Right Ventricular Hypertrophy Along With Malignant Ventricular Arrhythmias
An Uncommon Case of Sarcoidosis at Cardiac Magnetic Resonance Imaging
A 51-year-old black man without a personal or family history of cardiovascular disease was admitted to our hospital following syncope. Of note, he reported several episodes of chest pain and palpitations with lipothymia in the past few years associated with progressive dyspnea reaching New York Heart Association class II. ECG showed negative T waves in the precordium (V3 through V4) without significant ST deviation, monomorphic ventricular ectopies of septal origin with bursts of rapid polymorphic ventricular tachycardia, and mild first-degree atrioventricular (AV) block (Figure 1).
Clinical examination and chest radiography were normal. Laboratory tests showed mildly elevated ultrasensitive troponin at 36 ng/mL, normal blood cell count, and C-reactive protein. Transthoracic echocardiography found interventricular septal hypertrophy (25 mm) without left ventricular (LV) dilatation or regional wall motion abnormality and no pericardial effusion, and the diagnosis of hypertrophic cardiomyopathy was suspected at the first step. β-Blocker therapy was initiated and the patient was monitored showing severe lengthening of the PR interval (Figure 1). Cardiac MRI found atypical and severe concentric right ventricular (RV) hypertrophy with diffuse elevation of myocardial signal on T2-weighted short tau inversion recovery images (Figure 2 Movies I and II in the online-only Data Supplement), and severe RV free wall hypokinesia along with global asynchrony of RV contraction. The LV ejection fraction was confirmed normal, whereas the RV ejection fraction was markedly impaired at 35%. First-pass perfusion of the RV myocardium was slightly delayed in comparison with the LV. There was an intense and diffuse delayed enhancement of RV myocardium predominant in the right side of the septal wall but no LV delayed enhancement (Figure 2). Coronary angiography revealed no coronary artery disease. A dual-chamber cardiac defibrillator was implanted.
During the follow-up, the patient was admitted with electrical storm with recurrent polymorphic sustained ventricular tachycardia at 220 beats/min triggered by septal ventricular ectopies needing several appropriate implantable cardioverter-defibrillator discharges, despite that the patient was on β-blockers and amiodarone therapy. Radiofrequency ablation was performed after electrophysiological mapping of both ventricles with a primary success confirming the septal origin of ventricular arrhythmias (Figure 3). However, the condition of the patient secondarily worsened with the recurrence of ventricular tachycardia, state III New York Heart Association dyspnea, and apparition of a second-degree Mobitz 1 AV block when echocardiography revealed the reduction of LV ejection fraction at 35%. Endomyocardial biopsy from the septum was then performed revealing gigantocellular inflammatory granulomas without caseum among dystrophic cardiomyocytes (Figure 4). Computed tomography of the chest demonstrated diffuse lymphatic micronodules combined with mediastinal and right gastric lymph node hypertrophy, consistent with lung and lymph node sarcoidosis (Figure 5). The patient received daily intravenous corticosteroids followed by oral steroids at 0.7 mg·kg–1·d–1 and intravenous cyclophosphamide. Follow-up was clinically satisfactory, with complete LV ejection fraction recovery at echocardiography, disappearance of ventricular tachycardia, and partial conduction recovery with first-degree AV block along with a significant decrease in the total interventricular septum thickness (Figures 6 and 7 Movies III, IV, and V in the online-only Data Supplement).
Although cardiac involvement in sarcoidosis may be found in up to 40% of autopsic series, only 5% of patients presented with inaugural myocarditis in the pre-MRI era.1 Cardiac MRI has been considered as the best imaging modality for the diagnosis of acute myocarditis with sensitivity up to 100% and a specificity of 78%.2 Indeed, cardiac MRI is able to demonstrate subepicardial or transmural edema, necrosis, microvascular obstruction, and fibrosis in addition to highly accurate biventricular functional evaluation. However, such markers of tissue damage remain nonspecific with regard to etiology, and differential diagnoses such as sarcoidosis, which require a specific treatment, have to be considered. Formal diagnosis of cardiac sarcoidosis remains based on histopathologic proof of noncaseating granuloma that may be found in peripheral or cardiac tissue.2
Septal involvement in cardiac myocarditis is severe and may lead to a high mortality rate of 60% in the absence of treatment mainly owing to high-grade AV block and ventricular tachycardia or fibrillation.1 Implantable cardioverter-defibrillator placement along with medical treatment should be considered as soon as possible in the presence of ventricular arrhythmias even in the absence of severely altered LV ejection fraction.
Isolated and diffuse RV involvement in sarcoid myocarditis, such as described here, is an uncommon finding. Patchy RV delayed gadolinium myocardial enhancement may be seen in cardiac sarcoidosis, usually associated with LV involvement,2 and is thought to be a predictor of an adverse prognosis.
The presentation here is highly atypical, both in its imaging and rhythmic components with the combination of severe ventricular arrhythmia and aggravating conduction anomalies arising from the septum. Cardiac sarcoidosis presenting as severe RV myocardial hypertrophy is exceptional and has not been reported so far. RV hypertrophic cardiomyopathy could have been discussed as a potential alternative diagnosis according to the echocardiographic findings, but would have been highly unlikely without LV involvement at MRI. Both entities may present in MRI with concentric thickening of the myocardium associated with patchy late enhancement along with edema and may be associated with AV block. However, isolated RV hypertrophic cardiomyopathy is uncommon in hypertrophic cardiomyopathy and is essentially limited to focal hypertrophy and late enhancement of right-left ventricular junctions and associated to LV involvement.3,4
In conclusion, isolated RV concentric hypertrophy is an uncommon finding in cardiac MRI and, especially when associated with signs of edema and necrosis and combined with severe AV conduction and ventricular arrhythmia, should be considered as a potential cardiac sarcoidosis.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.114.014214/-/DC1.
- © 2015 American Heart Association, Inc.