- Complete blood count – normal
- Complete metabolic panel – normal
- Thyroid studies – normal
- Fasting lipid panel – normal
- Initial cardiac markers – normal except CPK slightly elevated at 698 (expected following defibrillation)
- Urine drug screen – negative
- Sickle cell screen - normal
Studies performed during initial hospitalization:
- EKG on arrival revealed inverted T-waves in Leads III, aVR, and aVF. Initial QTc interval noted to be 471ms. Repeat EKG examination of subsequent days showed normalization of T-wave pattern (see Figure 2), however, QTc continued to be prolonged (longest QTc 478ms).
- Cardiac catheterization revealed normal coronary arteries.
- Transthoracic 2-D echocardiogram revealed mild mitral regurgitation, mild tricuspid regurgitation, and mild pulmonary insufficiency – all resolved on subsequent exams. Ejection fraction was noted to be normal.
Studies performed at Mayo Clinic:
- Consultation EKG revealed normal T-wave pattern with normal QTc of 422ms. Repeat EKG at 3 month follow-up continued to show normal findings.
- High lead Brugada protocol EKG was normal with no evidence of Brugada Syndrome or QTc prolongation
- Holter monitor worn for 24 hours revealed no prolonged arrhythmias and no events noted.
- Cardiac MRI revealed normal anatomy. In addition, no evidence of ARVC was noted.
- Treadmill stress test at maximal exertion (evidenced by VO2max monitoring) was normal without inducible arrhythmia.
- Isoproterenol challenge was normal with no inducible arrhythmia.
- EP study revealed no inducible monomorphic ventricular arrhythmia with or without isoproterenol. However, external triple stimuli induced ventricular fibrillation.
During his initial hospitalization, the patient was evaluated by two independent cardiologists and an EP specialist. All three of these physicians came to the same initial diagnosis – presumed Long QT Syndrome. Because the patient survived a syncopal event, internal cardiac defibrillator (ICD) was recommended. As per the 36th Bethesda Conference Guidelines (2), these physicians also recommended that patient no longer participate in competitive athletics. The patient and his family were reluctant to accept these recommendations and refused ICD placement. At the patient and family’s request, the primary team proposed placement of an external defibrillator vest and further consultation at the Long QT Clinic at Mayo Clinic. Patient and family agreed to this plan. External defibrillator vest was placed prior to travel and the patient was evaluated at the Mayo Clinic within one week of his initial event.
Click here to continue. Challenge yourself by writing down a revised, working diagnosis before moving to the next slide.