Carotid Sinus Massage During Head-up Tilt Testing Can Predict the Test Outcome: Implications for Its Use as a Screening Tool in Patients with Unexplained Syncope

Head-up tilt testing (HUT) has been used for decades in the work-up of patients presenting with syncope and a suspected reflex etiology. Different protocols have been used with varying sensitivity and specificity. The standard protocols are relatively long, with various maneuvers employed to elicit a response and potentially abbreviate the test. The role of carotid sinus massage (CSM) as a provocative maneuver has not been well studied. The objective of this study was to assess whether CSM could predict the outcome of HUT. Fifty consecutive patients who had been referred for head-up tilt table testing were prospectively enrolled in the study. All patients underwent an identical protocol that involved provocation with CSM both initially in the supine posture and at the end of 30 min of HUT. Seventeen out of 50 (34%) patients ultimately had a positive tilt table test result. Fifteen of these 17 patients had a significant vasodepressor response (symptomatic blood pressure drop of >20 mmHg) without significant bradycardia (heart rate of <50 bpm) during the initial CSM in the supine posture. Of the 33 patients with a negative tilt table result, none had a vasodepressor response to CSM. The sensitivity of CSM in detecting a patient who would ultimately have a positive tilt table test was 88.24% (95% confidence interval [CI], 63.56%-98.54%), while the specificity was 100% (95% CI, 89.42%-100.00%). CSM performed in the supine posture at the beginning of a tilt table test was highly sensitive and specific for the outcome of the test after completion of the entire protocol. Based on these findings, CSM may obviate the need for completion of the protocol for diagnostic reasons.