EFFECT OF ACUTE VENTRICULAR PRESSURE CHANGES ON QRS DURATION

The effect of acute changes in ventricular pressure is examined on the QRS duration to clarify the mechanism of ventricular pressure-related arrhythmogenesis. Ventricular pressure was changed acutely by arteria l transfusion-bleeding into an open-air ventricular pressure reservoir that was either off or on a metaraminol intravenous drip. While maint aining ventricular pressure at several levels, the QRS duration was me asured at 200 mm/s paper speed. The QRS duration correlated significan tly with the left ventricular pressure in all 14 dogs examined. An ave rage change in ventricular by 100 mmHg was associated with a change of about 18% in the QRS duration. An acute ventricular pressure elevatio n impairs the ventricular conduction, which may contribute to ventricu lar pressure-related arrhythmogenicity.