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P Dubach

Publications and source records attributed to P Dubach.

At least 19 recordsLinked to original sources

Exercise training and myocardial remodeling in patients with reduced ventricular function: one-year follow-up with magnetic resonance imaging.

BACKGROUND: Exercise training is now an accepted therapeutic intervention in patients with reduced ventricular function after a myocardial infarction. However, there are conflicting reports on the effects of training on the remodeling process of the heart, and previous studies have only assessed short-term effects of training. METHODS AND RESULTS: Twenty-five patients with reduced ventricular function after myocardial infarction were randomly assigned to an intensive 2-month exercise training program or to a control group (control group: n = 13, aged 55 +/- 7 years, ejection fraction 33.3% +/- 6%; exercise group: n = 12, aged 56 +/- 5 years, ejection fraction 31.5% +/- 7%) and followed up for 1 year. Measures of left ventricular size, function, and wall thickness in the infarct and noninfarct areas were made by magnetic resonance imaging at baseline, after the 2-month training period, and 1 year later. Maximal oxygen uptake increased in the trained group, from 19.7 +/- 3 mL/kg per minute at baseline to 25.1 +/- 5 and 24.2 +/- 5 mL/kg per minute after 2 months and 1 year, respectively (P <.05 vs baseline for both), whereas the control group did not change significantly. Ejection fraction, end-diastolic volumes, and end-systolic volumes did not change at any measurement point throughout the study period in either the trained or control groups. Myocardial wall thickness measurements at end-diastole and end-systole and their differences determined by magnetic resonance imaging yielded no significant interactions between groups. When myocardial wall thickness measurements were classified by infarct or noninfarct areas, no differences were observed between groups over the study period. CONCLUSIONS: Intensive exercise training in patients with reduced ventricular function resulted in a significant improvement in exercise capacity after 2 months, and this improvement was sustained over 1 year. In contrast to some recent reports, training had no deleterious effects on left ventricular volume, function, or wall thickness regardless of infarct area.

Exercise Test↗

[Cardiovascular diseases and sports].

Regular physical activity has been found helpful--contrary to previous belief--in heart disease and has a positive effect on the wellbeing of the patient. A positive effect on the mortality rate from coronary heart disease with normal left ventricular function has been found. The physical performance of the patient with impaired left ventricular function increases via reduction of peripheral vascular resistance, increased blood flow and more efficient muscle metabolism. Patients with arterial hypertension profit equally from a regular workout. But in the presence of end organ damage high intensity sports should be avoided. In cases of congenital valvular disease with heart failure and right and left ventricular congestion the activity level should be adapted to the symptoms. Hypertrophic cardiomyopathy is the most common reason for sudden death in young athletes. If diagnosed, all high intensity sports are strictly forbidden. Threatening ventricular arrhythmias are seldom found in young adults. Symptomatic arrhythmias should be investigated for organic causes.

Adult↗

Influence of high-intensity exercise training on the ventilatory response to exercise in patients with reduced ventricular function.

BACKGROUND: Exercise training increases exercise capacity in patients with reduced ventricular function in part through improved skeletal muscle metabolism, but the effect training might have on abnormal ventilatory and gas exchange responses to exercise has not been clearly defined. METHODS: Twenty-five male patients with reduced ventricular function after a myocardial infarction were randomized to either a 2-month high-intensity residential exercise training program or to a control group. Before and after the study period, upright exercise testing was performed with measurements of ventilatory gas exchange, lactate, arterial blood gases, cardiac output, and pulmonary artery and wedge pressures. RESULTS: In the exercise group, peak VO2 and VO2 at the lactate threshold increased 29 and 39%, respectively, whereas no increases were observed among controls. Maximal cardiac output increased only in the exercise group (1.7 L x min(-1), P < 0.05), and no changes in rest or peak exercise pulmonary pressures were observed in either group. At baseline, modest inverse relationships were observed between pulmonary wedge pressure and peak VO2 both at rest (r = -0.56, P < 0.05) and peak exercise (r = -0.43, P < 0.05). Maximal VE/VCO2 was inversely related to maximal cardiac output (r = -0.72, P < 0.001). Training did not have a significant effect on these relationships. Training lowered VE/VO2, heart rate, and blood lactate levels at matched work rates throughout exercise and tended to lower maximal Vd/Vt. The slope of the relationship between VE and VCO2 was reduced after training in the exercise group (0.33 pre vs 0.27 post, P < 0.01), whereas control patients did not differ. CONCLUSIONS: Exercise training among patients with reduced left ventricular function results in a systematic improvement in the ventilatory response to exercise. Training increased maximal cardiac output, tended to lower Vd/Vt, and markedly improved the efficiency of ventilation. Peak VO2 and ventilatory responses to exercise were only modestly related to pulmonary vascular pressures, and training had no effect on the relationships between exercise capacity, ventilatory responses, and pulmonary pressures.

Anaerobic Threshold↗

Effects of exercise training on limb blood flow in patients with reduced ventricular function.

BACKGROUND: Among the factors that contribute to limiting exercise tolerance in chronic heart failure are reduced peripheral blood flow and impaired vasodilatory capacity. Exercise training improves vasodilatory capacity in normal subjects, but controlled studies of exercise training evaluating upper and lower limb blood flow rates have not been performed in patients with reduced ventricular function. Improved vasodilatory capacity could help explain how training increases exercise capacity in these patients. METHODS: Twenty patients (mean age 55 +/- 6 years) with reduced left ventricular function (mean ejection fraction 32% +/- 6%) after a myocardial infarction were randomized to a 2-month high-intensity residential rehabilitation program or to a control group and were monitored over the subsequent year. Both groups were treated according to current practice with angiotensin-converting enzyme inhibition therapy. Training began 1 month after myocardial infarction. Baseline and postischemic flow rates were measured by plethysmography in both the upper and lower limbs 1 month, 3 months, and 1 year after the infarction. Peak oxygen uptake (VO2) and cardiac output were measured before and after training, and peak VO2 was determined again after 1 year. RESULTS: After 2 months of training peak VO2 increased 25%, VO2 at the lactate threshold increased 40%, and maximal cardiac output increased from 12.1 +/- 1.6 L/min to 13.9 +/- 2.4 L/min in the exercise group (all p < 0.05), whereas no differences were observed in the control group. At the 1-year follow-up no further increases in peak VO2 were noted in either group, but the higher value persisted in the trained group. However, changes in limb flow rates were poorly related to changes in both peak VO2 and maximal cardiac output. Improvements in baseline and postischemic flow rates occurred mainly in the lower limbs and were observed in the two groups to a similar degree. CONCLUSION: Exercise training is highly effective in improving exercise capacity in patients with reduced ventricular function after myocardial infarction. These improvements parallel an increase in maximal cardiac output, but they are unrelated to vasodilatory capacity. In patients with reduced ventricular function after myocardial infarction, lower limb vasodilatory capacity improves gradually over the subsequent year, and these improvements occur irrespective of exercise training.

Adult↗

Influence of exercise training on blood viscosity in patients with coronary artery disease and impaired left ventricular function.

Exercise training has recently become an accepted therapeutic modality in chronic heart failure after myocardial infarction. Because the therapeutic mechanism behind it is controversial and not well understood, we analyzed the influence of exercise training on blood viscosity. Twenty-five patients with chronic heart failure (ejection fraction < 40%) after myocardial infarction were randomly assigned to either an 8-week intensive exercise program at a residential rehabilitation center or 8 weeks of sedentary life at home. Exercise consisted of two 1-hour walking sessions per day and four intensive bicycle ergometer training sessions of 40 minutes at 70% to 80% peak exercise capacity per week. Whole blood viscosity, viscosity at standardized hematocrit of 45% (P45) at high and low shear rates, and plasma viscosity were measured in a Couette-type viscometer before, during, and at the end of the study period. Exercise training, which significantly increased maximal cardiac output and oxygen uptake, did not change plasma viscosity, whole blood viscosity, and P45 significantly. Sedentary controls, however, had a higher whole blood viscosity and P45 after 8 weeks. No statistical difference was found, however, between the two groups. We conclude that blood rheology remains unaffected by exercise training in patients with chronic heart failure. The improvement of blood viscosity remains an interesting therapeutic option for the symptoms of these patients, which must be achieved by methods other than exercise training.

Blood Viscosity↗

A randomized comparison of exercise training in patients with normal vs reduced ventricular function.

BACKGROUND: Exercise training is recommended after myocardial infarction (MI) or bypass surgery in order to improve exercise tolerance. In some patients, the decrement in exercise capacity secondary to deconditioning and the left ventricular stunning associated with MI or coronary artery bypass graft (CABG) spontaneously improves after the event. However, the impact of the status of the left ventricle on these improvements is unknown. METHODS: Sixty-seven patients 1 month after MI or CABG were randomized to a training (n=34; age, 59+/-7 years) or a control group (n=33; age, 55+/-6 years). Forty-two patients had an ejection fraction >50% (22 in the training group and 20 in the control group), and 25 patients had an ejection fraction <40% (12 in the exercise group and 13 in the control group). After stabilization for approximately 1 month after the event, patients in the exercise group underwent 8 weeks of twice daily exercise at a residential rehabilitation center, while control patients received usual care. Initially and after 8 weeks, patients in both groups underwent maximal exercise testing with gas exchange and lactate analysis. RESULTS: Exercise training increased peak oxygen consumption (VO2) only in the reduced ejection fraction group (19.4+/-3.0 to 23.9+/-4.8 mL/kg/min; p<0.05); the exercise group with normal ventricular function did not change significantly. Changes in VO2 at the lactate threshold paralleled those of peak VO2 for both groups. Conversely, control patients with normal ventricular function increased peak VO2 spontaneously (20.8+/-3.9 to 24.8+/-3.5 mL/kg/min; p<0.01), whereas control patients with reduced ventricular function did not improve peak VO2. CONCLUSION: These data suggest that patients with depressed left ventricular function strongly benefit from rehabilitation, whereas most patients with preserved left ventricular function following MI or CABG tend to improve spontaneously 1 to 3 months after the event.

Coronary Artery Bypass↗

Optimal timing of phase II rehabilitation after cardiac surgery. The cardiologist's view.

Structured programmes of rehabilitation have been shown to be effective in restoring functional capacity, increasing return to work and improving the psychosocial status of patients following open heart surgery. However, uncertainty still exists about the optimal timing of rehabilitation after cardiac surgery. Data in the literature suggest that phase II rehabilitation can begin as early as one week after open heart surgery without having a negative influence on infections, mortality or readmissions. Early rehabilitation can even improve graft patency after CABG. However, age, operative complications and co-morbidities must be considered individually for each patient when determining the beginning of phase II rehabilitation.

Cardiology↗

Effect of exercise training on myocardial remodeling in patients with reduced left ventricular function after myocardial infarction: application of magnetic resonance imaging.

BACKGROUND: There are conflicting reports on the effects of training on the remodeling process in post-myocardial infarction patients with ventricular damage. METHODS AND RESULTS: Twenty-five patients with reduced ventricular function (mean ejection fraction, 32.3+/-6%) after an anteroseptal or inferolateral myocardial infarction were randomized to an exercise group (n=12) or a control group (n=13). Patients in the exercise group resided in a rehabilitation center for 2 months and underwent a training program consisting of two 1-hour sessions of walking daily, along with four monitored 45-minute sessions of stationary cycling weekly. Before and after the study period, maximal exercise testing and cardiac MRI were performed. Oxygen uptake increased 26% at maximal exercise (19.7+/-3 to 23.9+/-5, P<.05) and 39% at the lactate threshold (P<.01) in the exercise group, whereas control values did not change. No differences were observed within or between groups in MRI measures of end-diastolic (187+/-47 pre versus 196+/-35 mL post in the exercise group and 179+/-52 pre versus 180+/-51 mL post in the control group), end-systolic volume (118+/-41 pre versus 121+/-33 mL post in the exercise group and 119+/-54 pre versus 116+/-56 mL post in the control group), or ejection fraction (38.0+/-9 pre versus 38.2+/-10% post in the exercise group and 37.0+/-10 pre versus 38.3+/-13% post in the control group). Myocardial wall thickness measurements at end diastole and end systole and their difference in 80 myocardial segments determined by MRI yielded no significant interactions between groups. When myocardial wall thickness measurements were classified by infarct or noninfarct areas, no differences were observed between groups over the study period. CONCLUSIONS: A high-intensity, 2-month residential cardiac rehabilitation program resulted in substantial increases in exercise capacity among patients with reduced left ventricular function. In contrast to some recent reports, the training program had no deleterious effects on left ventricular volume, function, or wall thickness regardless of infarct area.

Exercise Test↗

Effect of high intensity exercise training on central hemodynamic responses to exercise in men with reduced left ventricular function.

OBJECTIVES: The aim of this study was to evaluate the effects of high intensity exercise training on left ventricular function and hemodynamic responses to exercise in patients with reduced ventricular function. BACKGROUND: Results of studies on central hemodynamic adaptations to exercise training in patients with chronic heart failure have been contradictory, and some research has suggested that training causes further myocardial damage in these patients after a myocardial infarction. METHODS: Twenty-five men with left ventricular dysfunction after a myocardial infarction or coronary artery bypass graft surgery were randomized to an exercise training group (mean age +/- SD 56 +/- 5 years, mean ejection fraction [EF] 32 +/- 7%, n = 12) or a control group (mean age 55 +/- 7 years, mean EF 33 +/- 6%, n = 13). Patients in the exercise group performed 2 h of walking daily and four weekly sessions of high intensity monitored stationary cycling (40 min at 70% to 80% peak capacity) at a residential rehabilitation center for a period of 2 months. Ventilatory gas exchange and upright hemodynamic measurements (rest and peak exercise cardiac output; pulmonary artery, wedge and mean arterial pressures; and systemic vascular resistance) were performed before and after the study period. RESULTS: Maximal oxygen uptake (VO2max) increased by 23% after 1 month of training, and by an additional 6% after month 2. The increase in VO2max in the trained group paralleled an increase in maximal cardiac output (12.0 +/- 1.8 liters/min before training vs. 13.7 +/- 2.5 liters/min after training, p < 0.05), but maximal cardiac output did not change in the control group. Neither stroke volume nor hemodynamic pressures at rest or during exercise differed within or between groups. Rest left ventricular mass, volumes and EF determined by magnetic resonance imaging were unchanged in both groups. CONCLUSIONS: High intensity exercise training in patients with reduced left ventricular function results in substantial increases in VO2max by way of an increase in maximal cardiac output combined with a widening of maximal arteriovenous oxygen difference, but not changes in contractility. Training did not worsen hemodynamic status or cause further myocardial damage.

Cardiac Output↗

Creatine kinase MB during myocardial infarction: relationship to preexisting coronary heart disease and medication.

Creatine kinase (CK) and its isoenzyme CK-MB are important tools for the diagnosis of acute myocardial infarction. The content of CK-MB relative to total CK in myocardial cells is variable; it is low in normal myocardium and increased several-fold in hypoxic myocardium. We tested the hypothesis that CK-MB mass (CK-MBm) could be related to cardiovascular history, preinfarctional medication and clinical course during myocardial infarction. In a prospective study CK and CK-MBm were measured 0, 6, 12, 18, 24, 36, 48 and 72 h after the admission to the coronary care unit. Peak values and areas under the curve (AUC) were determined and normalized for total CK activity (CK-MBm/CK). Of 185 patients with acute chest pain, 70 patients had 71 acute myocardial infarctions and were enrolled in the study. A history of chronic angina pectoris or hypertension had no influence on CK-MBm/CK levels. In contrast, treatment with beta-blockers before infarction resulted in a lower relative CK-MBm peak value (CK-MBm/CK 6.0 (median value), range 3.1-15.3, versus 7.0, range 0.5-17.3: p < 0.05). Other drugs had no influence. Patients with persistent pain on admission tended to have higher relative CK-MBm values (peak CK-MBm/CK: 6.8, range 0.5-17.3, versus 5.3, range 1.4-7.9, p = 0.08; AUC CK-MBm/CK: 0.05, range 0.01-0.10, versus 0.03, range 0.01-0.06, p < 0.05). Three vessel disease on coronary angiography was associated with higher peak CK-MBm/CK values during the acute phase of myocardial infarction than those with 1-2 vessel disease (Peak CK-MBm/CK: 7.9, range 5.5-17.3, versus 6.4, range 3.1-10.2, p < 0.05; AUC CK-MBm/CK: 0.06, range 0.02-0.11, versus 0.04, range 0.02-0.07, p < 0.05). We conclude that relative CK-MBm/CK levels reflect to a certain degree the extent of the coronary disease and that preinfarctional beta-blockade may result in lower CK-MBm levels.

Adrenergic beta-Antagonists↗

[Blood pressure reaction during exertion].

There are three types of abnormal blood pressure responses during exercise: hypotensive reaction, inadequate rise in blood pressure, and hypertensive reaction. At rest, an abnormal high blood pressure has an adverse prognostic implication. This is not true for a low blood pressure at rest. During exercise, however, the contrary is observed: an inadequate rise or even a fall in blood pressure below resting values indicates a significantly increased risk for cardiac events, whereas a hypertensive reaction in patients with a normal resting blood pressure has no adverse prognostic implications.

Blood Pressure↗

[Interrupted aortic arch: fortuitous diagnosis in a 72-year-old female patient with severe aortic insufficiency].

Interrupted aortic arch, defined as complete luminal and anatomic discontinuity between ascending and descending aorta, is an uncommon and highly lethal anomaly. We report the case of a 72-year-old woman scheduled for aortic valve replacement because of severe regurgitation. During preoperative catheterization, it was not possible to reach the ascending aorta from a femoral puncture. Further radiological investigation demonstrated interrupted aortic arch of type A without other cardiac or vascular anomalies. Postoperative course after aortic valve replacement and ascending-to-supraceliac aortic bypass was initially uneventful. Unfortunately, pericardial tamponade developed 10 days after the operation and required re-exploration, during which no active bleeding could be found. Recurrent effusion occurred and the patient finally died from severe shock and multiorgan failure. This exceptional case prompted a review of the literature which confirmed the rarity of this presentation in adult patients. It seems interesting that only mild arterial hypertension of the upper extremities was retrospectively found in this patient.

Aged↗

Effect of residential cardiac rehabilitation following bypass surgery. Observations in Switzerland.

BACKGROUND: Cardiac rehabilitation in central Europe traditionally involves isolating patients in a residential idyllic setting where exercise is performed frequently but in a relatively unstructured fashion. Few studies have been performed on the effects of these programs among patients who have undergone bypass surgery. Recent data suggest that postbypass patients may enter these programs too soon after surgery or that exercise is not structured enough to distinguish the benefits of rehabilitation from those experienced by a control group. METHODS: Forty-two male patients (mean age, 58 +/- 7 years) were divided into exercise and control groups approximately 1 month after undergoing bypass surgery. Exercise training consisted of 1 h of group walking twice daily, with the intensity stratified into four levels based on initial exercise capacity. Using a crossover design, patients in the exercise group participated in rehabilitation for 1 month, followed by 1 month of usual care, while control patients underwent the opposite sequence. At 1, 2, and 3 months, patients in both groups underwent pulmonary function testing and maximal ramp exercise testing using lactate and gas exchange analysis. RESULTS: A main effect for maximal oxygen uptake was observed; significant improvements within each group occurred across each testing period (range, 5 to 13%; p < 0.05). However, there was no significant interaction between groups. Mean lactate levels throughout exercise were reduced within both groups (p < 0.01). A reduction in oxygen uptake for test 2 at the lactate threshold in the exercise group resulted in differences between groups in lactate, heart rate, and other gas exchange variables at this point. CONCLUSION: Similar changes occur in the functional status of postbypass surgery patients regardless of their participation in the short but concentrated programs common in central Europe. This suggests that a significant spontaneous effect of healing occurs in the recovery phase after surgery. These programs may have greater efficacy if they began later after surgery, lasted longer, or were more structured, and studies are needed to determine their effect on psychosocial factors and return to work.

Aged↗

[Localized pulmonary edema in the right upper lobe--an important differential diagnostic hint for acute mitral insufficiency].

Differential diagnosis of unilateral alveolar pulmonary infiltration includes various possibilities. Acutely developing mitral insufficiency, often without any prior cardiac symptoms, may be the cause of pulmonary edema localized exclusively in the right upper lobe. This unusual and often misinterpreted radiologic presentation is brought to attention by two case reports.

Acute Disease↗

[Current aspects in ergometry].

Exercise testing remains an important non-invasive diagnostic test modality in patients with coronary artery disease. In recent years considerable advances have been achieved in the test methodology and in interpretation. The following points are important for the test methodology: (1.) The optimal exercise time is 8-12 minutes. (2.) The stepwise increases in work load should be as small as possible (ideally, according to the ramp protocol). (3.) Whenever possible patients should be tested on a symptom-limited basis. Submaximal ergometry is only indicated in the 2-3 weeks after acute myocardial infarction. (4.) The value of the exercise test depends mainly on the double product achieved (maximal systolic blood pressure x maximal heart rate). The interpretation of the exercise test should consider the clinical and hemodynamic responses and ST-segment changes. ST-segment depressions are the most important diagnostic parameter. The ECG localization (most frequently lateral wall) does not necessarily correspond to the anatomic localization. Exercise capacity and blood pressure response are important prognostic variables.

Cardiovascular Agents↗

Cardiac rehabilitation in Switzerland. Efficacy of the residential approach following bypass surgery.

BACKGROUND: The traditional central European approach to cardiac rehabilitation involves sending patients to an idyllic setting, where they reside for a specified period following a cardiac event. Favorable results have been demonstrated using this approach in Germany, but to our knowledge no data have been reported from Switzerland, where these programs tend to be short (4 weeks) and exercise training is concentrated (2 h daily, 6 days per week). METHODS AND RESULTS: Seventeen patients (aged 58 +/- 6 years) who resided in a rehabilitation center for 4 weeks were compared with 11 patients (aged 54 +/- 7 years) given usual community care beginning approximately 6 weeks after coronary artery bypass surgery (CABS). Exercise training consisted of 1 h of group walking twice daily, with the intensity stratified into 4 levels based on clinical status and initial exercise capacity. All patients underwent pulmonary function testing and maximal ramp exercise testing on a cycle ergometer with continuous ventilatory gas exchange and lactate analysis before and after the study period. Patients receiving beta-blockers and those with cardiomyopathy or valvular heart disease were excluded. Medication status was not changed during the study period. Although maximal oxygen uptake increased by approximately 12 percent within both groups, the change was not significant between groups. Analysis of variance demonstrated that mean lactate levels were reduced throughout exercise within both groups (p < 0.001); however, there were no differences between groups. Oxygen uptake at the lactate threshold was not different in either group after the study period. CONCLUSIONS: Similar changes occur in the functional status of post-CABS patients regardless of their participation in the short but concentrated rehabilitation programs common in Switzerland, suggesting that these programs either begin too soon after CABS or are too short to achieve training benefits.

Coronary Artery Bypass↗

The Omnicarbon tilting-disc heart valve prosthesis. A clinical and Doppler echocardiographic follow-up.

From 1986 to 1990, 172 patients with a median age of 60.5 years (range 20 to 79 years) received 187 Omnicarbon valves (109 aortic valve replacements, 48 mitral valve replacements, and 15 double valve replacements). Patients were followed-up for a median observation period of 2.5 years (range 4 months to 5.2 years) by clinical and Doppler echocardiographic examination. Follow-up was complete in 98%. Operative mortality (death within 30 days) was 1.7%, and linearized late mortality was 2.6% per patient-year, corresponding to an actuarial survival rate for operative survivors of 89% after 4 years. The overall 4-year postoperative survival was 87% (93% for aortic valve replacement, 77% for mitral valve replacement). Compared with age- and sex-adjusted Swiss death rates, there was an excess mortality of 5% after 4 years. Percentages for freedom from valve-related complications at 4 years are as follows: thromboembolism, 98% (aortic valve replacement, 98%, and mitral valve replacement, 96%); anticoagulant-related hemorrhage, 95%; valve endocarditis, 96%; reoperation, 96%; and permanent valve-related impairment, 99%. The overall 4-year event-free survival was 76% (80% for aortic valve replacement and 69% for mitral valve replacement). New York Heart Association class improved in 88% of the patients by 1 to 3 grades, and only 3% remained in class III after operation. For the most commonly used aortic valve (23 mm), Doppler echocardiography revealed a peak pressure gradient of 29 +/- 10 mm Hg, a fractional shortening/peak pressure gradient ratio of 1.34 +/- 0.61, and a performance index of 0.35 +/- 0.08. In the most commonly used mitral valve (27 mm), the mean pressure gradient was 4.0 +/- 2.1 mm Hg. We conclude that excellent clinical and hemodynamic results can be obtained with the Omnicarbon prosthesis, in both the aortic and mitral positions.

Adult↗