Ventricular extrasystoles during thiazide treatment.

The large studies in hypertension: what have they shown?

“…Although thiazide diuretics have undoubted benefits, a crucial issue, which was one of the principal objects of attention of the MRC trial, was whether they might also have adverse effects, especially in relation to cardiac events. In particular, it had been suspected (Robertson, 1978(Robertson, , 1983a(Robertson, ,b, 1984(Robertson, , 1986Poole-Wilson, 1983) that by diminishing serum and total body potassium and serum magnesium, diuretic therapy might predispose to ventricular arrhythmias and so enhance the risk of sudden death in hypertensive patients with coronary artery disease. It should be emphasized that the suggestion was not that thiazides were wholly bad, but that their undoubted benefits might be partly offset by some adverse aspects of their action.…”