Aims: To elucidate the usefulness of the early diastolic mitral flow propagation velocity (Vp) 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 Vp with the invasive minimum value of the first derivative of LV pressure decay (dP/dtmin) 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 Vp and dP/dtmin and τ, respectively, during rapid AF. After slowing the ventricular rate, the average value of Vp increased, while dP/dtmin increased and τ decreased. After inducing myocardial infarction, the average value of Vp decreased, while dP/dtmin decreased and τ increased. Conclusion The non-invasively obtained Vp evaluates LV relaxation even during AF regardless of ventricular rhythm or the presence of pathological changes.
- Atrial fibrillation
- Mitral flow propagation velocity
- The first derivative of left ventricular pressure decay
- The time constant of isovolumic left ventricular pressure decay
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine