Obesity and heart failure: epidemiology, pathophysiology, clinical manifestations, and management.

Obesity is a risk factor for heart failure (HF) in both men and women. The mortality risk of overweight and class I and II obese adults with HF is lower than that of normal weight or underweight adults with HF of comparable severity, a phenomenon referred to as the obesity paradox. Severe obesity produces hemodynamic alterations that predispose to changes in cardiac morphology and ventricular function, which may lead to the development of HF. The presence of systemic hypertension, sleep apnea, and hypoventilation, comorbidities that occur commonly with severe obesity, may contribute to HF in such patients. The resultant syndrome is known as obesity cardiomyopathy. Substantial weight loss in severely obese persons is capable of reversing most obesity-related abnormalities of cardiac performance and morphology and improving the clinical manifestations of obesity cardiomyopathy.

Assessing cardiovascular disease in the dialysis patient.

Cardiac causes account for nearly half of all deaths in patients with end-stage renal disease (ESRD). Coronary artery disease (CAD) is present in 38% - 40% of patients starting dialysis. Both traditional and chronic kidney disease-related cardiovascular risk factors contribute to this high prevalence rate. In patients with ESRD, CAD--particularly acute myocardial infarction--is underdiagnosed. Dobutamine stress echocardiography and, to a lesser extent, stress myocardial perfusion imaging have proved useful in screening for CAD in such patients. Coronary artery calcium scoring is less useful. Acute myocardial infarction is associated with high short- and long-term mortality in dialysis patients. Cardiac troponin I appears to be more specific than cardiac troponin T or CK-MB in the diagnosis of acute myocardial infarction.

Echocardiography predicts adverse cardiac remodelling in heart failure.

Congestive heart failure remains a primary cause of cardiovascular-related events. Heart failure patients face two health care challenges. First, they are uncertain about their prognosis and second, they have an unpredictable clinical course with recurrent exacerbations of heart failure. The echocardiogram is an easily accessible bedside test without any associated procedural complications. Additionally, it provides a wealth of information about chamber size and function, valve integrity and the pericardial sac. In the present review, the most common echocardiographic predictors of impending cardiac events in congestive heart failure are described.

Esmolol in acute ischemic syndromes.

BACKGROUND: beta-Blockers have been shown to reduce both morbidity and mortality rates in patients with acute coronary syndromes. However, because of potential side effects, their use is limited in patients who might benefit the most from such therapy. It was thought that the use of an ultra-short-acting intravenous beta-blocker might produce similar results with fewer complications in those patients with relative contraindications to beta-blocker therapy. METHODS: Accordingly, we evaluated the use of esmolol in patients with acute coronary syndromes and relative contraindication to beta-blocker therapy in a prospective randomized trial. One hundred eight patients at 21 sites received an infusion of intravenous esmolol or standard therapy on admission and were followed for 6 weeks from the day of admission. The primary efficacy outcome was a composite event consisting of any of the following that occurred during the index hospitalization: death, myocardial (re)infarction, recurrent ischemia, or arrhythmia as well as silent myocardial ischemia assessed by ambulatory electrocardiographic monitoring. Safety end points including hypotension, bradyarrhythmias, new or worsening congestive heart failure, and bronchospasm were also recorded. RESULTS: Event rates for primary end points were similar in the 2 groups: death (2% in the standard care group vs 4% in the group receiving esmolol), myocardial (re)infarction (4% standard vs 7% esmolol), ischemia (12% vs 13%), arrhythmias (4% vs 2%), and silent ischemia (13% vs 15%). There was a higher incidence of transient hypotension in the group receiving esmolol (2% vs 16%), but all such events were noted to resolve after discontinuation of the esmolol infusion. There were no additional differences in safety end points: bradycardia (2% for those receiving standard care vs 9% receiving esmolol), new congestive heart failure (10% vs 16%), bronchospasm (0% vs 7%), and heart block (2% vs 2%). CONCLUSIONS: The use of an ultra-short-acting beta-blocker such as esmolol might offer an alternative to patients with contraindications to standard beta-blocker therapy. Although this trial had limited power to detect safety and efficacy differences between the 2 therapies, it was observed that safety end points, which occurred during esmolol administration, resolved readily when the infusions were decreased or discontinued. Additional testing is needed to substantiate these findings.