Electrophysiologic effect of indomethacin on the rabbit sinus node.

The anti-inflammatory agent indomethacin has been shown to affect calcium in smooth muscle, cardiac muscle, and cardiac Purkinje cells. This study looked at the action of indomethacin on rabbit sinus node. High doses of indomethacin reduce the slope of diastolic depolarization, spontaneous rate, action potential amplitude and time of repolarization. These results are consistent with a reduction of inward transmembrane movement of calcium.