Key influences of VDD (DX) ICD selection: Results from a prospective, national survey.

BACKGROUND: To preserve the benefit of atrial sensing without the implantation of an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD) has been developed. The purpose of this nationwide survey was to provide an overview of the current key influences of device selection focusing on DX ICD and to test the applicability of a previously published decision-making flowchart of ICD-type selection. METHODS: An online questionnaire was sent to all implanting centers in Hungary. Eleven centers reported data from 361 DX ICD and 10 CRT-DX systems implantations between February 2021 and May 2023. RESULTS: The most important influencing clinical factors indicated by the participating doctors were elevated risk of atrial fibrillation (AF)/stroke (56%), risk of sinus/supraventricular tachycardias (SVT) (42%), and a potential need for CRT upgrade in the future (36%). The DX ICD was considered in the majority of cases instead of the VVI system (87%), and only in a small proportion instead of a DDD ICD (13%). 60% of the patients with DX ICDs were also included into remote monitoring-based follow-up. In 83% of the cases, good (>2 mV) or excellent (>5) atrial signal amplitude was recorded within 6 weeks after the implantation. CONCLUSION: In the current national survey, the most important influencing factors indicated by the implanters for selecting a DX ICD were the elevated risk of stroke or sinus/SVT and a potential need for CRT upgrade in the future. These findings support the use of a previously published decision-making flowchart.

Upgrade of right ventricular pacing to cardiac resynchronization therapy in heart failure: a randomized trial.

BACKGROUND AND AIMS: De novo implanted cardiac resynchronization therapy with defibrillator (CRT-D) reduces the risk of morbidity and mortality in patients with left bundle branch block, heart failure and reduced ejection fraction (HFrEF). However, among HFrEF patients with right ventricular pacing (RVP), the efficacy of CRT-D upgrade is uncertain. METHODS: In this multicentre, randomized, controlled trial, 360 symptomatic (New York Heart Association Classes II-IVa) HFrEF patients with a pacemaker or implantable cardioverter defibrillator (ICD), high RVP burden ≥ 20%, and a wide paced QRS complex duration ≥ 150 ms were randomly assigned to receive CRT-D upgrade (n = 215) or ICD (n = 145) in a 3:2 ratio. The primary outcome was the composite of all-cause mortality, heart failure hospitalization, or <15% reduction of left ventricular end-systolic volume assessed at 12 months. Secondary outcomes included all-cause mortality or heart failure hospitalization. RESULTS: Over a median follow-up of 12.4 months, the primary outcome occurred in 58/179 (32.4%) in the CRT-D arm vs. 101/128 (78.9%) in the ICD arm (odds ratio 0.11; 95% confidence interval 0.06-0.19; P < .001). All-cause mortality or heart failure hospitalization occurred in 22/215 (10%) in the CRT-D arm vs. 46/145 (32%) in the ICD arm (hazard ratio 0.27; 95% confidence interval 0.16-0.47; P < .001). The incidence of procedure- or device-related complications was similar between the two arms [CRT-D group 25/211 (12.3%) vs. ICD group 11/142 (7.8%)]. CONCLUSIONS: In pacemaker or ICD patients with significant RVP burden and reduced ejection fraction, upgrade to CRT-D compared with ICD therapy reduced the combined risk of all-cause mortality, heart failure hospitalization, or absence of reverse remodelling.

Cardiac resynchronization therapy with intraoperative epicardial mapping via minithoracotomy: 10 years' experience.

BACKGROUND: Cardiac resynchronization therapy (CRT) is considered an efficient method to improve the left ventricular (LV) dysfunction with left bundle branch block. However, coronary venous anatomy is not appropriate in about 10% of the cases; thus other alternatives, such as epicardial lead implantation via minithoracotomy are needed. METHODS: During the period 2007-2017, a total of 57 patients were operated at our institute via left anterior minithoracotomy after an unsuccessful transvenous CRT. The best position of the LV epicardial electrode was determined by intraoperative epicardial mapping, that is locating the latest activation spot relative to the right ventricular (RV) electrode. The authors analyzed the survival by Kaplan-Meier estimator with Tarone-Ware equality test and multiple Cox regression analysis, the changes of the LV ejection fraction (LVEF) and dimensions, the development of the impedance and threshold of the LV epicardial electrode, the possible associations between the survival and intraoperative sensed RV-LV activation delay. RESULTS: The intraoperative RV-LV activation delay was 92.250 ± 26.538 milliseconds. There were no intraoperative complications except ventricular fibrillation in three patients. Within 30 days there were neither wound healing complications nor pocket hematoma. There was no significant difference in survival with regard to gender or etiology, but significantly better survival was found in the cohort with intraoperative sensed RV-LV activation delay >86 milliseconds. The LVEF and dimensions improved following the operation and continued to be improved in the survivors. CONCLUSION: CRT via minithoracotomy with epicardial mapping is a safe, efficient, simple, and reproducible second-line alternative to the transvenous method.

Rationale and feasibility of the atrioventricular single-lead ICD systems with a floating atrial dipole (DX) in clinical practice.

Cardiac implantable electronic devices establish proper therapy for the prevention of sudden cardiac death, significantly reducing the morbidity and mortality of patients with arrhythmias and heart failure. It is well-known that the number of electrodes increases the risk of complications. To preserve the benefit of atrial sensing without the need to implant an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD lead) has been developed. Besides all of the potential benefits, the necessity of a reliable and stable atrial sensing via the floating dipole could be the main concern against the use of this lead type. In the current generation of DX devices, the specially filtered atrial signal seems to be high enough and stable over time, which is crucial in the early detection of atrial arrhythmias, discrimination between different forms of tachycardias in order to prevent inappropriate ICD therapy, and achieving an optimal atrioventricular and interventricular synchrony in patients with a two-lead CRT-DX system. The present review summarizes the benefits and potential drawbacks of the DX ICD systems based on the available literature, furthermore, proposes an evidence-based algorithm of ICD type selection.

Baseline clinical characteristics of heart failure patients with reduced ejection fraction enrolled in the BUDAPEST-CRT Upgrade trial.

AIMS: The BUDAPEST-CRT Upgrade study is the first prospective, randomized, multicentre clinical trial investigating the outcomes after cardiac resynchronization therapy (CRT) upgrade in heart failure (HF) patients with intermittent or permanent right ventricular (RV) pacing with wide paced QRS. This report describes the baseline clinical characteristics of the enrolled patients and compares them to cohorts from previous milestone CRT studies. METHODS AND RESULTS: This international multicentre randomized controlled trial investigates 360 patients having a pacemaker (PM) or implantable cardioverter defibrillator (ICD) device for at least 6 months prior to enrolment, reduced left ventricular ejection fraction (LVEF ≤35%), HF symptoms (New York Heart Association [NYHA] functional class II-IVa), wide paced QRS (>150 ms), and ≥20% of RV pacing burden without having a native left bundle branch block. At enrolment, the mean age of the patients was 73 ± 8 years; 89% were male, 97% were in NYHA class II/III functional class, and 56% had atrial fibrillation. Enrolled patients predominantly had conventional PM devices, with a mean RV pacing burden of 86%. Thus, this is a patient cohort with advanced HF, low baseline LVEF (25 ± 7%), high N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels (2231 pg/ml [25th-75th percentile 1254-4309 pg/ml]), and frequent HF hospitalizations during the preceding 12 months (50%). CONCLUSION: When compared with prior CRT trial cohorts, the BUDAPEST-CRT Upgrade study includes older patients with a strong male predominance and a high burden of atrial fibrillation and other comorbidities. Moreover, this cohort represents an advanced HF population with low LVEF, high NT-proBNP, and frequent previous HF events. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02270840.