To examine the importance of left ventricular chamber size in determining the response to vasodilator therapy, we performed echocardiography in 40 patients with chronic refractory heart failure before they were treated with oral hydralazine. The left ventricular end-diastolic dimension (LVEDD) correlated significantly with the per cent change in stroke volume (r = 0.77), left ventricular filling pressure (r = −0.68), and stroke work index (r = 0.87) during short-term drug administration. After 14 to 21 days of maintenance therapy, 15 of 24 patients with an LVEDD ≥60 mm were improved, and one was worse; mean blood urea nitrogen decreased from 45.6 to 30.6 mg per deciliter in the 21 patients in this group who completed the study (16.3 to 10.9 mmol per liter) (P<0.001). In contrast, only two of 16 patients with an LVEDD <60 mm improved, whereas 10 showed clinical deterioration; blood urea nitrogen increased from 49.3 to 64.2 mg per deciliter in the 13 patients in this group who completed the study (17.6 to 22.9 mmol per liter) (P<0.01). These findings indicate that left ventricular chamber size is an important factor in the response to hydralazine in patients with severe chronic heart failure. (N Engl J Med. 1980; 303:250–5.) HYDRALAZINE is of established value in the treatment of patients with severe chronic heart failure refractory to conventional therapy.1 However, although marked symptomatic improvement occurs in many patients, 2–6 others show little hemodynamic and clinical benefit6–8 and may have adverse cardiovascular reactions.9,10 Although the lack of effectiveness of hydralazine may be due to the administration of subtherapeutic doses in some patients, 11,12 the marked differences in the responses observed suggest nonuniformity of the patient population under study. Since left ventricular volume is a major factor determining the effects of other cardiovascular drugs, 13,14 we prospectively studied the hemodynamic and clinical responses to hydralazine.
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