Sunday, January 17, 2010
Resting Heart Rate Pattern During Follow-Up and Mortality in Hypertensive PatientsThere is a linear relationship between resting heart rate (HR) and mortality in normotensive anduntreated hypertensive individuals. However, it is not clear whether HR is a marker ofincreased risk in hypertensive patients on treatment. We investigated the relationshipbetween HR and mortality in patients with hypertension. We analyzed baseline HR, final HR,and HR change during follow-up in patients attending the Glasgow Blood Pressure Clinic.Using a threshold of 80 bpm, we classified patients into those who had a consistently high(high-high) or low (low-low) HR or patients whose HR increased (low-high) or decreased(high-low) over time. Survival analysis was carried out using Cox proportional hazards modelsadjusted for age, sex, body mass index, smoking, rate-limiting therapy, systolic blood pressure,and serum cholesterol. For each beat of HR change there was a 1% change in mortality risk.The highest risk of an all-cause event was associated with patients who had increased theirHR by 5 bpm at the end of follow-up (1.51 [95% CI: 1.03 to 2.20]; P=0.035). Compared withlow-low patients, high-high patients had a 78% increase in the risk of all-cause mortality (HR:1.78 [95% CI: 1.31 to 2.41]; P<0.001). Cardiovascular mortality showed a similar pattern ofresults. Rate-limiting therapy did not have an independent effect on outcomes in this analysis.Change in HR achieved during follow-up of hypertensive patients is a better predictor of riskthan baseline or final HR. After correction for rate-limiting therapy, HR remained a significantindependent risk factor.