Strength of clinical indication and therapeutic impact of the implantable cardioverter defibrillator in patients with hypertrophic cardiomyopathy

Candidacy and long-term outcomes of subcutaneous implantable cardioverter-defibrillators in current practice in patients with hypertrophic cardiomyopathy

BACKGROUND

In patients with Hypertrophic Cardiomyopathy (HCM) S-ICD is usually the preferred option as pacing is generally not indicated. However, limited data are available on its current practice adoption and long-term follow-up.

METHODS

Consecutive HCM patients with S-ICD implanted between 2013 and 2021 in 3 international centers were enrolled in this observational study. Baseline, procedural and follow-up data were regularly collected. Efficacy and safety were compared with a cohort of HCM patients implanted with a tv-ICD.

RESULTS

Seventy patients (64% males) were implanted with S-ICD at 41 ± 15 years, whereas 168 patients with tv-ICD at 49 ± 16 years. For S-ICD patients, mean ESC SCD risk score was 4,5 ± 1.9%: 25 (40%) at low-risk, 17 (27%) at intermediate and 20 (33%) at high-risk. Patients were followed-up for 5.1 ± 2.3 years. Two patients (0.6 per 100-person-years, vs 0.4 per 100 person-years with tv-ICD, p = 0.45) received an appropriate shock on VF, 17 (24%) were diagnosed with de-novo AF. Inappropriate shocks occurred in 4 patients (1.2 per 100-person-years, vs 0.9 per 100 person-years with tv-ICD, p = 0.74), all before Smart-Pass algorithm implementation. Four patients experienced device-related adverse events (1.2 per 100-person-years, vs 1 per 100 person-years with tv-ICD, p = 0.35%).

CONCLUSIONS

S-ICDs were often implanted in patients with an overall low-intermediate ESC SCD risk, reflecting both the inclusion of additional risk markers and a lower decision threshold. S-ICDs in HCM patients followed for over 5 years showed to be effective in conversion of VF and safe. Greater scrutiny may be required to avoid overtreatment in patients with milder risk profiles.

Prediction of incident atrial fibrillation in hypertrophic cardiomyopathy

BACKGROUND AND AIM

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with significant effects on outcome. We aim to compare the left atrial (LA) diameter measurement with HCM-AF Score in predicting atrial fibrillation (AF) development in HCM.

METHODS

From the regional cohort of the Campania Region, Italy, 519 HCM patients (38% women, age45 ± 17 years) without history of AF, were enrolled in the study. The primary clinical endpoint was the development of AF, defined as at least 1 episode documented by ECG.

RESULTS

During the follow-up (mean 8 ± 6, IQ range 2.5-11.2 years), 99 patients (19%) developed AF. Patients who developed AF were more symptomatic, had higher prevalence of ICD implantation, had larger LA diameter, greater left ventricular (LV) maximal wall thickness and LV outflow tract obstruction (p < 0.01). Both LA diameter and HCM-AF score were higher in patients who developed AF versus those who did not (LA diameter 49 ± 7 versus 43 ± 6 mm; HCM-AF score 22 ± 4 versus 19 ± 4; p < 0.0001); however, ROC curve analysis demonstrated that LA diameter had a significant greater area under the curve than HCM-AF Score (p < 0.0001). At 5 years follow-up, a LA diameter > 46 mm, showed a similar accuracy in predicting AF development of HCM-AF score ≥ 22, which identifies patients at high risk to develop AF.

CONCLUSION

Our analysis shows that LA diameter, a worldwide and simple echocardiographic measure, is capable alone to predict AF development in HCM patients.