- Email: [email protected]
Effects of rate, atropine and procainamide on human ventricular refractoriness
ABSTRACTS
EFFECTS
OF RATE, VENTRICULAR Stephen B. Guss, F.A.C.C.; Daniel Josephson, M.D.
HUMAN
Philadelphia,
ATROPINE AND PROCAINAMIDE ON REFRACTORINESS M.D.; John A. Kastor, M.D., L. Scharf, M.D.; Mark E. University of Pennsylvania,
Pa.
The effective refractory period of the ventricle (ERP-V) was measured in 25 patients. Right ventricle (RV) was paced at different basic cycle lengths (BCL) and premature beats were introduced at progressively shorter coupling interERP-V was defined as the longest Vl-V2 vals. interval when ventricular capture failed. QT interval was taken as approximation of ventricuMean ERP-V lar action potential duration (APD). ERP-V decreased at BCL 600 msec was 244 msec. at shorter BCL but ratio ERP-VIQT was constant regardless of BCL (0.60 + 0.3, for each patient, In 6 patients given 1 mg 84 determinations. in 4 and atropine (A), the ERP-V did not change increased 10% at 1 of 3 BCL tested in the other 2 patients. In 4 patients given procainamide 30%, QT in(PA) 500 mg IV, mean ERP-V increased ERP-V paralleled serum PA levels creased 4%. and fell quickly to control values within 30 Double and triple beating minutes after PA. occurred in 5 patients at short coupling interafter PA and reappeared as vals, disappeared These studies show that ERP-V drug levels fell. 1) can be safely determined; 2) is directly related to BCL and QT interval; 3) usually is unaffected by A; 4) is prolonged by PA more than is QT suggesting confirmation of -in vitro increase in ERP/APD ratio.
LONGITUDINAL EVALUATION OF PATIENTS AFTER CORONARY ARTERY BYPASS BY SERIAL TREADMILL TESTING Jorge Guttin MD, Efrain Garcia MD, FACC, Denton A. Cooley MD, FACC, Robert J. Hall MD, FACC; Clayton Foundation Exercise & Noninvasive Laboratory, St. Luke's Episcopal Hospital & Texas Heart Institute, Houston, Texas One hundred forty patients (pts) with symptomatic coronary artery disease who underwent coronary artery bypass (CAB) were studied postoperatively by serial multistage treadmill exercise testing (TET). No preop TET was performed in 26% (36/140). Preop TET response was positive (pos) [ reater than 1 mm ischemic ST depression] in 69% (72/104 7 and negative (neg) in 31% (32/104). Thirty-two pts who had neg TET preop remained neg postop (mean 14.6 months). Of these, 6% (2/32) subsequently converted to pos at 3 and 14 months. Of those pos preop, 32%(23/72)remained pos (mean 13.8 months) while 68% (49/72) had a neg TET postop (mean 8.6 months). Late reversal to pos TET occurred in 20% (10/49) at 23.6 months (mean). In pts with pos TET preoer pressure heart rate product (PRP) improved by 11% (from 233 to 262 ~10~) in those who remained pos postop, by 29% (from 219 to 308 ~10~) in pts who converted to neg, and‘by 13% (from 206 to 237 x102) in pts who reverted to pos. Pts with neg TET preop who remained neg postop experienced a 16% improvement (PRP from 251 to 301 ~10~). Maximum heart rate and TET stage increased in similar proportions. The magnitude of mm ST ischemic depression, frequency of extrasystoles and number of grafted vessels did not influence the postop results in TET performance or ischemic response. Serial TET is an excellent noninvasive test in CAB follow-up evaluation. Reversals from early postop neg TET to late pos TET suggest that while CAB may play an important palliative role, it probably does not alter the progressive nature of the disease.
742
January
1975
The American Journal of CARDIOLOGY
POSTEXTRASYSTOLIC POTENTIATION(PEP) AND IMPROVED LEFT VENTRICULAR CONTRACTION IN CORONARY ARTERY DISEASE(CAD). PREDICTION OF POSTOPERATIVE VENTRICULAR FUNCTION Robert I. tlamby, MD, FACC; Agop Aintablian, MD; Marvin L. Hartstein, MD; 8. George Wisoff, MD, Long Island JewishHillside Medical Center, New Hyde Park, New York The present study was to evaluate effect of PEP on myocardial function in CAD and relate these changes to effect of aortocoronary bypass surgery on left ventricular Group(Gp) I consisted of I4 (LV) contraction pattern. patients(pts) with no myocardial infarction and normal (nl) LV contraction; Gp II (I9 pts) had no Ml but had LV No CAD asynergy; Gp III (I7 pts) had Ml with LV asynergy. and nl LV function was present in I2 pts (nl Gp). Quantitative ventriculograms performed resulted in extrasystoles followed by a compensatory pause. End-diastolic, endsystolic(ESV) and stroke volume(SV) and ejection fraction (EF) were determined in the postextrasystolic beat(PEB) and the next beat (control beat). In all Gps the PEB revealed an increase in SV, EF and decrease in ESV as comGp I and nl Gp revealed no differpared to control beat. ence, while the decrease in ESV and increase in EF were greater in Gp II and III as compared to nl Gp and Gp I In Gp II and III PEP resulted in no change (71, (p
in Gp II and III the changes in contractile pattern after aortocoronary bypass surgery corresponded to that observed preoperatively in the postextrasystolic beat. This study indicates that PEP can detect residual myocardial function in pts with abnormal LV function and CAD and is useful for predicting postoperative improvement in LV contraction.
CLINICAL ASSESSMENT OF CORONARY ARTERY DISEASE IN
PATIENTS WITH AORTTC STFR~OSTS E. William Hancock, MD, FACC. Cardiology Division, Stanford University School of Medicine, Stanford, CA 94305 The relationships between aortic stenosis (AS), coronary artery disease (CAD), angina pectoris, and myocardial infarction were studied in 173 patients with calcific AS who had coronary arteriography as well as cardiac catheterization. All were over age 40 and had definitecardiac symptoms; 156 later had aortic valve replacement. CAD with areas of greater than 50% narrowing was present in 37% of those aged 40-59 (25/67) and in 68% of those aged 60-82 (72/106). CAD was present in 64% of those with angina (82/128) compared with 33% of those without angina (15/45). Patients with CAD in the absence of angina were over 60 years of age in 12 of 15 instances, and presented with congestive heart failure (7), dyspnea on exertion(3), effort syncope (4), or complete heart block with syncope (1). Angina which occurred only in association with dyspnea on exertion was associated with CAD in 45% of instances (26/58), whereas angina which also occurred on exertion without any dyspnea, or which occurred with emotional stress, after meals, during the night, or at rest unprovoked was associated with CAD in 80% of instances (56/70). QS patterns in Vl-V2 were not correlated with CAD, but pathological Q waves in the inferior and anterolateral leads were associated with CAD in 20/22 instances. Patients with relatively mild AS (valve area 0.55 to 0.80 cm2/M2) all had CAD, and in 11/12 instances had angina pectoris as their sole or predominant complaint. A helpful clinical assessment of CAD in patients with AS may be made by taking into consideration the age, the severity of the AS, the presence and type of angina1 syndrome, and the evidence of transmural inferior or anterolateral infarction in the electrocardiogram.
Volume 35
EFFECTS
OF RATE, VENTRICULAR Stephen B. Guss, F.A.C.C.; Daniel Josephson, M.D.
HUMAN
Philadelphia,
ATROPINE AND PROCAINAMIDE ON REFRACTORINESS M.D.; John A. Kastor, M.D., L. Scharf, M.D.; Mark E. University of Pennsylvania,
Pa.
The effective refractory period of the ventricle (ERP-V) was measured in 25 patients. Right ventricle (RV) was paced at different basic cycle lengths (BCL) and premature beats were introduced at progressively shorter coupling interERP-V was defined as the longest Vl-V2 vals. interval when ventricular capture failed. QT interval was taken as approximation of ventricuMean ERP-V lar action potential duration (APD). ERP-V decreased at BCL 600 msec was 244 msec. at shorter BCL but ratio ERP-VIQT was constant regardless of BCL (0.60 + 0.3, for each patient, In 6 patients given 1 mg 84 determinations. in 4 and atropine (A), the ERP-V did not change increased 10% at 1 of 3 BCL tested in the other 2 patients. In 4 patients given procainamide 30%, QT in(PA) 500 mg IV, mean ERP-V increased ERP-V paralleled serum PA levels creased 4%. and fell quickly to control values within 30 Double and triple beating minutes after PA. occurred in 5 patients at short coupling interafter PA and reappeared as vals, disappeared These studies show that ERP-V drug levels fell. 1) can be safely determined; 2) is directly related to BCL and QT interval; 3) usually is unaffected by A; 4) is prolonged by PA more than is QT suggesting confirmation of -in vitro increase in ERP/APD ratio.
LONGITUDINAL EVALUATION OF PATIENTS AFTER CORONARY ARTERY BYPASS BY SERIAL TREADMILL TESTING Jorge Guttin MD, Efrain Garcia MD, FACC, Denton A. Cooley MD, FACC, Robert J. Hall MD, FACC; Clayton Foundation Exercise & Noninvasive Laboratory, St. Luke's Episcopal Hospital & Texas Heart Institute, Houston, Texas One hundred forty patients (pts) with symptomatic coronary artery disease who underwent coronary artery bypass (CAB) were studied postoperatively by serial multistage treadmill exercise testing (TET). No preop TET was performed in 26% (36/140). Preop TET response was positive (pos) [ reater than 1 mm ischemic ST depression] in 69% (72/104 7 and negative (neg) in 31% (32/104). Thirty-two pts who had neg TET preop remained neg postop (mean 14.6 months). Of these, 6% (2/32) subsequently converted to pos at 3 and 14 months. Of those pos preop, 32%(23/72)remained pos (mean 13.8 months) while 68% (49/72) had a neg TET postop (mean 8.6 months). Late reversal to pos TET occurred in 20% (10/49) at 23.6 months (mean). In pts with pos TET preoer pressure heart rate product (PRP) improved by 11% (from 233 to 262 ~10~) in those who remained pos postop, by 29% (from 219 to 308 ~10~) in pts who converted to neg, and‘by 13% (from 206 to 237 x102) in pts who reverted to pos. Pts with neg TET preop who remained neg postop experienced a 16% improvement (PRP from 251 to 301 ~10~). Maximum heart rate and TET stage increased in similar proportions. The magnitude of mm ST ischemic depression, frequency of extrasystoles and number of grafted vessels did not influence the postop results in TET performance or ischemic response. Serial TET is an excellent noninvasive test in CAB follow-up evaluation. Reversals from early postop neg TET to late pos TET suggest that while CAB may play an important palliative role, it probably does not alter the progressive nature of the disease.
742
January
1975
The American Journal of CARDIOLOGY
POSTEXTRASYSTOLIC POTENTIATION(PEP) AND IMPROVED LEFT VENTRICULAR CONTRACTION IN CORONARY ARTERY DISEASE(CAD). PREDICTION OF POSTOPERATIVE VENTRICULAR FUNCTION Robert I. tlamby, MD, FACC; Agop Aintablian, MD; Marvin L. Hartstein, MD; 8. George Wisoff, MD, Long Island JewishHillside Medical Center, New Hyde Park, New York The present study was to evaluate effect of PEP on myocardial function in CAD and relate these changes to effect of aortocoronary bypass surgery on left ventricular Group(Gp) I consisted of I4 (LV) contraction pattern. patients(pts) with no myocardial infarction and normal (nl) LV contraction; Gp II (I9 pts) had no Ml but had LV No CAD asynergy; Gp III (I7 pts) had Ml with LV asynergy. and nl LV function was present in I2 pts (nl Gp). Quantitative ventriculograms performed resulted in extrasystoles followed by a compensatory pause. End-diastolic, endsystolic(ESV) and stroke volume(SV) and ejection fraction (EF) were determined in the postextrasystolic beat(PEB) and the next beat (control beat). In all Gps the PEB revealed an increase in SV, EF and decrease in ESV as comGp I and nl Gp revealed no differpared to control beat. ence, while the decrease in ESV and increase in EF were greater in Gp II and III as compared to nl Gp and Gp I In Gp II and III PEP resulted in no change (71, (p
in Gp II and III the changes in contractile pattern after aortocoronary bypass surgery corresponded to that observed preoperatively in the postextrasystolic beat. This study indicates that PEP can detect residual myocardial function in pts with abnormal LV function and CAD and is useful for predicting postoperative improvement in LV contraction.
CLINICAL ASSESSMENT OF CORONARY ARTERY DISEASE IN
PATIENTS WITH AORTTC STFR~OSTS E. William Hancock, MD, FACC. Cardiology Division, Stanford University School of Medicine, Stanford, CA 94305 The relationships between aortic stenosis (AS), coronary artery disease (CAD), angina pectoris, and myocardial infarction were studied in 173 patients with calcific AS who had coronary arteriography as well as cardiac catheterization. All were over age 40 and had definitecardiac symptoms; 156 later had aortic valve replacement. CAD with areas of greater than 50% narrowing was present in 37% of those aged 40-59 (25/67) and in 68% of those aged 60-82 (72/106). CAD was present in 64% of those with angina (82/128) compared with 33% of those without angina (15/45). Patients with CAD in the absence of angina were over 60 years of age in 12 of 15 instances, and presented with congestive heart failure (7), dyspnea on exertion(3), effort syncope (4), or complete heart block with syncope (1). Angina which occurred only in association with dyspnea on exertion was associated with CAD in 45% of instances (26/58), whereas angina which also occurred on exertion without any dyspnea, or which occurred with emotional stress, after meals, during the night, or at rest unprovoked was associated with CAD in 80% of instances (56/70). QS patterns in Vl-V2 were not correlated with CAD, but pathological Q waves in the inferior and anterolateral leads were associated with CAD in 20/22 instances. Patients with relatively mild AS (valve area 0.55 to 0.80 cm2/M2) all had CAD, and in 11/12 instances had angina pectoris as their sole or predominant complaint. A helpful clinical assessment of CAD in patients with AS may be made by taking into consideration the age, the severity of the AS, the presence and type of angina1 syndrome, and the evidence of transmural inferior or anterolateral infarction in the electrocardiogram.
Volume 35