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Sudden Unexpected Death Associated with Arrhythmogenic Cardiomyopathy: Study of the Cardiac Conduction System

Giulia Ottaviani1,2, Graziella Alfonsi1, Simone G Ramos3

  • 1Lino Rossi Research Center, Anatomic Pathology, Department of Biomedical, Surgical and Dental Sciences, Università Degli Studi di Milano, 20122 Milan, Italy.

Diagnostics (Basel, Switzerland)
|August 27, 2021
PubMed

Insights

Arrhythmogenic cardiomyopathy (ACM) involves significant cardiac conduction system (CCS) anomalies, including hypoplasia and fatty-fibrous changes. These CCS abnormalities contribute to arrhythmias and sudden unexpected cardiac death (SUCD) in ACM patients.

Area of Science:

  • Cardiovascular Pathology
  • Cardiac Electrophysiology
  • Medical Genetics

Background:

  • Arrhythmogenic cardiomyopathy (ACM) is a primary inherited disease of the myocardium.
  • Arrhythmias are a key feature of ACM, often leading to sudden unexpected cardiac death (SUCD).
  • The role of the cardiac conduction system (CCS) in ACM pathophysiology requires further investigation.

Purpose of the Study:

  • To investigate the prevalence and types of cardiac conduction system (CCS) anomalies in pathologically diagnosed arrhythmogenic cardiomyopathy (ACM) cases.
  • To correlate CCS abnormalities with sudden unexpected cardiac death (SUCD) in ACM.
  • To explore the potential of CCS anomalies as markers for increased SUCD risk in ACM.

Main Methods:

  • Retrospective analysis of 1109 suspected ACM cases over 34 years.
  • Detailed anatomo-pathological examination of 23 confirmed ACM hearts.
  • Histopathological analysis of the cardiac conduction system (CCS) in 15 ACM cases, focusing on Sino-atrial node (SAN), atrio-ventricular junction (AVJ), His bundle (HB), and bundle branches (BIF, LBB, RBB).

Main Results:

  • CCS anomalies were detected in 15 ACM cases, with high prevalence of Sino-atrial node (SAN) hypoplasia (80%) and atrio-ventricular junction (AVJ) hypoplasia (86.67%) due to fatty-fibrous involvement.
  • Other observed CCS anomalies included AVJ dispersion/septation (46.67%), central fibrous body (CFB) hypoplasia (33.33%), and fibromuscular dysplasia of SAN/AVN arteries (20-26.67%).
  • Hemorrhage, infarct-like lesions, and fibrotic blocks within the CCS were also noted, suggesting direct involvement of the conduction system in ACM pathology.

Conclusions:

  • Fatty-fibrous involvement and hypoplasia of the Sino-atrial node (SAN) and atrio-ventricular junction (AVJ) are common in arrhythmogenic cardiomyopathy (ACM).
  • These cardiac conduction system (CCS) anomalies contribute significantly to the arrhythmogenic substrate and sudden unexpected cardiac death (SUCD) risk in ACM.
  • Further research incorporating CCS anomalies into diagnostic criteria may improve risk stratification for sudden cardiac death in ACM patients.

Keywords:
arrhythmogenic cardiomyopathyarrhythmogenic right ventricular cardiomyopathyautopsycardiac conduction systemsudden unexpected cardiac death

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