Autoimmune Myocarditis and Arrhythmogenic Mitral Valve Prolapse: An Unexpected Overlap Syndrome

Figures

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  Figure 1. Diagnostic work-up for myocarditis. Legend. (A) Cardiac magnetic resonance shows hyperintensity in T2-weighted sequences in basal lateral left ventricular wall (upper panel, arrow) and subepicardial late gadolinium enhancement at the same site (lower panel, arrow). (B) Endomyocardial biopsy shows lymphomonocytic inflammatory infiltrates (upper panel, arrows), focal myocyte necrosis, and interstitial edema at hematoxylin eosin assay, associated with spotty replacement fibrosis (lower panel, arrows) at trichrome assay.

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  Figure 2. ECG: Ventricular arrhythmias. Legend. (A) ECG shows sinus rhythm, with frequent premature ventricular complexes of two morphologies, with bigeminal beats and a couple. The dominant clinical morphology is right-bundle branch block superior axis, suggesting an origin from the inferolateral wall of the left ventricle. (B) Ventricular fibrillation episode (49 s, 284 bpm) detected by implantable cardioverter defibrillator and terminated by appropriate shock, three years after immunosuppressive therapy termination.

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  Figure 3. Follow-up restaging of myocarditis. Legend. (A) Cardiac computed tomography shows subepicardial late iodine enhancement in the lateral left ventricular wall (upper panel, arrow), corresponding to baseline findings on cardiac magnetic resonance; at the same time, 18-F fluorodeoxyglucose positron emission tomography scan shows no remarkable myocardial inflammatory activity at the same site (lower panel, arrow). (B) Follow-up endomyocardial biopsy shows rare lymphocytic inflammatory cells (CD3+ < 7 mm2), lack of edema and no cardiac myocyte necrosis (upper panel); fibrosis is the dominant component (lower panel, arrow).

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  Figure 4. Echocardiographic findings. Legend. (A) Parasternal long axis view shows mild mitral valve regurgitation. Associated curling of the basal inferolateral wall is shown as Supplementary Video. (B) As a hallmark of increased arrhythmic risk, Pickelhaube sign (spiked systolic lateral mitral annular velocity >16 cm/s) is shown (arrow).

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  Figure 5. Mapping and ablation. Legend. (A) Intracardiac echography shows the target sites for radiofrequency ablation. In particular, the most common premature ventricular complex morphology originated from the posterior papillary muscle basis (B), whereas the second one, emerging after the targeting of the basal site, arose from the head (H) of the papillary muscle. Ablation catheter tip is shown (arrow). (B) activation map for both PVC morphologies is shown. Radiofrequency delivery sites appear as red dots at basis (upper panel) and head (lower panel) of the posterior papillary muscle.