Although Doppler transmitral flow velocities have been used to assess LV diastolic properties, many factors have been identified and its applicability is not universal. The effect of heart rate (HR) has been implicated although data on this relationship is sparse. Likewise, data on the effect of cycle length changes in atrial fibrillation (AF) on diastolic function indices and consequently on systolic function are lacking. Twenty (20) patients in permanent AF were studied with Doppler and M-mode echocardiography. Seven subjects had normal-sized LVs while 13 had concentric hypertrophy. Twenty consecutive displays from each of the twenty patients were analyzed and measurements were taken of the peak flow velocity of the E wave, E acceleration and E deceleration time. Isovolumic relaxation time (IVRT) was determined from the apical 5-chamber view. Systolic function was calculated by cube method from M-mode.
Results showed that alterations in RR interval did not affect the E velocity to a detectable magnitude in patients with AF in both groups. The same observation, was seen in the IVRTs of patients with and without left ventricular hypertrophy (LVH). Only the E acceleration time showed an RR related increase among the group with LVH, but not with the normal group. The positive response of E deceleration time to RR change was comparable in both groups. All in all, our findings suggest that most of the diastolic function indices cannot be used to assess compliance in patients with AE except for the E acceleration time.
In the assessment of systolic function by M-mode, this study showed the expected relationship in cycle length and ejection fraction (EF) in those patients with normal LVs. An increase in cycle length resulted in an increase in ejection fraction (p0.001). However, in patients with concentric hypertrophy this relationship was no longer true (p0.05). This finding suggests that patients with AF and concentric LVH may be at a higher risk for heart failure not only because of its inherent diastolic dysfunction but also through impaired systolic performance. (Author)