Role of arrhythmic phenotype in prognostic stratification and management of dilated cardiomyopathy

AIMS

Dilated cardiomyopathy (DCM) with arrhythmic phenotype combines phenotypical aspects of DCM and predisposition to ventricular arrhythmias, typical of arrhythmogenic cardiomyopathy. The definition of DCM with arrhythmic phenotype is not universally accepted, leading to uncertainty in the identification of high-risk patients. This study aimed to assess the prognostic impact of arrhythmic phenotype in risk stratification and the correlation of arrhythmic markers with high-risk arrhythmogenic gene variants in DCM patients.

METHODS AND RESULTS

In this multicentre study, DCM patients with available genetic testing were analysed. The following arrhythmic markers, present at baseline or within 1 year of enrolment, were tested: unexplained syncope, rapid non-sustained ventricular tachycardia (NSVT), ≥1000 premature ventricular contractions/24 h or ≥50 ventricular couplets/24 h. LMNA, FLNC, RBM20, and desmosomal pathogenic or likely pathogenic gene variants were considered high-risk arrhythmogenic genes. The study endpoint was a composite of sudden cardiac death and major ventricular arrhythmias (SCD/MVA). We studied 742 DCM patients (45 ± 14 years, 34% female, 410 [55%] with left ventricular ejection fraction [LVEF] <35%). During a median follow-up of 6 years (interquartile range 1.6-12.1), unexplained syncope and NSVT were the only arrhythmic markers associated with SCD/MVA, and the combination of the two markers carried a significant additive risk of SCD/MVA, incremental to LVEF and New York Heart Association class. The probability of identifying an arrhythmogenic genotype rose from 8% to 30% if both early syncope and NSVT were present.

CONCLUSION

In DCM patients, the combination of early detected NSVT and unexplained syncope increases the risk of life-threatening arrhythmic outcomes and can aid the identification of carriers of malignant arrhythmogenic genotypes.

207 RE-DEFINING ARRHYTHMOGENIC CARDIOMYOPATHY: CHARACTERIZATION AND LONG-TERM PROGNOSTIC IMPLICATIONS

Background

Arrhythmogenic dilated cardiomyopathy (AR-DCM) combines phenotypical aspects of dilated cardiomyopathy (DCM) and risk of sudden cardiac death (SCD), typical of the arrhythmogenic form (ACM). However, AR-DCM is often ambiguously defined leaving clinicians uncertain on how to identify these high-risk patients.

The aims of the study were to re-define AR-DCM based on outcome related arrhythmic markers and to test the usefulness of the novel AR-DCM definition in identifying arrhythmogenic genotypes (i.e., LMNA, FLNC, RBM20, and desmosomal genes).

Materials and methods

Consecutive DCM patients with genetic evaluation and Holter ECG monitoring or telemetry in two referral institution were analyzed. The arrhythmic markers tested to define AR-DCM were: SCD or major ventricular arrhythmias (MVA), unexplained syncope, rapid nonsustained ventricular tachycardia (nsTV), ≥1000 premature ventricular contractions/24 hours, or ≥50 ventricular couplets/24 hours. Patients were labeled as Early AR-DCM if criteria were met within 12 months from enrolment. The primary endpoint was a composite of SCD/MVA; the secondary endpoint was a composite of all-cause mortality/heart transplant/LVAD implantation (D/HTx/LVAD).

Results

Among the 743 DCM patients included, 290 had disease-related variants (39%), 94 (30%) of these carried arrhythmogenic genotype. Early AR-DCM was identified in 429 (58%) patients. During a median follow-up of 7.0 [2.2-13.8] years, among arrhythmic markers the occurrence of syncope and/or nsVT within 12 months from enrolment were the only arrhythmic markers independently associated with SCD/MVA (Figure), while the occurrence of early MVA and/or nsTV emerged as the strongest long-term predictors of D/ HTx/LVAD. Family history of MVA was also independently associated with primary and secondary endpoints, and together with MVA, nsTV or unexplained syncope increased the agreement between AR-DCM and arrhythmogenic genotypes in 1 out 2 patients.

Conclusions

A combination of early (i.e., within 1 year from diagnosis) MVA or nsVT or unexplained syncope might be proposed as a clinically useful new definition of AR-DCM, especially if associated to family history of MVA. This definition in fact allows clinicians to anticipates worse long-term arrhythmic and global outcomes, and to accurately identify malignant arrhythmogenic genotypes.

Sex-Specific Prognostic Implications in Dilated Cardiomyopathy After Left Ventricular Reverse Remodeling

BACKGROUND

Women affected by Dilated Cardiomyopathy (DCM) experience better outcomes compared to men. Whether a more pronounced Left Ventricular Reverse Remodelling (LVRR) might explain this is still unknown.

AIM

We investigated the relationship between LVRR and sex and its long-term outcomes.

METHODS

A cohort of 605 DCM patients with available follow-up data was consecutively enrolled. LVRR was defined, at 24-month follow-up evaluation, as an increase in left ventricular ejection fraction (LVEF) ≥ 10% or a LVEF > 50% and a decrease ≥ 10% in indexed left ventricular end-diastolic diameter (LVEDDi) or an LVEDDi ≤ 33 mm/m². Outcome measures were a composite of all-cause mortality/heart transplantation (HTx) or ventricular assist device (VAD) and a composite of Sudden Cardiac Death (SCD) or Major Ventricular Arrhythmias (MVA).

RESULTS

181 patients (30%) experienced LVRR. The cumulative incidence of LVRR at 24-months evaluation was comparable between sexes (33% vs. 29%; p = 0.26). During a median follow-up of 149 months, women experiencing LVRR had the lowest rate of main outcome measure (global p = 0.03) with a 71% relative risk reduction compared to men with LVRR, without significant difference between women without LVRR and males. A trend towards the same results was found regarding SCD/MVA (global p = 0.06). Applying a multi-state model, male sex emerged as an independent adverse prognostic factor even after LVRR completion.

CONCLUSIONS

Although the rate of LVRR was comparable between sexes, females experiencing LVRR showed the best outcomes in the long term follow up compared to males and females without LVRR. Further studies are advocated to explain this difference in outcomes between sexes.