the study was performed using physiological stress , such as the valsalva manoeuvre , isometric exercise and treadmill exercise , to initiate ventricular arrhythmias before and after intravenous propranolol or labetalol and to document arrhythmias during 24 hour electrocardiography before and after oral medication .
C0085612
ventricular arrhythmias
C0003811
arrhythmias