The management of cardiac arrhythmias.

The first and most important aspect of the management of a cardiac arrhythmia is its precise identification, and intracardiac recordings should be made in cases of doubt. When confronted with a patient with an arrhythmia the first decision is whether it needs treating at all. If it does the next problem is to decide whether to begin with electrical or pharmacological treatment, and here the important feature is the clinical state of the patient: the more ill the patient and the larger the haemodynamic disturbance, the greater the relative indication for electrical (cardioversion or pacing) therapy. Although there has been some progress in the understanding of the pathological physiology of arrhythmias and attempts have been made to rationalize the classification of cardioactive drugs, these sciences have not so far provided information of clinical value. The drug therapy of arrhythmias is largely arbitrary, but few drugs are involved. The most important thing of all is for an individual clinician to become familiar with the most significant of these drugs and not to indulge in polypharmacy, because all antiarrhythmic drugs can lead to either depression or overexcitation of the myocardium.