Cardiac pacing in intensive care.
Cardiac pacing techniques and equipment have developed dramatically in recent years. Bradycardias and tachycardias may be effectively treated by pacing. Bradyarrhythmias: It is generally accepted that pacing is indicated for a sustained symptomatic bradycardia. Prophylactic pacing for 'high-risk' bundle branch block in acute myocardial infarction is more controversial. A new era in cardiology has been introduced with the advent of 'physiological pacing', i.e. pacing of the heart with the maintenance of atrioventricular synchrony and varying the heart rate according to the body's metabolic leads. Modern pacing systems, which allow the atria and ventricles to contract in sequence, improve cardiac haemodynamics, result in subjective improvement and increase exercise tolerance. There are, however, pacemaker-associated and pacemaker-mediated tachyarrhythmias. Further advances in technology should overcome these problems. Tachyarrhythmias: Intracardiac electrocardiograms are often useful in the diagnosis of tachyarrhythmias, especially wide complex tachycardias. Rapid pacing of the atria in certain supraventricular tachycardias or of the ventricle in ventricular tachycardia is an alternative to cardioversion in many instances. This form of treatment is usually utilised in conjunction with drug therapy.