Bidirectional ventricular tachycardia in cardiac sarcoidosis

Abstract

A 73-year-old man with history of pulmonary sarcoidosis was found to have runs of non-sustained bidirectional ventricular tachycardia (BVT) with two different QRS morphologies on a Holter monitor. Cardiac magnetic resonance delayed gadolinium imaging revealed a region of patchy mid-myocardial enhancement within the left ventricular basal inferolateral myocardium. An 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased uptake in the same area, consistent with active sarcoid, with no septal involvement. Follow-up FDG-PET one year later showed disease progression with new septal involvement. Cardiac sarcoidosis, characterized by myocardial inflammation and interstitial fibrosis that can lead to conduction system disturbance and macro re-entrant arrhythmias, should be considered in differential diagnosis of BVT. BVT may indicate septal involvement with sarcoidosis before the lesions are large enough to be detected radiologically.

Keywords: Arrhythmias; BVT, Bidirectional ventricular tachycardia; Cardiac sarcoidosis; ICD, Implantable cardioverter defibrillator; Magnetic resonance tomography; PET, Positron emission tomography; PVC, Premature ventricular contraction; Positron emission tomography; VT, Ventricular tachycardia.; Ventricular tachycardia.

Fig. 1

(A) Rhythm strip with leads II and V (nonspecific ventricular), top and bottom, respectively, showing sinus rhythm and a run of ectopic ventricular beats with two alternating QRS morphologies; the sixth and eighth beats show a left bundle branch block morphology and inferior axis (black X), while the seventh and ninth show a right bundle branch block morphology and inferior axis (white X). This pattern was seen repeatedly on ambulatory monitoring. Note that the degree of the right bundle branch block increases during sinus rhythm; the QRS width in the fourth beat is about 120 ms, compared to approximately 160 ms in the fifth beat. A similar phenomenon is also seen between the tenth and eleventh beats even during a relatively long atrial cycle length of 600 ms. This suggests severe impairment of the conduction system. (B) A 12-lead electrocardiogram showing sinus rhythm with intraventricular conduction delay, with PVCs in a pattern of ventricular bigeminy. The PVCs resembles a left bundle branch block pattern with an inferior axis (arrows).

Fig. 2

Delayed enhancement cardiac magnetic resonance tomography with patchy mid-myocardial enhancement in the basal inferolateral left ventricular myocardium (arrow).

Fig. 3

Fasting 18-fluorodeoxyglucose (FDG) positron emission tomography at baseline (A) showing increased uptake, most pronounced in the basal inferolateral area of the myocardium (arrow), consistent with active cardiac sarcoid, and at follow-up (B), showing increased disease progress with FDG uptake in the basal to mid segments of the anterolateral and basal lateral wall segments as well as new FDG uptake in the basal anteroseptal region.