Access to magnetic resonance imaging of patients with magnetic resonance-conditional pacemaker and implantable cardioverter-defibrillator systems: results from the Really ProMRI study.

Aims: The Really ProMRI study evaluates magnetic resonance imaging (MRI) access for patients with cardiac implantable electronic devices (CIEDs) as well as the performance of magnetic resonance (MR)-conditional leads when undergoing MRI. Methods and results: Patients either with an MR-conditional pacemaker or implantable defibrillator (ICD) system or with at least a component (device or one or more leads) from an MR-conditional system, were asked to fill in a questionnaire when they were referred to a MR scan. The rate of prescription, denial, or execution of MR examinations was evaluated in a 1-year follow-up visit. In total, 555 patients [median age (interquartile range) 72.2 (62.2-78.6); 72% male] were enrolled, 49% (270) with a pacemaker, 51% (285) with an ICD system. Five-hundred and ten patients completed the follow-up period. A total of 37 MRI referrals were reported in 35 patients, with a consequent event rate of 7.0/100 patient-years (CI, 4.9-9.7). Fourteen were denied, while 23 [66%; (CI, 48-81%)] were performed. The number of patients with MR referrals was not statistically different between pacemaker and ICD groups (21 vs. 14; P = 0.178). The rate of scans performed was higher in the pacemaker subjects (19/23 vs. 4/14, P = 0.003), while it was similar between patients with or without a complete MR-conditional system (19/30 vs. 4/7, P = 0.606). Conclusion: In this study, we reported a 7.0/100 patient-year's event rate of MR prescriptions in CIED patients. Many examinations were denied, despite MR-conditional systems, especially in ICD patients. Regulatory and cultural changes are needed to allow wider access to MR imaging in CIED patients with MR-conditional systems.

Atrioventricular Interval Extension Is Highly Efficient in Preventing Unnecessary Right Ventricular Pacing in Sinus Node Disease: A Randomized Cross-Over Study Versus Dual- to Atrial Single-Chamber Mode Switch.

OBJECTIVES: This study sought to compare the Intrinsic Rhythm Support (IRSplus) and Ventricular Pace Suppress (VpS) in terms of right ventricular pacing percentage (VP %), mean atrioventricular interval (MAVI), atrial fibrillation, and cardiac volumes. BACKGROUND: Modern pacemakers are provided with algorithms for reducing unnecessary ventricular pacing. These may be classified as: periodic search for intrinsic atrioventricular (AV) conduction prolonging the AV delay accordingly; or DDD-ADI mode switch. The IRSplus and VpS algorithms belong to the former and latter classes, respectively. METHODS: Patients with sick sinus dysfunction without evidence of II/III degree AV block were 1:1 randomized to 6-month periods of either IRSplus or VpS, and then crossed over. Subsequent follow-ups were at the 12th month after randomization for device data retrieving, and at the 18th month with the same device programming for echocardiographic assessment. RESULTS: A total of 230 patients (62% males, median age 75 years [interquartile range: 69 to 79 years]) were enrolled. At a linear mixed-model analysis with order of treatment and investigational sites as nested random effects, differences in VP% and MAVI reached statistical significance: VP% was 1% (0% to 11%) during IRSplus and 3% (0% to 26%) during VpS (p = 0.029); MAVI was 225 ms (198 to 253 ms) during IRSplus and 214 ms (188 to 240 ms) during VpS (p = 0.014). No differences were observed in atrial fibrillation burden and incidence, ejection fraction, and cardiac volumes. CONCLUSIONS: Both IRSplus and VpS algorithms ensured VP% ≤3% in most patients with sinus node dysfunction and preserved AV conduction. The IRSplus was slightly more efficient in reducing VP% at the expense of a small MAVI increase, with statistical but clinically insignificant differences. (Ventricular Pace Suppression Versus Intrinsic Rhythm Support Study; NCT01528657).

The OPTI-MIND study: a prospective, observational study of pacemaker patients according to pacing modality and primary indications.

AIMS: The OPTI-MIND study aims to collect 2-year clinical outcomes of pacemaker patients in real-world clinical practice, overall and according to patient characteristics and pacemaker settings. METHODS AND RESULTS: The present analysis of the OPTI-MIND study describes the programmed device settings after discharge from the pacemaker implant. The objective was to determine whether these settings fit recent guidelines for device-programmed physiological pacing based on the preservation of atrioventricular synchrony, avoiding unnecessary pacing, ensuring rate increase during exercise or preventing neurally mediated symptoms. A total of 1740 patients were enroled at 68 centres worldwide. Baseline patient characteristics and device programming settings are available in 1674 of 1740 patients (96%). Guidelines to ensure physiological pacing were followed in 41% of patients: in patients with sinus node disease (SND), and without atrioventricular block (AVB), device programming could have led to unnecessary right ventricular pacing in 38% of patients. In SND patients with chronotropic incompetence, assisted rate increase during exercise was not programmed in 42% of patients. In 11% of patients with AVB, atrioventricular (AV) synchrony was not pursued; the main drivers being advanced age and history of atrial fibrillation. Patients with both SND and AVB were generally programmed physiologically (87%). CONCLUSION: The present analysis showed that frequent deviations occurred when comparing the device settings at discharge from the pacemaker implant in clinical practice to the available guidelines on pacing mode selection. Analysis of 2-year outcomes in the OPTI-MIND study will provide an insight into whether specific physiological settings could improve the quality of pacing with a positive effect on patient outcome.