ABSTRACT
Efficacy of external defibrillation of the heart with low energy (
Subject(s)
Electric Countershock/instrumentation , Tachycardia, Sinus/therapy , Ventricular Fibrillation/therapy , Adult , Aged , Aged, 80 and over , Female , Hospitalization , Humans , Male , Middle Aged , Tachycardia, Ventricular/therapy , Ventricular Fibrillation/rehabilitationABSTRACT
The thorax impedance (TI) was measured in 230 patients with atrial and ventricular rhythm impairments according to L. Geddes et al. Gauze napkins moistened in physiological solution (PS) and in 7% hypertonic solution NaCl (HS) were used as contact material. The electrode diameter was approx. 12 cm. The use of HS was shown to bring about a TI decrease by 21% (from 77.0 +/- 0.9 to 61.0 +/- 1.0 ohm) versus the former. A high TI (60-146 ohm) was registered in 41 of 230 patients for whom PS was applied. HS ensures a TI decrease by 17% (to 79-128 ohm). Forty-six patients with atrial fibrillation underwent the electropulse therapy (EPT). Low-energy bipolar discharges (< or = 65 J.) were effective in 31 (67.5%) of 46 patients, < or = 65 J. Discharges were more effective in patients with TI < or = 60 ohm versus patients with TI > 60 ohm (76.7 and 52%, respectively, p = 0.04). With HS the efficiency of bipolar < or = 90 J. discharges reached 83% (38/46). According to estimates, at least one more 100-115 J. discharge would be needed for 7 patients to ensure the similar EPT efficiency with PS.
Subject(s)
Atrial Fibrillation/therapy , Electric Countershock , Myocardial Ischemia/complications , Anti-Arrhythmia Agents/therapeutic use , Atrial Fibrillation/drug therapy , Atrial Fibrillation/etiology , Cardiography, Impedance , Electric Impedance , Electrodes , Humans , Saline Solution, Hypertonic , Treatment OutcomeABSTRACT
The efficacy of low-energy bipolar pulse is studied in 41 patients with sudden heart arrest caused by ventricular fibrillation (VF). Maximal energy of effective charges during defibrillation of patients with or without acute myocardial infarction and primary VF (30 episodes) was only 90 J x 1-2. For eliminating secondary VF (76 episodes), maximal energy of 165-195 J x 1-5 was needed in only 25% patients. Total efficacy of charges of at least 115 J x 1-2 in patients with primary and secondary VF was 87%. The results indicate a high efficacy of low-energy bipolar sinusoidal charges for elimination of VF in patients with acute myocardial infarction and other forms of coronary disease.
Subject(s)
Electric Countershock , Ventricular Fibrillation/therapy , Adult , Aged , Aged, 80 and over , Electric Countershock/methods , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Myocardial Infarction/complications , Ventricular Fibrillation/etiologyABSTRACT
Two widely used forms of defibrillating pulse were compared in experiments on narcotized dogs weighing 7 to 39 kg. Gurvich quasisinusoidal bipolar pulse was found to be much more effective than Edmark's critically dampered sinusoidal monopolar pulse. A close direct correlation between body weight (m) and threshold values of current (I) was found characteristic of both pulse forms. The following regression equations were derived: I = 0.32.m + 3.78 for a bipolar pulse and I = 0.76.m + 2.5 for monopolar one. A bipolar noncardiosynchronized pulse during exposure of an intact heart was found to induce a far less in duration reversible ventricular asystole and a much rarer development of fibrillation of cardiac ventricles.
