Author + information
- Received April 11, 1994
- Revision received July 7, 1994
- Accepted July 11, 1994
- Published online December 1, 1994.
- Tohru Masuyama, MD∗,
- Masaaki Uematsu, MD,
- Yasuji Doi, MD,
- Kazuhiro Yamamoto, MD,
- Toshiaki Mano, MD,
- Johji Naito, MD,
- Hiroya Kondo, MD,
- Reiko Nagano, MD,
- Masatsugu Hori, MD and
- Takenobu Kamada, MD
- ↵∗Address for correspondence: Dr. Tohru Masuyama, The First Department of Medicine, Osaka University School of Medicine, 2-2 Yamadaoka, Suita 565, Japan.
Objectives. This study attempted to clarify the efect of ventricular relaxation abnormalities on coronary flow dynamics at rest and during tachycardia in humans.
Background. Ventricular relaxation abnormality has been demonstrated in animals to have an adverse impact on early diastolic coronary flow dynamics. However, this relation has not been established in humans. Even if the advene effect were latent at rest, it might become evident during tachycardia because tachycardia reduces coronary flow reserve and facilitates the production of myocardial ischemia.
Methods. Doppler phasic left coronary flow velocity pattern was obtained at rest and during tachycardia in 23 patients without coronary stenosis. The time constant of left ventricular isovolumic pressure (tau) was used to assess ventricular relaxation.
Results. The time to peak flow velocity of the diastolic coronary flow wave was longer, and the fraction of the first third of diastolic coronary flow was smaller, in patients with a longer tau (r = 0.58, p < 0.01; r = −0.44, p < 0.05), indicating a close relation bstween early diastolic coronary flow dynamics and ventricular relaxation. Although rapid atrial pacing yielded an increase in the coronary flow velocity integral per minute in all patients, diastolic coronary flow velocity integral per minute increased in 9 patients with a normal (< 40 ms) tau at rest but decreased in 14 patients with a longer (> 40 ms) tau at rest.
Conclusions. Impaired left ventricular relaxation was associated with decreased coronary flaw in early diastole at rest and decreased coronary flow throughout diastole during tachycardia in patients without coronary stenosis. These findings may provide more insight into the mechanism of tachycardia-induced subendocardial ischemia in patients with impaired ventricular relaxation but without concomitant coronary stenosis.
- Received April 11, 1994.
- Revision received July 7, 1994.
- Accepted July 11, 1994.