Amplitudes, Durations, and Timings of Apically Directed Left Ventricular Myocardial Velocities: I. Their Normal Pattern and Coupling to Ventricular Filling and Ejection,☆☆,

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Abstract

Background:The left ventricular (LV) major axis shortening is an important determinant of its global function. But unlike the LV minor axis dynamics, the long-axis dynamics have not been well characterized. We investigated the amplitudes, durations, and timings of LV long-axis myocardial velocities and related them to LV filling and ejection in normal healthy volunteers. Methods and Results: Myocardial velocities from the basal, mid, and distal portions of the four LV walls were recorded from the apical window with spectral Doppler tissue imaging in 20 normal individuals. The timings, amplitudes, and durations were measured and compared both longitudinally and circumferentially. These were also related to mitral inflow and LV ejection. Analysis of the recordings indicated that there were three principal myocardial velocities: apically directed systolic velocity and atrially directed early and late diastolic velocities. The LV posterior wall had the highest shortening velocity and the amount of shortening. The lateral wall had the greatest amplitude of early diastolic lengthening velocity, amount of lengthening, and early to late lengthening velocity and integral ratios, probably indicating most favorable early diastolic properties. There was a striking synchrony in the myocardial velocities circumferentially. The myocardial velocities dropped progressively as the sampling site was moved distally and the LV apex was practically stationary. Although the onsets of the velocity profiles were simultaneous in the meridional orientation, their durations were shorter distally. All myocardial velocities preceded the corresponding blood flow velocities. They also ended before the corresponding blood flow velocities, this being more pronounced in the distal myocardial segments, indicating the presence of inertial factors responsible for the terminal portions of mitral and aortic flows. Conclusions: Recording of apically directed myocardial velocities gives valuable insights into the regional myocardial function. These velocities show significant regional variations in healthy normal individuals. It is speculated that analysis of regional myocardial velocities may have a role in the diagnosis of early myocardial disease. (J Am Soc Echocardiogr 1998;11:105–11.)

Section snippets

Study Subjects

Twenty healthy normal volunteers with no history of cardiac disease or any cardiovascular symptoms or signs were prospectively recruited for the study. All had normal sinus rhythm. None of the patients was taking any cardiovascular medications. All had normal two-dimensional and Doppler echocardiographic examinations with normal cardiac chamber size and ventricular and valvular functions. The mean ± SD age was 44 ± 16 years (range 25 to 72) years, and two of the volunteers were women.

Recording of Echocardiograms

The

Reproducibility of myocardial velocity measurements

The correlation coefficient for the independent measurements of myocardial velocity amplitudes by the same observer was 0.96 and by different observers was 0.95, and that for durations was 0.97 and 0.95, respectively. With the Bland-Altman method the mean difference between observations was <5% of the mean value of the observations for measurement of both amplitudes and durations.

Mitral and Aortic Flow

The baseline data of the timings and durations of the mitral and aortic flow velocity signals are summarized in

Discussion

Results of this study indicate that in individuals with no clinical or echocardiographic evidence of heart disease, (1) regional differences exist in the long-axis myocardial velocities and extent of shortenings and lengthenings among the four LV walls, (2) differences exist in the amount of early and late diastolic lengthening among the four walls, (3) myocardial velocity gradients exist along the LV long axis, the apex being fairly stationary, and (4) a close coupling of the myocardial

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From the Sections of Cardiology, Jerry L. Pettis VA Medical Center and Loma Linda University School of Medicine.

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Reprint requests: Ramdas G. Pai, MD, FRCP(E), Cardiology (111C), Jerry L. Pettis VA Hospital, 11201 Benton St., Loma Linda, CA 92357.

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