The 125 patients were divided into three groups: the normal group, the IR group and the PN group. The normal group included 34 patients with no symptoms or previous history of heart failure, hypertension or coronary artery disease. They all had a normal echocardiographic examination, including LV size and function, left atrial volumes and pulmonary artery systolic pressures by Doppler echocardiography. The IR group consisted of 40 patients with hypertension, coronary artery disease and/or LV hypertrophy, normal ejection fraction and a mitral inflow pattern with an early to late transmitral flow velocity (E/A) ratio <1.0. None of these patients had symptoms of heart failure. Twenty patients with hypertension were receiving beta-blockers or calcium channel blockers, or both; subjects with coronary artery disease were also receiving nitrates. A subgroup of 26 patients with invasive hemodynamic data had a mean pulmonary capillary wedge pressure (PCWP) ≤12 mm Hg (10 ± 1.5). The PN group consisted of 51 patients with symptoms of pulmonary congestion and elevated (>40 mm Hg) pulmonary artery systolic pressure by Doppler echocardiography, accompanied by an E/A ratio ≥1.0 and an IVRT ≤70 ms. Seventeen patients had idiopathic dilated cardiomyopathy; 20 were status post myocardial infarction (12 anterior, 8 inferoposterior); and 14 had normal systolic function with symptoms of heart failure. A subgroup of 34 patients with invasive hemodynamic data had a mean PCWP >12 mm Hg (23 ± 6). Five patients in the IR group and five in the PN group had bundle branch block (three with left bundle branch block).