[Thoracic transcutaneous cardiac pacing].

Transcutaneous cardiac pacing was abandoned when endocardial pacing was developed, but it has now come back, with a new methodology, in cardiological intensive care. Its safety and efficacy have been improved by 50 to 100 sq. cm electrodes, impulses of 20 to 40 ms duration and programmed energy.

[Then hemodynamic efficacy of transcutaneous cardiac stimulation].

Bradyarrhythmia or asystole is the most common rhythm disturbance with ventricular fibrillation and tachycardia, for 30-40% of patients admitted in intensive coronary care units. Already use in the therapy of bradyarrhythmia or asystole, as a method of emergency, immediately in place, the external pacing is very useful in an out of hospital therapy with personnel skilled in its use until the initiation of support therapy in coronary care units. Actually, with less significant side effects (no severe pain, no strong muscular contractions, no skin burns) and a best innocuity and tolerance based on the employment of larger adhesive pre-gelled patches, temporary transcutaneous cardiac stimulation is not only confined to unconscious patients but also in case of severe bradycardia, complete AV block in conscious patients.

Directional variability of stimulation threshold measurements in isolated guinea pig cardiomyocytes: relationship with orthogonal sequential defibrillating pulses.

Reports on delivery of separated orthogonal pulses markedly improving cardiac defibrillation have suggested that the stimulation threshold of heart fibers varies in accordance with their orientation within the electric field. The present work was aimed at investigating the directional variability of stimulation thresholds in isolated guinea pig cardiomyocytes. This variability was measured in 48 single myocytes by rotating each one through a theta (theta) angle between two-fixed parallel electrodes 1.

Reduction of energy required for defibrillation by delivering shocks in orthogonal directions in the dog.

Reduction of energy required to defibrillate (ERD) seems to represent a necessary condition for intensive development of implantable defibrillator, so as for minimization of cardiac and pulmonary damages provoked by high energy transthoracic defibrillation electric shocks. The present work describes a defibrillation method using shocks delivered in orthogonal directions and separated by a 100 ms delay. Defibrillation threshold measured with classical unidirectional shocks on 30 dogs has been found to be 286.