Treatment of Stokes-Adams disease by external electric stimulation of the heart.

An external cardiac pacemaker was developed and was used to stimulate the heart electrically in a series of patients with recent Stokes-Adams syncope. It resuscitated patients from attacks due to ventricular standstill; it maintained an adequate circulation during persistent ventricular standstill ; and it prevented the recurrence of irregular ventricular tachycardia. Several patients have now survived for many months without recurrent syncope. Such long survivals suggest that the periods of cardiac disturbance which cause syncope may subside if the patient is kept alive during the crucial period. T HE syncopal attacks of Stokes-Adams disease are unpredictable and often present desperate therapeutic problems. These episodes of circulatory arrest due to ventricular standstill, tachycardia or fibrilla-tion may become very frequent and severe. A fatal attack is always imminent. Furthermore, the available therapy with drugs and cardiac puncture is dangerous and may be ineffective in resuscitating patients from individual attacks or in maintaining adequate ventricular rhythms. We have developed a new therapeutic approach to this serious problem. This consists of electric stimulation of the heart by means of an externally-applied cardiac pacemaker which terminates ventricular standstill and maintains regular externally-paced ventricular beats until an adequate, spontaneous ventricular rhythm reappears. After experimental studies in animals established the efficacy and safety 482 of this procedure, it was used in the treatment of patients with recent Stokes-Adams attacks. APPARATUS The cardiac pacemaker* is a modification of existing physiologic stimulators. It produces mono-phasic, rounded electric impulses with an average duration of 2 to 3 milliseconds and with the entire wave form lying above the baseline. A variety of other wave forms (monophasic and biphasic spike, monophasic and biphasic rectilinear, and sinusoidal) were found to be less effective. The apparatus is light, portable and simple t~ use, with two controls permitting variation of frequency from 30 to 180 stimuli per minute and of amplitude from 0 to 150 volts. The low internal impedance of the instrument (approximately 50 ohms) permits adequate power output even across low body resistances. In the design of the instrument, the line voltage is carefully isolated to prevent its accidental transfer to the output circuit. The pacemaker is attached to the patient by two output wires connected to 3 cm. circular chest electrodes. The electrodes may be placed in any positions on the chest that provide current flow across the heart. For convenience, the negative electrode is placed at the point of maximum cardiac …