Effects of long-term vasodilator therapy in patients with carotid sinus hypersensitivity

• Published in: The American heart journal Vol. 136; no. 2; pp. 264 - 268
• Main Authors: Brignole, Michele, Menozzi, Carlo, Gaggioli, Germano, Musso, Giacomo, Foglia-Manzillo, Giovanni, Mascioli, Giosuè, Fradella, Giuseppe, Bottoni, Nicola, Mureddu, Roberto
• Format: Journal Article
• Language: English
• Published: New York, NY Mosby, Inc 01.08.1998; Elsevier
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Blood Pressure - drug effects; Carotid Sinus - innervation; Drug toxicity and drugs side effects treatment; Female; Heart Arrest - chemically induced; Homeostasis - drug effects; Humans; Long-Term Care; Male; Massage; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Pressoreceptors - drug effects; Reflex, Abnormal - drug effects; Risk Factors; Syncope - chemically induced; Syndrome; Toxicity: cardiovascular system; Vasodilator Agents - administration & dosage; Vasodilator Agents - adverse effects; Venous Pressure - drug effects; Human; Nervous system diseases; Vasodilator agent; Pathophysiology; Toxicity; Consciousness impairment; Calcium antagonist; Exploration; Slow release form; Nitrates; Long term; Concomitant disease; Syncope; Arterial hypotension; Diseases of the autonomic nervous system; Blood pressure; Massage; Neurological disorder; Carotid sinus; ACE inhibitor; Hypersensitive carotid sinus syndrome
• DOI: 10.1053/hj.1998.v136.89911
• ISSN: 0002-8703

Background In patients affected by carotid sinus hypersensitivity, long-term vasodilator therapy might increase the risk of syncopal episodes by reducing systolic blood pressure and venous return to the heart. Methods and Results Thirty-two patients (mean age 73 ± 9 years; 20 men) who met all the following criteria were included: (1) one or more episodes of syncope occurring during long-term (>6 months) treatment with angiotensin-converting enzyme inhibitors, long-acting nitrates, calcium antagonists, or a combination of these; (2) a positive response to carotid sinus massage, defined as the reproduction of spontaneous syncope in the presence of ventricular asystole ≥3 seconds or a fall in systolic blood pressure ≥50 mm Hg; (3) negative workup for other causes of syncope. The patients were randomly assigned to continue or to discontinue use of vasodilators; carotid sinus massage was repeated 2 weeks after randomization. By the end of the study period, the baseline values of systolic blood pressure were significantly different between the 2 groups of patients both in supine (P =.01) and upright (P =.03) positions. Syncope had been induced by carotid sinus massage in 81% of patients in the “on-vasodilator” group and in 62% of patients in the “off-vasodilator” group (P =.21). The cardioinhibitory reflex was of similar magnitude in the 2 groups, being found in 50% of the patients in each group, with a maximum ventricular pause of 7.1 ± 2.7 and 6.7 ± 1.8 seconds, respectively. The percentage decrease of blood pressure did not differ between the 2 groups, even if, in absolute values, the baseline difference of blood pressure roughly persisted for the duration of the test. In consequence of that, the rise of blood pressure to similar values was delayed approximately 30 seconds in the “on-vasodilator” group and took more than 2 minutes to return to baseline values. Conclusions In patients affected by carotid sinus hypersensitivity, chronic vasodilator therapy does not have a direct effect on carotid sinus reflexivity, although the delayed recovery of pretest blood pressure values could indirectly potentiate the severity of the clinical manifestations of the syndrome. The persistence of hypotension for a longer time after the end of the massage suggests that vasodilators cause an impairment of compensatory mechanisms. (Am Heart J 1998;136:264-8.)