Permanent single-chamber atrial pacing: an obsolete or viable alternative to dual-chamber pacing in selected patients with sinus node disease?

INTRODUCTION: Single atrial stimulation (AAI) has been commonly used for permanent pacing in sick sinus syndrome and significant bradycardia. OBJECTIVE: The study aimed to evaluate long­term AAI pacing and to identify timing and reasons for pacing mode change. PATIENTS AND METHODS: Retrospectively, we included 207 patients (60% women) with initial AAI pacing, who were followed­up for an average of 12 years. RESULTS: At the time of death or loss to follow­up, 71 patients (34.3%) had unchanged AAI pacing mode. The reason for an upgrade of the pacing system was development of atrial fibrillation (AF) in 43 patients (20.78%) and atrioventricular block (AVB) in 34 patients (16.4%). The cumulative ratio for a pacemaker upgrade reoperation reached 2.77 per 100 patient­years of the follow­up. Cumulative ventricular pacing below 10% after an upgrade to dual­chamber pacemaker was observed in 28.6% of the patients. Younger age at implant was the leading independent predictor of the change to dual­chamber simulation (hazard ratio, 1.98; 95% CI, 1.976-1.988; P = 0.001). There were 11 (5%) lead malfunctions that required reoperation. Subclavian vein occlusion was noted in 9 upgrade procedures (11%). One cardiac device-related infection was observed. CONCLUSIONS: The reliability of AAI pacing decreases with each year of observation due to development of AF and AVB. However, in the current era of effective AF treatment, the advantages of AAI pacemakers, such as lower incidence of lead malfunction, venous occlusion, and infection, as compared with dual-chamber pacemakers, may make AAI pacemakers a viable option.

Subcutaneous implantable cardioverter-defibrillator therapy in Poland: Results of the Polish S-ICD Registry.

BACKGROUND: The use of subcutaneous implantable cardioverter-defibrillators (S-ICD) has been growing in Poland since 2014. The Polish Registry of S-ICD Implantations was run by the Heart Rhythm Section of the Polish Cardiac Society between May 2020 and September 2022 to monitor the implementation of that therapy in Poland. AIMS: To investigate and present the state-of-the-art of S-ICD implantation in Poland. METHODS: Implanting centers reported clinical data of patients undergoing S-ICD implantations and replacements, including age, sex, height, weight, underlying disease, history of pacemaker and defibrillator implantations, indications for S-ICD, electrocardiographical parameters, procedural techniques, and complications. RESULTS: Four hundred and forty patients undergoing S-ICD implantation (411) or replacement (29) were reported by 16 centers. Most patients were in New York Heart Association class II (218 patients, 53%) or I (150 patients, 36.5%). Left ventricular ejection fraction was 10%-80%, median (IQR) was 33% (25%-55%). Primary prevention indications were present in 273 patients (66.4%). Non-ischemic cardiomyopathy was reported in 194 patients (47.2%). The main reason for the choice of S-ICD were: young age (309, 75.2%), risk of infectious complications (46, 11.2%), prior infective endocarditis (36, 8.8%), hemodialysis (23, 5.6%), and immunosuppressive therapy (7, 1.7%). Electrocardiographic screening was performed in 90% of patients. The rate of adverse events was low (1.7%). No surgical complications were observed.

[Cardiac remodelling and function after cardiovascular implantable electronic devices implantation]. / Przebudowa i funkcja serca po implantacji wszczepialnych sercowo-naczyniowych urzadzen elektronicznych.

Cardiovascular implantable electronic devices (CIED) encompass permanent cardiac pacemakers (PM) and implantable cardioverterdefibrillators (ICD). CIED play an important role in treatment of cardiac arrhythmias, including significant bradyarrhythmias and tachyarrhythmias. The conventional right ventricular endocardial leads as well as right ventricular pacing may increase valvular defects (especially dysfunction of tricuspid and mitral valve), cause adverse cardiac remodelling and lead to a decrease in left ventricular ejection fraction. These changes may be due to mechanical damage to the leaflets or other structures of the tricuspid apparatus, such as the annulus, papillary muscles or chordae tendineae. In addition, the endocardial lead passing through the tricuspid valve may adhere to it and exacerbate the inflammatory processes and fibrosis of its leaflets. On the other hand, right ventricular pacing leads to electromechanical dyssynchrony of the cardiac muscle. New forms of CIED therapy such as leadless pacemakers, His bundle pacing, synchronized left ventricular pacing or biventricular pacing may reduce some adverse changes induced by the right ventricular pacing with the use of conventional cardiac pacemakers. Similarly, subcutaneous cardioverter-defibrillators, despite limitations, may prevent some complications associated with traditional implantable cardioverterdefibrillator lead.