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Background Advances in technology and workflows have facilitated substantial reductions in fluoroscopy utilization and procedure times for atrial fibrillation (AF) ablations. A recently available steerable sheath, visualizable on a 3D electroanatomical map (EAM), may further simplify low/zero fluoroscopy ablation workflows by facilitating understanding of the relative positions of the catheter and sheath. The objective of this study was to demonstrate feasibility, safety, procedural efficiency, and clinical effectiveness of incorporating the new visualizable sheath into a low-fluoroscopy workflow. Methods Consecutive de novo paroxysmal AF procedures were performed with a porous tip contact force catheter at a high-volume site between January 2018 and May 2019. Procedures performed with and without the VIZIGO™ EAM-visualizable sheath (Vizigo) were compared. All ablations employed the same standardized low-fluoroscopy workflow. Statistical analyses employed stabilized inverse probability of treatment weights (IPTW) to balance cohorts by operator and key patient characteristics. Results Cohorts of 142 Vizigo and 173 non-Vizigo patients were similar at baseline. Use of the Vizigo sheath was associated with approximately 10% improvement in catheter stability (p = 0.0005), 16% reduction in radiofrequency time (p p = 0.0030). There was one cardiac tamponade in each cohort and no deaths, atrioesophageal fistulas, or strokes. Single-procedure freedom from atrial arrhythmia recurrence through 12 months was similar between cohorts (p = 0.9556). Conclusions Use of a 3D EAM-visualizable sheath resulted in improved catheter stability, reduced radiofrequency time, and more procedures performed without fluoroscopy, without compromise to safety or effectiveness.

Subcutaneous implantable cardioverter defibrillators (S-ICDs) have gained increasing popularity because of certain advantages over transvenous ICDs. However, while conventional ICDs require a single surgical incision to implant, S-ICDS need two or three incisions, making them less appealing.This study sought out to investigate the feasibility of using a single-incision technique to implant S-ICDs.Patients qualifying for S-ICDs were considered for a single incision. A single incision is performed by making a left inframammary incision and then the subcutaneous tissue is dissected medially toward the lower sternum. Two sutures are placed in the fascia in the xiphoid area to anchor the lead and a tunneling tool is used to dissect the tissue to place the lead parallel to the sternum. Then subcutaneous tissues are dissected down the lateral chest wall over the muscle fascia to create the pulse generator pocket in the vicinity of the fifth and sixth intercostal spaces and near the mid-axillary line.Eleven patients (six males and five females) successfully underwent S-ICD implantation with a single incision without acute complications (64% for primary prevention). The mean age is 47.4 ± 15.8 years. There were no lead dislodgements, inappropriate shocks, or any other issues during a median follow-up of 10 months (interquartile range 5-17). One patient had a successful appropriate shock for ventricular fibrillation about one year after device implant.A single incision for subcutaneous ICDs is feasible and safe in our early experience.

Adenosine Unmasking Dormant Conduction Across the Cavotricuspid IsthmusBackground Adenosine-induced hyperpolarization may identify pulmonary veins at risk of reconnection following electrical isolation for atrial fibrillation. The potential role of adenosine testing in other arrhythmic substrates, such as cavotricuspid isthmus (CTI)-dependent atrial flutter, remains unclear. We assessed whether dormant conduction across the CTI may be revealed by adenosine after ablation-induced bidirectional block, and its association with recurrent flutter. Methods and Results Patients undergoing catheter ablation for CTI-dependent flutter were prospectively studied. After confirming bidirectional block across the CTI by standard pacing maneuvers, adenosine (≥12 mg IV) was administered to assess resumption of conduction, followed by isoproterenol (ISP) bolus. Further CTI ablation was performed for persistent (but not transient) resumption of conduction. Bidirectional block across the CTI was achieved in all 81 patients (63 males), age 61.2 ± 11.0 years. The trans-CTI time increased from 71.9 ± 18.1 milliseconds preablation to 166.2 ± 26.4 milliseconds postablation. Adenosine elicited resumption of conduction across the CTI in 7 patients (8.6%), 2 of whom had transient recovery. No additional patient with dormant conduction was identified by ISP. Over a follow-up of 11.8 ± 8.0 months, atrial flutter recurred in 4 (4.9%) patients, 3/7(42.9%) with a positive adenosine challenge versus 1/74 (1.3%) with a negative response, P = 0.0016 (relative risk 31.7). Conclusion Adenosine challenge following atrial flutter ablation provoked transient or persistent resumption of conduction across the CTI in almost 9% of patients and identified a subgroup at higher risk of flutter recurrence. It remains to be determined whether additional ablation guided by adenosine testing during the index procedure may further improve procedural outcomes.

Medical societies and cardiac implantable electronic device (CIED) manufacturers recommend avoiding close or direct contact between the body of transvenous leads and ablation catheters used to treat cardiac arrhythmias. These recommendations are made despite the lack of clinical studies. However, the target myocardium for successful ablation can be contiguous to CIED leads.We examine in vitro the effects of direct application of radiofrequency (RF) and cryo-ablation energy on the integrity and functionality of CIED leads (excluding the pacing electrodes and defibrillation coils). A saline bath was created to mimic the body milieu. CIED leads, including all commercially available lead insulation materials, were connected to a CIED pulse generator and placed in direct contact with an ablation catheter in the tissue bath. RF and cryo-ablation energy were delivered under various conditions, including maximal ablation power, temperature, and impedance via the RF generator. CIED lead functionality, reflective of conductor integrity, was evaluated through lead impedance monitoring during ablation. CIED leads were then visually inspected, and examined with optic and electron microscopy as per protocol. A total of 42 leads were studied. All leads showed the absence of insulation damage at the site of ablation visually and with microscopy. Lead functionality was also preserved in all leads.Catheter ablation in contact with CIED leads using radiofrequency or cryo-ablation in vitro did not affect lead body integrity and function despite aggressive ablation settings. It may be reasonable to perform ablation in contact with the body of CIED leads when clinically necessary.

The authors aimed to determine whether electrical dental devices would interfere with the function of cardiac pacemakers or implantable cardioverter defibrillators (ICDs) in humans.The authors exposed asymptomatic nonpacemaker-dependent patients to commonly used electrical dental equipment (for example, battery-operated curing lights, ultrasonic baths, ultrasonic scalers, electric pulp testers, and electric toothbrushes) in an outpatient cardiology clinic. The authors operated dental devices at various distances and programmed cardiac devices to sense and pace. The authors obtained cardiac tracings using a cardiac programming unit and a cardiac provider who noted any interference interpreted the results in real time.The authors enrolled 32 consecutive patients and tested 12 pacemakers and 20 ICDs. They did not observe any significant clinical interference in sensing and pacing functions in any patient; however, they noted minor interference without clinical impact in the telemetry from the cardiac programming unit during use of the ultrasonic scaler and bath.The findings of this prospective study suggest that electrical devices commonly used in dental practices do not interfere with the sensing and pacing of contemporary cardiac patients' pacemakers or ICDs. However, they do interfere with the telemetry from the cardiac programming unit, without any clinical impact on patient safety. These findings should help in the development of clinical guidelines regarding dental management of patients with pacemakers or ICDs.Electrical dental devices (for example, ultrasonic baths, ultrasonic scalers) induced minor interference with programmers that interrogate cardiac devices implanted in patients; however, overall, dental devices do not appear to interfere with pacemakers' and defibrillators' pacing and sensing function.

Adenosine-induced hyperpolarization may identify pulmonary veins at risk of reconnection following electrical isolation for atrial fibrillation. The potential role of adenosine testing in other arrhythmic substrates, such as cavotricuspid isthmus (CTI)-dependent atrial flutter, remains unclear. We assessed whether dormant conduction across the CTI may be revealed by adenosine after ablation-induced bidirectional block, and its association with recurrent flutter.Patients undergoing catheter ablation for CTI-dependent flutter were prospectively studied. After confirming bidirectional block across the CTI by standard pacing maneuvers, adenosine (≥ 12 mg IV) was administered to assess resumption of conduction, followed by isoproterenol (ISP) bolus. Further CTI ablation was performed for persistent (but not transient) resumption of conduction. Bidirectional block across the CTI was achieved in all 81 patients (63 males), age 61.2 ± 11.0 years. The trans-CTI time increased from 71.9 ± 18.1 milliseconds preablation to 166.2 ± 26.4 milliseconds postablation. Adenosine elicited resumption of conduction across the CTI in 7 patients (8.6%), 2 of whom had transient recovery. No additional patient with dormant conduction was identified by ISP. Over a follow-up of 11.8 ± 8.0 months, atrial flutter recurred in 4 (4.9%) patients, 3/7(42.9%) with a positive adenosine challenge versus 1/74 (1.3%) with a negative response, P = 0.0016 (relative risk 31.7).Adenosine challenge following atrial flutter ablation provoked transient or persistent resumption of conduction across the CTI in almost 9% of patients and identified a subgroup at higher risk of flutter recurrence. It remains to be determined whether additional ablation guided by adenosine testing during the index procedure may further improve procedural outcomes.