during diagnostic cardiac catheterization for the evaluation of chest pain , his bundle electrograms were obtained in 32 male patients before and 2 to 5 minutes after each of two interventions known to acutely affect left ventricular volume and left ventricular end-diastolic pressure ( the injection of 40 to 60 cc of contrast medium during left ventriculography and the administration of 0.4 mg of sublingual nitroglycerin ) .
C0018787
cardiac
C0225897
left ventricular