Eligibility of patients with temporary paced rhythm for a subcutaneous implantable cardioverter-defibrillator

Abstract

Background: A concomitant use of a pacemaker and a subcutaneous implantable cardioverter-defibrillator (S-ICD) may be required in some patients.Aims: Our study aimed to evaluate the influence of permanent cardiac pacing on the morphology of the QRS complex in the context of S-ICD screening.Methods: One hundred patients with cardiac electronic implantable devices (CIEDs) were included in whom S-ICD screening could be performed both during intrinsic and paced rhythm. Results:The positive result of screening during spontaneous rhythm for at least one vector (in both supine and standing positions) was obtained in 80% and for 2 vectors in 59% of patients. Positive screening during paced rhythm for at least one vector was recorded in 36% of patients (78% right ventricular and 22% biventricular pacing) and for 2 vectors in 15% of patients (93% right ventricular and 7% biventricular pacing). At least one vector acceptable during both types of rhythm and in both positions was recorded in 23% of patients and at least 2 vectors in 8% of patients. Conclusions:The use of S-ICD in patients with paced ventricular rhythm is associated with a serious risk of inappropriate sensing due to different QRS morphology during intrinsic and paced rhythm, and it is particularly high in patients in whom periods of spontaneous rhythm interchange with periods of ventricular pacing. That risk has been hardly acknowledged in available reports, but according to our data, it is significant, and therefore it should be considered during S-ICD screening.

Comparison of Preoperative ECG Screening and Device-Based Vector Analysis in Patients Receiving a Subcutaneous Implantable Cardioverter-Defibrillator

“…In some clinical circumstances, ECG abnormalities may unpredictably fluctuate in long-term observations or even become permanent, which hinders the use of an S-ICD. Such an issue may occur in congenital heart disease [5][6][7]18], channelopathies [8,9], hypertrophic cardiomyopathy [19], or in patients with a paced rhythm [10,11,20]. In some patients, specific maneuvers are needed to improve the exclusion of truly ineligible candidates (ajmaline test in Brugada syndrome; exercise test in Brugada syndrome, hypertrophic cardiomyopathy (HCM), or ARVC) [9,[21][22][23].…”

“…In those patients, the specific ECG pattern or its variability in time may prove inappropriate for S-ICD sensing algorithms and result in inadequate interventions [5][6][7][8][9]. Patients with dynamic ECG patterns (transient intraventricular conduction abnormalities, intermittent bundle branch block, or transient ventricular pacing) are most problematic in those terms [10,11].…”

“…bundle branch block, or transient ventricular pacing) are most problematic in those terms [10,11]. The system producer recommends that at least one vector is positive in various body positions to consider a patient eligible for an S-ICD.…”

How likely is the sense‐B‐noise to affect patients with subcutaneous implantable cardioverter‐defibrillators and can we solve that problem in every case?

“…[7][8][9][10] There are also some clinical settings with alternating QRS morphology (such as intermittent cardiac pacing or transient bundle branch block), that are especially troublesome for the sensing algorithms of S-ICDs. 11 Unfortunately, one more issue has been recently described that may increase the rate of IAS in S-ICD recipients: the sense-B-noise. 12,13 Available data regarding that problem are scarce, coming from only two case series, one of which is multi-center 12 and the other onesingle-center.…”

“…Pre‐implant ECG screening is commonly used to ensure the correct sensing of the S‐ICD system, and it is of paramount importance in specific groups of patients with dynamic or atypical ECG patterns 7–10 . There are also some clinical settings with alternating QRS morphology (such as intermittent cardiac pacing or transient bundle branch block), that are especially troublesome for the sensing algorithms of S‐ICDs 11 . Unfortunately, one more issue has been recently described that may increase the rate of IAS in S‐ICD recipients: the sense‐B‐noise 12,13 …”