Differentiation between right and left ventricular origin of premature beats can be useful clinically.
The origin of ectopic ventricular beats are recognized best in lead V1 (oriented to differentiate right vs. left sided cardiac activity).
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PVCs arising from the right ventricle have a left bundle branch block morphology (dominant S wave in V1)
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PVCs arising from the left ventricle have a right bundle branch block morphology (dominant R wave in V1)
Left Ventricular premature beats are more often associated with heart disease and may precipitate ventricular fibrillation, whereas right ventricular premature beats are commonly seen in individuals with normal hearts.
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References
Wagner, Galen. Chapter 15 - Premature Beats. Marriott's Practical Electrocardiography, 12th Edition. 2013