Various types of supraventricular and
ventricular tachyarrhythmias causing severe clinical symptoms may be refractory to coventional antiarrhythmic
therapy. In a large number of cases, electrotherapeutical approaches such as DC-
cardioversion and cardiac pacing are effective in controlling ectopic
tachycardias. Electrical pacing offers certain advantages over standard DC-
cardioversion for the termination of
tachycardias: 1. No
general anesthesia is required. 2. Digitalis induced arrhythmias may be abolished, a situation in which DC-
cardioversion is dangerous and usually ineffective. 3. Pacing can be effected rapidly, simply and repeatedly leaving the pacing
catheter in place. At the present time different modes of cardiac pacing techniques are in use in order to suppress supraventricular, junctional and
ventricular tachycardias. These are: rapid atrial stimulation, overdrive pacing, coupled stimulation, patient initiated atrial pacing, precisely timed single or multiple premature stimulation, and programmed rate-related stimulation. Rate-related interval stimulation may be useful when applied in
drug-resistant junctional and
ventricular tachycardias or runs of
ventricular extrasystoles as precursors of a
tachycardia. DC-
cardioversion as well as the pacing techniques proved to be low risk alternative methods for treatment of
tachyarrhythmias unresponsive to
drug therapy.