Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE-VT): A pilot study.

INTRODUCTION: The utility of ablation index (AI) to guide ventricular tachycardia (VT) ablation in patients with structural heart disease is unknown. The aim of this study was to assess procedural characteristics and clinical outcomes achieved using AI-guided strategy (target value 550) or conventional non-AI-guided parameters in patients undergoing scar-related VT ablation. METHODS: Consecutive patients (n = 103) undergoing initial VT ablation at a single center from 2017 to 2022 were evaluated. Patient groups were 1:1 propensity-matched for baseline characteristics. Single lesion characteristics for all 4707 lesions in the matched cohort (n = 74) were analyzed. The impact of ablation characteristics was assessed by linear regression and clinical outcomes were evaluated by Cox proportional hazard model. RESULTS: After propensity-matching, baseline characteristics were well-balanced between AI (n = 37) and non-AI (n = 37) groups. Lesion sets were similar (scar homogenization [41% vs. 27%; p = .34], scar dechanneling [19% vs. 8%; p = .18], core isolation [5% vs. 11%; p = .4], linear and elimination late potentials/local abnormal ventricular activities [35% vs. 44%; p = .48], epicardial mapping/ablation [11% vs. 14%; p = .73]). AI-guided strategy had 21% lower procedure duration (-47.27 min, 95% confidence interval [CI] [-81.613, -12.928]; p = .008), 49% lower radiofrequency time per lesion (-13.707 s, 95% CI [-17.86, -9.555]; p < .001), 21% lower volume of fluid administered (1664 cc [1127, 2209] vs. 2126 cc [1750, 2593]; p = .005). Total radiofrequency duration (-339 s [-24%], 95%CI [-776, 62]; p = .09) and steam pops (-155.6%, 95% CI [19.8%, -330.9%]; p = .08) were nonsignificantly lower in the AI group. Acute procedural success (95% vs. 89%; p = .7) and VT recurrence (0.97, 95% CI [0.42-2.2]; p = .93) were similar for both groups. Lesion analysis (n = 4707) demonstrated a plateau in the magnitude of impedance drops once reaching an AI of 550-600. CONCLUSION: In this pilot study, an AI-guided ablation strategy for scar-related VT resulted in shorter procedure time and average radiofrequency time per lesion with similar acute procedural and intermediate-term clinical outcomes to a non-AI-guided approach utilizing traditional ablation parameters.

Procedural and Intermediate-term Results of the Electroanatomical-guided Cardioneuroablation for the Treatment of Supra-Hisian Second- or Advanced-degree Atrioventricular Block: the PIRECNA multicentre registry.

AIMS: Prior case series showed promising results for cardioneuroablation in patients with vagally induced atrioventricular blocks (VAVBs). We aimed to examine the acute procedural characteristics and intermediate-term outcomes of electroanatomical-guided cardioneuroablation (EACNA) in patients with VAVB. METHODS AND RESULTS: This international multicentre retrospective registry included data collected from 20 centres. Patients presenting with symptomatic paroxysmal or persistent VAVB were included in the study. All patients underwent EACNA. Procedural success was defined by the acute reversal of atrioventricular blocks (AVBs) and complete abolition of atropine response. The primary outcome was occurrence of syncope and daytime second- or advanced-degree AVB on serial prolonged electrocardiogram monitoring during follow-up. A total of 130 patients underwent EACNA. Acute procedural success was achieved in 96.2% of the cases. During a median follow-up of 300 days (150, 496), the primary outcome occurred in 17/125 (14%) cases with acute procedural success (recurrence of AVB in 9 and new syncope in 8 cases). Operator experience and use of extracardiac vagal stimulation were similar for patients with and without primary outcomes. A history of atrial fibrillation, hypertension, and coronary artery disease was associated with a higher primary outcome occurrence. Only four patients with primary outcome required pacemaker placement during follow-up. CONCLUSION: This is the largest multicentre study demonstrating the feasibility of EACNA with encouraging intermediate-term outcomes in selected patients with VAVB. Studies investigating the effect on burden of daytime symptoms caused by the AVB are required to confirm these findings.

Procedural and Intermediate-term Results of the Electroanatomical-guided Cardioneuroablation for the Treatment of Supra-Hisian Second- or Advanced-degree Atrioventricular Block: the PIRECNA multicentre registry.

AIMS: Prior case series showed promising results for cardioneuroablation in patients with vagally induced atrioventricular blocks (VAVBs). We aimed to examine the acute procedural characteristics and intermediate-term outcomes of electroanatomical-guided cardioneuroablation (EACNA) in patients with VAVB. METHODS AND RESULTS: This international multicentre retrospective registry included data collected from 20 centres. Patients presenting with symptomatic paroxysmal or persistent VAVB were included in the study. All patients underwent EACNA. Procedural success was defined by the acute reversal of atrioventricular blocks (AVBs) and complete abolition of atropine response. The primary outcome was occurrence of syncope and daytime second- or advanced-degree AVB on serial prolonged electrocardiogram monitoring during follow-up. A total of 130 patients underwent EACNA. Acute procedural success was achieved in 96.2% of the cases. During a median follow-up of 300 days (150, 496), the primary outcome occurred in 17/125 (14%) cases with acute procedural success (recurrence of AVB in 9 and new syncope in 8 cases). Operator experience and use of extracardiac vagal stimulation were similar for patients with and without primary outcomes. A history of atrial fibrillation, hypertension, and coronary artery disease was associated with a higher primary outcome occurrence. Only four patients with primary outcome required pacemaker placement during follow-up. CONCLUSION: This is the largest multicentre study demonstrating the feasibility of EACNA with encouraging intermediate-term outcomes in selected patients with VAVB. Studies investigating the effect on burden of daytime symptoms caused by the AVB are required to confirm these findings.

Mortality benefit of catheter ablation versus medical therapy in atrial fibrillation: An RCT only meta-analysis.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) in comparison to medical therapy alone is known to improve freedom from arrhythmia and quality of life, but the benefit regarding mortality is unclear. The publication of several recent large randomized controlled trials (RCT) comparing ablation with medical therapy has warranted an updated meta-analysis. METHODS: We sought to compare the effectiveness of catheter ablation versus medical therapy only in patients with AF. MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched from inception until 04/30/2021. Relevant RCTs comparing catheter ablation versus medical therapy in patients with AF were selected. RESULTS: A total of 24 RCTs involving 5730 adult patients were included (2992 in catheter ablation and 2738 in medical therapy). There was a reduction in all-cause mortality with catheter ablation compared with medical therapy only (risk ratio (RR) 0.70 [95% confidence interval (CI) 0.55-0.89]; p = .003). Catheter ablation also demonstrated a reduction in hospitalizations (RR 0.50 [95% CI 0.36-0.70]; p < .001), improvement in left ventricular ejection fraction (LVEF) (mean difference [MD] + 5.94% [95% CI 0.40-11.48] p = .04), greater freedom from atrial arrhythmia (RR 2.23 [95% CI 1.79-2.76]; p < .001), and AF (RR 1.95 [95% CI 1.44-2.66]; p < .001). In subgroup analysis, catheter ablation demonstrated a significant reduction in mortality and hospitalizations among patients with reduced LVEF, and when ablation was compared with antiarrhythmic drug use. CONCLUSIONS: In comparison to medical therapy only, catheter ablation for atrial fibrillation reduces mortality, hospitalizations, and increases freedom from arrhythmia.

Comparison of radiofrequency ablation from the coronary cusps and endocardial left ventricular outflow tract for left ventricular summit ventricular arrhythmias in a porcine and infrared thermal model.

INTRODUCTION: The coronary cusps (CCs) are utilized as an alternative vantage point for radiofrequency catheter ablation (RFCA) of left ventricular summit ventricular arrhythmias but are sometimes a challenge despite favorable activation timing and pace mapping. METHODS: Ex vivo experiments were performed in 12 intact porcine hearts submerged in a 37°C saline bath. Radiofrequency (RF) applications were delivered with an irrigated contact force sensing catheter oriented 45° to the endocardial left ventricular outflow tract (LVOT) surface and nadir of the CCs using different dosing parameters. Sections were stained in 2% triphenyltetrazolium chloride and lesion dimensions were measured. Thermal infrared imaging analysis was used to compare time-to-lethal tissue temperature and depth/area of lethal isotherms. RESULTS: A total of 60 RF applications were performed under different dosing parameters for (1) 30, 40, and 50 Watts (W) × 30 s and (2) 40 W × 30, 45, and 60 s. Lesion depth was greater with RFCA from LVOT than from the CCs (maximum depth 6.11 vs. 2.68 mm). Longer RF duration led to larger lesion volume in the CC group (40 W × 30 s: 8.1 ± 0.4 vs. 40 W × 60 s: 10.1 ± 0.96 mm; p = .002). One steam pop occurred in both the LVOT (50 W × 30 s) and CC groups (40 W × 60 s). Time-to-reach lethal temperature of 58°C was longer in the CC group than in the LVOT group (4.7 vs. 11.3 s; p = .02) CONCLUSIONS: RFCA from the CC led comparatively to shallower lesion depth than from the LVOT. Longer RF duration led to an increase in lesion volume during ablation from CCs.

Comparison of ablation index versus time-guided radiofrequency energy dosing using normal and half-normal saline irrigation in a porcine left ventricular model.

BACKGROUND: Ablation Index (AI) is a multiparametric quality marker to assess the durability of radiofrequency (RF) lesions. The comparative effectiveness and safety of AI versus time-based energy dosing for ablation of ventricular arrhythmias are unknown. OBJECTIVE: We compared AI and time-based RF dosing strategies in the left ventricles (LVs) of freshly harvested porcine hearts. METHODS: Ablation was performed in vitro with an open-irrigated ablation catheter (Thermocool ST/SF), 40 W, contact force 10-15 g. Tissue samples were stained in triphenyltetrazolium chloride for the measurement of lesion dimensions. RESULTS: A total of 560 lesions were performed (AI-group: [n = 360]; time-group: [n = 200]). Using normal saline (NS) (n = 280), growth in lesion depth slowed after 30 s and AI > 550 in comparison to width, volume, and magnitude of impedance drops which continued to increase with longer RF duration. Risk of steam pop (SP) was higher for RF > 30 s (RF < 30 s:1 SP [2.5%] vs. RF > 30 s: 15 SP [25%]; p = .002) or AI targets >550 (AI: 350-550: 2 SP [2%] vs. AI 600-750: 15 SP [19%]; p = .001). Using half-normal saline (HNS) (n = 280), lesion dimension and impedance drops were larger and growth in lesion depth slowed earlier (AI: 500). Risk of SPs was higher above AI 550 (AI: 350-550: 7 [7%] SPs vs. AI 600-750: 28 [35%] SPs; p < .00001). While codependent variables, correlation between AI and time was modest-to-strong but decreased with longer RF duration. CONCLUSION: In this ex vivo study, AI was a better predictor of lesion dimensions than ablation time and magnitude of impedance drop in the LV using NS and HNS irrigation. AI targets above 550 led to a higher risk of SPs. Future trials are required to verify these findings.

Feasibility and safety of laser balloon pulmonary vein isolation in patients with prior left atrial appendage occlusion device implantation.

INTRODUCTION: With the increasing adoption of left atrial appendage occlusion (LAAO) procedures and the eligibility of patients for pulmonary vein isolation (PVI) post device placement, we examined the feasibility and safety of laser balloon (LB) for PVI in patients with prior LAAO. METHODS: We retrospectively examined consecutive patients with paroxysmal or persistent, drug-resistant atrial fibrillation (AF) who underwent LB PVI, after Watchman FLX device implantation at Rush University Medical Center between January 2020 and December 2021. RESULTS: Seven patients (four persistent and three paroxysmal) with a mean age of 64 ± 11 years, predominantly male sex (86%), were included in the study. Two (29%) patients had prior cryoablation PVI with recurrence of AF. The mean CHA2 DS2 VASc is 2.6 ± 0.5 and the mean HAS-BLED score is 3.4 ± 0.8. The mean follow-up duration was 10 ± 7 months. The mean duration between Watchman FLX device implantation and LB PVI was 592 days. Acute first pass left pulmonary vein (PV) isolation was achieved in 100% of the procedures. There were no periprocedural complications such as death, pericardial tamponade or effusion, phrenic nerve injury, PV stenosis, device perforation or embolization, or worsening peri-device leak in any of the patients. None of the patients had AF recurrence after the blanking period. CONCLUSION: LB PVI was safe and effective with 100% acute isolation of left-sided veins in patients with prior LAAO device.

Use of infrared thermography to delineate temperature gradients and critical isotherms during catheter ablation with normal and half normal saline: Implications for safety and efficacy.

BACKGROUND: Radiofrequency (RF) ablation with half-normal saline (HNS) has shown promise as a bail-out strategy following failed ventricular tachycardia ablation using standard approaches. OBJECTIVE: To use a novel infrared thermal imaging (ITI) model to evaluate biophysical and lesion characteristics during RF ablation using normal saline (NS) and HNS irrigation. METHODS: Left ventricular strips of myocardium were excised from fresh porcine hearts. RF ablation was performed using an open-irrigated ablation catheter (Thermocool ST/SF) with NS (n = 75) and HNS (n = 75) irrigation using different power settings (40/50 W), RF durations (30/60 s), contact force of 10-15 g, and flow rate of 15 ml/min. RF lesions were recorded using an infrared thermal camera and border zone, lethal, 100° isotherms were matched with necrotic borders after 2% triphenyltetrazolium chloride staining. Lesion dimensions and isotherms (mm2 ) were measured. RESULTS: In total, 150 lesions were delivered. HNS lesions were deeper (6.4 ± 1.1 vs. 5.7 ±0.8 mm; p = .03), and larger in volume (633 ± 153 vs. 468 ± 107 mm3 ; p = .007) than NS lesions. Steam pops (SPs) occurred during 19/75 lesions (25%) in the NS group and 32/75 lesions (43%) in the HNS group (p = .34). Lethal (57.8 ± 6.5 vs. 36.0 ± 3.9 mm2 ; p = .001) and 100°C isotherm areas (16.9 ± 6.9 vs. 3.8 ± 4.2 mm2 ; p = .003) areas were larger and were reached earlier in the HNS group. CONCLUSIONS: RFA using HNS created larger lesions than NS irrigation but led to more frequent SPs. The presence of earlier lethal isotherms and temperature rises above 100°C on ITI suggest a potentially narrower therapeutic-safety window with HNS.

High-power short duration vs. conventional radiofrequency ablation of atrial fibrillation: a systematic review and meta-analysis.

AIMS: We sought to compare the effectiveness and safety of high-power short-duration (HPSD) radiofrequency ablation (RFA) with conventional RFA in patients with atrial fibrillation (AF). METHODS AND RESULTS: MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched until 15 May 2020 for relevant studies comparing HPSD vs. conventional RFA in patients undergoing initial catheter ablation for AF. A total of 15 studies involving 3718 adult patients were included in our meta-analysis (2357 in HPSD RFA and 1361 in conventional RFA). Freedom from atrial arrhythmia was higher in HPSD RFA when compared with conventional RFA [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.10-1.90; P = 0.009]. Acute PV reconnection was lower (OR 0.56, P = 0.005) and first-pass isolation was higher (OR 3.58, P < 0.001) with HPSD RFA. There was no difference in total complications between the two groups (P = 0.19). Total procedure duration [mean difference (MD) -37.35 min, P < 0.001], fluoroscopy duration (MD -5.23 min, P = 0.001), and RF ablation time (MD -16.26 min, P < 0.001) were all significantly lower in HPSD RFA. High-power short-duration RFA also demonstrated higher freedom from atrial arrhythmia in the subgroup analysis of patients with paroxysmal AF (OR 1.80, 95% CI 1.29-2.50; P < 0.001), studies with ≥50 W protocol in the HPSD RFA group (OR 1.53, 95% CI 1.08-2.18; P = 0.02] and studies with contact force sensing catheter use (OR 1.65, 95% CI 1.21-2.25; P = 0.002). CONCLUSION: High-power short-duration RFA was associated with better procedural effectiveness when compared with conventional RFA with comparable safety and shorter procedural duration.

Sensors for rate-adaptive pacing: How they work, strengths, and limitations.

Chronotropic incompetence is the inability of the sinus node to increase heart rate commensurate with increased metabolic demand. Cardiac pacing alone may be insufficient to address exercise intolerance, fatigue, dyspnea on exertion, and other symptoms of chronotropic incompetence. Rate-responsive (adaptive) pacing employs sensors to detect physical or physiological indices and mimic the response of the normal sinus node. This review describes the development, strengths, and limitations of a variety of sensors that have been employed to address chronotropic incompetence. A mini-tutorial on programming rate-adaptive parameters is included along with emphasis that patients' lifestyles and underlying medical conditions require careful consideration. In addition, special sensor applications used to respond prophylactically to physiologic signals are detailed and an in-depth discussion of sensors as a potential aid in heart failure management is provided.

Meta-analysis of pulmonary vein isolation ablation for atrial fibrillation conventional vs low- and zero-fluoroscopy approaches.

INTRODUCTION: Radiation exposure during catheter ablation procedures is a significant hazard for both patients and operators. Atrial fibrillation (AF) ablation procedures have been historically associated with higher fluoroscopy usage than other electrophysiology procedures. Recent efforts have been made to reduce dependence on fluoroscopy during pulmonary vein isolation (PVI) ablation procedures using alternative techniques. METHODS: We performed a meta-analysis of studies comparing zero or low fluoroscopy (LF) vs conventional fluoroscopy (CF) approaches for AF ablation. Outcomes of interest included acute and 12-month procedural efficacy, safety, procedure duration, fluoroscopy time, and dose area product. Aggregated data were analyzed with random-effects models, using a Bayesian hierarchical approach. RESULTS: A total of 2228 participants (LF, n = 1190 vs CF, n = 1038) from 15 studies were included in the meta-analysis. Risk of AF recurrence in 12 months (odds ratio [OR], 95% confidence interval [95% CI] = 1.343 [0.771-2.340]; P = .297), redo-ablation procedures (OR [95% CI] = 0.521 [0.198-1.323]; P = .186), and procedural complications (OR [95% CI] = 0.99 [0.485-2.204]; P = .979) were similar between LF- and CF-ablation groups. In comparison to CF ablation, LF ablation led to shorter procedure duration (weighted mean differences [WMDs] [95% CI] = -14.6 minutes [-22.5 to -6.8]; P < .001), fluoroscopy time (WMD [95% CI] = -8.8 minutes [-11.9 to -5.9]; P < .001), and dose area product (WMD [95% CI] = -1946 mGy/cm2 [-2685 to 1207]; P < .001). CONCLUSION: LF approaches have similar clinical efficacy and safety as CF approaches for PVI. LF approaches are associated with shorter procedure time, fluoroscopy usage, and dose area product during PVI.

A systematic review and meta-analysis comparing second-generation cryoballoon and contact force radiofrequency ablation for initial ablation of paroxysmal and persistent atrial fibrillation.

INTRODUCTION: Cryoballoon ablation (CBA) and radiofrequency ablation (RFA) are the preferred modalities for catheter ablation of atrial fibrillation (AF). Technological advances have improved procedural outcomes, warranting an updated comparison. We sought to evaluate the efficacy and safety of CBA-2nd generation (CBA-2G) in comparison to RFA-contact force (RFA-CF) in patients with AF. METHODS: MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched until 03/01/2020 for relevant studies comparing CBA-2G versus RFA-CF in patients undergoing initial catheter ablation for AF. RESULTS: A total of 17 studies, involving 11 793 patients were included. There was no difference between the two groups in the outcomes of freedom from atrial arrhythmia (p = .67) and total procedural complications (p = .65). There was a higher incidence of phrenic nerve palsy in CBA-2G (odds ratio: 10.7; 95% confidence interval [CI]: 5.85 to 19.55; p < .001). Procedure duration was shorter (mean difference: -31.32 min; 95% CI: -40.73 to -21.92; p < .001) and fluoroscopy duration was longer (+3.21 min; 95% CI: 1.09 to 5.33; p = .003) in CBA-2G compared to RFA-CF. In the subgroup analyses of patients with persistent AF and >1 freeze lesion delivered per vein, there was no difference in freedom from atrial arrhythmia. CONCLUSIONS: In AF patients undergoing initial ablation, CBA-2G and RFA-CF were equally efficacious. The procedure duration was shorter, but with a higher incidence of phrenic nerve palsy in CBA-2G. In patients with persistent AF, there was no difference in the efficacy between CBA-2G or RFA-CF techniques.

Comparison between minimal fluoroscopy and conventional approaches for visually guided laser balloon pulmonary vein isolation ablation.

INTRODUCTION: Although balloon-based techniques, such as the laser balloon (LB) ablation have simplified pulmonary vein isolation (PVI), procedural fluoroscopy usage remains higher in comparison to radiofrequency PVI approaches due to limited 3-dimensional mapping system integration. METHODS: In this prospective study, 50 consecutive patients were randomly assigned in alternating fashion to a low fluoroscopy group (LFG; n = 25) or conventional fluoroscopy group (CFG; n = 25) and underwent de novo PVI procedures using visually guided LB technique. RESULTS: There was no statistical difference in baseline characteristics or cross-overs between treatment groups. Acute PVI was accomplished in all patients. Mean follow up was 318 ± 69 days. Clinical recurrence of atrial fibrillation after PVI was similar between groups (CFG: 19% vs LFG: 15%; P = .72). Total fluoroscopy time was significantly lower in the LFG than the CFG (1.7 ± 1.4  vs 16.9 ± 5.9 minutes; P < .001) despite similar total procedure duration (143 ± 22 vs 148 ± 22 minutes; P = .42) and mean LA dwell time (63 ± 15 vs 59 ± 10 minutes; P = .28). Mean dose area product was significantly lower in the LFG (181 ± 125 vs 1980 ± 750 µGym2 ; P < .001). Fluoroscopy usage after transseptal access was substantially lower in the LFG (0.63 ± 0.43 vs 11.70 ± 4.32 minutes; P < .001). Complications rates were similar between both groups (4% vs 2%; P = .57). CONCLUSIONS: This study demonstrates that LB PVI can be safely achieved using a novel low fluoroscopy protocol while also substantially reducing fluoroscopy usage and radiation exposure in comparison to conventional approaches for LB ablation.

How to perform electroanatomic mapping-guided cardiac resynchronization therapy using Carto 3 and ESI NavX three-dimensional mapping systems.

AIMS: To examine the feasibility and safety of a novel protocol for low fluoroscopy, electroanatomic mapping (EAM)-guided Cardiac resynchronization therapy with a defibrillator (CRT-D) implantation and using both EnSite NavX (St. Jude Medical, St. Paul, MN, USA) and Carto 3 (Biosense Webster, Irvine, CA, USA) mapping systems. METHODS AND RESULTS: Twenty consecutive patients underwent CRT implantation using either a conventional fluoroscopic approach (CFA) or EAM-guided lead placement with Carto 3 and EnSite NavX mapping systems. We compared fluoroscopy and procedural times, radiopaque contrast dose, change in QRS duration pre- and post-procedure, and complications in all patients. Fluoroscopy time was 86% lower in the EAM group compared to the conventional group [mean 37.2 min (CFA) vs. 5.5 min (EAM), P = 0.00003]. There was no significant difference in total procedural time [mean 183 min (CFA) vs. 161 min (EAM), P = 0.33] but radiopaque contrast usage was lower in the EAM group [mean 16 mL (CFA) vs. 4 mL (EAM), P = 0.006]. Likewise, there was no significant change in QRS duration with BiV pacing between the groups [mean -13 (CFA) vs. -25 ms (EAM), P = 0.09]. CONCLUSION: Electroanatomic mapping-guided lead placement using either Carto or ESI NavX mapping systems is a feasible alternative to conventional fluoroscopic methods for CRT-D implantation utilizing the protocol described in this study.

Incidence and risk factors for symptomatic heart failure after catheter ablation of atrial fibrillation and atrial flutter.

AIMS: To determine the incidence and risk factors for development of symptomatic heart failure (HF) following catheter ablation for atrial fibrillation (AF) and atrial flutter. METHODS AND RESULTS: We prospectively enrolled consecutive patients undergoing pulmonary vein isolation (PVI) or cavotricuspid isthmus (CTI) ablation between November 2013 and June 2014. Post-discharge symptoms were assessed via telephone follow-up and clinic visits. The primary outcome was symptomatic HF requiring treatment with new/increased diuretic dosing. Secondary outcomes were prolonged index hospitalization and readmission for HF ≤30 days. Univariate and multivariable logistic regressions were used to assess the relationship between patient/procedural characteristic and post-ablation HF. Among 111 PVI patients [median age 62.0 years; left ventricular ejection fraction (LVEF) 55%], 29 patients (26.1%) developed symptomatic HF, 6 patients (5.4%) required prolonged index hospitalization, and 8 patients (7.2%) were readmitted for HF. In univariate analyses, persistent AF [odds ratio (OR) 2.97, P = 0.02], AF at start of the procedure (OR 2.99, P = 0.01), additional ablation lines (OR 11.07, P < 0.0001), and final left atrial pressure (OR 1.10 per 1 mmHg increase, P = 0.02) were associated with HF development. Peri-procedural diuresis, net fluid balance, and LVEF were not correlated. In multivariable analyses, only additional ablation lines (ORadj 9.17, P = 0.007) were independently associated with post-ablation HF. Six patients (16.7%) developed HF after CTI ablation. CONCLUSION: A 26.1% of patients undergoing PVI and 16.7% of patients undergoing CTI ablation developed symptomatic HF when prospectively and uniformly assessed. 12.6% of patients experienced prolonged index hospitalizations or readmission for management of HF within 1 week after PVI. Improved understanding of risk factors for post-ablation HF may be critical in developing strategies to address during AF ablation.

T wave inversions in leads with ST elevations in patients with acute anterior ST elevation myocardial infarction is associated with patency of the infarct related artery.

OBJECTIVES: Following reperfusion therapy, early T wave inversions (TWI) have been shown to be a marker of successful reperfusion. We aimed to evaluate the relationship of TWI on the presenting ECG with spontaneous reperfusion as assessed by coronary angiography in patients with ST elevation (STE) myocardial infarction (STEMI). METHODS: Data of 146 consecutive patients presenting to the St. Luke's Episcopal Hospital Emergency Department with acute STEMI undergoing primary percutaneous coronary intervention (p-PCI) between January, 2007 and October, 2010 were retrospectively analyzed. Clinical data, ECG and angiographic data were reviewed. Patients were dichotomized based on T wave morphology on the presenting ECG into 2 groups - those with TWI and those with positive T waves (PTW). RESULTS: Thirty-one patients (21.2%) had TWI, while 115 (78.8%) had PTW. Sixty-four (43.8%) patients had anterior STE and 75 (51.3%) had inferior STE. Anterior STE was more likely to have TWI than non-anterior (29.7% vs. 14.6; p=0.014). By angiography, infarct related artery (IRA) patency (TIMI 2-3 flow) was seen in 45 (30.8%). TWI was more likely to be associated with IRA patency compared to PTW (51.6% vs. 25.2%; p=0.008). In patients with anterior STEMI and TWI, patent IRA was seen more frequently compared to those with PTW (68.4% vs. 20%; p<0.001). There was no association of T wave morphology and TIMI flow in patients with non-anterior STEMI. Patients presenting with stuttering symptoms were more likely to have TWI (70.4% vs. 10.2%; p <0.001) suggesting recurrent episodes of reperfusion and ischemia. CONCLUSIONS: In anterior STEMI patients, TWI on the presenting ECG is associated with spontaneous reperfusion. This relationship was not found among patients with non-anterior STEMI.

Neuromodulation for Vasovagal Syncope and Bradyarrhythmias.

Catheter-based neuromodulation of intrinsic cardiac autonomic nervous system is increasingly being used to improve outcomes in patients with vasovagal syncope and bradyarrhythmias caused by vagal overactivity. However, there is still no consensus for patient selection, technical steps, and procedural end points. This review takes the reader on a practical exploration of neuromodulation for bradyarrhythmias, concentrating on the critical aspects of proper patient selection, evidence-based insights, and anatomic intricacies within the intrinsic cardiac autonomic nervous system. Also discussed are different mapping techniques and outcome measures. Future directions to optimize the utilization of this technique in clinical practice are highlighted.

In Vivo Findings of a Novel Focal Ablation Catheter: Focused Electric Field Catheter Tip.

Current catheter designs used for radiofrequency (RF) in cardiac tissue achieve limited ablation depth as lesion size is driven heavily by resistive heating at the tissue surface. A catheter with a truncated, dome-shaped tip with a toroidal surface designed for focal RF ablation was recently described. This in vivo study compares lesion characteristics between a second-generation focused electric field (FEF) catheter vs a standard irrigated catheter using RF energy in a beating heart model. We performed in vivo ablations using RF energy with the FEF ablation catheter tip (Focused Therapeutics) and an irrigated Blazer catheter (Boston Scientific) under identical power, duration, and irrigation rates. In addition, RF dosing at high power and duration was examined using the FEF catheter. Intracardiac echocardiography was used to evaluate steam pops and catheter tip angle relative to the tissue surface. Studies were terminal and lesion size was measured following 2,3,5-triphenyltetrazolium chloride staining. Ablations were performed in 6 swine (FEF, n = 31; control, n = 8). FEF ablation lesions (n = 7) were deeper (15.6 ± 2.6 mm vs 7.5 ± 1.9 mm; P < 0.001) and wider (18.4 ± 2.9 mm vs 12.6 ± 2.4 mm; P < 0.001) than lesions delivered with the control irrigated catheter (n = 8) under the same parameters. Thirty-two percent (n = 10 of 31) of lesions delivered from the left ventricle endocardial surface using the FEF catheter were transmural. No steam pops were observed with delivery of FEF lesions (n = 31). The angle of incidence did not significantly affect FEF lesion size. In this in vivo preclinical study, the FEF catheter, which provides focused energy delivery, resulted in significantly larger lesions than the irrigated control catheter without steam pops. Approximately one-third of ablations with the FEF catheter delivered from the endocardial left ventricular surface resulted in transmural lesions.

Evolving Concepts in Cardiac Physiologic Pacing in the Era of Conduction System Pacing.

Cardiac physiologic pacing (CPP) has become a well-established therapy for patients with cardiomyopathy (left ventricular ejection fraction <35%) in the presence of a left bundle branch block. In addition, CPP can be highly beneficial in patients with pacing-induced cardiomyopathy and patients with existing cardiomyopathy expected to have a right ventricular pacing burden of >40%. The benefits of CPP with traditional biventricular pacing are only realized if adequate resynchronization can be achieved. However, left ventricular lead implantation can be limited by individual anatomic variation within the coronary venous system and can be adversely affected by underlying abnormal myocardial substrate (i.e., scar tissue), especially if located within the basal lateral wall. In the last 7 years the investigation of conduction system pacing (CSP) and its potential salutary benefits are being realized and have led to a rapid evolution in the field of cardiac resynchronization pacing. However, supportive evidence for CSP for patients eligible for cardiac resynchronization remains limited compared with data available for biventricular cardiac resynchronization, mostly derived from leading CSP investigative centers. In this review, we perform an up-to-date comprehensive review of the available literature on CPP.