Assessment of the vasodepressor reflex in carotid sinus syndrome.
BACKGROUND
Assessment of the vasodepressor reflex in carotid sinus syndrome is influenced by the method of execution of the carotid sinus massage and the coexistence of the cardioinhibitory reflex.


RESULTS
Carotid sinus massage reproduced spontaneous symptoms in 164 patients in the presence of hypotension or bradycardia (method of symptoms). When an asystolic pause was induced, the vasodepressor reflex was reassessed after suppression of the asystolic reflex by means of 0.02 mg/kg IV atropine. An isolated vasodepressor form was found in 32 (20%) patients, who had lowest systolic blood pressure (SBP) of 65±15 mm Hg. Of these, only 21 (66%) patients had an SBP fall ≥50 mm Hg, which is the universally accepted cut-off value for the diagnosis of the vasodepressor form. Conversely, a lowest SBP value of ≤85 mm Hg (corresponding to the fifth percentile) detected 97% of vasodepressor patients, but was also present in 84% of the 132 patients with an asystolic reflex. These latter patients had both asystole ≥3 s (mean 7.6±2.2 s) and SBP fall to 63±22 mm Hg: in 46 (28%) patients, symptoms persisted after atropine (mixed form), in the remaining 86 (52%) patients, symptoms did not (cardioinhibitory form) persist.


CONCLUSIONS
The current definition of ≥50 mm Hg SBP fall failed to identify one third of patients with isolated vasodepressor form. A cut-off value of symptomatic SBP of ≤85 mm Hg seems more appropriate, but it is unable to identify cardioinhibitory forms. In asystolic forms, atropine testing is able to distinguish a cardioinhibitory form from a mixed form.
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Diana
D
Solari
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Roberto
R
Maggi
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Daniele
D
Oddone
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Alberto
A
Solano
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Francesco
F
Croci
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Paolo
P
Donateo
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.).
Wouter
W
Wieling
From the Department of Cardiology, Arrhythmologic Center, Ospedali del Tigullio, Lavagna, Italy (D.S., R.M., D.O., A.S., F.C., P.D., M.B.); and Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands (W.W.). mbrignole@ASL4.liguria.it.
Michele
M
Brignole
D000368:Aged; D000369:Aged, 80 and over; D001285:Atropine; D017704:Baroreflex / Q000187:drug effects* / Q000502:physiology; D001794:Blood Pressure; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008405:Massage; D011187:Posture; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013575:Syncope / Q000175:diagnosis*; D019462:Syncope, Vasovagal / Q000175:diagnosis*; D013577:Syndrome
D001285:Atropine
atropine; blood pressure; hypotension; nervous system; syncope