Exercise-induced arrhythmias in diuretic-treated patients with uncomplicated systemic hypertension.

Although hypertensive patients have been shown to have a higher prevalence of arrhythmias during ambulatory monitoring when treated with diuretic drugs than when untreated, the effects of maximal aerobic stress on arrhythmia frequency in such patients is unknown. The incidence of arrhythmias during graded maximal treadmill exercise in a group of 68 subjects with mild, clinically uncomplicated systemic hypertension treated chronically with diuretics alone for a median of 4.5 years was compared with that in an age-matched normotensive control group. The prevalence of exercise-induced arrhythmias was higher in the group treated with diuretics than in the control group, 57% vs 38% (p less than 0.05). This difference was entirely due to the higher incidence of isolated atrial or ventricular premature complexes in the diuretic-treated patients, 44% vs 26% (p less than 0.05). There was no difference in the incidence of frequent (more than 10% of beats) or complex supraventricular or ventricular premature complexes between the diuretic-treated and control groups. Within the diuretic group, no difference in the incidence of simple or complex arrhythmia was found between men and women, between those with and those without rest or exercise-induced electrocardiographic abnormalities or between those with a serum potassium level of less than 3.7 mEq/liter vs those with a level of 3.7 mEq/liter or greater. Thus, patients with uncomplicated hypertension treated with chronic diuretic monotherapy do not appear to be at increased risk for major arrhythmias during aerobic exercise.