Effect of weight loss on ventricular repolarization in normotensive severely obese patients with and without heart failure.

BACKGROUND: Obesity has been reported to be associated with delayed ventricular repolarization. The purpose of this study was to assess ventricular repolarization in normotensive severely obese subjects with and without heart failure (HF) and to assess the effect of weight loss on ventricular repolarization in such patients. METHODS: Twenty-eight patients with and 39 patients without HF (body mass index ≥ 40 kg/m(2)) were studied before and after weight loss from bariatric surgery. Corrected QT interval (QTc) was measured on 12-lead electrocardiograms using Bazett's formula. QTc dispersion was calculated by subtracting the minimum from the maximum QTc on each 12-lead electrocardiogram. Electrocardiograms and transthoracic echocardiograms were performed preoperatively and at the nadir of postoperative weight loss. RESULTS: Mean QTc and QTc dispersion were significantly longer/greater in subjects with HF than in those without HF (P < 0.0001). Weight loss produced significant reductions in mean QTc and QTc dispersion in both subgroups (P < 0.0001). Pre-weight loss left ventricular (LV) mass/height and presence or absence of HF independently predicted pre-weight loss QTc and QTc dispersion (P < 0.0001). Weight loss-induced decrease in LV mass/height independently predicted weight loss-induced decreases in QTc and QTc dispersion (P < 0.0001). CONCLUSIONS: HF independently predicts QTc and QTc dispersion in normotensive severely obese patients. Decrease in the LV mass resulting from weight loss independently predicts reduction in QTc and QTc dispersion in such patients.

Heart failure with a normal left ventricular ejection fraction: epidemiology, pathophysiology, diagnosis and management.

Heart failure (HF) with a normal left ventricular (LV) ejection fraction (HFNEF) occurs in 40-71% of patients with HF and carries a prognosis similar to that of HF with a reduced LV ejection fraction (LVEF). The pathophysiology of HFNEF is distinct from that of HF with a reduced LVEF and is characterized by impaired relaxation of myocardium, LV stiffness and, in many cases, increased arterial stiffness. Systemic hypertension accounts for most cases of HFNEF in the United States. Those with HFNEF tend to be older and obese. Diabetes mellitus and atrial fibrillation occur with disproportionately high frequency in HFNEF. The diagnosis of HFNEF requires the presence of symptoms or signs of HF, a normal or near-normal LVEF and evidence of LV diastolic dysfunction based on cardiac catheterization or Doppler echocardiographic techniques and/or elevation of plasma natriuretic peptide levels. Current guidelines for management of HFNEF include control of systolic and diastolic hypertension, control of the ventricular rate in patients with atrial fibrillation and judicious use of diuretics. In selected cases, coronary revascularization or restoration of sinus rhythm in those with atrial fibrillation may be indicated. To date, no drug or drug group has consistently improved survival in HFNEF. For this reason and because of the poor long-term prognosis, preventative measures and effective treatment of underlying causes and precipitating factors are particularly important in avoiding HF exacerbations in patients with HFNEF.

Risk factors for atherosclerosis in patients with chronic kidney disease: recognition and management.

Heart disease is the most common cause of death in patients with chronic kidney disease (CKD), particularly in those receiving dialysis. Atherosclerosic cardiovascular (CV) disease (CVD) accounts for a large number of these deaths. Atherosclerosis is accelerated in patients with CKD due predominantly to the high prevalence of traditional CVD risk factors in the CKD population. CKD aggravates pre-existent traditional risk factors such as hypertension and dyslipidemia due to secondary renal parenchymal hypertension and secondary dyslipidemia. In addition, a variety of non-traditional risk factors that occur commonly in CKD patients contribute to CV risk. Recent studies suggest that CKD itself may be an independent risk factor for CVD, particularly coronary heart disease (CHD). Many therapies aimed at CV risk factor modification that have been successful in reducing CV risk in the general population are less effective or ineffective in favorably modifying CV risk in CKD.

Chronic Inflammation and Coronary Atherosclerosis in Patients with End-Stage Renal Disease.

The key role of chronic inflammation in the pathogenesis of atherosclerosis has become increasingly apparent in recent years based on the results of experimental, epidemiologic and clinical studies. Coronary artery disease and its complications occur with disproportionately high frequency in patients with end-stage renal disease (ESRD) and contribute substantially to cardiovascular morbidity and mortality in this population. Traditional cardiovascular risk factors occur commonly in patients with ESRD. In addition, a variety of patient-related and dialysis-related factors unique to ESRD predispose to chronic inflammation and by doing so are thought to contribute to coronary atherosclerosis and its complications. These risk factors may serve as therapeutic targets and as such may offer the potential for altering the natural history of coronary atherosclerosis in ESRD.

Cardiovascular mortality in dialysis patients.

In their broad spectrum, cardiovascular diseases are, collectively, the major cause of death in patients on dialysis. The population of patients treated with peritoneal dialysis and hemodialysis are not only subject to the traditional risk factors for heart disease, but also to certain uremia-associated risk factors that are unique in this population. In the dialysis population, data regarding the effectiveness of routine pharmacologic and procedural interventions on cardiovascular outcomes are limited. Most dialysis patients are excluded from clinical trials, and so data from randomized controlled trials investigating outcomes in patients undergoing peritoneal dialysis or hemodialysis are almost absent. In this review, we discuss some of the major cardiovascular problems in the dialysis population, the impact of those problems on survival, and when data are available, the impact of therapeutic strategies.