The potential impact of acute coronary syndromes on automatic sensing system in Subcutaneous-ICDs

The Subcutaneous-ICD (S-ICD) is emerging as a suitable option for most ICD candidates, however some open issues regarding the sensing algorithm still remain.

We aimed to examine the performance of the S-ICD sensing algorithm in patients hospitalized for ST elevation myocardial infarction (STEMI), non ST elevation acute coronary syndrome (NSTE-ACS) or chronic coronary syndrome (CCS), before and after revascularization.

We performed a S-ICD automated screening on 75 patients, 21 hospitalized for STEMI, 23 for NSTE-ACS and 31 for CCS, before and after percutaneous revascularization, regardless their eligibility to ICD implantation.

Patients did not differ in clinical, electrocardiographic and echocardiographic parameters. Rates of screening pass were significantly lower in STEMI patients compared to NSTE-ACS and CCS (5% vs 56.7% vs 81% respectively, p < .0001). The viability of the primary vector was lower in STEMI patients compared to NSTE-ACS and CCS (33% vs 56% vs 71%, p .027 respectively). After revascularization, there were no more significant differences between groups. Pairing subjects at baseline and after revascularization, STEMI subjects percentages of screening success were respectively 5% and 81% (p < .001) and the rates of primary vector viability were 33% and 81% (p .002). STEMI was the only independent predictor of screening failure at multivariate logistic regression analysis (odds ratio 10.68 confidence interval 2.77-41.38, p = .001).

The performance of the S-ICD and possible malfunction detections in the context of an acute ischemic event deserve further evaluation. Adequate patient selection and the development of dynamic device programming are warranted.