Ventricular arrhythmia in untreated newly presenting hypertensive patients compared with a matched normal population

There is evidence to suggest that hypertensive patients are at increased risk of sudden death. However, to date this evidence is restricted to treated hypertensives and it is not clear whether this risk is due to the hypertension itself, its treatment, or its long-term consequences. This study has investigated, by 24-h ambulatory electrocardiography, a total of 58 newly diagnosed hypertensive patients who have never previously been treated and compared the first 50 of them with 50 matched control subjects. The results show that there is an increased prevalence of ventricular arrhythmia in hypertensive patients, compared with normal controls, and that this arrhythmia is present from the outset and thus not dependent on treatment or the development of long-term complications. Multivariate analysis showed that age (positive correlation) and potassium (negative correlation) made the most important independent contributions to the prevalence of arrhythmia in these patients, but even so only accounted for about 33% of the observed arrhythmia. This suggests that the precursors of arrhythmia in hypertension are multifactorial. One other factor appeared to make an important contribution to ventricular arrhythmia in these patients. In contrast to recent evidence from the study of treated hypertensives, the prevalence of ventricular arrhythmia was significantly lower in patients exhibiting electrocardiographic evidence of left ventricular hypertrophy. However, left ventricular hypertrophy did also appear to sensitize the myocardium to the arrhythmogenic effect of low serum potassium levels. These findings may help to explain some of the previous confusion surrounding treatment, hypertension and ventricular arrhythmia.