SEVERE CARDIAC-ARRHYTHMIAS IN ELDERLY SUB JECTS - A PROSPECTIVE HOSPITAL STUDY

The prevalence of arrhythmia increases with age. Considered as an ''or dinary'' event in elderly patients, these arrhythmias may nevertheless have serious consequences. This study was undertaken to determine the clinical, aetiological and prognostic features of serious arrhythmias in a population of elderly subjects (greater than or equal to 70 year s) hospitalised over a 20 months period and comprising 202 patients (1 03 women, 99 men, mean age 79.6 +/- 5.9 years). Supraventricular arrhy thmias are the most common by far (84.2%) : 51.4% of patients had atri al fibrillation, 15.3% had atrial flutter; 12.9% had focal atrial tach ycardia, 4.5% had junctional tachycardia. Of the ventricular arrhythmi as (15.8%), there were 12 sustained ventricular tachycardias, 4 torsad es de pointes and 1 ventricular fibrillation. The increased duration o f hospital stay (10 +/- 6 days on average) is related not to age but t o the type of arrhythmia (longer for ventricular arrhythmias) and to l eft ventricular dysfunction. The main complications of arrhythmias wer e cardiac failure (52.4%), neurological deficits (37.4%) and angina (1 8.6%). Electrocardiographic signs of atrioventricular block were prese nt in 62% of cases and QRS changes in 47.3% of cases. Ventricular arrh ythmias were more commonly associated with intraventricular conduction defects, signs of myocardial necrosis and prolongation of the QT inte rval ; they were also common in patients with left ventricular dysfunc tion and when the left ventricle was dilated. The aetiology of ventric ular arrhythmias was mainly iatrogenic (50%) and ischaemic (21.8%), wh ereas the aetiologies of the supraventricular arrhythmias were varied, 14.7% of cases being idiopathic. Conversion to stable sinus rhythm wa s obtained in half the patients. A pacemaker was implanted in 10.8% of cases. The hospital mortality was 4.9%. This study draws the attentio n to : 1) the preponderance of supraventricular arrhythmias in elderly patients; 2) the precocity of haemodynamics, particularly related to the conservation of atrial systole in this age group; 3) the need to b eware of iatrogenic complications in this population; 4) finally, the intricacy of abnormalities of excitability and of conduction, sometime s sustained by similar histological changes.