Characterization of Structural Changes in Arrhythmogenic Right Ventricular Cardiomyopathy With Recurrent Ventricular Tachycardia After Ablation: Insights From Repeat Electroanatomic Voltage Mapping.

BACKGROUND: Data characterizing structural changes of arrhythmogenic right ventricular (RV) cardiomyopathy are limited. METHODS: Patients presenting with left bundle branch block ventricular tachycardia in the setting of arrhythmogenic RV cardiomyopathy with procedures separated by at least 9 months were included. RESULTS: Nineteen consecutive patients (84% males; mean age 39±15 years [range, 20-76 years]) were included. All 19 patients underwent 2 detailed sinus rhythm electroanatomic endocardial voltage maps (average 385±177 points per map; range, 93-847 points). Time interval between the initial and repeat ablation procedures was mean 50±37 months (range, 9-162). No significant progression of voltage was observed (bipolar: 38 cm2 [interquartile range (IQR), 25-54] versus 53 cm2 [IQR, 25-65], P=0.09; unipolar: 116 cm2 [IQR, 61-209] versus 159 cm2 [IQR, 73-204], P=0.36) for the entire study group. There was a significant increase in RV volumes (percentage increase, 28%; 206 mL [IQR, 170-253] versus 263 mL [IQR, 204-294], P<0.001) for the entire study population. Larger scars at baseline but not changes over time were associated with a significant increase in RV volume (bipolar: Spearman ρ, 0.6965, P=0.006; unipolar: Spearman ρ, 0.5743, P=0.03). Most patients with progressive RV dilatation (8/14, 57%) had moderate (2 patients) or severe (6 patients) tricuspid regurgitation recorded at either initial or repeat ablation procedure. CONCLUSIONS: In patients with arrhythmogenic RV cardiomyopathy presenting with recurrent ventricular tachycardia, >10% increase in RV endocardial surface area of bipolar voltage consistent with scar is uncommon during the intermediate term. Most recurrent ventricular tachycardias are localized to regions of prior defined scar. Voltage indexed scar area at baseline but not changes in scar over time is associated with progressive increase in RV size and is consistent with adverse remodeling but not scar progression. Marked tricuspid regurgitation is frequently present in patients with arrhythmogenic RV cardiomyopathy who have progressive RV dilation.

Ventricular tachycardia in nonischemic cardiomyopathy: Anteroseptal vs inferolateral origin based on ICD ventricular electrogram timing.

INTRODUCTION: The majority of patients with nonischemic cardiomyopathy (NICM) present a perivalvular substrate that is either predominantly antero-septal (AS) or infero-lateral (IL), corresponding to specific ventricular tachycardia (VT) morphologies. The relative timing of far-field and near-field ventricular electrograms (EGMs) from stored implantable cardioverter-defibrillator (ICD) events of VT may be used to distinguish AS from IL VT in NICM. METHODS AND RESULTS: We analyzed 48 patients with NICM with either a primarily AS (54%) or IL (56%) VT source undergoing catheter ablation between 2003 and 2018. Only patients with retrievable ICD-EGMs of spontaneous VT events which could be matched with VTs induced during the ablation procedure were included. A total of 56 VT events (52% AS origin and 48% IL origin) were analyzed, yielding a mean far-field to near-field interval of 31 ± 13 milliseconds for AS VTs and 47 ± 19 milliseconds for IL VTs (P = .001). At receiver operating characteristic analysis (AUC = 0.734), a far-field to near-field interval of ≥ 60 milliseconds ruled out AS VTs in 29 (100%) cases and diagnosed IL VTs with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 63%. An interval of ≤ 20 milliseconds ruled out IL VTs in 25 (93%) cases and diagnosed AS VTs with a PPV of 83% and NPV of 57%. Significant overlap between the two groups was observed among far-field to near-field intervals in between 20 milliseconds and 60 milliseconds. CONCLUSIONS: The relative timing of far-field and near-field EGMs from stored clinical ICD events of VT can be helpful to differentiate AS vs IL origin of VT in NICM.

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.

Electrocardiographic and Electrophysiologic Characteristics of Idiopathic Ventricular Arrhythmias Originating From the Basal Inferoseptal Left Ventricle.

OBJECTIVES: This study sought to characterize ventricular arrhythmia (VA) ablated from the basal inferoseptal left ventricular endocardium (BIS-LVe) and identify electrocardiographic characteristics to differentiate from inferobasal crux (IBC) VA. BACKGROUND: The inferior basal septum is an uncommon source of idiopathic VAs, which can arise from its endocardial or epicardial (crux) aspect. Because the latter are often targeted from the coronary venous system or epicardium, distinguishing between the 2 is important for successful ablation. METHODS: Consecutive patients undergoing ablation of idiopathic VA from the BIS-LVe or IBC from 2009 to 2018 were identified and clinical characteristics and electrocardiographs of VA were compared. RESULTS: Of 931 patients undergoing idiopathic VA ablation, Virginia was eliminated from the BIS-LVe in 19 patients (2%) (17 male, age 63.7 ± 9.2 years, LV ejection fraction: 45.0 ± 9.3%). QRS complexes typically manifested right bundle branch block morphology with "reverse V2 pattern break" and left superior axis (more negative in lead III than II). VA elimination was achieved after median of 2 lesions (interquartile range [IQR]: 1-6; range 1 to 20) (radiofrequency ablation time: 123 s [IQR: 75-311]). Compared with 7 patients with IBC VA (3 male, age 51.9 ± 20.1 years, LV ejection fraction: 51.4 ± 17.7%), BIS-LVe VA less frequently had initial negative forces (QS pattern) in leads II, III, and/or aVF (p < 0.001), R-S ratio <1 in lead V1 (p = 0.005), and notching in lead II (p = 0.006) were narrower (QRS duration: 178.2 ± 22.4 vs. 221.1 ± 41.9 ms; p = 0.04) and more frequently had maximum deflection index of <0.55 (p < 0.001). CONCLUSIONS: The BIS-LVe region is an uncommon source of idiopathic VA. Distinguishing these from IBC VA is important for procedural planning and ablation success.

Comparison of the Ventricular Tachycardia Circuit Between Patients With Ischemic and Nonischemic Cardiomyopathies: Detailed Characterization by Entrainment.

BACKGROUND: There has been increasing awareness of the 3-dimensional nature of ventricular tachycardia (VT) circuits. VT circuits in patients with ischemic cardiomyopathies (ICM) and non-ICM (NICM) may differ in this regard. METHODS: Among patients with structural heart disease and at least 1 hemodynamically tolerated VT undergoing ablation, we retrospectively analyzed responses to all entrainment maneuvers. RESULTS: Of 445 patients (ICM 228, NICM 217) undergoing VT ablation, detailed entrainment mapping of at least 1 tolerated VT was performed in 111 patients (ICM 71, NICM 40). Of 89 ICM VTs, the isthmus could be identified by endocardial entrainment in 55 (62%), compared with only 8 of 47 (17%) NICM VTs ( P<0.01). With combined endocardial and epicardial mapping, the isthmus could be identified in 56 (63%) ICM VTs and 12 (26%) NICM VTs ( P<0.01), whereas any critical component (defined as entrance, isthmus or exit) could be identified in 76 (85%) ICM VTs and 37 (79%) NICM VTs ( P=0.3). Complete success (no inducible VT at the end of ablation, 82% versus 65%, P=0.04) and 1-year, single-procedure VT-free survival (82% versus 55%, P<0.01) were both higher among patients with ICM. CONCLUSIONS: Among mappable ICM VTs, critical circuit components can usually be identified on the endocardium. In contrast, among mappable NICM VTs, although some critical component can typically be identified with the addition of epicardial mapping, the isthmus is less commonly identified, possibly due to midmyocardial location.

Usefulness of ICD electrograms analysis to distinguish endocardial vs epicardial ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy.

INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by an epicardial (EPI) to endocardial (ENDO) fibrofatty infiltration of the RV predisposing to both EPI and ENDO ventricular tachycardia (VT). The relative timing between the VT QRS onset on the far-field ventricular electrogram (VEGM) to the local activation time recorded at the RV apex on the near-field VEGM from stored implantable cardioverter-defibrillator (ICD) events of VT can be helpful to discriminate ENDO from EPI VT in ARVC. METHODS AND RESULTS: We analyzed consecutive ARVC patients undergoing catheter ablation between 2006 and 2018. Only patients with retrievable ICD VEGMs of clinical VTs which could be matched with VTs induced at the time of ablation were included. A total of 26 VT events (16 ENDO, 10 EPI) from 19 ARVC patients were examined, yielding a mean far-field to near-field interval of 33 ± 15 ms for ENDO VTs and 52 ± 20 ms for EPI VTs (P = .020). At receiver-operating characteristic analysis, a far-field to a near-field interval of 60 ms or more ruled out ENDO VTs in 16 (100%) cases and identified EPI VTs with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 73%. An interval of less than or equal to 30 ms ruled out EPI VTs in eight (80%) cases and diagnosed ENDO VTs with a PPV of 80% and an NPV of 50%. CONCLUSION: Far-field to near-field ICD VEGM timing may be used to predict ENDO vs EPI VT in ARVC before ablation, indicating an ENDO origin if the timing is less than or equal to 30 ms and an EPI origin if greater than or equal to 60 ms.

Septal Coronary Venous Mapping to Guide Substrate Characterization and Ablation of Intramural Septal Ventricular Arrhythmia.

OBJECTIVES: This study describes the use of septal coronary venous mapping to facilitate substrate characterization and ablation of intramural septal ventricular arrhythmia (VA). BACKGROUND: Intramural septal VA represents a challenge for substrate definition and catheter ablation. METHODS: Between 2015 and 2018, 12 patients with structural heart disease, recurrent VA, and suspected intramural septal substrate underwent a septal coronary venous procedure in which mapping was performed by advancement of a wire into the septal perforator branches of the anterior interventricular vein. A total of 5 patients with idiopathic VA were also included as control subjects to compare substrate characteristics. RESULTS: Patients were 63 ± 14 years of age, and 11 (92%) were men. Most patients with structural heart disease had nonischemic cardiomyopathy (83%). Six patients underwent ablation for premature ventricular contractions (PVC) and 6 for ventricular tachycardia. All patients had larger septal unipolar voltage abnormalities than bipolar voltage abnormalities (mean area 35.3 ± 16.8 cm2 vs. 10.7 ± 8.4 cm2, respectively; p = 0.01), Patients with idiopathic VA had normal voltage. Septal coronary venous mapping revealed low-voltage, fractionated, and multicomponent electrograms in sinus rhythm in all patients with substrate compared to that in patients with idiopathic VA (amplitude 0.9 ± 0.9 mV vs. 4.4 ± 3.7 mV, respectively; p = 0.007; and duration 147 ± 48 ms vs. 92 ± 10 ms, respectively; p = 0.03). Ablation targeted early activation, pace map match, and/or good entrainment sites from intraseptal recording. Over a mean follow-up of 339 ± 240 days, the PVC and insertable cardioverter-defibrillator therapies burden were significantly reduced (from a mean of 22 ± 11% to 4 ± 8%; p = 0.005; and a mean 5 ± 2 to 1 ± 1; p = 0.001, respectively). Most patients (80%) with idiopathic VA remained arrhythmia free. CONCLUSIONS: In patients with suspected intramural septal VA, mapping of the septal coronary veins may be helpful to characterize the arrhythmia substrate, identify ablation targets, and guide endocardial ablation.

Outcomes of simultaneous unipolar radiofrequency catheter ablation for intramural septal ventricular tachycardia in nonischemic cardiomyopathy.

BACKGROUND: Radiofrequency (RF) ablation of intramural septal ventricular tachycardia (VT) in patients with nonischemic cardiomyopathy (NICM) is challenging. OBJECTIVE: The purpose of this study was to investigate the outcomes of simultaneous unipolar RF ablation for intramural septal VT in NICM. METHODS: We included patients with NICM and mid-myocardial septal substrate referred for VT ablation. After failed prolonged sequential unipolar RF lesions, simultaneous unipolar RF was delivered using 2 open-irrigated catheters at the site of earliest activation and/or best entrainment or pace mapping and at an anatomically adjacent/opposite site (up to 40 W for up to 3 minutes; RF energy independently titrated for each catheter to achieve an impedance drop of at least 15% from the baseline values). RESULTS: A total of 6 patients (mean age 62±13 years; mean left ventricular ejection fraction 38%±17%) were included. The clinical VTs were mapped at the anterior interventricular septum in 2 (33%) patients and at the inferior septum in 4 (67%). In all patients, prolonged sequential unipolar RF at the best activation/entrainment/pace-mapping site and at an anatomically opposite/adjacent site failed to eliminate VT. In 3 cases (50%), late VT termination with VT reinducibility was observed after sequential unipolar RF. Simultaneous unipolar ablation was then delivered, resulting in VT elimination and noninducibility in all patients. No procedural complications and no steam pops were observed. After a median follow-up of 20 months (range 13-20 months), 4 patients (67%) remained free of VT recurrence. CONCLUSION: In patients with NICM and intramural septal VT refractory to conventional RF ablation, simultaneous unipolar RF ablation is a safe and effective alternative ablation approach to improve long-term VT control.

Rivaroxaban for Periprocedural Anticoagulation Therapy in Japanese Patients Undergoing Catheter Ablation of Paroxysmal Non-Valvular Atrial Fibrillation.

Direct oral anticoagulants (DOACs) have been shown to be safe and effective for the prevention of stroke in nonvalvular atrial fibrillation (NVAF) patients, however, experience with peri-AF ablation management of DOACs is scarce. This study aimed to investigate the safety and feasibility of periprocedural anticoagulation therapy with rivaroxaban in Japanese patients undergoing paroxysmal non-valvular AF (NVAF) ablation using radiofrequency energy.This study was a multicenter, prospective pilot study. In paroxysmal NVAF patients, rivaroxaban (15 mg or 10 mg once-daily) was started at least 4 weeks prior to AF ablation, discontinued on the day of the procedure, resumed within 24 hours after ablation, and continued at least 3 months afterwards. During the interruption of rivaroxaban, bridging anticoagulation therapy with unfractionated heparin was given. Follow-up of the patients continued for 3 months.A total of consecutive 74 patients (mean age, 62 ± 9 years, 58 [78.4%] male) were enrolled. The mean follow-up period was 108 ± 79 days. Their mean CHADS2 score and CHA2DS2-VASc score were 1.2 ± 1.0 and 0.6 ± 0.7, respectively. Their mean HAS-BLED score was 1.0 ± 0.8. Neither major bleeding nor thromboembolic events, except in a case with bleeding from gastric cancer (1.4%), were observed in the periprocedural period of the AF ablation.The present multicenter study demonstrated the safety and feasibility of periprocedural anticoagulation therapy with rivaroxaban in Japanese patients undergoing catheter ablation of paroxysmal NVAF.

Preferential Pathway Pacing within the Aortic Sinus of Valsalva: Strong Evidence for the Existence of Preferential Conduction with Different Exit Sites Traversing the Ventricular Septum.

A 57-year-old male who presented with frequent ventricular premature contraction (VPC) was referred for catheter ablation. Two different QRS morphologies (VPC1 and VPC2) were recorded. Pace mapping at the right ventricular outflow (RVOT) was identical to VPC1 without latency. During the mapping within the right sinus of Valsalva where the RF applications were successful for elimination of VPC, discrete prepotential was recorded and the pace mapping produced both VPC1 and VPC2 morphology with different latency. These electrophysiological findings were thought to prove the existence of preferential pathway traversing the ventricular outflow septum with different exit sites.

Epicardial catheter ablation of ventricular tachycardia in no entry left ventricle: mechanical aortic and mitral valves.

BACKGROUND: In patients with mechanical aortic and mitral valves and left ventricular tachycardia, catheter ablation may be prevented by limited access to the left ventricle. METHODS AND RESULTS: In our series of 6 patients, 2 patients underwent direct surgical ablation and 4 underwent epicardial catheter ablation via a pericardial window. All patients had abnormal low voltage areas with fractionated or delayed isolated potentials on the apical epicardium. Most of the ventricular tachycardias were targeted by pace mapping. Sites with a good pace match or abnormal electrograms were ablated using an irrigated radiofrequency ablation catheter. A microscopic pathological evaluation of the resected tissue from 2 of the open-heart ablation patients revealed dense fibrosis on the epicardium compared with the endocardium, supporting the feasibility of an epicardial ablation for the ventricular tachycardia. CONCLUSIONS: Epicardial catheter ablation of ventricular tachycardia is a potentially useful therapy in patients who have mechanical aortic and mitral valves.

Association of intramural fat deposition in the interatrial septum with focal atrial tachyarrhythmias originating near the atrioventricular node.

We describe a case with three focal atrial tachycardias (ATs) and focal atrial fibrillation (AF) originating from the interatrial septum (IAS) near the atrioventricular node (AVN). Contrast-enhanced computed tomography demonstrated the association of fat deposition within the anterior IAS near the AVN with successful ablation sites of these ATs and AF. This is the first report that the intramural fat deposition in the IAS could be associated with the formation of AT and AF re-entry circuits originating near the AVN.