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Study objectives: The purpose of this study was to quantify the impact of baseline renal dysfunction on incidence and occurrence of cardiac arrhythmias in the coronary ICU. Background: Renal dysfunction is an established predictor of all-cause mortality in the ICU setting. We set out to evaluate the independent contributory effect of renal dysfunction to arrhythmias and mortality in this population. Design and setting: We analyzed a prospective coronary care unit registry of 12,648 admissions by 9,557 patients over 8 years at a single, tertiary center. An admission serum creatinine level was available for 9,544 patients. Those patients not receiving long-term dialysis were classified into quartiles of corrected creatinine clearance with cutpoints of 46.2 mL/min/72 kg (group 1), 63.1 mL/min/72 kg, and 81.5 mL/min/72 kg. Dialysis patients (n = 527) were considered as a fifth comparison group (group 5). Measurements and results: Baseline characteristics including older age, African-American race, diabetes, hypertension, history of previous coronary disease, and heart failure were incrementally more common with increasing renal dysfunction strata. There were graded, independent increased risks for accelerated idioventricular rhythm (relative risk [RR], 2.43; 95% confidence interval [CI], 1.40 to 4.20; p = 0.002), sustained ventricular tachycardia (RR, 2.07; 95% CI, 1.02 to 4.22; p = 0.04), ventricular fibrillation (RR, 2.42; 95% CI, 1.13 to 5.15; p = 0.02), and complete heart block (RR, 3.64; 95% CI, 1.77 to 7.48; p = 0.0004, group 5 vs group 1). Conclusions: We conclude that baseline renal function is a powerful, independent predictor of cardiac arrhythmias in the coronary ICU population. [ABSTRACT FROM AUTHOR]

Study Objectives: There is a lack of epidemiologic information about duration of QRS complex in the general heart failure population. We sought to describe age, sex, and clinical subset specific prevalence of QRS prolongation in this population.Methods: Data were abstracted from the Resource Utilization Among Congestive Heart Failure Study, which identified 29,686 patients with heart failure from a large, mixed-model managed-care organization during 1989 to 1999. A target population of 3,471 had echocardiographic data and ECG data obtained from automated sources during the first year of diagnosis. Systolic dysfunction was defined as heart failure plus a left ventricular ejection fraction < 45%.Measurements and Results: Among the heart failure population, 20.8% of the subjects had a QRS duration > or = 120 ms. A total of 425 men (24.7%) and 296 women (16.9%) had a prolonged QRS duration (p < 0.01). There was a linear relationship between increased QRS duration and decreased ejection fraction (p < 0.01). A prolonged QRS duration of 120 to 149 ms demonstrated increased mortality at 60 months (p = 0.001), when adjusted for age, sex, and race (p = 0.001). Systolic dysfunction was associated with graded increases in mortality across ascending levels of QRS prolongation.Conclusions: Approximately 20% of a generalized heart failure population can be expected to have a prolonged QRS duration within the first year of diagnosis, suggesting that as many as 20% of patients with heart failure may be candidates for biventricular pacing. [ABSTRACT FROM AUTHOR]