Atrial systole and left ventricular filling in hypertrophic cardiomyopathy: Effect of verapamil

Robert O. Bonow*, Terri M. Frederick, Stephen L. Bacharach, Michael V. Green, Pamela W. Goose, Barry J. Maron, Douglas R. Rosing

*Corresponding author for this work

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Abstract

Many patients with hypertrophic cardiomyopathy (HC) have impaired left ventricular (LV) rapid diastolic filling. To quantitate the contribution of atrial systole to LV filling, we used radionuclide angiography to study 30 normal volunteers and 42 patients with HC before and after oral administration of verapamil (320 to 560 mg/day). LV time-activity curves were constructed by combined forward and reverse gating from the R wave, and the onset of atrial systole was determined by the P-R interval. The percent of LV stroke volume filled during rapid diastolic filling and atrial systole was then computed. Peak LV filling rate during rapid diastolic filling was expressed in end-diastolic volume (EDV)/second. Peak rate of rapid diastolic filling was not different in normal patients and those with HC (3.3 ± 0.6 versus 3.3 ± 1.1 EDV/s) and was within the normal range in 34 patients with HC (81%). However, the contribution to LV filling volume by rapid diastolic filling was diminished in patients with HC (83 ± 7% normal, 67 ± 17% HC, p < 0.001) and the contribution of atrial systole was increased (16 ± 8% normal, 31 ± 18% HC, p < 0.001). LV filling volume during atrial systole was above the upper normal limit of 31% in 17 patients (40%), including 13 patients with a normal peak filling rate. After verapamil, peak filling rate increased (to 4.2 ± 1.2 EDV/s, p < 0.001), percent LV filling during rapid diastolic filling increased (to 83 ± 7%, p < 0.001), and percent LV filling during atrial systole decreased (to 16 ± 9%, p < 0.001). Percent LV filling volume during atrial systole was abnormal after verapamil in only 3 patients (7%). Hence, although the peak rate of rapid diastolic filling may be normal in patients with HC, the contribution to LV filling by rapid diastolic filling is reduced and that of atrial systole is thereby increased. Increased rate and magnitude of rapid diastolic filling during verapamil is associated with decrease and normalization of the contribution of atrial systole to LV filling. These data suggest that many patients with HC are at risk of hemodynamic decompensation with the onset of atrial fibrillation or other tachyarrhythmias and loss of the atrial contribution to LV filling. This risk may be reduced during verapamil therapy.

Original languageEnglish (US)
Pages (from-to)1386-1391
Number of pages6
JournalThe American journal of cardiology
Volume51
Issue number8
DOIs
Publication statusPublished - May 1 1983

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ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Bonow, R. O., Frederick, T. M., Bacharach, S. L., Green, M. V., Goose, P. W., Maron, B. J., & Rosing, D. R. (1983). Atrial systole and left ventricular filling in hypertrophic cardiomyopathy: Effect of verapamil. The American journal of cardiology, 51(8), 1386-1391. https://doi.org/10.1016/0002-9149(83)90317-X