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Epicardial activation of the human ventricle: effects of left ventricular hypertrophy
Insights
Left ventricular hypertrophy significantly alters epicardial activation patterns in the human heart. This condition leads to fewer left ventricular breakthrough points and delayed activation, potentially due to increased wall thickness.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Anatomy
Background:
- Left ventricular hypertrophy (LVH) is a common cardiac condition.
- Understanding its impact on heart electrical activation is crucial for patient management.
Purpose of the Study:
- To investigate the effects of left ventricular hypertrophy on epicardial activation patterns in the human heart.
Main Methods:
- Intraoperative epicardial mapping was conducted in 10 patients with LVH undergoing aortic valve replacement.
- Mapping involved 40 to 66 points per patient.
- Left ventricular mass and contraction were assessed.
Main Results:
- Earliest epicardial activation consistently occurred in the anterior right ventricle.
- Patients with LVH exhibited fewer left ventricular breakthrough points compared to controls (p < 0.001).
- Latest epicardial activation was more frequently observed at the left ventricular base in patients with LVH (p < 0.001).
Conclusions:
- Left ventricular hypertrophy is associated with significant alterations in epicardial activation patterns.
- These changes may be attributed to delayed electrical signal propagation through thickened ventricular walls.
Abstract:
To determine the effects of left ventricular hypertrophy on epicardial activation of the human heart, intraoperative epicardial mapping of 40 to 66 points was performed in 10 patients undergoing aortic valve replacement. Mean calculated left ventricular mass was 364 +/- 98 g. All patients had normal left ventricular contraction. Earliest epicardial activation occurred in the anterior right ventricle in all patients. In 9 patients, it was the only epicardial breakthrough point. One patient had a single inferior left ventricular breakthrough point. Epicardial activation spread from the right ventricle towards the left ventricle in both the anterior and inferior direction. Latest epicardial activation occurred at the base of the left ventricle in 9 patients and the base of the right ventricle in 1. When compared with patients with coronary artery disease, normal ventricular contraction, and no left ventricular hypertrophy, patients with hypertrophy had fewer left ventricular breakthrough points (p less than 0.001) and were more likely to have latest activation at the left ventricular base (p less than 0.0010. We conclude that left ventricular hypertrophy is associated with marked changes in the pattern of epicardial activation. These changes may reflect delay in spread from endocardium due to the increased wall thickness.