Phenotypic Expression and Outcomes in Arrhythmogenic Cardiomyopathies

Quick Takes

  • The incidence and recurrence of life-threatening ventricular arrhythmias (LTAs) is significantly higher in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and biventricular arrhythmogenic cardiomyopathy (BIV) forms than in those with an arrhythmogenic left ventricular cardiomyopathy (ALVC) phenotype.
  • In contrast, patients with ALVC and BIV forms have a higher incidence of HF and hot phase episodes.
  • Phenotypic data may help promote the adoption of personalized preventive measures to reduce the risk of LTAs and enable the use of therapeutic strategies for HF in affected individuals.

Study Questions:

What is the impact of phenotypic expression in arrhythmogenic cardiomyopathy (ACM) on patient outcomes?

Methods:

The investigators conducted an analysis of 446 patients diagnosed with ACM. These patients were categorized into three groups based on their phenotype: 1) arrhythmogenic right ventricular cardiomyopathy (ARVC) (right-dominant ACM), 2) arrhythmogenic left ventricular cardiomyopathy (ALVC) (left dominant ACM), and 3) biventricular arrhythmogenic cardiomyopathy (BIV) (biventricular ACM). The authors compared clinical, instrumental, and genetic findings among these groups and also evaluated their outcomes. Comparisons over follow-up time were based on McNemar test for binary variables and the Wilcoxon signed rank test for continuous variables. Recurrence was modeled under a competitive risk scenario with death and described using Cumulative Incidence Functions plots.

Results:

Overall, 44% of patients were diagnosed with ARVC, 23% with ALVC, and 33% with BIV forms. Subjects showing with ARVC and BIV phenotype had a significantly higher incidence of life-threatening ventricular arrhythmias (LTAs) compared to ALVC (p < 0.001). On the other hand, heart failure (HF), heart transplantation, and death due to cardiac causes were more frequent in individuals with BIV forms compared to those with ALVC and ARVC (p < 0.001). Finally, patients with an ALVC phenotype had a higher incidence of hot phases compared to those with ARVC and BIV forms (p = 0.013).

Conclusions:

The authors report that patients with right ventricular involvement, such as ARVC and BIV forms, exhibit a higher incidence of LTAs, while ACM forms characterized by left ventricular involvement, such as ALVC and BIV, show a higher incidence of HF, heart transplantation, and hot phases.

Perspective:

This study reports that the incidence and recurrence of LTAs is significantly higher in patients with ARVC and BIV forms than in those with an ALVC phenotype. In contrast, patients with ALVC and BIV forms have a higher incidence of HF and hot phase episodes. These data suggest that in the context of ACM, a specific phenotype may provide insights into predicting patient outcomes. Furthermore, phenotypic data may help promote the adoption of personalized preventive measures to reduce the risk of LTAs and enable the use of therapeutic strategies for HF in affected individuals. Additional studies are needed to elucidate the mechanisms linking phenotypic features to disparities in arrhythmogenicity and the frequency/severity of other clinical adverse events in ACM.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Genetic Arrhythmic Conditions, SCD/Ventricular Arrhythmias

Keywords: Arrhythmogenic Right Ventricular Dysplasia, Cardiomyopathies, Phenotype


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