- Email: [email protected]
Daily exercise augments antegrade flow following partial coronary occlusion
ABSTRACTS
COMPLETE ATRIOVENTRICULAR CANAL ASSOCIATED WITH TETRALOGY OF FALLOT Gideon Uretzky, MO; Francisco J. Puga, MO; Robert H. Feldt, MO, FACC; Paul R. Julsrud, MD; William D. Edwards, MD; Gordon K. Danielson, MD, FACC; Dwight C. McGoon, MD, FACC; Mayo Clinic and Mayo Foundation, Rochester, Minn. The surgical repair of complete atrioventricular canal associated with tetralogy of Fallot has been reported in a few cases. Between 1969-1979, a total of 14 patients with the combination of complete atrioventricular canal (13 type C, and 1 type B), associated with tetralogy of Fallot, had repair of both anomalies. Patient age ranged from 1 to 12 years. Five had a previous shunt operation. 13 had combined subpulmonary and valvular stenosis and 1 had subpulmonary stenosis only. Six patients had Down's syndrome. Eleven (79%) had associated anomalies including left superior vena cava (3), right aortic arch (2), atria1 septal defect secundum type (7), patent foramen ovale (l), anomalous left anterior descending coronary artery (l), and aberrant right subclavian artery (1). The precise preoperative diagnosis was established in 10 (71%) by angiography showing the characteristics of tetralogy of Fallot on RV angiogram and those of atrioventricular canal on LV angiogram. In 4 of these patients the diagnosis was supported by two dimensional echocardiography. The typical features of the condition include anterior displacement of the infundibular septum and "goose neck" LV outflow changes. Surgical repair is complex. The repair of the ventricular septal defect, with its large anterior subaortic extension required a combined atria1 and right ventricular approach in 4 patients. Outflow tract reconstruction (transanular patch) was performed in 9 patients. The hospital mortality rate was 21%, and there were two late deaths. Nine (64%) patients are still living having a satisfactory result.
WEDNESDAY, MARCH 18, 1981 PM EXERCISE PHYSIOLOGY AND TRAINING 2:00-3:30 DECREASED MYOCARDIAL OXYGEN DEMAND FROM EXERCISE TRAINING SECONDARY TO IMPROVED WORK EFFICIENCY: EFFECT OF HABITUATION VERSUS AEROBIC CONDITIONING Rudolph H. Dressendorfer, PhD; Joan L. Smith, MA; Ezra A. Amsterdam, MD. FACC, Human Performance Lab, University of California, Davis, California. Exercise training (ExT) in coronary patients (pts) has been shown to improve aerobic capacity, as measured.by an increase in total body maximal oxygen consumption.(VOz max), and to decrease myocardial oxygen demand (MVOz) during submaximal Ex. The lowering of MVOz with Ex at the same external workload after training most often results from utilization of a decreased percentage of VOzmax because of greater aerobic capacity. Our purpose was to determine whether MVOz during submaximal walking Ex could be reduced by improving work efficiency without a concomitant increase in SrOzmax. The pts were B men with ischemic heart disease who did not have symptomlimitations on maximal Ex testing. ExT was restricted to fast walking since jogging caused ischemic ST-segment depression. Walking speed was individually prescribed between 3.4 to 4.7 mph in order to maintain the heart rate (HR) x systolic blood pressure product just below the ischemic threshold. After 14 to 20 wks of ExT 3 x per wk, directly measured VOzmax was not significantly changed. However, significant (P < .05) reductions in HR (120 to 108 beats/min), rate-pressure product (195 to 162 x 102), total body VOz (20.0 to 18.2 ml/kg/min) and perceived exertion were found after ExT when the pts walked at their prescribed speeds. Total body VOz during submaximal Ex was reduced secondary to habituation, i.e:, enhanced work efficiency. Consequently, estimated MVOz was siqnificantlv lower after ExT due to decreased peripheral-oxygen demand, and not because of a reduction in t e r lative w rkload. .Coronary ts ma benefit from reguCf ar x even wRen aerobic capacit! is n8 t increased.
CONDUIT SURGERY FOR RIGHT VENTRICULAR AND PULMONARY EXPERIENCE IN BOTH INFANTS AND OtDER ARTERY CONTINUITY. Constantine Mavroudis, MD; Kevin Turley, MD, CHILDREN. FACC; Paul A. Ebert, MD, FACC; University of California, San Francisco, CA 94143.
DAILY EXERCISE AUGMENTS ANTEGRADE FLOW FOLLOWING PARTIAL CORONARY OCCLUSION Ming Hwang, MD, FACC; Alan Gabster, MD; Henry Loeb, MD, FACC; Rolf Gunnar, MD, FACC, Loyola University Medical Center, Maywood, 11 hnd VA Hospital, Hines 11
The conduit repair (Rastelli) of lesions requiring reconstitution of right ventricular (RV) to pulmonary artery Serious (PA) continuity has been demonstrated effective. questions have arisen as to the longevity of such conduit replacements with degeneration of the valve components and the development of gradients at both the anastomotic, These are of special imand valvular levels. conduit, During the period June 1, 1975port in the infant group. repairs were performed July 1, 1980, 110 RV to PA conduit at University of California, San Francisco. Ages ranged from 14 days to 35 years, median 15 months. Lesions intransposition of the great arcluded truncus arteriosus, teries with ventricular septal defect, tetralogy of Fallot Conduit size ranged from 12 to 22 and pulmonary atresia. operative survival was 80%. mm, median 14 mm. Overall Special risk factors identified included absence of pulassociated lesions (i.e. interrupted monary arteries, valvular insufficiency requiring replacement) and arch, When such patients were excluded,survival age < 6 weeks. 10 conduit replacements were undertaken at a was 90%. mean of 27 months in follow-up, while 100 patients from 3 months to 68 months postop. remain at risk. Operative survival in repaired patients in whom replacement was Conduit repair of RV to PA disconnecessary was 100%. tinuity results in stimulation of symmetrical anatomic Reoperation is necessary growth and hemodynamic repair. in these patients in response to both this growth and the intrinsic problems of valvular degeneration and pseudointimal proliferation associated with current conduits, but replacement is possible with low risk.
Previously we showed that dogs subjected to daily treadmill exercise (45 min, 4-6 mph, loo slope for 4-6 weeks) increased subendocardial blood flow (SEF) in an area supplied by partial (80-90%) circumflex artery occlusion (P-CFxO) when compared to similar dogs not exercised. All visible epicardial collaterals were ligated. To determine if the increased flow was across the partial constriction pasor from collaterals, 22 dogs were prepared as above. terior SEF was measured after P-CF,O and after total circumflex occlusion (TCF,O) to assess the proportion SEF which was antegrade. Results: In 6 experiments, PSEF measured immediately after PCF,O averaged .74f.20 ml/min/ gm (Mean + SEM) falling to .lOf.03 ml/min/gm upon TCF,O (p<.OOl). In 16 dogs, PSEF measurements were made 4-6 weeks after PCFxO. Eight dogs remained sedentary and 8 underwent daily exercise. In the 8 sedentary dogs, PSEF with PSFxO averaged .94?.12 ml/min/gm falling to .64f.11 ml/min/qm upon TCFxO (NS). In the 8 exercised dogs, PSEF with PCFxO averaged .95?.15 ml/min/qm falling to .38'.1S ml/min/gm after TCFxO (pc.05). Conclusion: Immediately following PCF,O, PSEF depends primarily on antegrade flow. After 4-6 weeks, retrograde collateral flow makes a siqnificant contribution to PSEF in sedentary dogs. Dogs subjected to daily exercise following PCFxO have a very significant increase in the proportion of blood flowing antegrade acioss the PCFXO. Therefore, daily exercise It is proseems to enhance antegrade flow in PCFxO dogs. posed that this enhanced antegrade flow is due to an effect of daily exercise on myocardial vascular resis'tance.
February 1981
The American Journal of CARDIOLOGY
Volume 47
467
COMPLETE ATRIOVENTRICULAR CANAL ASSOCIATED WITH TETRALOGY OF FALLOT Gideon Uretzky, MO; Francisco J. Puga, MO; Robert H. Feldt, MO, FACC; Paul R. Julsrud, MD; William D. Edwards, MD; Gordon K. Danielson, MD, FACC; Dwight C. McGoon, MD, FACC; Mayo Clinic and Mayo Foundation, Rochester, Minn. The surgical repair of complete atrioventricular canal associated with tetralogy of Fallot has been reported in a few cases. Between 1969-1979, a total of 14 patients with the combination of complete atrioventricular canal (13 type C, and 1 type B), associated with tetralogy of Fallot, had repair of both anomalies. Patient age ranged from 1 to 12 years. Five had a previous shunt operation. 13 had combined subpulmonary and valvular stenosis and 1 had subpulmonary stenosis only. Six patients had Down's syndrome. Eleven (79%) had associated anomalies including left superior vena cava (3), right aortic arch (2), atria1 septal defect secundum type (7), patent foramen ovale (l), anomalous left anterior descending coronary artery (l), and aberrant right subclavian artery (1). The precise preoperative diagnosis was established in 10 (71%) by angiography showing the characteristics of tetralogy of Fallot on RV angiogram and those of atrioventricular canal on LV angiogram. In 4 of these patients the diagnosis was supported by two dimensional echocardiography. The typical features of the condition include anterior displacement of the infundibular septum and "goose neck" LV outflow changes. Surgical repair is complex. The repair of the ventricular septal defect, with its large anterior subaortic extension required a combined atria1 and right ventricular approach in 4 patients. Outflow tract reconstruction (transanular patch) was performed in 9 patients. The hospital mortality rate was 21%, and there were two late deaths. Nine (64%) patients are still living having a satisfactory result.
WEDNESDAY, MARCH 18, 1981 PM EXERCISE PHYSIOLOGY AND TRAINING 2:00-3:30 DECREASED MYOCARDIAL OXYGEN DEMAND FROM EXERCISE TRAINING SECONDARY TO IMPROVED WORK EFFICIENCY: EFFECT OF HABITUATION VERSUS AEROBIC CONDITIONING Rudolph H. Dressendorfer, PhD; Joan L. Smith, MA; Ezra A. Amsterdam, MD. FACC, Human Performance Lab, University of California, Davis, California. Exercise training (ExT) in coronary patients (pts) has been shown to improve aerobic capacity, as measured.by an increase in total body maximal oxygen consumption.(VOz max), and to decrease myocardial oxygen demand (MVOz) during submaximal Ex. The lowering of MVOz with Ex at the same external workload after training most often results from utilization of a decreased percentage of VOzmax because of greater aerobic capacity. Our purpose was to determine whether MVOz during submaximal walking Ex could be reduced by improving work efficiency without a concomitant increase in SrOzmax. The pts were B men with ischemic heart disease who did not have symptomlimitations on maximal Ex testing. ExT was restricted to fast walking since jogging caused ischemic ST-segment depression. Walking speed was individually prescribed between 3.4 to 4.7 mph in order to maintain the heart rate (HR) x systolic blood pressure product just below the ischemic threshold. After 14 to 20 wks of ExT 3 x per wk, directly measured VOzmax was not significantly changed. However, significant (P < .05) reductions in HR (120 to 108 beats/min), rate-pressure product (195 to 162 x 102), total body VOz (20.0 to 18.2 ml/kg/min) and perceived exertion were found after ExT when the pts walked at their prescribed speeds. Total body VOz during submaximal Ex was reduced secondary to habituation, i.e:, enhanced work efficiency. Consequently, estimated MVOz was siqnificantlv lower after ExT due to decreased peripheral-oxygen demand, and not because of a reduction in t e r lative w rkload. .Coronary ts ma benefit from reguCf ar x even wRen aerobic capacit! is n8 t increased.
CONDUIT SURGERY FOR RIGHT VENTRICULAR AND PULMONARY EXPERIENCE IN BOTH INFANTS AND OtDER ARTERY CONTINUITY. Constantine Mavroudis, MD; Kevin Turley, MD, CHILDREN. FACC; Paul A. Ebert, MD, FACC; University of California, San Francisco, CA 94143.
DAILY EXERCISE AUGMENTS ANTEGRADE FLOW FOLLOWING PARTIAL CORONARY OCCLUSION Ming Hwang, MD, FACC; Alan Gabster, MD; Henry Loeb, MD, FACC; Rolf Gunnar, MD, FACC, Loyola University Medical Center, Maywood, 11 hnd VA Hospital, Hines 11
The conduit repair (Rastelli) of lesions requiring reconstitution of right ventricular (RV) to pulmonary artery Serious (PA) continuity has been demonstrated effective. questions have arisen as to the longevity of such conduit replacements with degeneration of the valve components and the development of gradients at both the anastomotic, These are of special imand valvular levels. conduit, During the period June 1, 1975port in the infant group. repairs were performed July 1, 1980, 110 RV to PA conduit at University of California, San Francisco. Ages ranged from 14 days to 35 years, median 15 months. Lesions intransposition of the great arcluded truncus arteriosus, teries with ventricular septal defect, tetralogy of Fallot Conduit size ranged from 12 to 22 and pulmonary atresia. operative survival was 80%. mm, median 14 mm. Overall Special risk factors identified included absence of pulassociated lesions (i.e. interrupted monary arteries, valvular insufficiency requiring replacement) and arch, When such patients were excluded,survival age < 6 weeks. 10 conduit replacements were undertaken at a was 90%. mean of 27 months in follow-up, while 100 patients from 3 months to 68 months postop. remain at risk. Operative survival in repaired patients in whom replacement was Conduit repair of RV to PA disconnecessary was 100%. tinuity results in stimulation of symmetrical anatomic Reoperation is necessary growth and hemodynamic repair. in these patients in response to both this growth and the intrinsic problems of valvular degeneration and pseudointimal proliferation associated with current conduits, but replacement is possible with low risk.
Previously we showed that dogs subjected to daily treadmill exercise (45 min, 4-6 mph, loo slope for 4-6 weeks) increased subendocardial blood flow (SEF) in an area supplied by partial (80-90%) circumflex artery occlusion (P-CFxO) when compared to similar dogs not exercised. All visible epicardial collaterals were ligated. To determine if the increased flow was across the partial constriction pasor from collaterals, 22 dogs were prepared as above. terior SEF was measured after P-CF,O and after total circumflex occlusion (TCF,O) to assess the proportion SEF which was antegrade. Results: In 6 experiments, PSEF measured immediately after PCF,O averaged .74f.20 ml/min/ gm (Mean + SEM) falling to .lOf.03 ml/min/gm upon TCF,O (p<.OOl). In 16 dogs, PSEF measurements were made 4-6 weeks after PCFxO. Eight dogs remained sedentary and 8 underwent daily exercise. In the 8 sedentary dogs, PSEF with PSFxO averaged .94?.12 ml/min/gm falling to .64f.11 ml/min/qm upon TCFxO (NS). In the 8 exercised dogs, PSEF with PCFxO averaged .95?.15 ml/min/qm falling to .38'.1S ml/min/gm after TCFxO (pc.05). Conclusion: Immediately following PCF,O, PSEF depends primarily on antegrade flow. After 4-6 weeks, retrograde collateral flow makes a siqnificant contribution to PSEF in sedentary dogs. Dogs subjected to daily exercise following PCFxO have a very significant increase in the proportion of blood flowing antegrade acioss the PCFXO. Therefore, daily exercise It is proseems to enhance antegrade flow in PCFxO dogs. posed that this enhanced antegrade flow is due to an effect of daily exercise on myocardial vascular resis'tance.
February 1981
The American Journal of CARDIOLOGY
Volume 47
467