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[Left ventricular blood flow dynamics caused by ventricular premature contraction: pulsed Doppler echocardiographic
J Sanada1, K Nakamura, M Tokudome
1Second Department of Internal Medicine, Faculty of Medicine, Kagoshima University.
Insights
Ventricular premature contractions (VPCs) affect left ventricular blood flow differently based on their origin. Right ventricular VPCs generally preserve ejection flow, while left ventricular VPCs can cause disturbed flow patterns, especially with left axis deviation.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Echocardiography
Context:
- Ventricular premature contractions (VPCs) are common arrhythmias.
- Previous research focused on intracardiac pressure dynamics during VPCs.
- Left ventricular blood flow dynamics during VPCs remain less understood.
Purpose:
- To investigate left ventricular blood flow dynamics in relation to the origin of VPCs.
- To characterize blood flow patterns using pulsed Doppler echocardiography.
- To differentiate flow dynamics based on VPC origin (right vs. left ventricle).
Summary:
- Pulsed Doppler echocardiography examined left ventricular outflow, central, and inflow tracts in 18 VPC patients.
- VPCs originating from the right ventricle showed preserved left ventricular ejection flow.
- VPCs originating from the left ventricle, particularly with left axis deviation, demonstrated significant flow disturbances, including apical backflow and diminished ejection flow.
Impact:
- The study reveals that the site of VPC origin significantly influences left ventricular ejection flow dynamics.
- Left ventricular VPCs cause more pronounced flow disturbances than right ventricular VPCs.
- Understanding these dynamics is crucial for assessing cardiac function during arrhythmias.
Abstract:
Cardiac function at the time of ventricular premature contractions (VPC) is influenced by the coupling interval or the site of those origin. Clinical and experimental studies of the effects of VPC on intracardiac pressure dynamics have been performed; however, little is known about left ventricular blood flow dynamics. This study was attempted to determine the characteristics of blood flow dynamics in respect to the site of origin of VPC using pulsed Doppler echocardiography. The subjects consisted of 18 cases with VPC but without apparent organic heart disease. Seven cases had VPCs with a left bundle branch block pattern suggesting possible origin in the right ventricle. The other 11 cases had VPCs with a right bundle branch block pattern indicating the left ventricular origin. With the probe in the apical position, the blood flow patterns of the left ventricular outflow, central and inflow tracts were examined. The results were as follows; 1. Except for one case with shortened coupling interval, all six cases with VPCs originated from the right ventricle showed preservation of left ventricular ejection flow. 2. In two of the three cases with VPC which originated from the left ventricle and with left axis deviation, systolic flow in the left ventricular central area showed "back flow" to the apex. Ejection flow at the outflow tract was markedly diminished or disappeared in all three cases. 3. In all eight cases with VPC which originated from the left ventricle and with right axis deviation, ejection flow was slightly disturbed both in the left ventricular outflow and in the central area. 4. Ejection flow volume assessed by velocity integral indicated similar dynamics as did the ejection flow velocity. 5. In left ventriculography, asynchrony due to dyskinetic motion of the anteroapical wall was observed at the times of VPCs with left axis deviation. In conclusion, the patterns of left ventricular ejection flow dynamics depend on the site of origin of VPCs. This disturbed flow is more apparent in VPCs originating from the left ventricle compared to the right ventricle. This is especially true in cases with left axis deviation, in which VPCs arise from the posterior site of the left ventricle.