CHARACTERISTICS AND INFLUENCE OF DIFFEREN T CLINICAL FORMS ON THE EVOLUTION AND PROGNOSIS OF CAROTID-SINUS SYNDROMES - RESULTS IN 215 CASES

The carotid sinus syndrome is a well-known cause of syncope: the cardi o-inhibitory forms are the easiest to diagnose and probably the easies t to treat. However, the vasodepressive forms are as common but their outcome is mainly unknown. Eight hundred and fifty-three patients unde rwent endocavitary electrophysiological studies with invasive blood pr essure measurement for unexplained syncope between October 1984 and Ja nuary 1990. A carotid sinus syndrome was diag nosed in 215 cases. Fift y-two patients (24.2 %) had a cardio-inhibitory form (ventricular stan dstill greater than or equal to 3 s during carotid sinus massage), 40 (18.6 %) had a pure vasodepressive form (isolated fall of systolic blo od 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 t he 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 fo rms were more often associated with a history of transient ischaemic a ttacks (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 < 0.0 5), 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 p acemaker 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 patien ts, reduction of antihypertensive and/or potentially bradycardia-induc ing drugs in 30 patients, prescription of antiarrhythmic therapy in 30 patients. In comparison with cardio-inhibitory forms, the vasodepress ive forms were characterised by a higher cardiovascular death rate (11 .4 vs 2 %), sudden death rate (9 vs 0 %), full-blown or transient cere brovascular accidents (9 vs 0 %). In vasodepressive forms, 36 % of sur vivors had a stable functional status. These results show that the car otid sinus syndrome is a disorder of the autonomic nervous system affe cting mainly elderly patients. The vasodepressive forms are usually ob served in polyvascular disease; the difficulties in their treatment an d the difference in prognosis justifies their recognition.