Presented by: Angelica Peritore(1), Massimo Imazio(2), Alberto Roghi(3) and Patrizia Pedrotti(3)(1)Bicocca University, Milano, Italy; (2)Ospedale Maria Vittoria, Cardiology, Torino, Italy; (3)Ospedale Niguarda Cà Granda, Cardiac Magnetic Resonance Laboratory, Milano, Italy
A 40-year-old Caucasian female patient, with unremarkable past medical history, presented to the emergency department of our hospital for a 5-day history of pleuritic left anterior chest pain radiating to the trapezius ridge, exacerbated by breathing and relieved by leaning forward; the symtoms were accompanied by fever (38,5 °C). The patient was allergic to acetylsalicylic acid and suffered from gastroesophageal reflux disease. Physical examination was negative, blood pressure was 100/60 mmHg without paradoxical pulse, neither jugular venous distension nor pericardial friction rub were detected. Electrocardiogram (ECG) showed right bundle branch block, minimum ST-segment elevation in aVL lead and negative T waves in anterior leads. Serum C-reactive protein level was 22.6 mg/L, leukocyte count was 17.600/L and high sensitivity cardiac troponin T was not elevated. Chest X-ray showed moderate bilateral pleural effusion and cardiac silhouette in the upper limit of normal range. Echocardiography revealed mild ubiquitous pericardial effusion, measuring 1 cm. There were no echocardiographic signs of right atrial or right ventricular compression and mitral flow velocities variation was normal, but inferior vena cava was dilated (21 mm) and not collapsing. Left ventricular contractile function was normal and there were not wall motion abnormalities. Acute pericarditis was diagnosed. Autoimmune disease was ruled out. Coombs test was negative. Extensive viral serology was negative and blood cultures were sterile. Tuberculosis was ruled out.Normal levels of immunoglobulins, normal lymphocyte count and immunophenotype CD4/CD8 excluded immunologic deficit. Symptoms responded very slowly to oral indomethacin and colchicine, fever persisted, with elevated levels of inflammatory indices and mild signs of visceral congestion developed.
Cardiac magnetic resonance imaging (CMR) was performed in order to better evaluate the pericardium and the myocardium and to exclude the evolution towards constriction. Cardiac MRI showed severe diffuse pericardial thickening with marked signs of inflammation atT2-weighted short-tau inversion recovery (STIR) images and extensive post-contrast enhancement of the pericardium (Figure1). No myocardium enhancement was detected. No significant pericardial effusion was found. Dynamic tagging images showed localized pericardial adhesion between inflamed visceral and parietal pericardial surfaces.
Free breathing, real-time cine images showed inspiratory septal flattening, indicating mild accentuation of interventricular interdependence (Figure 2). CMR also showed bilateral pleural effusion and dilatation of the inferior vena cava with slow flow. Steroid therapy was introduced, with rapid positive clinical response.
Follow up CMR scan at 6 months showed significant reduction of pericardial thickness and of inflammation signs (Figure 3), with regression of the septal bounce (Figure 4).
T1-weighted image (Panel A), 4 chamber view, showing thickened pericardium (green arrows) and bilateral pleural effusion (red arrows). STIR T2-weighted image (Panel B), 4 chamber view, showing hyperintense signal of the pericardial layers (green arrows); bilateral pleural effusion (red arrows). Post-contrast image (Panel C), 4 chamber view, showing late enhancement of the pericardium (green arrows).
Real time, free breathing cine images, mid-ventricular short axis view, in expiration (Panel A) and inspiration (Panel B), showing inspiratory septal flattening (Panel B), indicating accentuated interventricular interdependence.
T1 and STIR –T2-weighted images, showing significant reduction of pericardial thickness and inflammation (Panel A and B). Late enhancement of the pericardium is still present (Panel C), indicating previous injury of the pericardium.
Accentuated interventricular interdependence is no longer present (Panel A expiration; Panel B inspiration) at real time, free breathing cine images (short axis view).
Presented by: Alexandros Protonotarios, MD; Adalena Tsatsopoulou, MD; Aris Anastasakis, MD.
Based on the 2010 diagnostic TFC for Arrhythmogenic Cardiomyopathy (ACM), T wave inversion on V1-V4 consist one of the major, while ventricular arrhythmias with superior axis consist one of the minor criteria making the diagnosis of ACM borderline or suspected.
In the context of ACM diagnosis, not cardiac arrest, syncope, ventricular fibrillation or episodes of hemodynamically unstable ventricular tachycardia from patient’s history were recorded. Also there was not any structural/ functional abnormality of the right or left ventricle. Up to the time of sudden death none of the reported risk factors for ACM was documented. Very recently, repolarization abnormalities have been revealed to be an independent risk factor for major arrhythmic event in mutation carriers of desmosomal related ACM.
In the setting of an otherwise normal heart, the only finding was focal transmural fibrosis of the crista supraventricularis of the right ventricle in correspondence of the ablated area for RVOT tachycardia. Expert histological evaluation of the Left and Right ventricular myocardium did not show relevant changes in terms of inflammation, necrosis, small vessel disease or replacement type fibrosis.
Immunohistochemical investigation of myocardium showed virtually undetectable signal for plakoglobin and desmoplakin in all samples from right ventricular myocardium while there was some localization of Cx43 (Figure 6). However, no signal reduction at intercalated disks for plakoglobin and desmoplakin was identified in left ventricular myocardium and interventricular septum. The distribution of Cx43 was heterogeneous in left ventricular myocardium. Distribution of N-Cadherin and Plakophillin2 was not affected.
This patient suffered from some form of arrhythmogenic cardiomyopathy not classifiable in any of the existing types of cardiomyopathies. It might be considered as a form of idiopathic right ventricular outflow tract tachycardia if T wave inversion on precordial leads was not underscoring a potential severe myocardial defect. However, postmortem analysis revealed a structurally normal heart consisting with the repetitive findings from 2-Dimensional echocardiography and the recently performed CMR with gadolinium late enhancement.
Abnormal distribution of plakoglobin at intercalated disks has been associated with the diagnosis of ACM with high specificity and sensitivity. It has also been described as an early finding during the genesis of the disease in a child with Naxos disease and ventricular arrhythmias on an otherwise normal heart on postmortem pathology and histology. Cardiac sarcoidosis and giant cell myocarditis have been associated with reduced plakoglobin signal from intercalated disks, however in both conditions there are characteristic histological findings, which were not identified in this patient.
There are no data from the literature concerning the distribution of desmosomal proteins and Cx43 in the heart of patients with idiopathic ventricular arrhythmias from RVOT. There are several reports suggestive of a possible malignant pathophysiology underlying an otherwise idiopathic RVOT VT, making the later diagnosis a “cardiologist nightmare”.
The present case suggests that ventricular arrhythmias from RVOT when accompanied by precordial T wave inversion might express an arrhythmogenic substrate possibly related to plakoglobin redistribution and ultrastructural cardiac myocyte changes causing potentially severe ventricular arrhythmias.
Whole genome sequencing, that follows, might also reveal new arrhythmic markers in this family. Studies of larger series with RVOT VT and tissue characterization might illuminate this conflicting cardiac pathophysiology.
We are thankful to Professor Cristina Basso, Padua for detailed histopathological investigation and of Dr Angeliki Asimaki, Harvard, for immunohistochemical investigation of the patient’s heart.
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