Electrocardiogram in evaluation of resistance to antihypertensive therapy.

The effect of blood pressure control on the evolution of electrocardiographic evidence of left ventricular hypertrophy was investigated 50 patients with hypertension who were followed up for an average period of nine years. Blood pressure response to treatment was determined both from casual office readings and from weekly averages of twice daily home readings. Changes in the ECG, judged from both alteration in QRS voltage and in ST-T segment, were related to the degree of arterial pressure control. Usually, both home and office arterial pressure responded similarly to antihypertensive therapy, but when there was a difference, electrocardiographic changes correlated best with home prssure averages. Reduction in maximum precordial QRS voltage (Sv1+Rv5-6) correlated best with changes in home systolic pressure (r = .460; P less than .001), but correlation with diastolic pressure variation either at home or in the office did not attain statistical significance (P greater than .10). The present data stress the importance of home pressure measurements in the management of some patients with hypertension and provide evidence that casual office readings may sometimes misjudge the effectiveness of antihypertensive therapy.