Positive GTN Tilt Table Test

20 minutes into the test both systolic blood pressure and heart rate are steady. Following 400 mcg of sublingual GTN the heart rate rose from 90 beats per minute to 150 beats per minute while the systolic blood pressure drifted down from 110 mmHg to 80 mmHg. The heart rate then suddenly dropped to 80 beats per minute accompanied by a swift fall in systolic blood pressure to 20 mmHg at the point of syncope. The patient experienced his usual symptoms prior to blacking out. He made a quick recovery on lying flat.