RESUMO
In this study, isovolumetric relaxation time (IVRT) flow velocities recorded by pulsed Doppler were induced or augmented in nine patients (aged 60 +/- 20 years) with permanent pacemakers. Six subjects had evidence of IVRT flow (>/=0.2 m/sec) during native rhythm, only three of whom exhibited cavity obliteration. Mean +/- SD left ventricular (LV) ejection fraction and end-diastolic and end-systolic volumes were 60% +/- 5%, 104 +/- 50 mL, and 39 +/- 27 mL, respectively. IVRT flows were induced or augmented (P < 0.003) in all patients during paced ectopic stimulation of the right ventricle and during pacing combined with sublingual nitroglycerin (NTG; 0.4 mg). However, IVRT flows were not significantly increased with NTG alone. IVRT flow duration was prolonged >50% by pacing (P < 0.05). These data suggest that IVRT flows may be present in patients without cavity obliteration and may be accentuated by asynchronous LV relaxation. (ECHOCARDIOGRAPHY, Volume 13, January 1996)