Pulsed Doppler echocardiography has been established as an accurate technique for measuring mitral inflow velocity from which peak filling rate and other related parameters of left ventricular (LV) filling can be easily derived.1-3 Several Doppler studies have recently shown that these parameters of diastolic function are dependent on a host of factors such as heart rate, age, LV relaxation and compliance, ratio of LV radius to wall thickness and left atrial (LA) pressure.4-8 Ishida et al7 have demonstrated that the instantaneous pressure gradient between left atrium and left ventricle at the time of peak mitral inflow has a direct influence on peak mitral flow and consequently filling rate. Since the height of the V wave in the left atrium depends on the completeness of atrial emptying during diastole, it is conceivable that the effectiveness of atrial contraction could have an influence on early peak mitral flow. The present investigation was designed using a population of patients with programmable atrioventricular (AV) sequential pacemakers as a model to examine the relation between the effectiveness of LA contraction induced by changing the sequence of LV contraction and peak mitral flow velocity and filling rate by Doppler.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine