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Evaluation of external counterpulsation for the treatment of angina pectoris
ABSTRACTS
EVALUATION OF EXTERNAL COUNTEHPULSATION FOR THE TREATMENT OF ANGINA PECTORIS John S. Banas, MD, FACC; Alfred Brilla, MD; Herbert J. Levine, MD, FACC; New England Medical Center Hospital, Boston, Massachusetts External counterpulsation (ECP) was performed on 21 patients (pts) with angina pectoris (AP). Fourteen pts were Functional Class (FC) IV, six FC III, and one FC II. Sixteen pts were on propranolol (40-400 mg. daily). ECP was performed one hour daily for five days. Significant aortic diastolic pressure augmentation (DPA) was produced in eighteen pts (75.3 + 1.8 to 123.3 f 2.7 mmHg, pc.001). Three pts had no significant DPA produced. Seventeen pts with significant DPA were free of AP by day four of ECP, one was not. After one month, ten pts were FC I, six of the FC IV and two of the FC III pts became FC II. The three pts without DPA had no improvement in AP. Only one of the eighteen improved pts required propranolol (40 mg.) after ECP. Nine pts who developed AP or heart block (one pt) during atria1 pacing improved their mean pressure time per minute at which AP developed from 3165 ? 226 to 4000 * 162 mmHg * secfmin, pc.01. Repeat coronary angiography performed four to eight weeks after ECP in eleven pts showed a definite increase in vascularity in five, equivocal in four and no visible changes in two. Four pts had recurrence of AP four to six months follovlng initial ECP. Repeat ECP was again effective in relieving AP. ECP is a noninvasive, atraumatic technique that can produce significant DPA and may produce significant subjective and objective improvement in some pts with AP, possibly by enhancing collateral circulation.
MICROELECTRODE STUDY OF ALTERNATING RESPONSES TO REPETITIVE PRmTURE EXCITATION Jack P. Bandura, PhD, and Daniel A. Brody, MD, FACC, University of Tennessee, Memphis, Tennessee Previous in viuo studies demonstrated alternating patterns of response to premature ventricular excitation, and indicated that these patterns were related to alternating changes in the refractoriness of the specialized conduction system. The proposed mechanism for these change8 in refractoriness was related to cycle-length change8 produced by delayed retrograde activation of a forward-blocked segment of the specialized conduction system. Hence we investigated 1) whether 2:l forward b,lockwith retrograde activation could be produced in isolated bifurcating Purklnje bundles ("Y preparation," with both branches terminating in a single piece of excised myocardium) and 2) what changes in cycle length were associated with this alternating block. In vitro Y preparations of canine Purkinje tissue were electrically stimulated (in the stem of the Y) with 60 pulse pairs/minute. Beyond the bifurcation of the stem 2 microelectrodes were placed proximally and distally in the same branch. Critical coupling of the paired stimuli produced a 2:l forward block in the recorded branch. When forward conduction failed the impulse was transmitted through the other branch, entered the distal muscle interconnecting the branches, and then retrogradely activated the blocked branch. The results also demonstrated that the alternating block was related to the preceding cycle length. Thus our study demonstrates alternation of the impulse pathway in the distal Purkinje system in response to repetitive premature excitation and provides basic electrophysiological evidence for previously proposed mechanisms.
118
January 1973
The American Journal of CARDIOLOGY
LIMITATIONS OF MYOCARDIAL REVASCUIARIZATION IN RESTORATION OF REGIONAL CONTRACTION ABNORMALITIES PRODUCED BY CORONARY OCCLUSION Vidya S. Banka, MD, Ku1 D. Chadda, MD, Steven G. Meister, MD and Richard H. Helfant, MD, Presbyterian-University of Pennsylvania Medical Center, Philadelphia, Pennsylvania The contraction characteristics of central, border zone and nonischemic myocatdium were studied utith 3 WaltonBrodie strain gauge arches fixed on the left ventricle with deep sutures and 40% stretch in 18 open chested dogs. Revascularization was instituted after 30 minutes (min), 45 min, 1, 2, and 3 hours (hr) of total occlusion of left anterior descending coronary artery. Measurements of f8ometric tension (ISOM), rate of rise of ISOM (dT/dt), isotonic tension (ISOT) and total tension (TT) were made. After both 30 and 45 min of occlusion, significant improvement occurred with a 140% increase in ISOM, 116% in dT/dt, 165% in ISOT and 65% in TT in the central zone with parallel improvements in the border zone. The aneurysmal bulging (decrease in ISOT) completely dieappeared. However, after 1 hr of occlusion the central zone exhibited a 42.3 + 8.6% in significant (p(O.01) further decrease of ISOM, 35.6 + 3.0% in dT/dt, -0.33 +_ 0.33 to -3 + 1.0 in ISOT and 39.4 + 9.0% in TT. Aneurysmal bulging worsened imuzdiately after revascularization. The border zone in 4 of these studies exhibited similar decreases in function, however in 2 experiments, there was an improvement. After 2 and 3 hr, revascularization was uniformly followed by further decreases in function of both centeral and border zones. The change8 in the nonischemic zone were minimal. In sutmnary, contraction abnormalities produced by 45 min of coronary occlusion are reversible with revascularization. However, these abnormalities are often accentuated with revasculariestion 1 hr after occlusion and uniformly deteriorated further after two hours.
COMPLICATIONSOFFEMORALARTERYCATHETERIZATION: PROSPECTIVE EVALUATIONWITH THEDOPPLERULTRASONICVELOCITYDETECTOR R.W. Barnes,MD, J. Petersen,MD, FACC, R.B. Krugmire, of Jr., and D.E. Strandness, Jr., MD, University Washington School of Medicine, Seattle, Washington Observer discrepancy in pulse detection suggested the need for objective physiologic monitoring of patients for complications following percutaneous femoral artery catheterization. In 160 procedures in 142 patients the quality of arterial signals and the arm and ankle systolic blood pressures were assessed by the ultrasonic velocity detector before and after cardiac catheterization. An arterial thromboembolic complication was detected and localized by an abnormal arterial signal, a drop in ankle pressure below that of the arm, and an abnormal segmental blood pressure gradient in the leg. There were 23 arterial complications (14%) including 7 femoral and 15 distal thromboemboli and 1 iliac dissection. Complications were more frequent in females with mitral valve disease. Pre-existing peripheral arterial occlusive disease was detected by ultrasound in 18 patients (13%); 8 complications developed after catheterization of 11 diseased arteries. Fifteen of 22 patients with thromboembolic complications were asymptomatic irrespective of the level of arterial occlusion. Six patients with femoral artery occlusion underwent successful thrombectomy . The remainder, including all with distal thromboemboli, had adequate collateral circulation by ultrasound and did not require operation. The Doppler ultrasonic velocity detector is a simple, reliable, noninvasive aid in the detection and management of complications of femoral artery catheterization.
Volume 31
EVALUATION OF EXTERNAL COUNTEHPULSATION FOR THE TREATMENT OF ANGINA PECTORIS John S. Banas, MD, FACC; Alfred Brilla, MD; Herbert J. Levine, MD, FACC; New England Medical Center Hospital, Boston, Massachusetts External counterpulsation (ECP) was performed on 21 patients (pts) with angina pectoris (AP). Fourteen pts were Functional Class (FC) IV, six FC III, and one FC II. Sixteen pts were on propranolol (40-400 mg. daily). ECP was performed one hour daily for five days. Significant aortic diastolic pressure augmentation (DPA) was produced in eighteen pts (75.3 + 1.8 to 123.3 f 2.7 mmHg, pc.001). Three pts had no significant DPA produced. Seventeen pts with significant DPA were free of AP by day four of ECP, one was not. After one month, ten pts were FC I, six of the FC IV and two of the FC III pts became FC II. The three pts without DPA had no improvement in AP. Only one of the eighteen improved pts required propranolol (40 mg.) after ECP. Nine pts who developed AP or heart block (one pt) during atria1 pacing improved their mean pressure time per minute at which AP developed from 3165 ? 226 to 4000 * 162 mmHg * secfmin, pc.01. Repeat coronary angiography performed four to eight weeks after ECP in eleven pts showed a definite increase in vascularity in five, equivocal in four and no visible changes in two. Four pts had recurrence of AP four to six months follovlng initial ECP. Repeat ECP was again effective in relieving AP. ECP is a noninvasive, atraumatic technique that can produce significant DPA and may produce significant subjective and objective improvement in some pts with AP, possibly by enhancing collateral circulation.
MICROELECTRODE STUDY OF ALTERNATING RESPONSES TO REPETITIVE PRmTURE EXCITATION Jack P. Bandura, PhD, and Daniel A. Brody, MD, FACC, University of Tennessee, Memphis, Tennessee Previous in viuo studies demonstrated alternating patterns of response to premature ventricular excitation, and indicated that these patterns were related to alternating changes in the refractoriness of the specialized conduction system. The proposed mechanism for these change8 in refractoriness was related to cycle-length change8 produced by delayed retrograde activation of a forward-blocked segment of the specialized conduction system. Hence we investigated 1) whether 2:l forward b,lockwith retrograde activation could be produced in isolated bifurcating Purklnje bundles ("Y preparation," with both branches terminating in a single piece of excised myocardium) and 2) what changes in cycle length were associated with this alternating block. In vitro Y preparations of canine Purkinje tissue were electrically stimulated (in the stem of the Y) with 60 pulse pairs/minute. Beyond the bifurcation of the stem 2 microelectrodes were placed proximally and distally in the same branch. Critical coupling of the paired stimuli produced a 2:l forward block in the recorded branch. When forward conduction failed the impulse was transmitted through the other branch, entered the distal muscle interconnecting the branches, and then retrogradely activated the blocked branch. The results also demonstrated that the alternating block was related to the preceding cycle length. Thus our study demonstrates alternation of the impulse pathway in the distal Purkinje system in response to repetitive premature excitation and provides basic electrophysiological evidence for previously proposed mechanisms.
118
January 1973
The American Journal of CARDIOLOGY
LIMITATIONS OF MYOCARDIAL REVASCUIARIZATION IN RESTORATION OF REGIONAL CONTRACTION ABNORMALITIES PRODUCED BY CORONARY OCCLUSION Vidya S. Banka, MD, Ku1 D. Chadda, MD, Steven G. Meister, MD and Richard H. Helfant, MD, Presbyterian-University of Pennsylvania Medical Center, Philadelphia, Pennsylvania The contraction characteristics of central, border zone and nonischemic myocatdium were studied utith 3 WaltonBrodie strain gauge arches fixed on the left ventricle with deep sutures and 40% stretch in 18 open chested dogs. Revascularization was instituted after 30 minutes (min), 45 min, 1, 2, and 3 hours (hr) of total occlusion of left anterior descending coronary artery. Measurements of f8ometric tension (ISOM), rate of rise of ISOM (dT/dt), isotonic tension (ISOT) and total tension (TT) were made. After both 30 and 45 min of occlusion, significant improvement occurred with a 140% increase in ISOM, 116% in dT/dt, 165% in ISOT and 65% in TT in the central zone with parallel improvements in the border zone. The aneurysmal bulging (decrease in ISOT) completely dieappeared. However, after 1 hr of occlusion the central zone exhibited a 42.3 + 8.6% in significant (p(O.01) further decrease of ISOM, 35.6 + 3.0% in dT/dt, -0.33 +_ 0.33 to -3 + 1.0 in ISOT and 39.4 + 9.0% in TT. Aneurysmal bulging worsened imuzdiately after revascularization. The border zone in 4 of these studies exhibited similar decreases in function, however in 2 experiments, there was an improvement. After 2 and 3 hr, revascularization was uniformly followed by further decreases in function of both centeral and border zones. The change8 in the nonischemic zone were minimal. In sutmnary, contraction abnormalities produced by 45 min of coronary occlusion are reversible with revascularization. However, these abnormalities are often accentuated with revasculariestion 1 hr after occlusion and uniformly deteriorated further after two hours.
COMPLICATIONSOFFEMORALARTERYCATHETERIZATION: PROSPECTIVE EVALUATIONWITH THEDOPPLERULTRASONICVELOCITYDETECTOR R.W. Barnes,MD, J. Petersen,MD, FACC, R.B. Krugmire, of Jr., and D.E. Strandness, Jr., MD, University Washington School of Medicine, Seattle, Washington Observer discrepancy in pulse detection suggested the need for objective physiologic monitoring of patients for complications following percutaneous femoral artery catheterization. In 160 procedures in 142 patients the quality of arterial signals and the arm and ankle systolic blood pressures were assessed by the ultrasonic velocity detector before and after cardiac catheterization. An arterial thromboembolic complication was detected and localized by an abnormal arterial signal, a drop in ankle pressure below that of the arm, and an abnormal segmental blood pressure gradient in the leg. There were 23 arterial complications (14%) including 7 femoral and 15 distal thromboemboli and 1 iliac dissection. Complications were more frequent in females with mitral valve disease. Pre-existing peripheral arterial occlusive disease was detected by ultrasound in 18 patients (13%); 8 complications developed after catheterization of 11 diseased arteries. Fifteen of 22 patients with thromboembolic complications were asymptomatic irrespective of the level of arterial occlusion. Six patients with femoral artery occlusion underwent successful thrombectomy . The remainder, including all with distal thromboemboli, had adequate collateral circulation by ultrasound and did not require operation. The Doppler ultrasonic velocity detector is a simple, reliable, noninvasive aid in the detection and management of complications of femoral artery catheterization.
Volume 31