Heart rate as independent prognostic factor for mortality in normotensive hemodialysed patients

Several epidemiological studies have reported heart rate (HR) as a predictor of cardiovascular and noncardiovascular mortality in the general population. Aim of the present study was to investigate a possible relation between increased HR and mortality in normotensive end-stage renal disease (ERSD) patients.

Between 1997 and 2001 we recruited 407 normotensive ESRD patients (mean age 56.6 +/- 3.3 years) without coronary artery disease, left ventricular systolic dysfunction or on antiarrhythmic therapy. Baseline electrocardiography (ECG) at rest, 48-hour ambulatory Holter ECG monitoring and standard echocardiography were performed. After a mean follow-up of 46 months (range 12-60 months), cardiovascular and sudden death were considered as end points.

Echocardiogram showed a normal left ventricular ejection fraction (>55%) in 370 patients (91%) and left ventricular hypertrophy (LVH) in 290 patients (71.2%). Mean HR by 48-hour Holter ECG was 81 +/- 10.6 bpm. During the follow-up, all-cause mortality rate was 12% (49 patients); 40 patients died from cardiac cause (9.8%) of which 20 patients (4.9%) by sudden death. By univariate analysis, age, diabetes, ECG-LVH with signs of left ventricular strain, and increased mean HR by 48-hour Holter ECG were all significantly related to global, cardiovascular and sudden death. ROC curve analysis identified optimal cutoff points for HR >85 bpm and age >65 years associated with increased cardiovascular risk (p<0.001). By Cox regression analysis, only age >65 years (p<0.0001) and mean HR >85 bpm (p<0.0001) were independent predictors of cardiovascular events.

In normotensive ERSD patients, increased mean HR detected by 48-hour Holter ECG is an independent determinant of global and cardiovascular mortality.