than in dynalnic exercise. In this study, therefore, DT and systolic tiIne intervals were obtained at three Ininutes of static and dynalnic exercise to evaluate the difference in the helllodynalllic response in the early phase of exercise. Both \veight load and dynanlic exercise \\'ere \veJl tolerated without clinical evidence of ischelnia, but a significantly higher HR and pressllre-HR product, as \vell as a disproportionate shortening of DT, \vere observed at three Ininutes of dynalnic exercise, compared \vith static exercise. The ear densito~raphicpulse derivative, because of the delnonstrated stability of the pulse transmission time, is a reliable pulse Illeasurelnent for determining all of the systolic time intervals and DT during exercise. 2,5-7 The duration of diastole is determined by HR (cardiac cycle) and the duration ofQS2' An increase in HR and a lengthening of QS2 \\'ill shorten DT. The two main components of QS2 are preejection period and left ventricular ejection tiIne. Although there \\'ere no significant differences in preejection period and left ventricular ejection tiJne frOlll control to three Ininutes of static exercise, preejection period shortened and left ventricular ejection tiIne lengthened si~nificant)y at three Inillutes of dynalnic exercise. Despite an increase in HR as a result, left ventricular ejection tilne and QS~ during dynulnic exercise \\'ere longer at any given H R ('onlpared to static exercise (Fi~ 1 and 2). The initial rise in left ventricular ejection titne observed in the early phase of dynalnic exercise \\'as paradoxic in relation to its cllstomary clinical correlate, HR, which sho\ved an expected increase. The t\\,O factors determining left ventricular ejection time are stroke vohnne, \vith a direct relation, and ejection rate, with an inverse relation.17,1~ The action of the contracting muscles on the nluscle veins returns the translocated blood (muscle venous pump) and restores the central blood flo\\' at the beginning of 670
exercise. 19 Although stroke volume was not Ineasured at three Ininutes of dynanlic exercise, our data from radionllclide study showed left ventricular end-diastolic volume and stroke volume increased significantly froin control to low-level upright ergometric exercise (at HR of 105± 14 beats per minute) in all patients. Thus, the explanation filr the prolongation of left ventricular ejection time and QS2 at three minutes of dynamic exercise, compared with static exercise, may be related to the increase in left ventricular enddiastolic volume and possible increase in stroke vollllne \\,hich overrode the effect of the increased ejection rate in the early phase of upright dynamic exercise. 20 Most coronary blood flow occurs in diastole, and coronary perfusion to the subendocardial layers is related not only to aortic diastolic pressure but also to left ventricular end-diastolic pressure and to DT.3.21 In addition to a decrease in subendocardial coronary blood flow as a result of increased HR, a disproportionate shortening of diastole at any given HR in dynamic exercise (Fi~ 3) permitted a further reduction of subendocardial blood flow compared ",ith that of static exercise. On the other hand, a higher pressure-HR product increases myocardial oxygen consumption. Thus, a larger increase in HR (righnvard movement along the DT-HR curve) and the disproportionate shortening of DT (downward shift of the DT-HR curve) with higher pressure-HR product in the early phase of dynamic exercise have a potential for initiating imbalance of Iuyocardial oxygen supply and demand. REFERENCES Boudoulas H, Ritt~ers SE, Ley/is R~ Leier C~ \Veissler AM. in diastolic time \\'ith various pharmaco)oJ,Fic agents. Circulation 1979; 60: 164-69 Su~iura T, Iwasaka T, Takahashi N, Matsntani M, Takayama Y, Inada M, et al. Effect of exercise on ventricular diastolic time in coronary artery disease. Am J Cardiol1987; 59:1089-92 rvfeiler SEL, Boudoulas I-I~ Unverferth D~ Leier CV: Diastolic time in c()n~estive heart failure. Am Heart J 1987; 114:1192-98 Hasegawa T, SUJ.,'iura T, lhkahashi N, Iwasaka T, Inada M. Diastolic tilne durin~ low-level exercise in the late hospital phase of acute Inyocardial infarction. Chest 1989; 96:601-05 Quarry-Pi~ot 'I, Chi rife R, Spodick DB. Ejection time hy ear densitogram and its derivative: dinical and physiologic applications. Circulation 1973; 48:239-46 Spodick DB, Lance VQ. Noninvasive stress testing: methodol()~. filr elimination of the phonocardiogram. Circulation 1976; 53:673-76 Lance VQ, Spodick DH. Systolic time intervals utilizing ear densitography: advantages and the reliahility filr stress testing. Arn Heart J 1977; 94:62-6 Chirife R, Spodick DB. A new method fclr evaluation of cardiac performance at rest and during exercise. Am Heart J 1972; 83: 493-503 \Vilke NA, Sheldahl LM, Levandoski SG, Hofflnall ~tD, Tristani FE. \Veight carrying versus handgrip exercise testing in men with coronary artery disease. Aln J Cardiol 1989; 64:736-40 Chan~es
2
3 4
5
6
7
8
9
Diastolic Time during Exercise in MI (Hasegawa et al)
10 D()d~e HT, Sandler II, Ballow D~ Lord JD Jr. The use of biplane an~iocardio~raphyfor the measurement of left ventricular volume in man. Am Heart J 1960; 60:762-76 11 Dyke D~ An~er D, Sullivan R~ Vetter \VR, Yano Y, Parker HC. Cardiac evaluation fronl radioisotope dynamics. J Nucl Med 1972; 13:583-92 12 Scholz PM, Rerych SK, Moran JF. Quantitative radionucJide angio~raphy. Cath Cardiovasc Diag 1980; 6:265-83 13 Haissly Je, Messin R, Der~e 5, Vandermoten ~ Delnaret B, Denolin H, Comparative response to isonletric (static) and dynamic exercise tests in (.'oronary disease. Aln J Cardiol 1974; 33:791-96 14 Lowe DK, Rothhaum DA, Mcllenry PL,Corya Be, Knoehel SB. Myocardial blood flow response to isometric (hand~rip) and treadmill exercise in coronary artery disease. Circulation 1975; 51:126-31 15 Kerber RE, Miller RA, Najjar SM. Myocardial ischenlia effects of is 01net ric, dynamic and (.'C)mbined exercise in (.'C)rouary artery disease. Chest 1975; 67:388-94
16 lIer~ ~fK, Bai JX, ~farin J. ChaJl~t"s in Ipft ,,("ntricular wall stress durin~ isolnetrit, and isotonic t~xercise in Ilt"althy .nen. Aln J Cardiol 1988; 62:794-98 17 Braunwald E, Sarnoff SJ, Stains),y \VN. Dt"tt"rrninailis of duration and mean rate of ventricular {"jet,tioll. (:ire Ht'S I H5k: 6:31 u2S 18 \Veissler AM, Peeler RG, Rot'hll \VII Jr. Relationships Iwh\'een left ventricular ejection titne, strokl' VOh'1l1t', and heart rate in nonnal individuals and patients with cardiovascular dist"ase. Aln Heart J 19tH; 62:369-7H 19 Shepherd]T. Circulatory response to exerl'ist" in health. Cir<:ulation 1987; 76(suppI6):VI-3-VI-I0 20 Stl~itlra T, Doi YL, Bishop RL, lIaffty B(;, Spo(lick I) II. Elucidation of physiol()~iclen~thenin~ofleft ventricular ejection tilne durin~ upri~ht exercise. Aln Heart J HJH1; 101:309-13 21 Ellis AK, Klocke F. Effects of preload on tht" transilltlral distrihution of perfusion and pressure-How relationships in tht' canine eoronary vascular hed. Circ Res IHH(); 46:68-77
Infectious Disease Update The University of Arizona Health Sciences Center will present this program October 6 at Loews Ventana Canyon Resort, Tucson. For more information, contact the University of Arizona Colle~e of Medicine, Continuing Medical Education, Tucson 85724 (602:626-7832),
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