1Klinikum Fürth Med. Klinik I - Kardiologie Fürth, Deutschland
Patient Presentation:
A 56-year-old male experienced sudden fatigue and measured his heart rate 170/min. Upon the ambulance's arrival an ECG showed a monomorphic ventricular tachycardia with an inferior axis, negative in leads DI and avL (missing precordial leads). The patient was hemodynamically stable. 300 mg of Amiodarone were administered , and the patient was subsequently transported to our emergency department. During transport, the rhythm converted to sinus rhythm with ventricular pacing. His medical history included the implantation of a pacemaker approximately 12 years prior due to third-degree atrioventricular block and an upgrade to a CRT-D device in 2023 for secondary prophylaxis after sustained ventricular tachycardias.
Initial Workup:
Laboratory tests indicated signs of heart failure (pro BNP 6900 pg/ml) and minimally elevated troponin markers, with normal electrolyte levels. The ECG showed sinus rhythm with a heart rate of 66/min and biventricular pacing with occasional ventricular extrasystoles. The echocardiogram revealed a non-dilated, non-hypertrophic left ventricle with an ejection fraction of 47% and no significant valvular pathology. Speckle tracking showed GLS -18% (normal lower limit -17.2%) with reduced segmental strain and time-to-peak strain, raising suspicion of hypokinetic non-dilated cardiomyopathy (HNDC) with basal interventricular septal thinning. The device interrogation detected 15 sustained ventricular tachycardias below the minimum therapeutic threshold (185/min). The monitoring zone and VT1 zone were expanded. An antiarrhythmic therapy with sotalol was initiated.
Diagnosis and Management:
A PET-CT scan was performed by suspicion of cardiac sarcoidosis. The exam showed increased FDG uptake in the antero-basal septum and in the right ventricle, consistent with this diagnosis. There was also FDG-positive lymphadenopathy in the bilateral hilar and mediastinal regions, along with isolated FDG-positive granulomatous changes in the lungs. Prednisolone therapy at 60 mg/day was initiated on top of heart failure management. A myocardial biopsy was suggested, but the patient refused.
Follow Up:
One month after discharge, the patient remained asymptomatic and tolerated sotalol therapy. During the follow-up, there were no sustained or non-sustained ventricular tachycardias, but the biventricular stimulation remained suboptimal (<80%) due to frequent ventricular extrasystoles. Prednisolone dosage was reduced to 30 mg/day until the next two-month follow-up. Following the prednisolone therapy, a reassessment of biventricular stimulation and arrhythmic burden will determine the appropriateness of ventricular extrasystole ablation to ensure biventricular stimulation above 90%.
Conclusions:
Cardiac sarcoidosis remains a challenging diagnosis due to the lack of defined diagnostic criteria. Despite its rarity, young patients with a history of conduction system dysfunction or signs of heart failure should be evaluated for this disease which can manifest as non-dilated or hypokinetic cardiomyopathy, with typical echocardiographic signs including basal septal thinning and abnormal speckle tracking. Arrhythmologically, sarcoidosis may present with both life-threatening bradycardias and tachycardias, as in this case. The Japanese circulation society has the newest guidelines which encompass major and minor criteria to establish this often missed diagnosis.