Ventricular arrhythmias in patients with bicuspid aortic valves.

INTRODUCTION: Bicuspid aortic valves (BAV) are the most common congenital heart defects and the extent of ventricular arrhythmias (VA) in patients with BAV is unclear. The objective of this study is to describe VAs and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) in patients with BAV. METHODS: A total of 19 patients with BAV (18 males, age: 58 ± 13 years) were referred for VA ablation procedures. Ten patients had BAVs at the time of ablation, nine patients had prior aortic valve replacement for a BAV. All but one patient had LGE-CMR and all patients underwent programmed ventricular stimulation at the time of the ablation. RESULTS: Frequent PVCs were the targeted VAs in 17/19 patients and VT in 2/19 patients. Monomorphic ventricular tachycardia (VT) was inducible in 6 patients. A total of 15 VTs were inducible (2.5 ± 1.0 VTs per patient with a mean cycle length of 322 ± 83 msec). LGE was present in 13 patients. Patients with inducible VT had larger borderzone and core scar compared to non-inducible patients (7.8 ± 2.1 cm3 vs. 2.5 ± 3.1 cm3 and 5.1 ± 2.6 cm3 vs. 1.9 ± 3.0 cm3, p-value < .05 for both). PVCs and VTs were mapped to the periaortic valve area in 12 patients and 4 patients, respectively. The PVC burden was reduced from 27 ± 13 to 3 ± 6 (p < .001) and the ejection fraction improved from 49 ± 13% to 55 ± 9% (p = .005). CONCLUSIONS: VAs in patients with BAV often originate from the perivalvular area and patients often have LGE and inducible VT. LGE may be due to ventricular remodeling secondary to the presence of BAV and harbors the arrhythmogenic substrate for VT.

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.

Long-term outcomes of patients with ventricular arrhythmias and negative programmed ventricular stimulation followed with implantable loop recorders: Impact of delayed-enhancement cardiac magnetic resonance imaging.

BACKGROUND: Programed ventricular stimulation (PVS) is a risk stratification tool in patients at risk for adverse arrhythmia outcomes. Patients with negative PVS may yet be at risk for adverse arrhythmia-related events, particularly in the presence of symptomatic ventricular arrhythmias (VA). OBJECTIVE: To investigate the long-term outcomes of real-world patients with symptomatic VA without indication for device therapy and negative PVS, and to examine the role of cardiac scaring on arrhythmia recurrence. METHODS: Patients with symptomatic VA, and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR), and negative PVS testing were included. All patients underwent placement of implantable cardiac monitors (ICM). Survival analysis was performed to investigate the impact of LGE-CMR findings on survival free from adverse arrhythmic events. RESULTS: Seventy-eight patients were included (age 60 ± 14 years, women n = 36 (46%), ejection fraction 57 ± 9%, cardiomyopathy n = 26 (33%), mitral valve prolapse [MVP] n = 9 (12%), positive LGE-CMR scar n = 49 (62%), history of syncope n = 23 (29%)) including patients with primarily premature ventricular contractions (n = 21) or nonsustained VA (n = 57). Patients were followed for 1.6 ± 1.5 years during which 14 patients (18%) experienced VA requiring treatment (n = 14) or syncope due to bradycardia (n = 2). Four/9 patients (44%) with MVP experienced VA (n = 3) or syncope (n = 1). Baseline characteristics between those with and without adverse events were similar (p > 0.05); however, the presence of cardiac scar on LGE-CMR was independently associated with an increased risk of adverse events (hazard ratio: 5.6 95% confidence interval: [1.2-27], p = 0.03, log-rank p = 0.03). CONCLUSIONS: In a real-world cohort with long-term follow-up, adverse arrhythmic outcomes occurred in 18% of patients with symptomatic VA despite negative PVS, and this risk was significantly greater in patients with positive DE-CMR scar. Long term-monitoring, including the use of ICM, may be appropriate in these patients.

Value of genotyping and scar-phenotyping for VT ablation procedures in patients with nonischemic left ventricular cardiomyopathies.

INTRODUCTION: Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE-CMR) imaging which may impact ventricular tachycardia (VT) management. METHODS: The objective was to compare the findings of cardiomyopathy genetic testing on DE-CMR imaging and long-term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0-3 mm, 3-5 mm and >5 mm projected on the closest endocardial surface) was determined. RESULTS: Forty-three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring-like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p = .001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p = .005), and increased VT recurrence (HR 5.7 95% CI[1.8-18.4], p = .003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22-18.0], p = .02). CONCLUSIONS: Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation.

Incidental left atrial appendage isolation after catheter ablation of persistent atrial fibrillation: Mechanisms and long-term risk of thromboembolism.

INTRODUCTION: Incidental left atrial appendage (LAA) isolation may occur during radiofrequency ablation of persistent atrial fibrillation (AF). The study aims to describe the mechanisms and long-term thromboembolic risk related to incidental LAA isolation. METHODS: Patients who experienced incidental LAA isolation after AF ablation were included. Culprit sites where ablation resulted in LAA isolation were identified. Thromboembolic risk despite oral anticoagulation (OAC) was compared to that in a propensity-matched control group without LAA isolation. RESULTS: Forty-one patients with LAA isolation, and 82 matched patients without LAA isolation were included. The patient age, ejection fraction, LA diameter, and CHA2 DS2 -VASc score were 64 ± 11 years, 55 ± 12%, 45.0 ± 7 mm and 2.62 ± 1.5, respectively. Culprit sites included the LAA base, mitral isthmus, inferior LA, Bachmann's bundle, coronary sinus, and Marshall vein. After 4.2 ± 3.6 years follow-up, thromboembolism occurred in 7 of 41 patients (17%) with LAA isolation versus 3 of 82 patients (4%) without isolation (log rank p < .009, HR 5.14, 95% CI [1.32-19.94], p = .02). Patients with and without thromboembolism had similar CHA2 DS2 -VASc scores (2.65 ± 1.3 vs. 2.71 ± 0.76, p = .89). Thromboembolism occurred during noncompliance with or temporary discontinuation of OAC in four of the seven patients. CONCLUSIONS: Incidental LAA isolation may occur during ablation of atrial arrhythmias in the vicinity of, or even at sites remote from the appendage. Patients with incidental LAA isolation had higher rates of thromboembolism compared to patients without isolation. Since thromboembolism may occur despite prescription for OAC, the risks of LAA isolation must be weighed against clinical benefit and appendage occlusion devices should be considered in vulnerable patients.

Comparison of warfarin with direct oral anticoagulants for thromboembolic prophylaxis after catheter ablation of ventricular tachycardia.

INTRODUCTION: Thromboembolic events after catheter ablation of ventricular tachycardia (VT) can result in significant morbidity. Thromboembolic prophylaxis after catheter ablation can be achieved by the use of antiplatelet agents, vitamin K antagonists, or direct oral anticoagulants (DOACs). The relative safety and efficacy of these modes of prophylaxis are uncertain. We sought to compare the outcomes of patients who received warfarin or DOACs for thromboembolic prophylaxis after catheter ablation of VT. METHODS AND RESULTS: Anticoagulation with DOACS was started after left ventricular VT ablation in a series of 42 consecutive patients with structural heart disease (67 ± 11 years, 3 women, ejection fraction 32 ± 14%). Duration of hospital stay, bleeding episodes, and thromboembolic events were compared to a historic consecutive group of patients (n = 38, 65 ± 13 years, 14 women, ejection fraction 36 ± 13%) in whom anticoagulation with a formerly described protocol of heparin and vitamin K antagonist was used after VT ablation procedures. Hospital stay was significantly shorter in the group where DOACs were used as compared to vitamin K antagonists (3.3 ± 1.8 vs. 5.0 ± 2.5 days postablation; p = 0.001) without an increase of bleeding or thromboembolic events. CONCLUSION: Anticoagulation with DOACs is safe and shortens hospital stay in patients with structural heart disease undergoing left ventricular VT ablation procedures.

Anatomical location of leadless pacemaker and the risk of pacing-induced cardiomyopathy.

BACKGROUND: It is unclear if the location of implantation of the leadless pacemaker (LP) makes a difference in the incidence of pacing-induced cardiomyopathy (PICM). AIM: The aim of this study was to compare the incidence of PICM based on the location of implantation of LP. METHODS: A total of 358 consecutive patients [women: 171 (48%), mean age: 73 ± 15 years] with left ventricular ejection fraction (EF) > 50%, who received an LP (Micra) between January 2017 and June 2022, formed the study cohort. Micra-AV and Micra-VR were implanted in 122 (34%) and 236 (66%) patients, respectively. Fluoroscopically, the location of implantation of LP in the interventricular septum (IS) was divided into two equal halves (apex/apical septum [AS] and mid/high septum [HS]). During follow-up, PICM was defined as an EF drop of ≥10%. RESULTS: LP was implanted in 109 (34%) and 249 (66%) patients at AS and HS locations, respectively. During a mean 18 ± 8 months follow-up, 28 patients (7.8%) developed PICM. Among the 249 patients with HS placement of LP, 10 (4%) developed PICM, whereas among the 109 patients with AS placement of LP, 18 (16.5%) developed PICM (p = .002). AS location was associated with a higher risk of PICM compared to HS locations (adjusted hazard ratio: 4.42, p < .001). CONCLUSION: AS location of LP was associated with a higher risk of PICM compared to HS placement. Larger randomized studies are needed to confirm our findings.

Three-dimensional-guided and ICE-guided transseptal puncture for cardiac ablations: A propensity score match study.

INTRODUCTION: Transseptal puncture (TSP) is routinely performed for left atrial ablation procedures. The use of a three-dimensional (3D) mapping system or intracardiac echocardiography (ICE) is useful in localizing the fossa ovalis and reducing fluoroscopy use. We aimed to compare the safety and efficacy between 3D mapping system-guided TSP and ICE-guided TSP techniques. METHODS: We conducted a prospective observational study of patients undergoing TSP for left atrial catheter ablation procedures (mostly atrial fibrillation ablation). Propensity scoring was used to match patients undergoing 3D-guided TSP with patients undergoing ICE-guided TSP. Logistic regression was used to compare the clinical data, procedural data, fluoroscopy time, success rate, and complications between the groups. RESULTS: Sixty-five patients underwent 3D-guided TSP, and 151 propensity score-matched patients underwent ICE-guided TSP. The TSP success rate was 100% in both the 3D-guided and ICE-guided groups. Median needle time was 4.00 min (interquartile range [IQR]: 2.57-5.08) in patients with 3D-guided TSP compared to 4.02 min (IQR: 2.83-6.95) in those with ICE-guided TSP (p = .22). Mean fluoroscopy time was 0.2 min (IQR: 0.1-0.4) in patients with 3D-guided TSP compared to 1.2 min (IQR: 0.7-2.2) in those with ICE-guided TSP (p < .001). There were no complications related to TSP in both group. CONCLUSIONS: Three-dimensional mapping-guided TSP is as safe and effective as ICE-guided TSP without additional cost.

Electrophysiological characteristics and long-term outcome of substrate-based catheter ablation for left posterior fascicular ventricular tachycardia targeting fragmented antegrade Purkinje potentials during sinus rhythm.

AIMS: The aim of this study was to investigate the electrophysiological characteristics and long-term outcome of patients undergoing substrate-based ablation of left posterior fascicular ventricular tachycardia (LPF-VT) guided by targeting of fragmented antegrade Purkinje potentials (FAPs) during sinus rhythm. METHODS AND RESULTS: This study retrospectively analysed 50 consecutive patients referred for ablation. Substrate mapping during sinus rhythm was performed to identify the FAP that was targeted by ablation. FAPs were recorded in 48 of 50 (96%) patients during sinus rhythm. The distribution of FAPs was located at the proximal segment of posterior septal left ventricle (LV) in two (4.2%) patients, middle segment in 33 (68.8%) patients, and distal segment in 13 (27.1%) patients. In 32 of 48 (66.7%) patients, the FAP displayed a continuous multicomponent fragmented electrogram, while a fragmented, split, and uncoupled electrogram was recorded in 16 (33.3%) patients. Entrainment attempts at FAP region were performed successfully in seven patients, demonstrating concealed fusion and the critical isthmus of LPF-VT. Catheter ablation targeting at the FAPs successfully terminated the LPF-VT in all 48 patients in whom they were seen. Left posterior fascicular (LPF) block occurred in four (8%) patients after ablation. During a median follow-up period of 61.2 ± 16.8 months, 47 of 50 (94%) patients remained free from recurrent LPF-VT. CONCLUSION: Ablation of LPF-VT targeting FAP during sinus rhythm results in excellent long-term clinical outcome. FAPs were commonly located at the middle segment of posterior septal LV. Region with FAPs during sinus rhythm was predictive of critical site for re-entry.

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study.

AIMS: Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs). METHODS AND RESULTS: This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation. CONCLUSION: Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Comparison of strategies for catheter ablation of left posterior fascicular ventricular tachycardia.

AIMS: Traditional ablation strategies including targeting the earliest Purkinje potential (PP) during left posterior fascicular (LPF) ventricular tachycardia (VT) or linear ablation at the middle segment of LPF during sinus rhythm are commonly used for the treatment of LPF-VT. Catheter ablation for LPF-VT targeting fragmented antegrade Purkinje (FAP) potential during sinus rhythm is a novel approach. We aimed to compare safety and efficacy of different ablation strategies (FAP ablation vs. traditional ablation) for the treatment of LPF-VT. METHODS AND RESULTS: Consecutive patients with electrocardiographically documented LPF-VT referred for catheter ablation received either FAP ablation approach or traditional ablation approach. Electrophysiological characteristics, procedural complications, and long-term clinical outcome were assessed. A total of 189 consecutive patients who underwent catheter ablation for LPF-VT were included. Fragmented antegrade Purkinje ablation was attempted in 95 patients, and traditional ablation was attempted in 94 patients. Acute ablation success with elimination of LPF-VT was achieved in all patients. Left posterior fascicular block occurred in 11 of 95 (11.6%) patients in the FAP group compared with 75 of 94 (79.8%) patients in the traditional group (P < 0.001). Fragmented antegrade Purkinje ablation was associated with significant shorter procedure time (94 ± 26 vs. 117 ± 23 min, P = 0.03) and fewer radiofrequency energy applications (4.1 ± 2.4 vs. 6.3 ± 3.5, P = 0.003) compared with the traditional group. One complete atrioventricular block and one left bundle branch block were seen in the traditional group. Over mean follow-up of 65 months, 89 (93.7%) patients in the FAP group and 81 (86.2%) patients in the traditional group remained free of recurrent VT off antiarrhythmic drugs (P = 0.157). CONCLUSION: Left posterior fascicular-ventricular tachycardia ablation utilizing FAP and traditional ablation approaches resulted in similar acute and long-term procedural outcomes. Serious His-Purkinje injury did occur infrequently during traditional ablation. The use of FAP ablation approach was associated with shorter procedure time and fewer radiofrequency energy applications, especially for non-inducible patients.

Feedback regulation of steady-state epithelial turnover and organ size.

Epithelial organs undergo steady-state turnover throughout adult life, with old cells being continually replaced by the progeny of stem cell divisions. To avoid hyperplasia or atrophy, organ turnover demands strict equilibration of cell production and loss. However, the mechanistic basis of this equilibrium is unknown. Here we show that robustly precise turnover of the adult Drosophila intestine arises through a coupling mechanism in which enterocyte apoptosis breaks feedback inhibition of stem cell division. Healthy enterocytes inhibit stem cell division through E-cadherin, which prevents secretion of mitogenic epidermal growth factors (EGFs) by repressing transcription of the EGF maturation factor rhomboid. Individual apoptotic enterocytes promote divisions by loss of E-cadherin, which releases cadherin-associated ß-catenin (Armadillo in Drosophila) and p120-catenin to induce rhomboid. Induction of rhomboid in the dying enterocyte triggers activation of the EGF receptor (Egfr) in stem cells within a discrete radius. When we blocked apoptosis, E-cadherin-controlled feedback suppressed divisions, and the organ retained the same number of cells. When we disrupted feedback, apoptosis and divisions were uncoupled, and the organ developed either hyperplasia or atrophy. Together, our results show that robust cellular balance hinges on the obligate coupling of divisions to apoptosis, which limits the proliferative potential of a stem cell to the precise time and place at which a replacement cell is needed. In this way, localized cell-cell communication gives rise to tissue-level homeostatic equilibrium and constant organ size.

Prognostic Value of Nonischemic Ringlike Left Ventricular Scar in Patients With Apparently Idiopathic Nonsustained Ventricular Arrhythmias.

BACKGROUND: Left ventricular (LV) scar on late gadolinium enhancement (LGE) cardiac magnetic resonance has been correlated with life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). We investigated the prognostic significance of a specific LV-LGE phenotype characterized by a ringlike pattern of fibrosis. METHODS: A total of 686 patients with apparently idiopathic nonsustained VA underwent contrast-enhanced cardiac magnetic resonance. A ringlike pattern of LV scar was defined as LV subepicardial/midmyocardial LGE involving at least 3 contiguous segments in the same short-axis slice. The end point of the study was time to the composite outcome of all-cause death, resuscitated cardiac arrest because of ventricular fibrillation or hemodynamically unstable ventricular tachycardia and appropriate implantable cardioverter defibrillator therapy. RESULTS: A total of 28 patients (4%) had a ringlike pattern of scar (group A), 78 (11%) had a non-ringlike pattern (group B), and 580 (85%) had normal cardiac magnetic resonance with no LGE (group C). Group A patients were younger compared with groups B and C (median age, 40 vs 52 vs 45 years; P<0.01), more frequently men (96% vs 82% vs 55%; P<0.01), with a higher prevalence of family history of sudden cardiac death or cardiomyopathy (39% vs 14% vs 6%; P<0.01) and more frequent history of unexplained syncope (18% vs 9% vs 3%; P<0.01). All patients in group A showed VA with a right bundle-branch block morphology versus 69% in group B and 21% in group C (P<0.01). Multifocal VAs were observed in 46% of group A patients compared with 26% of group B and 4% of group C (P<0.01). After a median follow-up of 61 months (range, 34-84 months), the composite outcome occurred in 14 patients (50.0%) in group A versus 15 (19.0%) in group B and 2 (0.3%) in group C (P<0.01). After multivariable adjustment, the presence of LGE with ringlike pattern remained independently associated with increased risk of the composite end point (hazard ratio, 68.98 [95% CI, 14.67-324.39], P<0.01). CONCLUSIONS: In patients with apparently idiopathic nonsustained VA, nonischemic LV scar with a ringlike pattern is associated with malignant arrhythmic events.

Late gadolinium enhancement cardiac magnetic resonance imaging of ablation lesions after postinfarction ventricular tachycardia ablation: Implications for ventricular tachycardia recurrence.

BACKGROUND: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging distinguishes between intrinsic postinfarction scar and radiofrequency ablation lesion related scar (dark core lesions [DCLs]) in patients with prior ventricular tachycardia (VT) ablation procedures. OBJECTIVE: To combine LGE-CMR and electroanatomic mapping data to describe the relationship between DCLs and recurrent VT among patients undergoing repeat ablations for postinfarction VT. METHODS: Consecutive patients with repeat ablation for postinfarct VT with LGE-CMR before the repeat procedures were studied. Prior ablation procedures and implantable cardiac defibrillator electrograms were analyzed to determine new versus previously documented VT. DCLs were identified on preprocedure LGE-CMR and registered to electroanatomic maps. A control group of patients undergoing repeat ablation procedures without imaging was included. RESULTS: Nineteen study patients and 14 control patients were followed for 2.6 (1.6-5.6) years (31 [94%] men, age 65.8 ± 8.4 years, ejection fraction 24.7 ± 10.3, p > 0.10 for all). DCLs corresponded to unexcitable tissue during repeat procedures (area 22.4 ± 15.1 vs. 22.9 ± 16.8 cm3 , correlation coefficient = .93). Most VT target sites (39/50 [78%]) were in close proximity (<1 cm) to DCLs. Most DCL related VTs 32/39 (82%) were new VTs. Patients with LGE-CMR imaging incorporated into their ablation procedures had improved 24-month survival from VT (64% vs. 38%, log rank p < 0.02). CONCLUSION: LGE-MRI can identify prior ablation lesions corresponding to nonexcitable tissue during repeat ablation procedures for postinfarction VT. VT target sites are often located in close proximity to the DCL area that may function as a fixed border for reentry circuits. Registration of DCL from prior ablation may facilitate repeat ablation procedures.

Anatomy of the proximal septal vein in patients with focal intramural ventricular arrhythmias.

BACKGROUND: Focal ventricular arrhythmias (VAs) originating from the intramural myocardium of the basal septum are difficult to localize and ablate. Proximal septal veins emptying into the great cardiac vein can reach close to the origin of intramural arrhythmias. OBJECTIVE: To assess characteristics of proximal septal coronary veins in patients with intramural VAs. METHODS AND RESULTS: Among 84 consecutive patients with intramural VAs, 29 patients (age 60 ± 11years, 16 males, ejection fraction 47 ± 13%) underwent preprocedural cardiac computed tomographic angiography (CTA). In 14 of these patients, the intramural site of origin (SOO) was identified with multipolar catheters. The intramural SOO could not be accessed with mapping catheters in the other 15 patients while mapping the coronary venous system. The CTA identified sizable proximal septal veins in all patients in whom the SOO could be accessed with mapping catheters. In the patients in whom the intramural SOO was not identified, the proximal septal veins were often either small (<2 mm at the branching site) or non-existent (n = 9, p = .001). The proximal septal veins in patients in whom the SOO was identified were larger than in the patients in whom the SOO could not be identified (3.0 ± 0.6 mm vs. 2.1 ± 0.9 mm, p = .01). CONCLUSIONS: Preprocedural imaging with CTAs can be beneficial in identifying the anatomy of proximal septal coronary veins that allow adequate mapping of patients with suspected intramural VAs.

Intramural mapping of intramural septal ventricular arrhythmias.

BACKGROUND: Intramural ventricular arrhythmias (VAs) can originate in patients with or without structural heart disease. Electrogram (EGM) recordings from intramural sources of VA have not been described thoroughly. OBJECTIVE: We hypothesized that the presence of scar may be linked to the site of origin (SOO) of focal, intramural VAs. METHODS: In a series of 21 patients (age: 55 ± 11 years, 12 women, mean ejection fraction 43 ± 14%) in whom the SOO of intramural VAs was identified, we analyzed bipolar EGM characteristics at the SOO and compared the findings with the endocardial breakout site. The patients were from a pool of 86 patients with intramural VAs referred for ablation. RESULTS: In 16/21 patients intramural scarring was detected by cardiac magnetic resonance (CMR) imaging In patients in whom the intramural SOO was reached, intramural bipolar EGMs showed a lower voltage and had broader EGMs compared to the endocardial breakout sites (0.97 ± 0.56 vs. 2.28 ± 0.15 mV, p = .001; and 122.3 ± 31.6 vs. 96.5 ± 26.3 ms, p < .01). All intramural sampled sites at the SOO had either low voltage or broad abnormal EGMs. The activation time was significantly earlier at the intramural SOO than at breakout sites (-36.2 ± 11.8 vs. -23.2 ± 9.1 ms, p < .0001). CONCLUSIONS: Sites of origin of intramural VAs with scar by CMR display EGM characteristics of scarring, supporting that scar tissue localizes to the SOO of intramural outflow tract arrhythmias in some patients. Scarring identified by CMR may be helpful in planning ablation procedures in patients with suspected intramural VAs.

Association between biventricular pacing and incidence of ventricular arrhythmias in the early post-operative period after left ventricular assist device implantation.

INTRODUCTION: Cardiac resynchronization therapy (CRT) and left ventricular assist devices (LVAD) improve outcomes in heart failure patients. Early ventricular arrhythmias (VA) are common after LVAD and are associated with increased mortality. The association between left ventricular pacing (LVP) with CRT and VAs in the early post-LVAD period remains unclear. METHODS: This was a retrospective study of all patients undergoing LVAD implantation from 1/2016 to 12/2019. Patients were divided into those with CRT and active LVP (CRT-LVP) immediately post-LVAD implant versus those without CRT-LVP. Implantable cardiac defibrillator electrograms were reviewed and early VAs were defined as sustained ventricular tachycardia (VT)/ventricular fibrillation occurring within 30 days of LVAD implantation. RESULTS: Of 186 included patients (mean age 53 years, 75% male, mean body mass index 28), 72 had CRT devices, 63 of whom had LV pacing enabled after LVAD implant (CRT-LVP group). Patients with CRT-LVP were more likely to have VA in the early postoperative period (21% vs. 4%; p = .0001). All 9 patients with CRT in whom LVP was disabled had no early VA. Among those with early VA, patients with CRT-LVP were more likely to have monomorphic VT (77% vs. 40%; p = .07). In multiple logistic regression, CRT-LVP pacing remained an independent predictor of early VA after adjustment for history of VA and AF. CONCLUSIONS: Patients with CRT-LVP after LVAD implant had a higher incidence of early VA (specifically monomorphic VT). Epicardial LV pacing may be proarrhythmic in the early postoperative period after LVAD.

A comparison of clinical outcomes and cost of radiofrequency catheter ablation for atrial fibrillation with monitored anesthesia care versus general anesthesia.

INTRODUCTION: Monitored anesthesia care (MAC) or general anesthesia (GA) can be used during catheter ablation (CA) of atrial fibrillation (AF). However, each approach may have advantages and disadvantages with variability in operator preferences. The optimal approach has not been well established. The purpose of this study was to compare procedural efficacy, safety, clinical outcomes, and cost of CA for AF performed with MAC versus GA. METHODS: The study population consisted of 810 consecutive patients (mean age: 63 ± 10 years, paroxysmal AF: 48%) who underwent a first CA for AF. All patients completed a preprocedural evaluation by the anesthesiologists. Among the 810 patients, MAC was used in 534 (66%) and GA in 276 (34%). Ten patients (1.5%) had to convert to GA during the CA. RESULTS: Although the total anesthesia care was longer with GA particularly in patients with persistent AF, CA was shorter by 5 min with GA than MAC (p < 0.01). Prevalence of perioperative complications was similar between the two groups (4% vs. 4%, p = 0.89). There was no atrioesophageal fistula with either approach. GA was associated with a small, ~7% increase in total charges due to longer anesthesia care. During 43 ± 17 months of follow-up after a single ablation procedure, 271/534 patients (51%) in the MAC and 129/276 (47%) patients in the GA groups were in sinus rhythm without concomitant antiarrhythmic drug therapy (p = 0.28). CONCLUSION: With the participation of an anesthesiologist, and proper preoperative assessment, CA of AF using GA or MAC has similar efficacy and safety.

Cardiac Involvement and Arrhythmias Associated with Myotonic Dystrophy.

Myotonic dystrophy is an autosomal dominant genetic disease of nucleotide expansion resulting in neuromuscular disease with two distinct subtypes. There are significant systemic manifestations of this condition including progressive muscular decline, neurologic abnormalities, and cardiac disease. Given the higher prevalence of cardiac dysfunction compared to the general population, there is significant interest in early diagnosis and prevention of cardiac morbidity and mortality. Cardiac dysfunction has an origin in abnormal and unstable nucleotide repeats in the DMPK and CNBP genes which have downstream effects leading to an increased propensity for arrhythmias and left ventricular systolic dysfunction. Current screening paradigms involve the use of routine screening electrocardiograms, ambulatory electrocardiographic monitors, and cardiac imaging to stratify risk and suggest further invasive evaluation. The most common cardiac abnormality is atrial arrhythmia, however there is significant mortality in this population from high-degree atrioventricular block and ventricular arrhythmia. In this review, we describe the cardiac manifestations of myotonic dystrophy with an emphasis on arrhythmia which is the second most common cause of death in this population after respiratory failure.

Diagnosis, significance, and management of ventricular thrombi in patients referred for VT ablation.

INTRODUCTION: In patients with structural heart disease presenting with ventricular tachycardia (VT), detection of ventricular thrombi and subsequent management can be challenging. This study aimed to assess the value of multimodality imaging with cardiac magnetic resonance imaging (CMR), contrast-enhanced transthoracic echocardiography (TTE), and computed tomography (CT) for thrombus detection as well as a management algorithm geared towards anticoagulation and deferred ablation for patients referred for VT ablation. METHODS AND RESULTS: A total of 154 consecutive patients referred for VT ablation underwent preprocedural multimodality imaging with CMR, CT, and TTE. In 9 patients (6%) a new ventricular thrombus was detected and anticoagulation was initiated. Thrombi were detected by CMR in nine patients, by CT in seven patients, and by TTE in two patients. Five patients eventually underwent endocardial VT ablation procedures 6.0 ± 2.0 months after initiation of anticoagulation with one patient also requiring an epicardial approach. Two patients died while on anticoagulation, unrelated to ventricular arrhythmia. Four of five patients were rendered non-inducible and no testing was performed in 1/5 patients. Areas containing left ventricular thrombi were non-excitable with pacing. Six of thirty-two inducible VTs were mapped in close vicinity of ventricular thrombi. No clinical embolic events occurred during the ablation procedures. CONCLUSIONS: Ventricular thrombus was detected in 6% of consecutive patients with structural heart disease undergoing VT ablation. CMR was the most sensitive modality, while contrast-enhanced TTE failed to detect the majority of thrombi. Anticoagulation followed by ablation can be safely and successfully performed in patients with ventricular thrombi.