Sudden Cardiac Death due to Giant Cell Inflammatory Processes

Unerkannte letale idiopathische Riesenzellmyokarditis – ein Fallbericht

Myokarditiden stellen nach der hypertrophen Kardiomyopathie und der stenosierenden Koronararteriensklerose die dritthäufigste Ursache des plötzlichen Herztodes dar. Die Klinik der Myokarditis ist wie ihr Verlauf äußerst variabel, und ihr Therapieerfolg hängt stark von der Ätiologie und somit einer umfassenden diagnostischen Abklärung ab. Zum Goldstandard gehört nach wie vor die Endomyokardbiopsie, deren Ergebnisse bedeutenden Einfluss auf die Therapieplanung haben können. Vorgestellt wird der Fall einer 35 Jahre alt gewordenen Frau, bei der zu Lebzeiten eine chronisch aktive lymphozytäre Myokarditis mit Nachweis des humanen Herpesvirus 6 (HHV 6) diagnostiziert wurde. Acht Monate nach der Diagnose verstarb sie unerwartet. Die Obduktion mit nachfolgender histopathologischer Aufarbeitung der Myokardproben erbrachte den Nachweis einer Riesenzellmyokarditis, die als Differenzialdiagnose zu Lebzeiten nicht gestellt worden war. Der Fall verdeutlicht die Problematik der Diagnosestellung zu Lebzeiten, wenn Myokardproben nicht repräsentativ sind zum Nachweis der Grunderkrankung und illustriert die autoptischen Befunde dieser seltenen Form der Myokarditis.

Myocardial Involvement in Patients With Histologically Diagnosed Cardiac Sarcoidosis: A Systematic Review and Meta-Analysis of Gross Pathological Images From Autopsy or Cardiac Transplantation Cases

Background

In patients with suspected cardiac sarcoidosis, late gadolinium enhancement on cardiovascular magnetic resonance imaging and/or ¹⁸F‐fluorodeoxyglucose uptake on positron emission tomography are often used to reach a clinical diagnosis of cardiac sarcoidosis. On the basis of data from the imaging literature of clinical cardiac sarcoidosis, no specific features of myocardial involvement are regarded as pathognomonic for cardiac sarcoidosis. Thus, a diagnosis of cardiac sarcoidosis is challenging to make. There has been no systematic analysis of histologically diagnosed cardiac sarcoidosis for patterns of myocardial involvement. We hypothesized that certain patterns of myocardial involvement are more frequent in histologically diagnosed cardiac sarcoidosis.

Methods and Results

We performed a systematic review and meta‐analysis of gross pathological images from the published literature of patients with histologically diagnosed cardiac sarcoidosis who underwent autopsy or cardiac transplantation. Thirty‐three eligible articles provided images of 49 unique hearts. Analysis of these hearts revealed certain features of myocardial involvement in >90% of cases: left ventricular (LV) subepicardial, LV multifocal, septal, and right ventricular free wall involvement. In contrast, other patterns were seen in 0% to 6% of cases: absence of gross LV myocardial involvement, isolated LV midmyocardial involvement, isolated LV subendocardial involvement, isolated LV transmural involvement, absence of septal involvement, or isolated involvement of only one LV level.

Conclusions

In this systematic review and meta‐analysis of histologically diagnosed cardiac sarcoidosis, we identified certain features of myocardial involvement that occurred frequently and others that occurred rarely or never. These patterns could aid the interpretation of cardiovascular magnetic resonance imaging and positron emission tomography imaging and improve the diagnosis and the prognostication of patients with suspected cardiac sarcoidosis.

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Role of CMR imaging in risk stratification for sudden cardiac death

Left ventricular ejection fraction as determined by echocardiography has a limited sensitivity in predicting risk for sudden cardiac death (SCD). Subsequent efforts to improve cost-effectiveness of device implantation and identify a better risk-stratifying tool have been quite desirable. The presence of scar and myocardial tissue heterogeneity has been linked to ventricular arrhythmia, which is believed to be the major cause of SCD. Cardiac magnetic resonance is a noninvasive imaging modality that visualizes and quantifies scar, with growing evidence delineating its additive value in identifying patients at higher risk for SCD.

Myocarditis at Post-Mortem Examination: A Forensic Perspective

Myocarditis is an uncommon cause of death but its myriad clinical presentations, young target population, diverse etiologies and potential to cause sudden unexpected death warrant its review. Myocarditis has been defined as myocardial necrosis and/or degeneration in the presence of an inflammatory infiltrate adjacent to the damaged myocytes. The type of predominant inflammatory cell present may assist with elucidating its pathoetiology. Ancillary testing as an adjunct to routine histopathological examination, such as immunohistochemical or immunofluorescence staining or detection of viral nucleic acid are of debatable diagnostic use in either the biopsy or autopsy setting. Myocarditis may clinically and/or histologically mimic other disease entities such as acute or organizing myocardial infarction, or hematological malignancy. There are no macroscopic pathognomonic features suggestive of myocarditis, thus in cases of unexplained sudden death it is vital to sample the heart extensively to rule out myocarditis. It is important to recognize that myocarditis may be an incidental finding in an autopsy. To attribute the cause of death to myocarditis, all relevant case findings including scene investigation, autopsy and ancillary testing including toxicology should be assessed.

Evaluation of postmortem measurement of NT-proBNP as a marker for cardiac function

Clinical biomarkers of cardiac function could also be monitored postmortem. Among the natriuretic peptides, the aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be a more reliable postmortem tool than the BNP, owing to its longer half-life and greater stability. In living persons, NT-proBNP is considered to be a marker of heart failure, and its level rises after cardiac ischemia. The goal of this study was first to evaluate the postmortem stability of NT-proBNP, then to measure the NT-proBNP levels in postmortem cases of heart failure related to coronary ischemia. The goal of this study was also to evaluate the correlations between different specimens collected at autopsy (e.g. blood, serum, vitreous humor and pericardial fluid). The study included 96 cases, which were classified into 4 groups according to the autopsy and histological findings. The NT-proBNP levels were significantly higher in individuals who had suffered from chronic cardiac ischemia, with or without acute coronary events, than in either control cases or those who had suffered from acute thromboembolism or acute rupture of a plaque without chronic cardiac ischemia. The highest levels were registered in individuals who had suffered from acute coronary thromboembolism in association with chronic coronary ischemia. Good correlations in the NT-proBNP levels for the different specimens were observed between samples of femoral blood, serum, and pericardial fluid. Our data indicated that postmortem measurements of NT-proBNP are reliable and compatible with clinical findings.