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.

Continuous rhythm monitoring-guided anticoagulation after atrial fibrillation ablation.

INTRODUCTION: Oral anticoagulation (OAC) based on estimated stroke risk is recommended following catheter ablation (CA) of atrial fibrillation (AF), regardless of the extent of arrhythmia control. However, discontinuing OAC in selected patients may be safe. We sought to evaluate a strategy of OAC discontinuation following AF ablation guided by continuous rhythm monitoring. METHODS AND RESULTS: We prospectively studied AF ablations performed at our institution from June 2015 to December 2019. Patients that had pre-existing cardiac implantable electronic devices (CIEDs) or underwent insertable cardiac monitor (ICM) implantation immediately following AF ablation were included. OAC was continued for 6 weeks following CA in all patients, following which OAC management was guided by CHA2 DS2 -VASc score and continuous rhythm monitoring results, according to a prespecified protocol. AF recurrence was defined as ≥30 s (CIEDs) or ≥2 min (ICM). We studied 196 patients (mean age 64.7 ± 11.3 years, 66.8% male, 85.7% ICM, 14.3% CIEDs). Mean CHA2 DS2- VASc score was 2.2 ± 1.5. One-year AF-free survival following CA was 83% for paroxysmal AF and 63% for persistent AF patients. Over 3 year follow-up, OAC was discontinued in 57 (33.7%) patients, mean 7.4 ± 7.1 months following ablation. Following discontinuation, OAC was restarted for AF recurrence in 9 (15.8%) patients, mean 11.7 ± 6.8 months after stopping. This discontinuation protocol led to a 21.9% reduction in overall time exposed to OAC. There were no thromboembolic or major bleeding events. CONCLUSION: OAC can be discontinued in a significant percentage of patients following CA of AF. When guided by continuous rhythm monitoring, this practice does not unacceptably increase the risk of thromboembolic events.

Collateral injury of the conduction system during catheter ablation of septal substrate in nonischemic cardiomyopathy.

INTRODUCTION: In patients with nonischemic cardiomyopathy (NICM) little is known about the clinical impact of catheter ablation (CA) of septal ventricular tachycardia (VT) resulting in the collateral injury of the conduction system (CICS). METHODS AND RESULTS: Ninety-five consecutive patients with NICM underwent CA of septal VT. Outcomes in patients with no baseline conduction abnormalities who developed CICS (group 1, n = 28 [29%]) were compared to patients with no CICS (group 2, n = 17 [18%]) and to patients with preexisting conduction abnormalities or biventricular pacing (group 3, n = 50 [53%]). Group-1 patients were younger, had a higher left ventricular ejection fraction and a lower prevalence of New York Heart Association III/IV class compared to group 3 while no significant differences were observed with group 2. After a median follow-up of 15 months, VT recurred in 14% of patients in group 1, 12% in group 2 (P = .94) and 32% in group 3 (P = .08) while death/transplant occurred in 14% of patients in group 1, 18% in group 2 (P = .69) and 28% in group 3 (P = .15). A worsening of left ventricular ejection fraction (LVEF) (median LVEF variation, -5%) was observed in group 1 compared to group 2 (median LVEF variation, 0%; P < .01) but not group-3 patients (median LVEF variation, -4%; P = .08) with a consequent higher need for new biventricular pacing in group 1 (43%) compared to group 2 (12%; P = .03) and group 3 (16%; P < .01). CONCLUSIONS: In patients with NICM and septal substrate, sparing the abnormal substrate harboring the conduction system provides acceptable VT control while preventing a worsening of the systolic function.

Impact of a nurse-led limited risk factor modification program on arrhythmia outcomes in patients with atrial fibrillation undergoing catheter ablation.

BACKGROUND: We have previously demonstrated the feasibility of a nurse-led risk factor modification (RFM) program for improving weight loss and obstructive sleep apnea (OSA) care among patients with atrial fibrillation (AF). OBJECTIVE: We now report its impact on arrhythmia outcomes in a subgroup of patients undergoing catheter ablation. METHODS: Participating patients with obesity and/or need for OSA management (high risk per Berlin Questionnaire or untreated OSA) underwent in-person consultation and monthly telephone calls with the nurse for up to 1 year. Arrhythmias were assessed by office ECGs and ≥2 wearable monitors. Outcomes, defined as Arrhythmia control (0-6 self-terminating recurrences, with ≤1 cardioversion for nonparoxysmal AF) and Freedom from arrhythmias (no recurrences on or off antiarrhythmic drugs), were compared at 1 year between patients undergoing catheter ablation who enrolled and declined RFM. RESULTS: Between 1 November 2016 and 1 April 2018, 195 patients enrolled and 196 declined RFM (body mass index, 35.1 ± 6.7 vs 34.3 ± 6.3 kg/m2 ; 50% vs 50% paroxysmal AF; P = NS). At 1 year, enrolled patients demonstrated significant weight loss (4.7% ± 5.3% vs 0.3% ± 4.4% in declined patients; P < .0001) and improved OSA care (78% [n = 43] of patients diagnosed with OSA began treatment). However, outcomes were similar between enrolled and declined patients undergoing ablation (arrhythmia control in 80% [n = 48] vs 79% [n = 38]; freedom from arrhythmia in 58% [n = 35] vs 71% [n = 34]; P = NS). CONCLUSION: Despite improving weight loss and OSA care, our nurse-led RFM program did not impact 1-year arrhythmia outcomes in patients with AF undergoing catheter ablation.

Three-dimensional myocardial scar characterization from the endocardium: Usefulness of endocardial unipolar electroanatomic mapping.

Epicardial ablation may be required to eliminate ventricular tachycardia (VT) in patients with underlying structural heart disease. The decision to gain epicardial access is frequently based on the suspicion of an epicardial origin for the VT and/or presence of an arrhythmogenic substrate. Epicardial pathology and VT is frequently present in patients with nonischemic right and/or left cardiomyopathies even in the setting of modest or no endocardial bipolar voltage substrate. In this setting, unipolar voltage mapping from the endocardium serves to help identify midmyocardial and/or epicardial VT substrate. The additional value of endocardial unipolar mapping includes its usefulness to predict the clinical outcome after VT ablation, to determine the irreversibility of myocardial disease, and to guide endomyocardial biopsy procedures to specific areas of intramural scarring. In this review, we aim to provide a guide to the use of endocardial unipolar mapping and its appropriate interpretation in a variety of clinical situations.

Catheter ablation of premature ventricular complexes with low intraprocedural burden guided exclusively by pace-mapping.

BACKGROUND: Catheter ablation (CA) of idiopathic premature ventricular complexes (PVCs) is typically guided by both activation and pace-mapping, with ablation ideally delivered at the site of the earliest local activation. However, activation mapping requires sufficient intraprocedural quantity of PVCs. This study aimed to investigate the outcome of CA of infrequent PVCs guided exclusively by pace-mapping. METHODS: We retrospectively analyzed all patients undergoing CA of idiopathic PVCs between 2014 and 2017. RESULTS: Among 327 patients, 24 (7.3%) had low intraprocedural PVC burden despite isoproterenol, including two patients with zero PVCs, rendering activation mapping impractical/impossible. All 24 had a history of symptomatic PVCs. During ablation, a median of 27 (17-55) pace-maps were performed, with best median PASO score of 97 (96-98)%. A median of 12 (8.75-18.75) radiofrequency (RF) lesions were delivered with 11.4 (8.5-17.6) minutes of total RF time. Clinical success, defined as more than 80% reduction in the burden of previously frequent PVCs and/or absence of symptoms as well as any documented clinical PVCs among those with infrequent or exercise-induced PVCs, was achieved in 19 (79%) patients over 9.2 (2.0-15.0) months of follow-up. CONCLUSIONS: When activation mapping cannot be performed due to inadequate intraprocedural PVC burden, detailed pace-mapping can frequently identify the precise arrhythmia site of origin, thereby guiding successful CA.

Long term follow-up after ventricular tachycardia ablation in patients with congenital heart disease.

BACKGROUND: Ventricular tachycardia (VT) is frequently encountered in patients with repaired and unrepaired congenital heart disease (CHD), causing significant morbidity and sudden cardiac death. Data regarding underlying VT mechanisms and optimal ablation strategies in these patients remain limited. OBJECTIVE: To describe the electrophysiologic mechanisms, ablation strategies, and long-term outcomes in patients with CHD undergoing VT ablation. METHODS: Forty-eight patients (mean age 41.3 ± 13.3 years, 77.1% male) with CHD underwent a total of 57 VT ablation procedures at two centers from 2000 to 2017. Electrophysiologic and follow-up data were analyzed. RESULTS: Of the 77 different VTs induced at initial or repeat ablation, the underlying mechanism in 62 (81.0%) was due to scar-related re-entry; the remaining included four His-Purkinje system-related macrore-entry VTs and focal VTs mainly originating from the outflow tract region (8 of 11, 72.7%). VT-free survival after a single procedure was 72.9% (35 of 48) at a median follow-up of 53 months. VT-free survival after multiple procedures was 85.4% (41 of 48) at a median follow-up of 52 months. There were no major complications. Three patients died during the follow-up period from nonarrhythmic causes, including heart failure and cardiac surgery complication. CONCLUSION: While scar-related re-entry is the most common VT mechanism in patients with CHD, importantly, nonscar-related VT may also be present. In experienced tertiary care centers, ablation of both scar-related and nonscar-related VT in patients with CHD is safe, feasible, and effective over long-term follow-up.

Anatomical proximity dictates successful ablation from adjacent sites for outflow tract ventricular arrhythmias linked to the coronary venous system.

AIMS: Catheter ablation of outflow tract ventricular arrhythmias (OTVAs) with the earliest activation within the coronary venous system (CVS) can be challenging. When ablation from the CVS is not feasible or ineffective, an approach from anatomically adjacent site(s) can be considered. We report the outcomes of an anatomical approach for OTVAs linked to the CVS. METHODS AND RESULTS: We retrospectively analysed 665 OTVA patients. Of these, 65 (9.8%) had the earliest activation within the CVS. In 53 (82%) cases, an anatomical approach was attempted. The targeted adjacent anatomical structure was the endocardial left ventricular outflow tract (LVOT) in 24 (45%), the left coronary cusp or the left/right cusp junction in 17 (32%) patients, and the right ventricular outflow tract (RVOT) in 12 (23%). The anatomical approach was successful in 26 (49%) patients (27% from the coronary cusps, 65% from the LVOT, and 8% from the RVOT). The difference in activation times between the earliest activation site within the CVS and the targeted site was not significantly different between the successful and unsuccessful groups (14.2 ± 11.2 ms vs. 13.2 ± 9.3 ms; P = 0.89). The anatomical distance from the earliest activation site to the targeted site was shorter for the successful group (9.7 ± 2.4 mm vs. 13.1 ± 6.5 mm; P < 0.05). In particular, when the anatomical distance was >12.8 mm, anatomical approach was successful in only 1/13 (8%). CONCLUSION: In patients with OTVAs linked to the CVS, an anatomical approach targeting an adjacent site can be effective, particularly when the distance between the sites is <12.8 mm.

Catheter Ablation of Idiopathic Ventricular Arrhythmias.

Ventricular arrhythmias (VA) are observed in the setting of structural heart disease. However, in a proportion of patients presenting with VT, the routine diagnostic modalities fail to demonstrate overt myocardial abnormality. These arrhythmias have been called idiopathic VAs. They consist of various subtypes that have been defined by their anatomic location of origin within the heart and/or their underlying mechanism. While the majority of patients are asymptomatic, some experience debilitating symptoms and may develop reversible ventricular dysfunction. Catheter ablation has been traditionally reserved for patients with incapacitating symptoms or progressive ventricular dysfunction. However, as many patients are young, and catheter ablation can be curative in >90% of cases with a low risk (<1%) of serious complications, it is increasingly being offered as a first-line treatment in symptomatic patients. The approach to arrhythmia mapping is guided by the 12-lead electrocardiograph (ECG) morphology of the ventricular tachycardia (VT). Use of three dimensional (3D) electroanatomic mapping systems and intra-cardiac echocardiography are helpful in localising sites for successful ablation.

QRS morphology shift following catheter ablation of idiopathic outflow tract ventricular arrhythmias: Prevalence, mapping features, and ablation outcomes.

INTRODUCTION: In patients with monomorphic idiopathic outflow tract ventricular arrhythmias (OT-VAs), catheter ablation (CA) at the earliest activation site can result in a shift in QRS morphology indicating a change in the activation patterns. This study aimed to investigate the prevalence, mapping features, and ablation outcomes of OT-VAs displaying a QRS morphology shift following CA. METHODS AND RESULTS: We retrospectively analyzed 446 patients with monomorphic OT-VAs. A QRS morphology shift following CA was observed in 17 (4%) patients. Initially, the earliest activation site was within the right ventricular outflow tract (RVOT) in one (6%) patient, the left ventricular outflow tract (LVOT) in 10 (59%) patients (left coronary cusp/right coronary cusp junction in seven patients and LVOT endocardium in three patients), and within the distal coronary venous system in six (35%) patients. The VA was suppressed in all 17 patients, but VA recurrence with a different QRS morphology was observed after a waiting period. The recurrent VA was remapped in all patients and was eliminated targeting the new earliest site in 15 (88%) cases. In 11 of 15 successful cases, the ablation site for the recurrent VA shifted to an anatomical structure distinct from but adjacent to the initial site. In the remaining four patients, the recurrent VA was eliminated within the same anatomical structure. CONCLUSIONS: In patients with idiopathic OT-VAs, a QRS morphology shift following CA can be observed in 4% of the cases. In these cases, detailed remapping is necessary since the successful ablation site for the VAs with altered QRS morphology shifts to different anatomical structures in most patients.

Lead I R-wave amplitude to differentiate idiopathic ventricular arrhythmias with left bundle branch block right inferior axis originating from the left versus right ventricular outflow tract.

INTRODUCTION: Differentiation of right versus left ventricular outflow tract (RVOT vs. LVOT) arrhythmia origin with left bundle branch block right inferior axis (LBRI) morphology is relevant to ablation planning and risk discussion. Our aim was to determine if lead I R-wave amplitude is useful for differentiation of RVOT from LVOT arrhythmias with LBRI morphology. METHODS: The R-wave amplitude in lead I was measured in a retrospective cohort of 75 consecutive patients with LBRI pattern ventricular arrhythmias (VAs) successfully ablated from the RVOT (n = 54), LVOT (n = 16), or the anterior interventricular vein (AIV; n = 5). The optimal R-wave threshold was identified and diagnostic indices were compared with the previously reported transitional zone (TZ) index and V2S/V3R index. RESULTS: An R-wave amplitude greater than or equal to 0.1 mV predicted LVOT origin with 75% sensitivity and 98.2% specificity. In comparison, the TZ and V2S/V3R indices had 50% and 68.8% sensitivity, and 75.9% and 88.9% specificity, respectively, for predicting LVOT origin. The area under the curve (AUC) was 0.85 for lead I R-wave amplitude, 0.87 for V2S/V3R, and 0.72 for the TZ index. Of 36 cases with QS in lead I, 30 (83.3%) were from the anterior RVOT, three (8.3%) from the LVOT, and three (8.3%) from the AIV. CONCLUSION: The presence of R-wave amplitude in lead I (≥0.1 mV) is a simple and useful criterion to identify LVOT cusp or endocardium focus in LBRI arrhythmias. A QS pattern in lead I suggests an origin in the anterior RVOT, or less commonly the adjacent LV summit.

Epicardial ventricular tachycardia in ischemic cardiomyopathy: Prevalence, electrophysiological characteristics, and long-term ablation outcomes.

INTRODUCTION: The characteristics of the epicardial (EPI) substrate responsible for ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM) are undefined, and data on the long-term outcomes of EPI catheter ablation limited. We evaluated the prevalence, electrophysiologic features, and outcomes of catheter ablation of EPI VT in ICM. METHODS AND RESULTS: From December 2010 to June 2013, a total of 13 of 93 (14%) patients with ICM underwent catheter ablation at our institution and had conclusive evidence of critical EPI substrate demonstrated to participate in VT with activation, entrainment and/or pace mapping during sinus rhythm (two other patients underwent EPI mapping but had no optimal ablation targets). The electrophysiologic substrate characteristics and activation/entrainment mapping data were compared with a reference group of ICM patients without evidence of critical EPI substrate (N = 44), defined as a complete procedural success (noninducibility of any VT at programmed stimulation) after endocardial (ENDO)-only ablation. Patients with failed EPI access (N = 2) or history of cardiac surgery (N = 92) were excluded from the study. All 13 patients had evidence of abnormal EPI substrate with fractionated/late/split electrograms and low-bipolar voltage areas. The critical VT ablation sites were all located within the EPI bipolar "dense" scar (<1.0 mV) opposite the ENDO bipolar scar in 77% of cases and extending beyond the ENDO bipolar scar (within the ENDO unipolar low-voltage area) in the remaining patients. Compared with the reference ENDO-only group, patients with EPI VT had a smaller ENDO bipolar scar area, 54.0 (37.1-84) vs 86.7 (55.6-112) cm2 ; P = 0.0159, with a similar extent of ENDO unipolar low voltage. No other substrate characteristics or location differed between the two groups. After 35.2 ± 24.2 months of follow-up, VT-free survival was 73% in patients with EPI VT compared with 66% in the ENDO-only group (log-rank P = 0.56). CONCLUSIONS: The presence of the critical EPI substrate responsible for VT can be demonstrated in at least 14% of patients with ICM. The majority of EPI critical ablation sites are distributed opposite the ENDO bipolar scar area and catheter ablation is effective in achieving long-term arrhythmia control.

Percutaneous cryoablation for papillary muscle ventricular arrhythmias after failed radiofrequency catheter ablation.

BACKGROUND: Catheter ablation of ventricular arrhythmias (VA) from the papillary muscles (PM) is challenging due to limited catheter stability and contact on the PMs with their anatomic complexity and mobility. OBJECTIVE: This study aimed to evaluate the effectiveness of cryoablation as an adjunctive therapy for PM VAs when radiofrequency (RF) ablation has failed. METHODS: We evaluated a retrospective series of patients who underwent cryoablation for PM VAs when RF ablation had failed. The decision to switch to cryoablation was at the operator's discretion when intracardiac echocardiography (ICE) suggested that cryoablation might be more effective in achieving catheter stability and energy delivery. RESULTS: Sixteen patients underwent cryoablation of PM VAs between 2014 and 2016 after RF ablation was unsuccessful. VAs originated from the anterolateral left ventricle (LV) PM (six patients), posterolateral LV PM (six patients), and right ventricle PM (four patients). VAs were predominantly frequent premature ventricular complexes (PVCs); however, patients with sustained ventricular tachycardia and PVC-triggered VF were also represented. Fifteen of the 16 patients were treated with cryoablation; in one patient, a procedural complication with retrograde aortic access precluded treatment. In all patients treated with cryoablation, contact and stability was confirmed with ICE to be superior to the RF catheter, and there was acute and long-term elimination of VAs. CONCLUSION: Cryoablation is a useful adjunctive therapy in ablation of PM VAs, providing excellent procedural outcomes even when RF ablation has failed. Cryoablation catheters are less maneuverable than RF ablation catheters and care is required to avoid complications.

Imaging characteristics of papillary muscle site of origin of ventricular arrhythmias in patients with mitral valve prolapse.

BACKGROUND: Mitral valve prolapse has been associated with increased risk of ventricular arrhythmias. We aimed to examine whether certain cardiac imaging characteristics are associated with papillary muscle origin of ventricular arrhythmias in these patients. METHODS AND RESULTS: We screened electronic medical records of all patients documented to have mitral valve prolapse on either transthoracic echocardiogram (TTE) or cardiac magnetic resonance imaging (CMR) in our center, who also underwent an electrophysiologic study (EPS) between 2007 and 2016. Anterior and posterior mitral leaflet thickness and prolapsed distance were measured on TTE and late gadolinium enhancement (LGE) was assessed on CMR. Patients were categorized as papillary muscle positive (pap (+)) or negative (pap (-)) using EPS. Eighteen patients were included in this study. Of the 15 patients who underwent TTE, a significantly higher proportion of patients in the pap (+) group had an anterior to posterior leaflet prolapse ratio of >0.45 indicating more symmetric leaflet prolapse. There were no differences in anterior or posterior leaflet thickness or prolapse distance between the groups. Patients in the pap (+) group were more likely to be women. Of the 7 patients who underwent CMR, those who were pap (+) were more likely to have LGE in the region of the papillary muscles than those who were pap (-). CONCLUSION: Female gender, more symmetric bileaflet prolapse on TTE, and the presence of papillary muscle LGE on CMR may be associated with papillary muscle origin of ventricular arrhythmias in patients with mitral valve prolapse.

Anticoagulation use and clinical outcomes after catheter ablation in patients with persistent and longstanding persistent atrial fibrillation.

INTRODUCTION: Whether successful catheter ablation for atrial fibrillation (AF) reduces risk of cerebrovascular events (CVEs) remains controversial and whether oral anticoagulation therapy (OAT) can be safely discontinued in patients rendered free of AF recurrences remains unknown. We evaluated OAT use patterns and examined long-term rates of CVEs (stroke/TIA) and major bleeding episodes (MBEs) in patients with nonparoxysmal AF treated with catheter ablation. METHODS AND RESULTS: Four hundred patients with nonparoxysmal AF (200 persistent, 200 longstanding persistent; mean age 60.3 ± 9.7 years, 82% male) undergoing first AF ablation were followed for 3.6 ± 2.4 years. OAT discontinuation during follow-up was permitted in selected patients per physician discretion. At last follow-up, allowing for multiple ablations, 172 (43.0%) patients were free of AF recurrence. Two hundred and seven (51.8%) discontinued OAT at some point; 174 (43.5%) were off OAT at last follow-up. Patients without AF recurrence were more likely to remain off OAT (HR 0.23 [95% CI 0.17-0.33]). Patients with persistent (versus longstanding persistent) AF type prior to ablation (HR 0.6 [CI 0.44-0.83]) and those with CHA2 DS2 -VASc score <2 (HR 0.56 [0.39-0.80]) were less likely to continue OAT. Seven patients had CVEs (incidence: 0.49/100 patient years) and 14 experienced MBE during follow-up (incidence: 0.98/100 patient years). Older age (P  =  0.001) and coronary artery disease (P  =  0.028) were associated with CVE. CONCLUSION: Anticoagulation discontinuation in well selected, closely monitored patients following successful ablation of nonparoxysmal AF was associated with a low rate of clinical embolic CVEs. Prospective studies are required to confirm safety of OAT discontinuation after successful AF ablation.

Prognostic role of serial quantitative evaluation of 18F-fluorodeoxyglucose uptake by PET/CT in patients with cardiac sarcoidosis presenting with ventricular tachycardia.

BACKGROUND: Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) has shown to be useful in diagnosis, staging and monitoring of cardiac sarcoidosis (CS) but its interpretation is not standardized. OBJECTIVES: We sought to investigate the clinical impact of serial quantitative FDG uptake analysis in patients with CS presenting with ventricular tachycardia (VT) treated by catheter ablation (CA). METHODS: We followed 20 patients (51 ± 9 years, 70% males) with CS and VT who underwent CA, with 92 serial FDG-PET scans (3-10 per patient). Myocardial FDG-avid lesions were quantified using three parameters: maximum standardized uptake value (SUVmax), partial-volume corrected mean standardized uptake value (SUVmean) and partial-volume corrected volume-intensity product [lesion metabolic activity (LMA)]. The volume-intensity product of the entire heart [global cardiac metabolic activity (gCMA)] and the background cardiac metabolic activity (bCMA: difference between gCMA and LMA) were also calculated. The primary end-point was the occurrence of major adverse cardiac events (MACE), including death, heart transplant, hospitalization for heart failure and implantable cardioverter defibrillator (ICD) appropriate interventions. Evolution of echocardiographic parameters over follow-up was also assessed. RESULTS: During a median follow-up of 35 (20-66) months, 18 MACE (1 death, 2 heart transplants, 12 ICD appropriate interventions, 3 hospitalizations) occurred in 12 (60%) patients. At univariable analysis, lack of PET improvement (defined by decrease in LMA of at least 25%) was the only variable associated with cardiac events during follow-up. In particular, non-responders had a 20-fold higher risk of MACE at follow-up (HR 18.96, 95% CI 2.26-159.27; p = 0.007). Moreover, a significant linear inverse relationship was observed between changes in LMA and changes in left ventricular ejection fraction over follow-up (ß = -20.11; p = 0.003). CONCLUSIONS: In patients with CS and VT, temporal change in FDG uptake evaluated by a quantitative approach is associated with parallel change in systolic function. Moreover, reduction in FDG uptake is strongly associated with fewer MACE at long-term follow-up.

Avoiding damage to transvenous leads-A comparison of electrocautery techniques and two insulated electrocautery blades.

BACKGROUND: Electrocautery (cautery) can damage transvenous cardiac device leads. The purpose of this study was to compare lead damage from an insulated cautery blade when used with several different techniques that included coagulation (COAG) versus cutting (CUT) mode, perpendicular active edge (active) versus parallel flat blade (flat) orientation (phase 1), and using one commercially available blade (PhotonBlade) versus another (PlasmaBlade) (phase 2). METHODS: In phase 1, lesions were delivered using combinations of: (1) COAG and CUT; (2) active and flat orientation; and (3) polyurethane, silicone, and copolymer insulation. In phase 2, lesions were delivered using combinations of: (1) PlasmaBlade and PhotonBlade, (2) four power output levels, and (3) eight different lead models. Lead damage was scored on an ordinal scale of 0 to 4. RESULTS: Phase 1: more leads were damaged using COAG than CUT (48% vs 2%, P < 0.0001). When using COAG, 74% of lesions using active orientation had damage versus 22% of lesions using flat orientation (P  =  0.0002). COAG lesions to copolymer (61%) and polyurethane (68%) leads had greater damage than silicone (17%) (P  =  0.006 and P  =  0.003, respectively). Phase 2: 75% of treatments using PlasmaBlade had damage versus 40% of treatments with PhotonBlade (P < 0.0001). Higher power resulted in more damage. At the commonly used setting of CUT 20 W, damage occurred in 39% of treatments using PlasmaBlade versus 13% using PhotonBlade (P  =  0.0006). CONCLUSIONS: COAG resulted in more damage than CUT; this effect was greatest with the active edge, and with polyurethane or copolymer insulation. PhotonBlade was associated with less damage to leads than PlasmaBlade.

Outcomes of catheter ablation of ventricular tachycardia with mechanical hemodynamic support: An analysis of the Medicare database.

INTRODUCTION: There is a paucity of data in favor of mechanical support during catheter ablation of ventricular tachycardia (VT). This study investigated the outcomes of VT ablation associated with mechanical support using percutaneous ventricular assist device (PVAD) versus intra-aortic balloon pump (IABP). METHODS AND RESULTS: We retrospectively examined the outcomes of patients who underwent VT ablation associated with PVAD versus IABP from 2010 to 2013, captured by the Medicare Inpatient Standard Analytic File database. Data from 345 patients (PVAD = 230, IABP = 115) were examined. On admission, the incidence of heart failure was higher in PVAD (84.3% vs. 73.0%; P = 0.01) with similar rates of renal failure in PVAD versus IABP (33.0% vs. 37.4%; P = 0.42). However, PVAD was associated with reduced in-hospital cardiogenic shock (9.1% vs. 23.5%; P  <  0.001), renal failure (11.7% vs. 21.7%; P = 0.01), and length of stay (8.4 ± 7.9 vs. 10.6 ± 7.5; P < 0.001), but with greater hospital discharges to home/self-care (66.0% vs. 51.6%; P = 0.02). Index mortality (6.5% vs. 19.1%; P = 0.001) and mortality in patients with cardiogenic shock (18.2% vs. 41.2%; P = 0.03) were significantly lower with PVAD versus IABP. Furthermore, PVAD was associated with lower all-cause (27.0% vs. 38.7%; P = 0.04) and heart failure-related (21.4% vs. 33.3%; P = 0.03) 30-day hospital readmissions, but with similar redo-VT ablation rates at 1 year (10.2% vs. 14.0%; P = 0.34). CONCLUSION: Among the cases captured by the Medicare database, catheter ablation of VT associated with mechanical support using PVAD was associated with reduced in-hospital cardiogenic shock, renal failure, length of stay, hospital readmissions and mortality, but no difference in redo-VT ablation at 1 year.

Inferior lead discordance in ventricular arrhythmias: A specific marker for certain arrhythmia locations.

BACKGROUND: Most idiopathic ventricular arrhythmias (VAs) originate from the outflow tracts and are characterized by an inferior axis on the 12-lead ECG. A group of patients will exhibit inferior lead discordance (ILD), demonstrating a positive QRS in lead II with negative QRS in III or the opposite finding. METHODS AND RESULTS: We identified patients undergoing ablation of idiopathic premature ventricular contractions (PVCs) or ventricular tachycardia (VT) between 2013 and 2015. The site of earliest activation was determined using electroanatomic mapping and intracardiac echocardiography. Out of 281 patients, 25 (8.9%) exhibited ILD. In patients with positive/negative discordance (n = 18), the source was mapped to the parahisian region in 14 cases and to the right ventricular (RV) moderator band (MB) or papillary muscles (PMs) in 4, while all those with negative/positive discordance (n = 7) were mapped to the anterolateral PM (ALPM). In the group with positive/negative discordance, a later precordial transition (>V4), wider QRS duration, and the presence of notch in the inferior leads pointed toward a RV MB/PM origin. Complete PVC/VT suppression was achieved in 72%. In 2 patients with parahisian PVCs, ablation was not attempted due to risk of heart block. CONCLUSIONS: The presence of ILD is associated with particular anatomical locations, namely, the parahisian region, RV MB/PM, and ALPM. The outcomes of ablation are more modest compared to other idiopathic VAs, reflecting the technical difficulties associated with these anatomical locations, such as the proximity to the conduction system in parahisian VAs or stability issues when ablating the PMs or MB.

Outcomes of Catheter Ablation of Idiopathic Outflow Tract Ventricular Arrhythmias With an R Wave Pattern Break in Lead V2: A Distinct Clinical Entity.

INTRODUCTION: In outflow tract ventricular arrhythmias (OT-VAs), an abrupt loss of the R wave in lead V2 compared to V1 and V3 (pattern break in V2-PBV2) suggests an origin close to the anterior interventricular sulcus (anatomically opposite to lead V2) and adjacent to proximal coronaries. We studied the outcome of catheter ablation of OT-VAs with a PBV2. METHODS AND RESULTS: Of 130 consecutive patients with idiopathic left bundle block morphology OT-VAs and transition ≤V4, 12 (9%) had PBV2. Outcomes in this group were compared to the remaining 118 patients. Patients with PBV2 were more likely to be younger (41 ± 18 vs. 50 ± 14 years, P = 0.0384) and women (11 [92%] vs. 70 [59%], P = 0.0302). The earliest activation was at the RVOT in seven, left coronary cusp (LCC) in one, anterior interventricular vein (AIV) in two and the epicardium in two. In five (42%) cases (earliest activation in the AIV in two, epicardium in two, and RVOT below the valve level in one), ablation was aborted due to proximity to the left anterior descending (LAD) coronary artery. After 36 ± 17 months and 1.3 ± 0.5 procedures, VAs elimination was achieved in 58% of patients with PBV2 compared to 89% of the reference population (P = 0.0125) with effective site in five of seven at the most anterior and leftward RVOT adjacent to the pulmonic valve (PV). CONCLUSIONS: OT-VAs with PBV2 demonstrate a unique ECG pattern and challenging catheter ablation. Proximity to LAD precludes ablation in about half. Long-term VA suppression could be achieved in only 58% of cases most commonly when the earliest site is at the anterior and leftward RVOT just under the PV.