[Characteristics and influence of different clinical forms on the development and prognosis of carotid sinus syndrome. Apropos of 215 cases].

The carotid sinus syndrome is a well-known cause of syncope: the cardio-inhibitory forms are the easiest to diagnose and probably the easiest to treat. However, the vasodepressive forms are as common but their outcome is mainly unknown. Eight hundred and fifty-three patients underwent endocavitary electrophysiological studies with invasive blood pressure measurement for unexplained syncope between October 1984 and January 1990. A carotid sinus syndrome was diagnosed in 215 cases. Fifty-two patients (24.2%) had a cardio-inhibitory form (ventricular standstill > or = 3 s during carotid sinus massage), 40 (18.6%) had a pure vasodepressive form (isolated fall of systolic blood pressure > 50 mmHg during massage) and 123 patients (57.2%) had a mixed form. The average age was 74.1 +/- 9.7 years with no difference between the different forms. A number of parameters was different on the cardio-inhibitory and vasodepressive forms: the number of men (75.6 vas 24.4%; p < 0.05) and the number of syncopes (83.3 vs 60%; p < 0.02) were greater in the cardio-inhibitory form; the vasodepressive forms were more often associated with a history of transient ischaemic attacks (15 vs 0%), a poor cardiovascular status (hypertension: 47.5 vs 15.7%; p < 0.01), coronary artery disease (47.5 vs 25.5%; p < 0.05), cardiac failure (27.5 vs 11.7%; p < 0.05), induction of sustained supraventricular tachycardia (50 vs 23.5%; p < 0.05) and a greater pacemaker effect (53.6 vs 34.8 mmHg; p < 0.01); of the 191 patients (84.9% of the population) followed up for an average of 21.2 months, 168 received treatment: implantation of a cardiac pacemaker in 108 patients, reduction of antihypertensive and/or potentially bradycardia-inducing drugs in 30 patients, prescription of antiarrhythmic therapy, in 30 patients.(ABSTRACT TRUNCATED AT 250 WORDS)