Diagnostic electrophysiological study in a highly trained young woman with presyncopal symptoms during exercise: a case report

Right ventricular outflow tract (RVOT) ventricular tachycardia (VT) is frequent and occurs in patients without structural heart disease, especially in highly trained athletes. Most of the studies on cardiac adaptations to exercise have been investigated in male athletes. Women, however, are increasingly participating in sports and electrical and structural adaptations in male and female athletes differ significantly. These cardiac adaptations dissimilarities between males and females have potential implications in diagnosing certain types of arrhythmias. We present here a case of a 35-year-old highly-trained woman endurance athlete that attended the clinic complaining about chest pain and dyspnea on exertion, dizziness and presyncope occurring during maximum-intensity exercise training sessions. An exercise stress testing was performed on cycle ergometer. The test elapsed normally until the patient reached a heart rate of 169 bpm, when she presented identical symptoms to those described during the first interview in the clinic. A wide-complex and notched QRS tachycardia was observed in the inferior leads, inferior axis leads and transition from leads V4 to V5, suspending the test immediately. The patient was referred to perform an electrophysiological study and eventually radiofrequency catheter ablation in order to eliminate the culprit VT. Precocity occurred in the posterior lateral wall of the RVOT, immediately below the pulmonary valve. Radiofrequency application in the arrhythmogenic focus suppressed all ectopic activity despite maintaining isoproterenol infusion. After 30 minutes, the effect was maintained, and the ectopic focus was successfully ablated. The recognition of this clinical entity in females may be challenging since cardiac remodeling in response to exercise may be invaluable due to their biological, anatomical, and hormonal characteristics. In effect, electrical and structural adaptations in males and females may differ considerably. Both exercise stress testing and diagnostic electrophysiological study represent essential and invaluable tools to reach a final diagnosis, especially in highly trained females.