Syncope in a Collegiate Rower

Abstract

HISTROTY: A 21 yr collegiate female rower was referred for evaluation of syncope. During freshman year, a screening ECG for evaluation of a heart murmur revealed an abnormal QT interval: notched & prolonged in the chest leads, not lead II. Initial work-up: normal cardiac function & QT shortening. No provocable arrhythmias during a Bruce protocol exercise test. Multiple long QT experts disagreed on interpretation of her ECG. After signing a waiver, she competed her freshman and sophomore year without incident. During jr year, when returning the boat to the boathouse after an intense competition, she developed acute onset of lightheadedness, diminished vision and fell to the floor. She regained consciousness immediately and did not seize or become incontinent. After this event, she was disqualified from participation in competitive sports. PHYSICAL EXAMINATION: BP seated 126/76 mmHg. Pulse 76 bpm and regular. Lungs clear. Cardiac exam: carotids 2+ without bruits. S1 normal, S2 physiologically split. No S3 or S4. Grade I/VI systolic flow murmur unchanged with Valsalva. DIFFERENTIAL DIAGNOSIS: Long QT with Torsades de Pointes Other cardiac arrhythmia causing syncope Orthostatic hypotension with exercise associated collapse (EAC) TESTS AND RESULTS: Rowing ergometer exercise test: Resting HR 78 bpm, QT interval range 443 - 459 msec, no notching. Submax exercise: QTc interval 383 msec.a. Post warm up; bursts of rapid narrow complex tachycardia followed by periods of trigeminy with multi-form couplets which gradually resolved.Max effort: heart rate 183 bpm, QTc interval 389 msec. Post-exercise: One minute post-exercise; narrow complex tachycardia returned, HR 203 bpm. BP normal. upon standing HRT, BP 80/50 mmHg and became symptomatic. when supine, BP and symptoms improved. Arrhythmia persisted. QT interval returned to 440 msec. Arrhythmia broke spontaneously FINAL/WORKING DIAGNOSIS: Possible long QT syndrome Post-exercise syncope precipitated by PAT with orthostatic hypotension TREATMENT AND OUTCOMES: β-blockade therapy and resume dry land training. RevealR heart rate monitor implantation to determine clinical arrhythmia if it recurs. Risk of next syncope being fatal if truly LQTS approx. 5% Genetic scan for known QT channelopathy. Immediate access to AED on training site.