Early Catheter Ablation Versus Initial Medical Therapy for Ventricular Tachycardia Storm.

BACKGROUND: Ventricular tachycardia (VT) storm is associated with significantly increased morbidity, mortality, and exponential healthcare utilization. Although catheter ablation (CA) may be curative, there are limited data directly comparing outcomes of early CA with initial medical therapy. METHODS: We compared outcomes of patients presenting with VT storm treated with initial CA versus those treated with initial medical therapy during their first storm presentation in an observational study. Retrospective data from the host institution from January 2014 to April 2020 of 129 patients with their first VT storm presentation were analyzed (58 underwent initial CA, 71 underwent treatment with initial medical therapy). Outcomes were compared in follow-up. RESULTS: Median time to initial CA was 6 days. Over a median follow-up of 702 days, patients who underwent initial CA compared with those treated with initial medical therapy had significantly less: (i) VA recurrence (43% versus 92%; P=0.002); (ii) VT storm recurrence (28% versus 73%; P<0.001); (iii) composite end point of death, heart transplant, VT storm recurrence, and VT-related hospitalization (47% versus 89%; P=0.002); (iv) iatrogenic complications (at 12 months: 17% versus 45%; P<0.001); (v) cardiovascular-related hospitalizations (50% versus 89%; P=0.01); (vi) total number of hospitalizations (median 1 versus 4; P<0.001); and (vi) cumulative days in hospital (median 0.5 versus 18; P<0.001). There were no intraprocedural deaths in patients treated with early CA. CONCLUSION: In an observational setting in which patients presenting with storm, early CA appears superior to initial medical therapy in terms of VT recurrence, storm recurrence, iatrogenic complications, cardiovascular hospitalizations, and cumulative days in hospital in follow-up.

Clinician-Created Educational Video Resources for Shared Decision-making in the Outpatient Management of Chronic Disease: Development and Evaluation Study.

BACKGROUND: The provision of reliable patient education is essential for shared decision-making. However, many clinicians are reluctant to use commonly available resources, as they are generic and may contain information of insufficient quality. Clinician-created educational materials, accessed during the waiting time prior to consultation, can potentially benefit clinical practice if developed in a time- and resource-efficient manner. OBJECTIVE: The aim of this study is to evaluate the utility of educational videos in improving patient decision-making, as well as consultation satisfaction and anxiety, within the outpatient management of chronic disease (represented by atrial fibrillation). The approach involves clinicians creating audiovisual patient education in a time- and resource-efficient manner for opportunistic delivery, using mobile smart devices with internet access, during waiting time before consultation. METHODS: We implemented this educational approach in outpatient clinics and collected patient responses through an electronic survey. The educational module was a web-based combination of 4 short videos viewed sequentially, followed by a patient experience survey using 5-point Likert scales and 0-100 visual analogue scales. The clinician developed the audiovisual module over a 2-day span while performing usual clinical tasks, using existing hardware and software resources (laptop and tablet). Patients presenting for the outpatient management of atrial fibrillation accessed the module during waiting time before their consultation using either a URL or Quick Response (QR) code on a provided tablet or their own mobile smart devices. The primary outcome of the study was the module's utility in improving patient decision-making ability, as measured on a 0-100 visual analogue scale. Secondary outcomes were the level of patient satisfaction with the videos, measured with 5-point Likert scales, in addition to the patient's value for clinician narration and the module's utility in improving anxiety and long-term treatment adherence, as represented on 0-100 visual analogue scales. RESULTS: This study enrolled 116 patients presenting for the outpatient management of atrial fibrillation. The proportion of responses that were "very satisfied" with the educational video content across the 4 videos ranged from 93% (86/92) to 96.3% (104/108) and this was between 98% (90/92) and 99.1% (107/108) for "satisfied" or "very satisfied." There were no reports of dissatisfaction for the first 3 videos, and only 1% (1/92) of responders reported dissatisfaction for the fourth video. The median reported scores (on 0-100 visual analogue scales) were 90 (IQR 82.5-97) for improving patient decision-making, 89 (IQR 81-95) for reducing consultation anxiety, 90 (IQR 81-97) for improving treatment adherence, and 82 (IQR 70-90) for the clinician's narration adding benefit to the patient experience. CONCLUSIONS: Clinician-created educational videos for chronic disease management resulted in improvements in patient-reported informed decision-making ability and expected long-term treatment adherence, as well as anxiety reduction. This form of patient education was also time efficient as it used the sunk time cost of waiting time to provide education without requiring additional clinician input.

Importance of the Interventricular Septum as Part of the Ventricular Tachycardia Substrate in Nonischemic Cardiomyopathy.

OBJECTIVES: This study sought to characterize septal substrate in patients with nonischemic left ventricular cardiomyopathy (NILVCM) undergoing ventricular tachycardia (VT) ablation. BACKGROUND: The interventricular septum is an important site of VT substrate in NILVCM. METHODS: The authors studied 95 patients with NILVCM and VT. Electroanatomic mapping using standard bipolar (<1.5 mV) and unipolar (<8.3 mV) low-voltage criteria identified septal scar location and size. Analysis of unipolar voltage was performed and scars quantified using graded unipolar cutoffs from 4 to 8.3 mV were correlated with delayed gadolinium-enhanced cardiac magnetic resonance (DE-CMR), performed in 57 patients. RESULTS: Detailed LV endocardial mapping (mean 262 ± 138 points) showed septal bipolar and unipolar voltage abnormalities (VAs) in 44 (46%) and 79 (83%) patients, most commonly with basal anteroseptal involvement. Of the 59 patients in whom the septum was targeted, bipolar and unipolar septal VAs were seen in 36 (61%) and 54 (92%). Of the 35 with CMR-defined septal scar, bipolar and unipolar septal VAs were seen in 18 (51%) and 31 (89%). In 12 patients without CMR septal scar, 6 (50%) had isolated unipolar septal VAs on electroanatomic mapping, a subset of whom the septum was targeted for ablation (44%). In the graded unipolar analysis, the optimal cutoff associated with magnetic resonance imaging septal scar was 4.8 mV (sensitivity 75%, specificity 70%; area under the curve: 0.75; 95% confidence interval: 0.60 to 0.90). CONCLUSIONS: Septal substrate by unipolar or bipolar voltage mapping in patients with NILVCM and VT is common. A unipolar voltage cutoff of 4.8 mV provides the best correlation with DE-CMR. A subset of patients with septal VT had normal DE-CMR or endocardial bipolar voltage with abnormal unipolar voltage.

Catheter Ablation in the Right Ventricular Outflow Tract Associated With Occlusion of Left Anterior Descending Coronary Artery.

Major vessel injury during right ventricular outflow tract ablation is not something widely recognized, and routine evaluation of the left anterior descending (LAD) artery location in relation to the septal right ventricle is not routinely performed. In the present article, we report a case of acute LAD occlusion after right ventricular outflow tract ablation and then illustrate the intimately close relationship of the LAD artery to the anterior septal site of the RVOT (approximately 2-3 cm under the pulmonic valve), using a combination of intracardiac echocardiography and 3-dimensional electroanatomical mapping recorded during a second case, in order to specifically point to the area at risk.

Recovery of renal dysfunction after catheter ablation of outflow tract ventricular arrhythmias in patients with ventricular premature depolarization-mediated cardiomyopathy.

PURPOSE: Frequent ventricular premature depolarizations (VPDs) may cause cardiomyopathy (VPDCM), which often improves after VPD suppression. This study aimed to evaluate whether ablation of outflow tract ventricular arrhythmias (OT VAs) in patients with VPDCM improves renal in addition to left ventricular (LV) function. METHODS: We retrospectively evaluated 153 patients with OT VAs and examined VPD burden and LV ejection fraction (LVEF), as well as estimated glomerular filtration rate (eGFR) pre- and post-ablation. LV dysfunction was defined as LVEF <50 % and impaired renal function was defined as eGFR of <60 mL/min/1.73m2. RESULTS: Fifty-five patients had VPDCM. During mean follow-up of 14 months, 140 (92 %) were free from arrhythmia. In patients with VPDCM, patients with baseline LVEF 40-50 % had greater improvement in the post-ablation LVEF compared to patients with baseline LVEF <40 % (p < 0.01). At baseline, 36 (72 %) patients had renal dysfunction, 29 (81 %) of whom had improvement in eGFR from baseline after successful ablation from eGFR 51 to 57 mL/min/1.73m2. There was a significant association between cardiac (ΔLVEF ≥10 %) and renal (ΔeGFR ≥10 %) improvement (r = 0.54, p = 0.04). Using logistic regression analysis, procedural success was an independent predictor of improvement of cardiac (odds ratio [OR] = 13.7, p = 0.03) and renal function (OR = 21.0, p = 0.047). CONCLUSIONS: Successful catheter ablation of OT VA reduces VPD burden and is associated with improved cardiac and renal function in patients with VPDCM.

Early recurrence of atrial arrhythmias following pulmonary vein antral isolation: Timing and frequency of early recurrences predicts long-term ablation success.

BACKGROUND: Early recurrence of atrial arrhythmia (ERAA) is common after atrial fibrillation (AF) ablation and is associated with long-term recurrence. However, the association between timing or frequency of ERAA and long-term ablation success remains unclear. OBJECTIVE: We aimed to examine whether timing or frequency of ERAA after pulmonary vein antral isolation (PVAI) affects long-term ablation success. METHODS: Three hundred AF patients (100 paroxysmal, 100 persistent, 100 long-standing persistent; mean age 59.5 ± 9.6 years, 79% male) undergoing PVAI were included. All patients underwent 30-day monitoring with mobile continuous outpatient telemetry after PVAI and were followed for >1 year. ERAA was defined as AF or organized atrial tachycardia (OAT) in the first 6 weeks, and was categorized as early (weeks 1-2), intermediate (weeks 3-4), or late (weeks 5-6). Long-term ablation success was defined as the absence of AF/OAT lasting >30 seconds off antiarrhythmic drugs 1 year after a single ablation (excluding first 6 weeks). RESULTS: ERAA occurred in 169 patients (53%); of those, 79 (46.7%) had single ERAA and 90 (53.3%) had multiple ERAAs. ERAA occurred less commonly with paroxysmal versus persistent or long-standing persistent AF (46% vs 57% and 66%; P = .017). ERAA was associated with worse ablation success at 1 year (38.1% vs 79.5% [no ERAA]; P < .001). Multiple (vs single) ERAA more strongly predicted long-term ablation failure (OR: 4.5; 95% CI [2.3-8.8]). CONCLUSIONS: ERAA after PVAI is associated with decreased long-term ablation success. Patients experiencing multiple ERAA events are at greatest risk for long-term arrhythmia recurrence and represent a subgroup in whom early reablation may be considered.

Effects of Age-Related Aortic Root Anatomic Changes on Left Ventricular Outflow Tract Pace-Mapping Morphologies: A Cardiac Magnetic Resonance Imaging Validation Study.

INTRODUCTION: Outflow tract ventricular arrhythmias (OT VAs) are common and catheter ablation is an effective treatment option. We sought to investigate the relationship between age-related anatomic aortic root changes and QRS morphology during left ventricular outflow tract (LVOT) pace-mapping using cardiac magnetic resonance (CMR) imaging. METHODS AND RESULTS: Fifty-one patients undergoing CMR imaging were divided into 3 groups based on age (<40, 40-60, >60 years). We measured the angle of the aortic root, the aorta to ventricular septal angle, the distance between the right coronary cusp (RCC) and left coronary cusp (LCC), and the distance between the ascending and descending aorta. Additionally, we evaluated the QRS morphologies obtained during pace-mapping from the LVOT. In older patients, LCC was more superior to the RCC (P < 0.01). Age was positively correlated with the aortic root angle (r2 = 0.481, P < 0.01) as well as the distances between the ascending and descending aorta at a level below the arch (r2 = 0.569, P < 0.01). In older patients, LVOT pace-mapping (performed in 16 patients) demonstrated higher maximal R-wave amplitude, and was greater when pacing from the LCC versus the RCC in lead III (1.8 ± 0.7 vs. 1.0 ± 0.5 mV, P = 0.02). CONCLUSION: The anatomy of the aortic root changes with age, and age-related aortic root changes may affect the QRS morphology during pace-mapping. Understanding the potential anatomic changes that accompany aging is important to maximize the efficacy of catheter ablation of OT VAs.

Ablation of ventricular arrhythmia in patients with heart failure.

Ventricular arrhythmias (VAs) in patients with cardiomyopathy and advanced-symptom class heart failure (HF) are associated with significant morbidity and mortality. VAs are typically managed with antiarrhythmic drug therapy and implantable cardiac defibrillators (ICD). Although ICDs are highly effective in reducing sudden cardiac death by termination of VA, they do not prevent arrhythmia recurrences. Recurrent shocks are not only associated with poor quality of life but also progressive HF and increased mortality and morbidity. Radiofrequency catheter ablation has emerged as an important therapeutic option for patients with drug-refractory ventricular tachycardia to reduce or prevent ICD shocks.

Acoustic signal emission monitoring as a novel method to predict steam pops during radiofrequency ablation: preliminary observations.

UNLABELLED: Steam pop is an explosive rupture of cardiac tissue caused by tissue overheating above 100 °C, resulting in steam formation, predisposing to serious complications associated with radiofrequency (RF) ablations. However, there are currently no reliable techniques to predict the occurrence of steam pops. We propose the utility of acoustic signals emitted during RF ablation as a novel method to predict steam pop formation and potentially prevent serious complications. METHODS: Radiofrequency generator parameters (power, impedance, and temperature) were temporally recorded during ablations performed in an in vitro bovine myocardial model. The acoustic system consisted of HTI-96-min hydrophone, microphone preamplifier, and sound card connected to a laptop computer. The hydrophone has the frequency range of 2 Hz to 30 kHz and nominal sensitivity in the range -240 to -165 dB. The sound was sampled at 96 kHz with 24-bit resolution. Output signal from the hydrophone was fed into the camera audio input to synchronize the video stream. An automated system was developed for the detection and analysis of acoustic events. RESULTS: Nine steam pops were observed. Three distinct sounds were identified as warning signals, each indicating rapid steam formation and its release from tissue. These sounds had a broad frequency range up to 6 kHz with several spectral peaks around 2-3 kHz. Subjectively, these warning signals were perceived as separate loud clicks, a quick succession of clicks, or continuous squeaking noise. Characteristic acoustic signals were identified preceding 80% of pops occurrence. Six cardiologists were able to identify 65% of acoustic signals accurately preceding the pop. An automated system identified the characteristic warning signals in 85% of cases. The mean time from the first acoustic signal to pop occurrence was 46 ± 20 seconds. The automated system had 72.7% sensitivity and 88.9% specificity for predicting pops. CONCLUSIONS: Easily identifiable characteristic acoustic emissions predictably occur before imminent steam popping during RF ablations. Such acoustic emissions can be carefully monitored during an ablation and may be useful to prevent serious complications during RF delivery.

First case of left posterior fascicle in a bystander circuit of idiopathic left ventricular tachycardia.

We describe a case of idiopathic left ventricular tachycardia in which the left posterior fascicle was clearly delineated to be a bystander in a re-entry circuit, with participation of the left interventricular myocardium as the retrograde limb instead. To the best of our knowledge, this is the first case report that has directly proven the left posterior fascicle to be a bystander during idiopathic left ventricular tachycardia.

Electrogram-gated radiofrequency ablations with duty cycle power delivery negate effects of ablation catheter motion.

BACKGROUND: Cardiac and respiratory movements cause catheter instability. Lateral catheter sliding over target endocardial surface can lead to poor tissue contact and unpredictable lesion formation. We describe a novel method of overcoming the effects of lateral catheter sliding movements using an electrogram-gated pulsed power ablation. METHODS AND RESULTS: All ablations were performed on a thermochromic gel myocardial phantom. Ablation settings were randomized to conventional (nongated) 30 W versus electrogram-gated at 20% duty cycle (30 W average power) at 0-, 3-, 6-, and 9-mm lateral sliding distances. Forty-eight radiofrequency ablations were performed. Deeper lesions were created in electrogram-gated versus conventional ablations at 3 mm (4.36±0.08 versus 4.05±0.17 mm; P=0.009), 6 mm (4.39±0.10 versus 3.44±0.15 mm; P<0.001), and 9 mm (4.41±0.06 versus 2.94±0.16 mm; P<<0.001) sliding distances. Electrogram-gated ablations created consistent lesions at a quicker rate of growth in depth when compared with conventional ablations (P<0.001). CONCLUSIONS: (1) Lesion depth decreases and length increases in conventional ablations with greater degrees of lateral catheter movements; (2) electrogram-gated pulsed radiofrequency delivery negated the effects from lateral catheter movement by creating consistently deeper lesions irrespective of the degree of catheter movement; and (3) target lesion depths were reached significantly faster in electrogram-gated than in conventional ablations.

Voltage mapping for delineating inexcitable dense scar in patients undergoing atrial fibrillation ablation: a new end point for enhancing pulmonary vein isolation.

BACKGROUND: Characterization of left atrial scar using bipolar voltage (BiV) mapping is not well defined. We have previously shown that the BiV range of 0.2-0.45 mV can identify chronic scar from prior pulmonary vein isolation (PVI). OBJECTIVE: This study sought to determine a BiV range that can identify atrial inexcitable dense scar (IDS) in patients acutely and chronically after PVI. METHODS: Thirty consecutive patients undergoing first time (n = 15) or redo (n = 15) PVI were included. A left atrial shell was created using electroanatomic mapping, and IDS was defined by inability to capture at an output of 10 mA and a pulse width of 2 ms in sinus rhythm, circumferentially at the edge of PVI-related scar (≤5 mm). At each pacing site, BiV amplitude and atrial capture were recorded. RESULTS: Overall, 837 pacing sites were assessed. BiV predicted IDS (receiver operating characteristic curve area 0.93 for first time PVI and 0.90 for redo PVI). In first time PVI, the best BiV value to predict IDS was 0.45 mV for the left pulmonary vein-left atrial appendage (LAA-LPV) ridge (sensitivity 0.98; specificity 1.0) and 0.2 mV for other localizations (sensitivity 0.91; specificity 0.86). In redo PVI, the best BiV value to predict IDS was 0.2 mV for the LAA-LPV ridge (sensitivity 0.77; specificity 1.0) and 0.15 mV for other localizations (sensitivity 0.81; specificity 0.82). CONCLUSION: BiV reproducibly identifies acute and chronic IDS using a cutoff value of 0.2 mV (0.45 mV for the LAA-LPV ridge) in patients undergoing first time PVI and 0.15 mV (0.2 mV for the LAA-LPV ridge) in patients undergoing redo PVI. IDS thus identified may be a rigorous tool for validating PVI.

In vitro evaluation of ice-cold saline irrigation during catheter radiofrequency ablation.

INTRODUCTION: Irrigated radiofrequency (RF) catheters allow tissue-electrode interface cooling, decreasing thrombus risk while enabling higher RF power delivery. The impact of irrigation with ice-cold saline (ICS) instead of conventional ambient-temperature saline (ATS) on lesion formation is unknown. METHODS AND RESULTS: We performed 120 RF ablations in vitro on porcine left ventricles, using ICS (<5 °C) or ATS (21 °C) irrigation. For ICS irrigation, the irrigation circuit was cooled externally to maintain delivery of cooled saline at the catheter's tip. We applied 20 g of contact force, and delivered 20 W (irrigation 8 or 17 mL/min) or 30 W (irrigation 17 or 30 mL/min) RF power. Temperatures at tissue-electrode interface and 3-mm depth were assessed by fluoroptic probes. Lesion dimensions were assessed. ICS irrigation cooled the tissue-electrode interface better than ATS (53.9 ± 9.6 °C vs. 63 ± 11.4 °C, P < 0.001). Temperatures at 3-mm depth were similar at 30 W using ICS and ATS (104.2 ± 9.3 °C vs. 105.8 ± 7.3 °C, P = 0.5), but were cooler at 20 W using ICS (71.3 ± 11.6 °C vs. 100.2 ± 11.9 °C, P < 0.001). This translated into smaller lesions at 20 W with ICS versus ATS. At 30 W with 17 mL/min flow rate, lesions had the same depth with ICS and ATS (4.9 ± 0.8 mm vs. 5.4 ± 0.7 mm, P = 0.13) but were narrower with ICS (7.7 ± 0.8 mm vs. 9.3 ± 1.2 mm, P = 0.001). At 30 mL/min, lesions had the same dimensions. Steam pop rate was similar using ICS or ATS irrigation. CONCLUSION: ICS irrigation more effectively cools tissue-electrode interface than ATS. This may improve RF safety by potentially decreasing thrombus formation, thus facilitating safe ablation at a low saline volume load. However at lower RF power, ICS reduced lesion size compared to ATS.