Atrioventricular Re‐entry Tachycardia (AVRT) occurs in patients with accessory pathways (AP) via a re‐entry circuit between the AV node and the AP. Anterograde conduction through the AP causes antidromic AVRT with wide QRS complexes, which may mimic ventricular tachycardia (VT). We report a 59‐year‐old male with ischemic cardiomyopathy (EF 35%) and recurrent wide QRS tachycardia who was referred for ICD implantation. Electrophysiology study identified a left posterolateral AP, and radiofrequency ablation successfully eliminated pre‐excitation. ICD implantation was subsequently performed without complications. Antidromic AVRT should be considered in the differential diagnosis of wide QRS tachycardia, and catheter ablation remains a safe and effective treatment.

Background and Objectives: Idiopathic ventricular arrhythmias commonly occur in patients without structural heart disease and most often present as premature ventricular contractions (PVCs). Although generally considered benign, a high PVC burden may cause symptoms, reduce quality of life, and lead to reversible PVC-induced cardiomyopathy. This study aimed to evaluate long-term outcomes after radiofrequency catheter ablation of idiopathic outflow tract PVCs. Materials and Methods: This single-center retrospective study included 101 patients with idiopathic PVCs who underwent radiofrequency catheter ablation. PVC burden and clinical outcomes were assessed at baseline and during follow-up at 3 months, 12 months, and 5 years. Procedural success, predictors of success, and changes in antiarrhythmic drug therapy were analyzed. Results: During follow-up, a marked reduction in PVC burden was observed compared with baseline values. The median PVC burden decreased from 21.89% at baseline to 0.79% at 3 months, 0.23% at 12 months, and 0.09% at the 5-year follow-up after ablation. Acute procedural success was achieved in 88.1% of patients. Long-term success at 5 years was observed in 80.2% of patients. The use of antiarrhythmic drugs decreased during follow-up. Left ventricular ejection fraction remained stable, with no significant difference between baseline and 5-year values. Monomorphic PVC morphology and procedural success at 12 months were identified as independent predictors of long-term success. Conclusions: Radiofrequency catheter ablation provides effective and sustained reduction in PVC burden in patients with idiopathic outflow tract PVCs, with high acute success rates, durable long-term outcomes, and reduced reliance on antiarrhythmic drug therapy.

Background/Objectives: Atrial fibrillation (AF) is closely associated with adverse remodeling of the left atrium (LA). This study evaluated the impact of LA diameter on long-term outcomes following radiofrequency ablation (RFA) of the pulmonary veins and assessed LA and left ventricular (LV) remodeling over a seven-year follow-up period. Methods: A total of 117 patients with symptomatic, drug-refractory AF underwent RFA. Structural remodeling was evaluated using echocardiography. Long-term outcomes were categorized using the Pulmonary Vein Isolation Outcome Degree (PVIOD), a four-level classification reflecting procedural and clinical success. Results: After seven years, 32.5% of patients who achieved successful sinus rhythm maintenance after a single RFA (PVIOD 1) demonstrated significant reverse remodeling of LA and LV. LA diameter decreased from 39.3±0.6 mm to 36.5±0.6 mm (p< 0.001); LV end-diastolic diameter (LVEDD) from 53.1±0.6 mm to 50.9±0.7 mm (p=0.008); LV end-systolic diameter (LVESD) from 34.7±0.8 mm to 32.0±0.1 mm (p=0.005); and LV ejection fraction (LVEF) increased from 56.8±0.8% to 62.1±1.1% (p< 0.001). Among patients with long-term success after multiple procedures (PVIOD 2; 29.1%), LA diameter decreased significantly from 41.9±0.7 mm to 40.2±0.6 mm (p=0.044), without significant ventricular changes. Patients achieving clinical success (PVIOD 3; 14.5%) showed no significant structural changes. Those with procedural and clinical failure (PVIOD 4; 23.9%) exhibited progressive negative remodeling: LA diameter increased from 44.7±0.7 mm to 47.4±0.7 mm (p=0.006); LVEDD from 52.8±0.9 mm to 57.1±0.6 mm (p< 0.001); LVESD from 36.5±1.1 mm to 40.7±1.2 mm (p=0.006); and LVEF decreased from 50.7±1.7% to 43.8±1.8% (p=0.004). Conclusions: Early and successful single RFA performed in patients with normal LA diameter is associated with complete reverse remodeling and prevention of AF recurrence. As LA size increases, the likelihood of achieving durable procedural success decreases, emphasizing the importance of timely intervention before significant left atrial enlargement develops.

Radiofrequency catheter ablation of accessory pathways is considered the treatment of choice for patients with atrioventricular reentry tachycardia due to its proven safety and effectiveness. The aim of this study was to compare the outcomes of this treatment for left-sided accessory pathways in 58 consecutive patients with manifest preexcitation who were treated at the Institute for Cardiovascular Diseases Dedinje. The procedure duration varied significantly (p<0.05) depending on the localization of accessory pathways along the mitral annulus (anterior 60.0±26.0 min; anterolateral 45.2±28.4 min; lateral 73.9±27.9 min; posterolateral 59.1±25.5 min; posterior 83.1±29.6 min), as did the number of applied radiofrequency pulses (anterior 9.0±4.5; anterolateral 4.3±4.7; lateral 8.1±5.8; posterolateral 4.0±2.9; posterior 8.1±4.2; p<0.05). Fluoroscopy exposure time did not differ significantly (p=0.078). Atrial fibrillation was recorded in 15.5% of patients prior to the procedure. For the ablation of left-sided accessory pathways, the transaortic approach was used significantly more often (74.1%) than the transseptal approach. There were no significant differences among the groups in terms of primary procedural success (100% for anterior and anterolateral, 82.1% for lateral, 100% for posterolateral, and 88.9% for posterior; p=0.672), recurrence rate (10.7% for lateral and 5.5% for posterior; p=0.023), or final success rate, defined as definitive cure (100% for anterior, anterolateral, and posterolateral, 94.8% for lateral, and 89.3% for posterior; p=0.421). Despite the increased time and more radiofrequency energy pulses necessary for ablating laterally and posteriorly positioned accessory pathways, the procedure's success rate remained comparable regardless of accessory pathways location along the mitral annulus.

Background and Objectives: Cardiac resynchronization therapy (CRT) is one of the effective therapeutic options in the treatment of systolic heart failure (HF) with persistent symptoms. This prospective study was designed to determine whether CRT with biventricular pacing would reduce the risk of development of atrial fibrillation (AF) and to identify predictors for AF occurrence. Materials and Methods: The study population consisted of 126 patients, with a mean age of 63.8 ± 9.1 years, who were eligible for CRT with biventricular pacing. Inclusion criteria were left ventricular ejection fraction (LVEF) ≤ 35%, QRS duration ≥ 130 msec, and persistent HF symptoms of New York Heart Association (NYHA) II or III, despite optimal drug therapy. Patients were followed for a period of 24 months and were evaluated through clinical, electrocardiographic, and echocardiographic examination at baseline (prior to CRT implantation), as well as at 6 and 24 months post-implantation. At the end of follow-up, patients were divided into clinical responders and non-responders based on the following criteria: decrease in NYHA class ≥ I, increase in LVEF ≥ 10%, and reduction in QRS duration ≥ 20 msec. Results: At follow-up, CRT was associated with a significant increase in LVEF (20.6 ± 6.9% pre-implantation, 32.9 ± 9.3% 24 months after implantation; p < 0.001), reduction in left ventricular end-diastolic and end-systolic diameters, and decrease in QRS duration (167.6 ± 14.3 msec pre-implantation, 131.7 ± 11.7 msec 24 months after implantation; p < 0.001), while left atrial (LA) diameter was slightly increased (p = 0.070). The frequency of AF occurrence increased after two years of follow-up (52.4% to 56.9%, p < 0.001). Significant predictors of AF occurrence in our study population were response to CRT—AF more frequent in non-responders (B = 8.134; p < 0.001), LA diameter—AF more frequent with larger LA diameter (B = 0.813; p < 0.001), and coronary sinus (CS) lead position—AF more frequent with posterolateral in comparison with lateral CS lead position (B = 5.159; p = 0.005). Conclusions: The results of our study provide new data on AF predictors in patients with HF subjected to CRT. There remains a permanent need for new predictors, which might help in patient selection and improvement in response rate.

Background: Refractory atrioventricular nodal reentrant tachycardia (AVNRT) is a rare condition, but poses a clinical challenge after failed standard ablation. Very high-power, short-duration (vHPSD) radiofrequency (RF) ablation has not yet been explored in slow pathway ablation/modification. Case Summary: A 61-year-old woman with recurrent AVNRT despite two prior ablations and multiple antiarrhythmics underwent successful slow pathway ablation using a 90-watt, 4-s vHPSD protocol. CARTO-guided mapping localized the presumed slow pathway, followed by several 90 W applications. Transient second-degree AV block (Wenckebach type) occurred and resolved spontaneously. The patient remained arrhythmia-free at 6-month follow-up. Conclusions: This is the first reported clinical use of 90 W/4 s RF energy for AVNRT. The vHPSD approach may offer an effective alternative for patients with refractory AVNRT.