procainamide ( 1 ) lengthened the effective refractory period of the right ventricle , ( 2 ) affected the tachycardia zone , ( 3 ) reduced ventricular rate during tachycardia , and ( 4 ) lengthened the interval between the tachycardia-initiating premature ventricular beat and the first qrs complex of tachycardia .
C0033216
procainamide
C0151636
premature ventricular beat