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Effect of preload and heart rate manipulation on Doppler transmitral flow velocity pattern: search for
J C Mohan1, R Aggarwal, R Arora
1Department of Cardiology, G.B. Pant Hospital, New Delhi.
Insights
Pulsed Doppler transmitral flow-velocity is a non-invasive tool for diastolic function assessment. However, preload and heart rate significantly affect its parameters, with only specific A-wave metrics remaining reliable under small changes.
Area of Science:
- Cardiology
- Non-invasive cardiovascular diagnostics
Background:
- Pulsed Doppler transmitral flow-velocity is used for serial diastolic function evaluation.
- Loading conditions and heart rate can confound transmitral flow analysis, questioning study conclusions.
Purpose of the Study:
- To investigate the effect of preload changes on Doppler mitral spectrum parameters.
- To identify transmitral diastolic flow-velocity parameters that are relatively independent of preload and heart rate.
Main Methods:
- Studied 11 patients with coronary artery disease before and after isosorbide dinitrate (Group 1).
- Administered atrial pacing in 10 age-matched patients to mimic heart rate changes (Group 2).
- Analyzed various Doppler mitral spectrum parameters, including peak velocities, velocity-time integrals, and filling periods.
Main Results:
- Isosorbide dinitrate increased heart rate and decreased left ventricular end-diastolic volume, reducing peak E velocity, E velocity-time integral, and E/A ratio.
- Atrial pacing decreased E velocity-time integral and E/A ratio but did not significantly alter other parameters.
- Absolute A velocity time integral, acceleration, and deceleration times were least affected by preload and heart rate variations.
Conclusions:
- Transmitral flow-velocity parameters are significantly influenced by preload and heart rate.
- Absolute A velocity time integral, acceleration, and deceleration times show relative independence from preload and heart rate changes.
- These specific parameters may offer more reliable assessment of diastolic function when loading conditions fluctuate.
Abstract:
Pulsed Doppler transmitral flow-velocity provides a non-invasive method for serial evaluation of diastolic function. However confounding influence of loading conditions and heart rate on transmitral flow makes many conclusions suspect. To study the effect of preload, various parameters of Doppler mitral spectrum were studied in 11 patients with stable effort angina, angiographic coronary artery disease and intact global and segmental systolic function, before and after administration of sublingual isosorbide dinitrate (group 1). Following isosorbide dinitrate administration, there was a significant increase in heart rate (p less than 0.001), decrease in left ventricular end-diastolic volume (p less than 0.01), no change in left ventricular ejection fraction and systolic blood pressure. Peak E velocity, E velocity-time integral, E/A velocity time integrals ratio, acceleration and deceleration rates and diastolic filling period were significantly reduced whereas peak A velocity, A velocity time integral, acceleration and deceleration times and atrial filling period were unchanged. In 10 age-matched patients (group 2), atrial pacing performed to achieve similar degree of increase in heart rate as in group 1 (10 +/- 1 vs 12. +/- 4, p = NS), resulted in a decrease in E velocity time integral, E/A velocity time integrals ratio and diastolic filling period (p less than 0.01) without any significant change in any other parameter. Absolute A velocity time integral, acceleration and deceleration times are the only parameters of transmitral diastolic flow-velocity profile which are relatively independent of preload and heart rate provided the change is small.