Prevention and treatment of supraventricular arrhythmias

In the absence of underlying cardiac disease, atrial arrhythmias may be of little significance other than causing a sensation of palpitation. They are usually self limited and rarely have serious hemodynamic consequences. Occasionally, they can cause symptoms of cerebral ischemia. In the presence of underlying cardiac disease, however, they may be very important. With underlying coronary artery disease, the higher myocardial oxygen requirements caused by the rapid heart rate plus the reduction of time spent in diastole, the part of the cardiac cycle when coronary blood flow is greatest, may provoke symptoms of angina or, rarely, infarction itself. If there is underlying mitral stenosis, the decrease in diastolic filling time may produce high left atrial pressures which may cause pulmonary edema in severe cases. The loss of effective atrial systole in hypertrophic states, such as hypertrophic myopathies or aortic valve disease, may seriously reduce left ventricular filling with corresponding severe reductions in cardiac output. Even in the absence of underlying pathology, if the tachyarrhythmias are prolonged or refractory to treatment, they may lead to deterioration of myocardial function. This review examines the mechanisms of origin, clinical significance, treatment, and prevention of supraventricular tachyarrhythmias.