Donald J. Mertens

Prediction of Long-Term Prognosis in 12 169 Men Referred for Cardiac Rehabilitation

Background—Predicting the risk of cardiac and all-cause death in patients with established coronary heart disease is important in counseling the individual and designing risk-stratified rehabilitation and secondary prevention programs. Cox proportional hazards and Kaplan-Meier survival curves were thus completed on initial assessment data obtained from patients referred to an outpatient cardiac rehabilitation center. Methods and Results—A single-center prospective observational design took peak cardiorespiratory exercise test data for 12 169 male rehabilitation candidates aged 55.0±9.6 years (7096 myocardial infarctions [MIs], 3077 coronary artery bypass grafts [CABGs], and 1996 documented cases of ischemic heart disease [IHD]). A follow-up of 4 to 29 years (median, 7.9) yielded 107 698 man-years of experience. Entry data were tested for associations with time to cardiac and all-cause death. We recorded 1336 cardiac deaths (953 MI, 225 CABG, and 158 IHD) and 2352 all-cause deaths. A powerful predictor of cardiac and all-cause mortality was measured peak oxygen intake (&OV0312;o2peak). For the overall sample, values of <15, 15 to 22, and >22 mL/kg per minute yielded respective multivariate adjusted hazard ratios of 1.00, 0.62, and 0.39 for cardiac and 1.00, 0.66, and 0.45 for all-cause deaths. For the separate diagnostic categories, apart from &OV0312;o2peak, the only other significant predictors of cardiac death common to all 3 were smoking and digoxin, and for all-cause death, age, smoking, digoxin, and diabetes. Conclusions—Exercise capacity, as determined by direct measurement of &OV0312;o2peak, exerts a major long-term influence on prognosis in men after MI, CABG, or IHD and can play a valuable role in risk stratification and counseling.

Cardiorespiratory responses to exercise training after orthotopic cardiac transplantation.

We have tested the feasibility and effectiveness of a 2 year (average 16 +/- 7 months) walk/jog exercise program on 36 male orthotopic cardiac transplant patients (21 to 57 years old) seen initially 2 to 23 months after surgery. Comparison of initial exercise test results with those in 45 age-matched normal men showed the patients to have a lesser lean body mass (56 +/- 7 vs 63 +/- 8 kg, p less than .001), with a higher resting heart rate (104 +/- 12 vs 77 +/- 14 beats/min, p less than .001) and systolic (138 +/- 16 vs 129 +/- 17 mm Hg, p less than .001) and diastolic (95 +/- 14 vs 84 +/- 10 mm Hg, p less than .001) blood pressures. Peak power output was less than normal (101 +/- 27 vs 219 +/- 41 W, p less than .001), as was peak heart rate (136 +/- 15 vs 176 +/- 13 beats/min, p less than .001), peak oxygen intake (VO2max) (22 +/- 5 vs 34 +/- 6 ml.kg.min-1, p less than .001), and absolute anaerobic threshold (1.18 +/- 0.40 vs 2.04 +/- 0.40 liters.min-1, p less than .001). Peak ventilatory equivalent was h...

Exercise training for patients with chronic atrial fibrillation.

BACKGROUND Patients with atrial fibrillation (AF) referred for exercise rehabilitation exemplify the problem inherent in reliance on pulse rate to prescribe and monitor training intensity. METHODS Exercise training was accomplished by specifying a training walking pace based on 60% to 80% of the peak oxygen intake (VO2max), as determined by the analysis of expired air (Horizon metabolic cart), and/or the ventilatory threshold (VT), together with a perceived exertion of 12 to 14 on the original Borg scale of perceived exertion. RESULTS At the end of 1 year, a significant training effect was demonstrated (VO2max average increase 15%, 14.8 +/- 3.6 mL/kg/min to 17.0 +/- 3.6 mL/kg/min, P < .02; VO2 at VT, average increase 14%, 11.2 +/- 2.2 to 12.8 +/- 2.6 mL/kg/min, P < .01; peak power output increase 21%, 92.5 +/- 29.3 Watts to 112 +/- 3.7 Watts, P < .05) in a group of 20 patients (13 men, 7 women) with chronic atrial fibrillation. CONCLUSIONS Patients with chronic atrial fibrillation can achieve significant functional gains from an exercise rehabilitation program.

Marathon Running After Cardiac Transplantation: A Case History

A 45-year-old male cardiac transplant patient (one of 58 such subjects taking part in an ongoing pilot project involving Harefield Hospital, Middlesex, England, and the Toronto Rehabilitation Centre, Canada) was given a medically prescribed 11-month endurance-type (walking/jogging) rehabilitation ex

Timeline for Peak Improvements During 52 Weeks of Outpatient Cardiac Rehabilitation

PURPOSE Cardiac rehabilitation is an integral component of comprehensive care for patients with coronary heart disease. Although the typical programmatic delivery of outpatient cardiac rehabilitation services often involves 36 sessions over 12 weeks, that format is based more on historical practice than on outcome data. This study aimed to determine the point at which during 52 weeks of outpatient cardiac rehabilitation, patients achieved peak values for selected outcomes, and whether the number of supervised exercise sessions had any effect on these outcomes. METHODS In this study, 623 male patients with coronary heart disease admitted to an outpatient cardiac rehabilitation program were randomized to one of two 52-week program formats. One format (CR1) used one supervised exercise session per week over 52 weeks, and the second format (CR2) used weekly supervised sessions for 26 weeks followed by one supervised session per month for the remaining 26 weeks. Both formats used four unsupervised, documented exercise sessions per week. Selected clinical, physiologic, and psychological variables were measured at baseline, then at 4, 12, 26, 38, and 52 weeks. The program costs for both the CR1 and CR2 formats were calculated from known expenses. RESULTS Because there were no significant intercohort differences between CR1 and CR2 and no significant interaction (time x group), data from the two cohorts were pooled for statistical analysis. Peak oxygen intake (VO(2peak)) significantly increased by 4.4 mL/kg per minute at 38 weeks, and the greatest percentage of patients (30.1%) also achieved their highest VO(2peak) at this time. The largest gain in Medical Outcomes Survey Short Form 36 role physical scores was from baseline to 38 weeks (52.4 versus 85.2), and the highest percentage of patients (72%) with role physical scores in the excellent category occurred at 38 weeks. Clinical depression at baseline (Beck Depression Inventory score > 10) had no significant effect on the dropout rate or the gain in VO(2peak) with exercise training. Program costs for these alternative formats of service were similar to the cost for a standard program format of 36 sessions. CONCLUSIONS Patients achieved their highest functional capacity after 38 weeks of outpatient cardiac rehabilitation using a program format of only 29 to 38 supervised exercise sessions. The results of this study show that an outpatient cardiac rehabilitation program combining supervised with unsupervised exercise sessions and continuing for 38 weeks results in the greatest improvement in these selected outcomes.

Risk profile and health awareness in male offspring of parents with premature coronary heart disease.

BACKGROUND The offspring of parents who suffer from premature coronary heart disease have a significantly higher risk of early cardiac death than controls. A genetic predisposition is compounded by a commonality of environmental risk factors within families. Increasing awareness, early detection and modification of risk factors are essential components of an effective public health strategy to protect this highly vulnerable population. METHODS The sons (n = 571) of parents with premature coronary heart disease attended the Toronto Rehabilitation Centre for a risk factor evaluation that included an interview with questionnaire, measurement of body dimensions and blood lipids, and cardiopulmonary exercise testing. A follow-up questionnaire was sent out 2 years after the evaluation. RESULTS Despite concern about family history, 23% of subjects were smokers and 75% were inactive. Objective data confirmed a substantial prevalence of cardiac risk factors: less than optimal cardiovascular fitness (48%), overweight (34%), total cholesterol > or = 200 mg/dL (46%), high-density lipoprotein cholesterol < or = 35 mg/dL (26%), low-density lipoprotein cholesterol > or = 160 mg/dL (16%), triglycerides > or = 200 mg/dL (27%), and lipoprotein (a) > 30 mg/dL (24%). Although almost all had a family physician whom they had seen an average of 1.8 times in the past year, and 4.7 times in the previous 3 years, screening and risk factor intervention strategies were disappointing. Two-year follow-up data showed a heightened health awareness, with a greater proportion of subjects exercising and attempting to maintain an appropriate body mass. CONCLUSIONS The male offspring of parents who have suffered a premature coronary event exhibit a substantial prevalence of modifiable risk factors. The family physician can play an essential role in promoting a healthy lifestyle through risk reduction counselling and screening.

Cardiorespiratory Responses to Exercise Training After Orthotopic Cardiac Transplantation

We have tested the feasibility and effectiveness of a 2 year (average 16 +/- 7 months) walk/jog exercise program on 36 male orthotopic cardiac transplant patients (21 to 57 years old) seen initially 2 to 23 months after surgery. Comparison of initial exercise test results with those in 45 age-matched normal men showed the patients to have a lesser lean body mass (56 +/- 7 vs 63 +/- 8 kg, p less than .001), with a higher resting heart rate (104 +/- 12 vs 77 +/- 14 beats/min, p less than .001) and systolic (138 +/- 16 vs 129 +/- 17 mm Hg, p less than .001) and diastolic (95 +/- 14 vs 84 +/- 10 mm Hg, p less than .001) blood pressures. Peak power output was less than normal (101 +/- 27 vs 219 +/- 41 W, p less than .001), as was peak heart rate (136 +/- 15 vs 176 +/- 13 beats/min, p less than .001), peak oxygen intake (VO2max) (22 +/- 5 vs 34 +/- 6 ml.kg.min-1, p less than .001), and absolute anaerobic threshold (1.18 +/- 0.40 vs 2.04 +/- 0.40 liters.min-1, p less than .001). Peak ventilatory equivalent was higher (48 +/- 9 vs 37 +/- 61.1-1, p less than .001). Cardiac output (Q), as estimated by the CO2 rebreathing method, was slightly above normal at rest (p less than .01), but below normal at two submaximal work rates. The groups average weekly training distance was 24 km, with eight highly compliant patients progressing to 32 km or more weekly. After training, lean tissue increased (+2.4 +/- 3.1 kg, p less than .001), and resting values were reduced for heart rate (-4 +/- 11 beats/min, p less than .05), systolic (-13 +/- 20 mm Hg, p less than .001), and diastolic (-9 +/- 17 mm Hg, p less than .001) blood pressures. There were significant reductions in submaximal values for minute ventilation (VE), ratings of perceived exertion, and diastolic blood pressure at equivalent workloads. Peak values increased for power output (+49 +/- 34 W, p less than .001), VO2max (+4.0 +/- 6.0 ml.kg.min-1, p less than .001), VE (+20 +/- 20 l.min-1, p less than .001), and heart rate (+13 +/- 17 beats/min, p less than .001), and decreased for diastolic blood pressure (-8 +/- 15 mm Hg, p less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)