Hybrid Endo-Epicardial Therapies for Advanced Atrial Fibrillation.

Atrial fibrillation (AF) is a growing health problem that increases morbidity and mortality, and in most patients progresses to more advanced diseases over time. Recent research has examined the underlying mechanisms, risk factors, and progression of AF, leading to updated AF disease classification schemes. Although endocardial catheter ablation is effective for early-stage paroxysmal AF, it consistently achieves suboptimal outcomes in patients with advanced AF. Identification of the factors that lead to the increased risk of treatment failure in advanced AF has spurred the development and adoption of hybrid ablation therapies and collaborative heart care teams that result in higher long-term arrhythmia-free survival. Patients with non-paroxysmal AF, atrial remodeling, comorbidities, or AF otherwise deemed difficult to treat may find hybrid treatment to be the most effective option. Future research of hybrid therapies in advanced AF patient populations, including those with dual diagnoses, may provide further evidence establishing the safety and efficacy of hybrid endo-epicardial ablation as a first line treatment.

Cryothermal energy demonstrates shorter ablation time and lower complication rates compared with radiofrequency in surgical hybrid ablation for recurrent ventricular tachycardia.

BACKGROUND: Recurrent ventricular tachycardia (VT) after prior endocardial catheter ablation(s) presents challenges in the setting of prior cardiac surgery where percutaneous epicardial access may not be feasible. OBJECTIVE: The purpose of this study was to compare the outcomes of cryothermal vs radiofrequency ablation in direct surgical epicardial access procedures. METHODS: We performed a retrospective study of consecutive surgical epicardial VT ablation cases. Surgical cases using cryothermal vs radiofrequency ablation were analyzed and outcomes were compared. RESULTS: Between 2009 and 2022, 43 patients underwent either a cryothermal (n = 17) or a radiofrequency (n = 26) hybrid epicardial ablation procedure with direct surgical access. Both groups were similarly matched for age, sex, etiology of VT, and comorbidities with a high burden of refractory VT despite previous endocardial and/or percutaneous epicardial ablation procedures. The surgical access site was lateral thoracotomy (76.5%) in the cryothermal ablation group compared with lateral thoracotomy (42.3%) and subxiphoid approach (38.5%) in the radiofrequency group, with the remainder in both groups performed via median sternotomy. The ablation time was significantly shorter in those undergoing cryothermal ablation vs radiofrequency ablation (11.54 ± 15.5 minutes vs 48.48 ± 23.6 minutes; P < .001). There were no complications in the cryothermal ablation group compared with 6 patients with complications in the radiofrequency group. Recurrent VT episodes and all-cause mortality were similar in both groups. CONCLUSION: Hybrid surgical VT ablation with cryothermal or radiofrequency energy demonstrated similar efficacy outcomes. Cryothermal ablation was more efficient and safer than radiofrequency in a surgical setting and should be considered when surgical access is required.

Left atrial posterior wall isolation in conjunction with pulmonary vein isolation using cryoballoon for treatment of persistent atrial fibrillation (PIVoTAL): study rationale and design.

BACKGROUND: There is growing evidence in support of pulmonary vein isolation (PVI) with concomitant posterior wall isolation (PWI) for the treatment of patients with symptomatic persistent atrial fibrillation (persAF). However, there is limited data on the safety and efficacy of this approach using the cryoballoon. OBJECTIVE: The aim of this multicenter, investigational device exemption trial (G190171) is to prospectively evaluate the acute and long-term outcomes of PVI versus PVI+PWI using the cryoballoon in patients with symptomatic persAF. METHODS: The PIVoTAL is a prospective, randomized controlled study ( ClinicalTrials.gov : NCT04505163) in which patients with symptomatic persAF refractory/intolerant to ≥ 1 class I-IV antiarrhythmic drug, undergoing first-time catheter ablation, will be randomized to PVI (n = 183) versus PVI+PWI (n = 183) using the cryoballoon in a 1:1 fashion. The design will be double-blind until randomization immediately after PVI, beyond which the design will transform into a single-blind. PVI using cryoballoon will be standardized using a pre-specified dosing algorithm. Other empiric ablations aside from documented arrhythmias/arrhythmias spontaneously induced during the procedure will not be permitted. The primary efficacy endpoint is defined as AF recurrence at 12 months, after a single procedure and a 90-day blanking period. Arrhythmia outcomes will be assessed by routine electrocardiograms and 7-14 day ambulatory electrocardiographic monitoring at 3, 6, and 12 months post-ablation. CONCLUSION: The PIVoTAL is a prospective, randomized controlled trial designed to evaluate the outcomes of PVI alone versus PVI+PWI using the cryoballoon, in patients with symptomatic persAF. We hypothesize that PVI+PWI will prove to be superior to PVI alone for prevention of AF recurrence.

Recurrent ventricular tachycardia after cardiac sympathetic denervation: Prolonged cycle length with improved hemodynamic tolerance and ablation outcomes.

INTRODUCTION: Cardiac sympathetic denervation (CSD) is utilized for the management of ventricular tachycardia (VT) in structural heart disease when refractory to radiofrequency ablation (RFA) or when patient/VT characteristics are not conducive to RFA. METHODS: We studied consecutive patients who underwent CSD at our institution from 2009 to 2018 with VT requiring repeat RFA post-CSD. Patient demographics, VT/procedural characteristics, and outcomes were assessed. RESULTS: Ninety-six patients had CSD, 16 patients underwent RFA for VT post-CSD. There were 15 male and 1 female patients with mean age of 54.2 ± 13.2 years. Fourteen patients had nonischemic cardiomyopathy. A mean of 2.0 ± 0.8 RFAs for VT was unsuccessful before the patient undergoing CSD. The median time between CSD and RFA was 104 days (interquartile range [IQR] = 15-241). The clinical VT cycle length was significantly increased after CSD both spontaneously on ECG and/or ICD interrogation (355 ± 73 ms pre-CSD vs. 422 ± 94 ms post-CSD, p = .001) and intraprocedurally (406 ± 86 ms pre-CSD vs. 457 ± 88 ms post-CSD, p = .03). Two patients had polymorphic and 14 had monomorphic VT (MMVT) pre-CSD, and all patients had MMVT post-CSD. The proportion of mappable, hemodynamically stable VTs increased from 35% during pre-CSD RFA to 58% during post-CSD RFA (p = .038). At median follow-up of 413 days (IQR = 43-1840) after RFA, eight patients had no further VT. CONCLUSION: RFA for recurrent MMVT post-CSD is a reasonable treatment option with intermediate-term clinical success in 50% of patients. Clinical VT cycle length was significantly increased after CSD with associated improvement in mappable, hemodynamically tolerated VT during RFA.

Relationship between sinus rhythm late activation zones and critical sites for scar-related ventricular tachycardia: systematic analysis of isochronal late activation mapping.

BACKGROUND: It is not known whether the most delayed late potentials are functionally most specific for scar-related ventricular tachycardia (VT) circuits. METHODS AND RESULTS: Isochronal late activation maps were constructed to display ventricular activation during sinus rhythm over 8 isochrones. Analysis was performed at successful VT termination sites and prospectively tested. Thirty-three patients with 47 scar-related VTs where a critical site was demonstrated by termination of VT during ablation were retrospectively analyzed. In those who underwent mapping of multiple surfaces, 90% of critical sites were on the surface that contained the latest late potential. However, only 11% of critical sites were localized to the latest isochrone (87.5%-100%) of ventricular activation. The median percentage of latest activation at critical sites was 78% at a distance from the latest isochrone of 18 mm. Sites critical to reentry were harbored in regions with slow conduction velocity, where 3 isochrones were present within a 1-cm radius. Ten consecutive patients underwent ablation prospectively guided by isochronal late activation maps, targeting concentric isochrones outside of the latest isochrone. Elimination of the targeted VT was achieved in 90%. Termination of VT was achieved in 6 patients at a mean ventricular activation percentage of 78%, with only 1 requiring ablation in the latest isochrone. CONCLUSIONS: Late potentials identified in the latest isochrone of activation during sinus rhythm are infrequently correlated with successful ablation sites for VT. The targeting of slow conduction regions propagating into the latest zone of activation may be a novel and promising strategy for substrate modification.

Analysis of emergency department visits for palpitations (from the National Hospital Ambulatory Medical Care Survey).

Palpitations is a common complaint in patients who visit the emergency department (ED), with causes ranging from benign to life threatening. We analyzed the ED component of the National Hospital Ambulatory Medical Care Survey for 2001 through 2010 for visits with a chief complaint of palpitations and calculated nationally representative weighted estimates for prevalence, demographic characteristics, and admission rates. ED and hospital discharge diagnoses were tabulated and categorized, and recursive partitioning was used to identify factors associated with admission. An estimated 684,000 visits had a primary reason for visit of "palpitations" representing a national prevalence of 5.8 per 1,000 ED visits (0.58%, 95% confidence interval 0.52 to 0.64). Women and non-Hispanic whites were responsible for most visits. A cardiac diagnosis made up 34% of all ED diagnoses. The overall admission rate was 24.6% (95% confidence interval 21.2 to 28.1), with higher rates seen in the Midwest and Northeast compared with the West. Survey-weighted recursive partitioning revealed several factors associated with admission including age >50 years, male gender, cardiac ED diagnosis, tachycardia, hypertension, and Medicare insurance. In conclusion, palpitations are responsible for a significant minority of ED visits and are associated with a cardiac diagnosis roughly 1/3 of the time. This was associated with a relatively high admission rate, although significant regional variation in these rates exists.

Impact of local ablation on interconnected channels within ventricular scar: mechanistic implications for substrate modification.

BACKGROUND: The extent to which channels within scar are interconnected is not known. The objective of the study was to evaluate the impact of local ablation of late potentials (LPs) on adjacent and remote areas of slow conduction with simultaneous multipolar mapping. METHODS AND RESULTS: Analysis was performed on consecutive patients referred for ablation of scar-mediated ventricular tachycardia with double ventricular access. Ablation was performed targeting the earliest of LPs visualized on the multipolar catheter, and the impact on later LPs was recorded. In 21 patients, a multipolar catheter placed within scar visualized spatially distinct LPs. Among 39 radiofrequency applications, ablation at earlier LPs had an effect on neighboring and remote LPs in 31 (80%), with delay in 8 (21%), partial elimination in 9 (23%), and complete elimination in 14 (36%). The mean distance where an ablation impact was detected was 17.6±14.7 mm (range, 2-50 mm). Among all patients, 9.7±7.8 radiofrequency applications were delivered to homogenize the targeted scar region with a mean number of 23±12 LPs targeted. CONCLUSIONS: Ablation can eliminate neighboring and remote areas of slow conduction, suggesting that channels within scar are frequently interconnected. This is the first mechanistic demonstration to show that ablation can modify electrical activity in regions of scar outside of the known radius of an radiofrequency lesion. The targeting of relatively earlier LPs can expedite scar homogenization without the need for extensive ablation of all LPs.