Leonida Compostella

Cardiac rehabilitation after transcatheter versus surgical prosthetic valve implantation for aortic stenosis in the elderly.

Background Transcatheter aortic valve implantation plays a leading role in the management of aortic stenosis in patients with comorbidities but no data are available about cardiac rehabilitation in these subjects. This study aimed to compare safety and efficacy of an early, exercise-based, cardiac rehabilitation programme in octogenarians after a traditional surgical aortic valve replacement versus transcatheter aortic valve implantation. Methods Seventy-eight consecutive transcatheter aortic valve implantation patients were studied in order to evaluate the effect of an exercise-based cardiac rehabilitation programme in comparison to 80 of a similar age having surgical aortic valve replacement. Functional capacity was assessed by a 6 min walking test on admission and at the end of the programme. When possible, a cardiopulmonary exercise test was also performed before discharge. Results The two groups were similar in terms of gender and length of stay in cardiac rehabilitation; as expected, the transcatheter aortic valve implantation group had more comorbidities but no major complications occurred in either group during rehabilitation. All patients enhanced autonomy and mobility and were able to walk at least with the assistance of a stick. In those patients who were able to perform the 6 min walking test, the distance walked at discharge did not significantly differ between the groups (272.7 ± 108 vs. 294.2 ± 101 m, p = 0.42), neither did the exercise capacity assessed by cardiopulmonary exercise test (peak-VO2 12.5 ± 3.6 vs. 13.9 ± 2.7 ml/kg/min, p = 0.16). Conclusions Cardiac rehabilitation is feasible, safe and effective in octogenarian patients after transcatheter aortic valve implantation as well as after traditional surgery. An early cardiac rehabilitation programme enhances independence, mobility and functional capacity and should be highly encouraged.

Exercise performance of chronic heart failure patients in the early period of support by an axial-flow left ventricular assist device as destination therapy.

Axial-flow left ventricular assist devices (LVADs) are increasingly used as destination therapy in end-stage chronic heart failure (CHF), as they improve survival and quality of life. Their effect on exercise tolerance in the early phase after implantation is still unclear. The aim of this study was to evaluate the effect of LVADs on the exercise capacity of a group of CHF patients within 2 months after initiation of circulatory support. Cardiopulmonary exercise test data were collected for 26 consecutive LVAD-implanted CHF patients within 2 months of initiation of assistance; the reference group consisted of 30 CHF patients not supported by LVAD who were evaluated after an episode of acute heart failure. Both LVAD and reference groups showed poor physical performance; LVAD patients achieved lower workload (LVAD: 36.3 ± 9.0 W, reference: 56.6 ± 18.2 W, P < 0.001) but reached a similar peak oxygen uptake (peak VO2 ; LVAD: 12.5 ± 3.0 mL/kg/min, reference: 13.6 ± 2.9 mL/kg/min, P = ns) and similar percentages of predicted peak VO2 (LVAD: 48.8 ± 13.9%, reference: 54.2 ± 15.3%, P = ns). While the values of the O2 uptake efficiency slope were 12% poorer in LVAD patients than in reference patients (1124.2 ± 226.3 vs. 1280.2 ± 391.1; P = ns), the kinetics of VO2 recovery after exercise were slightly better in LVAD patients (LVAD: 212.5 ± 62.5, reference: 261.1 ± 80.2 sec, P < 0.05). In the first 2 months after initiation of circulatory support, axial-flow LVAD patients are able to sustain a low-intensity workload; though some cardiopulmonary exercise test parameters suggest persistence of a marked physical deconditioning, their cardiorespiratory performance is similar to that of less compromised CHF patients, possibly due to positive hemodynamic effects beginning to be produced by the assist device.

Peripheral Adaptation Mechanisms in Physical Training and Cardiac Rehabilitation: The Case of a Patient Supported by a Cardiowest Total Artificial Heart

BACKGROUND The benefits of exercise training in patients with chronic heart failure (CHF) are due to a combination of cardiac and peripheral adaptations. Separating these 2 components is normally impossible, except for patients implanted with total artificial heart (TAH), where cardiac adaptation cannot occur. METHODS AND RESULTS We report the case of a patient implanted with a CardioWest-TAH who underwent a comprehensive strength and endurance training program and was evaluated by repeated peak cardiopulmonary exercise tests. The patient experienced a 24% increase of peak oxygen consumption and an improvement in recovery kinetics during the training period of 29 months. CONCLUSION This unique situation of a patient with a TAH, and therefore a fixed peak cardiac output, allows us to isolate training-induced changes in the periphery, that suggest greater oxygen extraction and more efficient metabolic gas kinetics during the exercise and recovery phases.

Anemia does not preclude increments in cardiac performance during a short period of intensive, exercise-based cardiac rehabilitation

Background and aims: Anemia seems to be rather common in cardiac rehabilitation patients but it is not known whether it could influence cardiovascular performance indexes and prognosis immediately after an acute cardiac event. The purposes of this study were to define its prevalence and to investigate the safety and efficacy of an intensive exercise-based cardiac rehabilitation in patients with and without anemia. Methods: 436 participants (77% males; mean age 64 ± 13 years) were submitted to a two-week cardiac rehabilitation program consisting of low to medium intensity, individualized training with respiratory, aerobic and callisthenic exercises (three sessions daily, six times per week). A six-minute walking test was performed at enrolment and repeated at discharge together with a cardiopulmonary test. Results: Anemia, as defined according to World Health Organization criteria, was detected in 328 patients (75.2% of the entire population). The distance walked increased from 381 ± 117 m at baseline to 457 ± 110 m (p < 0.001) after a mean period of 12.4 ± 4 days. A direct correlation was found between hemoglobin concentrations and both the absolute distance walked (r = 0.48; p < 0.001) and peak VO2 (r = 0.39; p < 0.001). Anemic patients walked a significantly shorter distance at baseline and at discharge (p < 0.001); however, both groups showed the same increment in the distance walked: 76.0 ± 61 m vs 76.0 ± 60 m (p = 0.99). Conclusions: Our data indicate: 1) a high prevalence of anemia in the study population and 2) that, in spite of a clear reduction in exercise capacity, a moderate anemia does not preclude increments in cardiac performance during a short period of intensive, exercise-based cardiac rehabilitation.

A practical review for cardiac rehabilitation professionals of continuous-flow left ventricular assist devices: historical and current perspectives.

An increasing number of patients with end-stage heart failure are being treated with continuous-flow left ventricular assist devices (cf-LVADs). These patients provide new challenges to the staff in exercise-based cardiac rehabilitation (CR) programs. Even though experience remains limited, it seems that patients supported by cf-LVADs may safely engage in typical rehabilitative activities, provided that some attention is paid to specific aspects, such as the presence of a short external drive line. In spite of initial physical deconditioning, CR allows progressive improvement of symptoms such as fatigue and dyspnea. Intensity of rehabilitative activities should ideally be based on measured aerobic capacity and increased appropriately over time. Regular, long-term exercise training results in improved physical fitness and survival rates. Appropriate adjustment of cf-LVAD settings, together with maintenance of adequate blood volume, provides maximal output, while avoiding suction effects. Ventricular arrhythmias, although not necessarily constituting an immediate life-threatening situation, deserve treatment as they could lead to an increased rate of hospitalization and poorer quality of life. Atrial fibrillation may worsen symptoms of right ventricular failure and reduce exercise tolerance. Blood pressure measurements are possible in cf-LVAD patients only using a Doppler technique, and a mean blood pressure ⩽80 mmHg is considered “ideal.” Some patients may present with orthostatic intolerance, related to autonomic dysfunction. While exercise training constitutes the basic rehabilitative tool, a comprehensive intervention that includes psychological and social support could better meet the complex needs of patients in which cf-LVAD may offer prolonged survival.

Prediabetes influences cardiac rehabilitation in coronary artery disease patients

Background: An abnormal glucose tolerance (AGT) in coronary artery disease (CAD) patients could negatively influence recovery after an acute event but the question, relevant in the field of cardiac rehabilitation (CR), is still controversial. Design: Prospective study, aiming to establish the prevalence of AGT and its possible influence on functional recovery in CAD patients without a previous diagnosis of diabetes mellitus (DM). Methods: An oral glucose tolerance test was performed on 230 CAD patients without known DM, submitted to a 2-week period of intensive exercise-based CR after a recent acute myocardial infarction or coronary artery bypass graft. Functional capacity was assessed by a cardiopulmonary exercise test (CPET) and by 6-minute walking tests (6MWT) performed both on admission and at discharge. Results: The prevalence of AGT in our population was 53%. Exercise capacity was lower in AGT patients (maximum workload achieved at CPET 79.3 ± 29.9 vs. 91.8 ± 36.9 W, p = 0.01; peak-VO2 17.8 ± 4.7 vs. 19.8 ± 5.6 ml/kg/min, p = 0.01). In the subgroup of AGT patients characterized by an inferior walking capacity at baseline, the increment in the distance walked was less than in the controls (Δ6MWT: 81.9 ± 60.1 vs. 109.1 ± 72.1, p = 0.04). An independent, negative, association was observed between AGT and Δ6MWT in patients with lower baseline test, and between maximum workload and peak-VO2 in the whole population. Conclusions: A high prevalence of AGT was observed in a population of CAD patients without known DM after an acute coronary event. AGT is associated to a lower functional recovery, and to a reduced exercise capacity at the end of CR.

History of erectile dysfunction as a predictor of poor physical performance after an acute myocardial infarction.

Background Erectile dysfunction may predict future cardiovascular events and indicate the severity of coronary artery disease in middle-aged men. The aim of this study was to evaluate whether erectile dysfunction (expression of generalized macro- and micro-vascular pathology) could predict reduced effort tolerance in patients after an acute myocardial infarction. Patients and methods One hundred and thirty-nine male patients (60 ± 12 years old), admitted to intensive cardiac rehabilitation 13 days after a complicated acute myocardial infarction, were evaluated for history of erectile dysfunction using the International Index of Erectile Function questionnaire. Their physical performance was assessed by means of two six-minute walk tests (performed two weeks apart) and by a symptom limited cardiopulmonary exercise test (CPET). Results Patients with erectile dysfunction (57% of cases) demonstrated poorer physical performance, significantly correlated to the degree of erectile dysfunction. After cardiac rehabilitation, they walked shorter distances at the final six-minute walk test (490 ± 119 vs. 564 ± 94 m; p < 0.001); at CPET they sustained lower workload (79 ± 28 vs. 109 ± 34 W; p < 0.001) and reached lower oxygen uptake at peak effort (18 ± 5 vs. 21 ± 5 ml/kg per min; p = 0.003) and at anaerobic threshold (13 ± 3 vs.16 ± 4 ml/kg per min; p = 0.001). The positive predictive value of presence of erectile dysfunction was 0.71 for low peak oxygen uptake (<20 ml/kg per min) and 0.69 for reduced effort capacity (W-max <100 W). Conclusions As indicators of generalized underlying vascular pathology, presence and degree of erectile dysfunction may predict the severity of deterioration of effort tolerance in post-acute myocardial infarction patients. In the attempt to reduce the possibly associated long-term risk, an optimization of type, intensity and duration of cardiac rehabilitation should be considered.

AJMALINE TEST IN A PATIENT WITH CHRONIC-RENAL-FAILURE - A PHARMACOKINETIC AND PHARMACODYNAMIC STUDY

SummaryPharmacokinetic and pharmacodynamic properties were studied after intravenous administration of ajmaline 1 mg/kg in an anuric patient, who underwent the electrophysiological ajmaline test. The magnitude and rate of onset of the typical electrophysiological effects of ajmaline (prolongation in atrio-Hisian and His-ventriculum conduction times) were within the range of normal values. The plasma concentration curve showed a triexponential decay with half-lives as follows: initial phase (t½α) 1.34 min, fast elimination phase (t½β) 10.13 min and terminal (slow) phase (t½γ) 258.6 min. Other relevant pharmacokinetic parameters calculated were: total plasma clearance 45.91 L/h; volume of distribution 285.6L; protein binding 47%. Five hours after administration the patient underwent a 3.5h haemodialysis without any substantial increase in the slope of the final elimination phase of the curve. A major problem in interpreting the pharmacokinetic results is the lack of reliable reference data in healthy subjects. It is likely that the ajmaline t½ reported in the literature (13.4 min) does not reflect the true terminal t½ of the drug, because it was determined during an unduly short sampling period (30 min). Nevertheless, if we compare just the first 30 min of the concentration-time curves, our results are nearly superimposable on those found in healthy subjects.

Cardiac autonomic dysfunction in the early phase after left ventricular assist device implant: Implications for surgery and follow-up

Purpose In congestive heart failure (CHF) patients, a profound cardiac autonomic derangement, clinically expressed by reduced heart rate variability (HRV), is present and is related to the degree of ventricular dysfunction. Implantation of a left ventricular assist device (LVAD) can progressively improve HRV, associated with an increased circulatory output. Data from patients studied at different times after LVAD implantation are controversial. The aims of this study were to assess cardiac autonomic function in the early phases after axial-flow LVAD implantation, and to estimate the potential relevance of recent major surgical stress on the autonomic balance. Methods HRV (time-domain; 24-h Holter) was evaluated in 14 patients, 44.8 ± 25.8 days after beginning of Jarvik-2000 LVAD support; 47 advanced stage CHF, 24 cardiac surgery (CS) patients and 30 healthy subjects served as control groups. Inclusion criteria: sinus rhythm, stable clinical conditions, no diabetes or other known causes of HRV alteration. Results HRV was considerably reduced in LVAD patients in the early phases after device implantation in comparison to all control groups. A downgrading of HRV parameters was also present in CS controls. Circadian oscillations were highly depressed in LVAD and CHF patients, and slightly reduced in CS patients. Conclusions In CHF patients supported by a continuous-flow LVAD, a profound cardiac dysautonomia is still evident in the first two months from the beginning of circulatory support; the degree of cardiac autonomic imbalance is even greater in comparison to advanced CHF patients. The recent surgical stress could be partly linked to these abnormalities.

Does heart rate variability correlate with long-term prognosis in myocardial infarction patients treated by early revascularization?

AIM To assess the prevalence of depressed heart rate variability (HRV) after an acute myocardial infarction (MI), and to evaluate its prognostic significance in the present era of immediate reperfusion. METHODS Time-domain HRV (obtained from 24-h Holter recordings) was assessed in 326 patients (63.5 ± 12.1 years old; 80% males), two weeks after a complicated MI treated by early reperfusion: 208 ST-elevation myocardial infarction (STEMI) patients (in which reperfusion was successfully obtained within 6 h of symptoms in 94% of cases) and 118 non-ST-elevation myocardial infarction (NSTEMI) patients (percutaneous coronary intervention was performed within 24 h and successful in 73% of cases). Follow-up of the patients was performed via telephone interviews a median of 25 mo after the index event (95%CI of the mean 23.3-28.0). Primary end-point was occurrence of all-cause or cardiac death; secondary end-point was occurrence of major clinical events (MCE, defined as mortality or readmission for new MI, new revascularization, episodes of heart failure or stroke). Possible correlations between HRV parameters (mainly the standard deviation of all normal RR intervals, SDNN), clinical features (age, sex, type of MI, history of diabetes, left ventricle ejection fraction), angiographic characteristics (number of coronary arteries with critical stenoses, success and completeness of revascularization) and long-term outcomes were analysed. RESULTS Markedly depressed HRV parameters were present in a relatively small percentage of patients: SDNN < 70 ms was found in 16% and SDNN < 50 ms in 4% of cases. No significant differences were present between STEMI and NSTEMI cases as regards to their distribution among quartiles of SDNN (χ2 =1.536, P = 0.674). Female sex and history of diabetes maintained a significant correlation with lower values of SDNN at multivariate Cox regression analysis (respectively: P = 0.008 and P = 0.008), while no correlation was found between depressed SDNN and history of previous MI (P = 0.999) or number of diseased coronary arteries (P = 0.428) or unsuccessful percutaneous coronary intervention (PCI) (P = 0.691). Patients with left ventricle ejection fraction (LVEF) < 40% presented more often SDNN values in the lowest quartile (P < 0.001). After > 2 years from infarction, a total of 10 patients (3.1%) were lost to follow-up. Overall incidence of MCE at follow-up was similar between STEMI and NSTEMI (P = 0.141), although all-cause and cardiac mortality were higher among NSTEMI cases (respectively: 14% vs 2%, P = 0.001; and 10% vs 1.5%, P = 0.001). The Kaplan-Meier survival curves for all-cause mortality and for cardiac deaths did not reveal significant differences between patients with SDNN in the lowest quartile and other quartiles of SDNN (respectively: P = 0.137 and P = 0.527). Also the MCE-free survival curves were similar between the group of patients with SDNN in the lowest quartile vs the patients of the other SDNN quartiles (P = 0.540), with no difference for STEMI (P = 0.180) or NSTEMI patients (P = 0.541). By the contrary, events-free survival was worse if patients presented with LVEF < 40% (P = 0.001). CONCLUSION In our group of patients with a recent complicated MI, abnormal autonomic parameters have been found with a prevalence that was similar for STEMI and NSTEMI cases, and substantially unchanged in comparison to what reported in the pre-primary-PCI era. Long-term outcomes did not correlate with level of depression of HRV parameters recorded in the subacute phase of the disease, both in STEMI and in NSTEMI patients. These results support lack of prognostic significance of traditional HRV parameters when immediate coronary reperfusion is utilised.