Left ventricular long axis tissue Doppler systolic velocity is independently related to heart rate and body size

Abstract

Background: The physiological factors which affect left ventricular (LV) long-axis function are not fully defined. We investigated the relationships of resting heart rate and body size with the peak velocities and amplitudes of LV systolic and early diastolic long axis motion, and also with long-axis contraction duration.

Methods: Two groups of adults free of cardiac disease underwent pulsed-wave tissue Doppler imaging at the septal and lateral mitral annular borders. Group 1 (n = 77) were healthy subjects <50 years of age and Group 2 (n = 65) were subjects between 40-80 years of age referred for stress echocardiography. Systolic excursion (SExc), duration (SDur) and peak velocity (s') and early diastolic excursion (EDExc) and peak velocity (e') were measured.

Results: SExc was not correlated with heart rate, height or body surface area (BSA) for either LV wall in either group, but SDur was inversely correlated with heart rate for both walls and both groups, and after adjustment for heart rate, males in both groups had a shorter septal SDur. Septal and lateral s` were independently and positively correlated with SExc, heart rate and height in both groups, independent of sex and age. There were no correlations of heart rate, height or BSA with either e` or EDExc for either wall in either group.

Conclusion: Heart rate and height independently modify the relationship between s` and SExc, but neither are related to EDExc or e`. These findings suggest that s` and SExc cannot be used interchangeably for the assessment of LV long-axis contraction.

Fig 1. Example of the method for tracing the velocity time integrals of the systolic and early diastolic tissue Doppler signals from the mitral annulus.

Fig 2

Scatter plots of heart rate v septal systolic signal duration (A) and heart rate v lateral systolic signal duration (B) in Group 1.

Fig 3

Scatter plots of heart rate v septal s` (A) and heart rate v lateral s` (B) in Group 1.

Fig 4

Scatter plots of heart rate v septal SExc (A) and heart rate v lateral SExc (B) in Group 1.