<b>Usefulness of Head-up Tilt Test in the Evaluation and Management of Unexplained Syncope or Pre-syncope</b>

Abstract

SUMMARYThis study included 87 consecutive patients with unexplained syncope or pre-syncope who had undergone the head-up tilt (HUT) test with concomitant isoproterenol infusion. A positive response was defined as development of syncope or pre-syncope in association with substantial hypotension (decline of systolic blood pressure > 20 mmHg). Coronary artery spasm was suggested from the clinical symptoms and electrocardiographic findings in 1 patient (1 / 87 = 1.1%). Intolerance to isoproterenol infusion was noted in 8 cases (8 / 87 = 9%). Of the 78 patients who completed the study, 73 showed positive responses (73 / 78 = 94%). (baseline systolic blood pressure = 125 ± 23 mmHg vs endpoint systolic blood pressure = 76 ± 11 mmHg, p < 0.05; baseline heart rate = 73 ± 14 beats per minute vs endpoint HR = 80 ± 24 beats per minute, p < 0.05). In 73 patients who showed positive responses, the systolic blood pressure (SBP) and heart rate (HR) returned to a safe level at 2 minutes when the patients were returned to a supine position (post-study 2 minutes SBP = 124 ± 18 mmHg vs baseline SBP = 125 ± 23 mmHg, p = NS; post-study 2 minutes HR = 82 ± 18 beats per minute vs baseline HR = 73 ± 14 beats per minute, p < 0.05). All 73 patients with a positive HUT test received Atenolol therapy (50 mg daily). Only 35 of these 73 patients took Atenolol regularly and had a repeat HUT test. After atenolol therapy, persistent positive responses were observed in 19 cases (19 / 35 = 54%) and negative responses were noted in 16 cases (16 / 35 = 46%). The mean dosage of isoproterenol needed to provoke a positive HUT test in 19 patients who had received Atenolol therapy and had a positive repeat HUT test was 2.3 ± 1.2 µg / min at baseline and 3.5 ± 0.9 µg / min for post-Atenolol therapy (p < 0.001). Sixteen patients with a negative repeat HUT test were treated continuously with Atenolol and followed for a mean period of 13 ± 11 months (range, 1-34 months). All 16 patients were free of syncope or pre-syncope during the period of follow up. In conclusion, the HUT test is mostly well tolerated and safe, even though the test has a low rate of adverse effects. Atenolol is effective for the prevention of provoked or spontaneous recurrent syncope or pre-syncope. (Jpn Heart J 2000; 41: 623-631)

Can Type of Dizziness Influence the Vestibular Caloric Test Result?

“…The most important parameter for the quantitative evaluation of caloric test is the maximum Slow-Phase Velocity (SPV) of the nystagmus in degrees per second. 15 - 19 …”

“…The most important parameter for the quantitative evaluation of caloric test is the maximum Slow-Phase Velocity (SPV) of the nystagmus in degrees per second. [15][16][17][18][19] The 4 responses were represented by the subsequent codes: WR-warm stimulus in right ear; WL-warm stimulus in left ear; CR-cool stimulus in right ear; CL-cool stimulus in left ear. 20,21…”

“…14,21 Pre syncope Symptoms of pre transient loss of consciousness, characterized by rapid onset, short duration and spontaneous complete recovery. 15 Lightheadedness Symptoms of brief dizziness, unsteadiness triggered with changes in position. 21 Unilateral Weakness (UW) or Canal Paresis (CP) and Directional Preponderance (DP) were characterized by the follow formulas.…”