Abstract

Aims

To elucidate the usefulness of the early diastolic mitral flow propagation velocity (V p ) obtained from colour M-mode Doppler for non-invasively assessing left-ventricular (LV) relaxation during atrial fibrillation (AF).

Methods and results

Ten healthy adult dogs were studied to correlate V p with the invasive minimum value of the first derivative of LV pressure decay (dP/dt min ) and the time constant of isovolumic LV pressure decay (τ) at baseline, during rapid and slow AF, and during AF after inducing myocardial infarction. There were significant positive and negative curvilinear relationships between V p and dP/dt min and τ, respectively, during rapid AF. After slowing the ventricular rate, the average value of V p increased, while dP/dt min increased and τ decreased. After inducing myocardial infarction, the average value of V p decreased, while dP/dt min decreased and τ increased.

Conclusion

The non-invasively obtained V p evaluates LV relaxation even during AF regardless of ventricular rhythm or the presence of pathological changes.

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