Background  Cardiac resynchronization therapy (CRT) is an option for treatment for chronic heart failure (HF) associated with left bundle branch block (LBBB). Patients with HF and right bundle branch block (RBBB) have potentially worse outcomes in comparison to LBBB. Traditional CRT in RBBB can increase mortality and HF deterioration rates over native disease progression. His bundle pacing may improve the results of CRT in those patients. Furthermore, atrioventricular node ablation (AVNA) for rate control in atrial fibrillation (AF) can be challenging in patients with previously implanted leads in His region. Case summary  We report the case of 74-year-old gentleman with a 5-year history of HF, permanent AF with a rapid ventricular response, and RBBB. He was admitted to the hospital with complaints of severe weakness and shortness of breath. Left ventricular ejection fraction (LVEF) was decreased (41%), right ventricle (RV) was dilated (41 mm), and QRS was prolonged (200 ms) with RBBB morphology. The patient underwent His-optimized CRT with further left-sided AVNA. As a result, LVEF increased to 51%, RV dimensions decreased to 35 mm with an improvement of the clinical status during a 6-month follow-up. Discussion  Patients with AF, RBBB, and HF represent the least evaluated clinical subgroup of individuals with less beneficial clinical outcomes according to CRT studies. Achieving the most effective resynchronization could require pacing fusion from sites beyond traditional with the intention to recruit intrinsic conduction pathways. This approach can be favourable for reducing RV dilatation, improving LVEF, and maximizing electrical resynchronization.

Cardiac pacing is an established treatment option for patients with bradycardia and heart failure. In the recent decade, there is an increasing scientific and clinical interest in the topic of direct His bundle pacing (HBP) and left bundle branch pacing (LBBP) as options for cardiac conduction system pacing (CSP). The concept of CSP started evolving from the late 1970s, passing several historical landmarks. HBP and LBBP used in CSP proved to be successful in small cohorts of patients with various clinical conditions, including binodal disease, atrioventricular blocks, and in patients with bundle branch blocks with indications for cardiac resynchronization therapy. The scope of this chapter is synthesis and analysis of works devoted to this subject, as well as representation of the author’s experience in this topic. The chapter includes historical background, technical, anatomical, and clinical considerations of CSP, covers evidence base, discusses patient outcomes in line with the pros and cons of the abovementioned methods. The separate part describes practical aspects of different pacing modalities, including stages of the operation and pacemaker programming. The textual content of the chapter is accompanied by illustrations, ECGs, and intracardiac electrograms.

The aim: To study the predictive power of demographic, hemodynamic and electrocardiographic factors for atrial fibrillation recurrence after radiofrequency ablation (RFA) in patients with chronic heart failure. Materials and methods: Study included 120 patients, aged 59,80±10,08 years old with chronic heart failure with preserved left ventricular ejection fraction who were undergo RFA due to atrial fibrillation (AF). A standard 12-lead electrocardiogram (ECG) was registered. Before the procedure the standard echocardiographic parameters were obtained. After 12 months, patients were divided into 2 groups: non-recurrence group and recurrence group. Results: As a result of prospective follow-up within 12 months AF recurrences were observed in 32 patients (27%), 88 patients remained non-recurrent (73%). The left atrium (LA) diameter and aortic root diameter were lager in the recurrence group (4,59±0,45 vs. 4,08±0,61 cm, p<0,001; 3,37±0,60 vs. 2,80±0,67 cm, p<0,001). The AF recurrence group before RFA had a significantly longer QTc interval than the non-recurrence group (387,23±2,31 vs. 341,22±8,91 ms, p<0,010). ROC curve analysis revealed LA diameter the most sensitive factor for AF recurrence after RFA. Conclusions: QTc duration before radiofrequency ablation and its prolongation after intervention are independent predictors of atrial fibrillation recurrence; left atrium diameter before ablation is a highly sensitive predictor in patients with chronic heart failure with preserved left ventricular ejection fraction.

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