Ashish Patwala

Maximizing Patient Benefit From Cardiac Resynchronization Therapy With the Addition of Structured Exercise Training : A Randomized Controlled Study

OBJECTIVES We evaluated the benefits of additional exercise training after cardiac resynchronization therapy (CRT). BACKGROUND Cardiac resynchronization therapy results in improved morbidity and mortality in appropriate patients. We hypothesized that a structured exercise training program in addition to CRT would maximize the improvements in exercise capacity, symptoms, and quality of life (QOL). METHODS Fifty patients referred for CRT were recruited. Patients were assessed before and 3 and 6 months after CRT. Functional class and QOL scores were recorded, and exercise tests were performed with hemodynamic measurements. Peak lower limb skeletal muscle torque was measured during extension, and echocardiography was undertaken at each visit. At 3 months, patients were randomized with a simple sealed envelope method to exercise training (n = 25) or control group (n = 25). The exercise group underwent an exercise program consisting of 3 visits/week for 3 months. Paired sample t tests were used to look for in-group differences and independent sample t tests for between-group differences. RESULTS Three months after CRT there were significant improvements in all functional, exercise hemodynamic, and echocardiographic measures. After randomization the exercise group showed further significant improvements in functional, exercise hemodynamic, and QOL measures compared with the control group. There were also significant in-group improvements in peak skeletal muscle function and ejection fraction that did not reach statistical significance on intergroup analysis. CONCLUSIONS Exercise training leads to further improvements in exercise capacity, hemodynamic measures, and QOL in addition to the improvements seen after CRT. Therefore, exercise training allows maximal benefit to be attained after CRT.

How many patients fulfil the surface electrocardiogram criteria for subcutaneous implantable cardioverter-defibrillator implantation?

AIMS To determine the number of patients with a primary or secondary prevention implantable cardioverter-defibrillator (ICD) indication who are eligible for subcutaneous ICD (S-ICD) implantation according to the S-ICD manufacturers surface electrocardiogram (ECG) screening template. METHODS AND RESULTS One hundred and ninety-six ICD patients with a non-paced ventricle were assessed using erect and supine ECG limb lead recordings to simulate the three S-ICD sensing vectors. Each ECG lead was scrutinized by two independent observers. Subcutaneous ICD eligibility required two or more leads to satisfy the S-ICD screening template in both erect and supine positions. Overall, 85.2% of patients [95% confidence interval (CI): 80.2-90.2%] fulfilled surface ECG screening criteria. The proportion of patients with 3, 2, 1, and 0 qualifying leads were 37.2% (95% CI: 30.4-44.0%), 48.0% (95% CI: 41.0-55.0%), 11.2% (95% CI: 6.8-15.6%), and 3.6% (95% CI: 1.0-6.2%). The S-ICD screening template was satisfied more often by Lead III (primary vector, 83.7%, 95% CI: 78.5-88.9%) and Lead II (secondary vector, 82.7%, 95% CI: 77.4-88.0%) compared with Lead I (alternate vector, 52.6%, 95% CI: 45.6-59.6%). A prolonged QRS duration was the only baseline characteristic independently associated with ineligibility for S-ICD implantation. There was 92.9% agreement between the two independent observers in assessment of eligibility using the S-ICD screening template. CONCLUSION About 85.2% of patients with an indication for a primary or secondary prevention ICD have a surface ECG that is suitable for S-ICD implantation when assessed with an S-ICD screening template. There is minor inter-observer variation in assessment of eligibility using the S-ICD screening template.

Exercise duration and peak systolic blood pressure are predictive of mortality in ambulatory patients with mild-moderate chronic heart failure.

Background and Aims: It is a prevailing concept in chronic heart failure (CHF) that ventricular remodelling (evaluated via imaging) and neurohormonal activation (via biomarkers) exert major influences, such that the need to subject patients to haemodynamic evaluations and exercise testing has been questioned. We sought to investigate whether exercise and haemodynamic parameters lack independent prognostic value in a cohort of unselected ambulatory patients with mild-moderate CHF. Methods: Eighty-five consecutive patients with stable CHF in New York Heart Association functional classes I–IV, aged 55 ± 12 years, 84% males, left ventricular ejection fraction (LVEF) 37 ± 15%, participated in this study. Survivors were followed for a median of 5.08 years. All subjects underwent cardiopulmonary exercise testing to measure standard parameters including peak oxygen consumption, exercise duration and blood pressure. A sample of venous blood was taken to determine the N-terminal pro-brain natriuretic peptide (N-BNP) level. Echocardiography was performed at rest to measure LVEF. Predictors of mortality were sought using the Cox proportional hazards model. Results: All-cause mortality was 19% (16 deaths, 95% CI 11–29%). Age and LVEF did not independently predict mortality. Although various parameters including New York Heart Association class, peak oxygen consumption and N-BNP level were all predictive of outcome on univariate analysis, multivariate analysis identified reduced exercise duration and peak systolic blood pressure (SBP) to be the only independent predictors of all-cause mortality. Hazard ratios of 0.78 (95% CI 0.65–0.93, p = 0.007) and 0.79 (95% CI 0.66–0.95, p = 0.01) were associated with an increase in exercise duration of 1 min and 10 mm Hg peak SBP, respectively. Conclusions: Two simple parameters (exercise duration and peak SBP) that are easily measured by standard exercise testing are the strongest independent predictors of mortality which outperform LVEF and N-BNP in ambulatory patients with mild-moderate CHF.

A prospective longitudinal evaluation of the benefits of epicardial lead placement for cardiac resynchronization therapy

AIMS Cardiac resynchronization therapy (CRT) is a recognized treatment for appropriate patients. However, placement of the transvenous left ventricular lead is unsuccessful in 5-10% of patients and a further 20% fail to respond. For these groups, epicardial left ventricular lead placement is one alternative. We prospectively evaluated the effects of epicardial vs. transvenous placed CRT. METHODS AND RESULTS Twenty-three subjects with unsuccessful transvenous coronary sinus lead placement underwent epicardial implantation. The subjects underwent clinical evaluation, cardiopulmonary exercise testing, and echocardiography before 3 and 6 months after. The results were compared with a control group (n = 35) who had received transvenous CRT. In both groups, there were significant improvements in all measures at 3 and 6 months. The improvement in peak VO(2) was delayed in the epicardial group compared with the transvenous group. At 6 months, the improvements seen in all variables showed no difference between the groups. CONCLUSION Epicardial lead placement is a viable option for patients with unsuccessful coronary sinus lead placement. The improvements in most variables were of a similar magnitude and over a similar time scale compared with transvenous placement. Improvements in peak VO(2) were delayed in the epicardial group, probably as a result of a prolonged recovery time.

A study of presbycardia, with gender differences favoring ageing women

BACKGROUND The impact of ageing on the human cardiovascular system has been the subject of several studies in recent years, but with insufficient emphasis on defining sex-specific differences. To rectify this, gender-specific differences in structure and function in the human cardiovascular system were studied in a European population during natural ageing. METHODS Cardiac power output (CPO) was measured and integrated with changes in left ventricular (LV) mass, diastolic, systolic and limb blood flow, blood pressure and exercise capacity in 93 health-screened men and 122 women, aged 20 to 75 years. RESULTS Correlating with a 21% loss of LV mass, maximum cardiac pumping (i.e. CPOmax=QmaxxMAPmax) and reserve (CR=CPOmax-CPOrest) capacities decreased 20-25% with age in male hearts. In contrast, CPOmax, CR and LV mass were all preserved in ageing women. Maximum cardiac output (Qmax; 26-32%), peak forearm blood flow (FBFpeak; 61%) and exercise capacity (40-50%) all decreased, but more so in men than women. In contrast, systemic vascular resistance (68-75%) and mean arterial pressure (MAPmax; 14-26%) increased in both sexes. CPOrest decreased 27% in men, but was unchanged in women, despite lower early:late diastolic filling (48-51%), Qrest (19-23%) and FBFrest (56%) in both sexes. CONCLUSIONS Understanding sex-specific differences in cardiovascular ageing is important for public health and biomedical research, given increasingly larger older populations and the need to prevent and treat cardiovascular disease.

Principles of Treatment and Pharmacotherapy

Within the medical career covering the past 3–4 decades, heart failure (HF) management has been transformed from that of resignation and mainly palliative treatments to options of proactive prophylactic pharmacological, device and interventional treatments. The prognosis and quality of life of HF patients have also significantly improved over the same period, although they are generally still far below that of normal healthy subjects. A most gratifying of triumphs is that of observing occasionally reversals of severe failure towards normality in cardiac function. However, we are far from being able to ensure such a process in every patient, perhaps until cardiac or myocardial replacement therapy can in practice be as standard a procedure as valve or pacemaker replacement therapies.