Jackson J. Liang

Long-Term Outcome After Catheter Ablation of Ventricular Tachycardia in Patients With Nonischemic Dilated Cardiomyopathy

Background—Catheter ablation (CA) of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy can be challenging because of the complexity of underlying substrates. We sought to determine the long-term outcomes of endocardial and adjuvant epicardial CA in nonischemic dilated cardiomyopathy. Methods and Results—We examined 282 consecutive patients (aged 59±15 years, 80% males) with nonischemic dilated cardiomyopathy who underwent CA. Ablation was guided by activation/entrainment mapping for tolerated VT and pacemapping/targeting of abnormal electrograms for unmappable VT. Adjuvant epicardial ablation was performed for recurrent VT or persistent inducibility after endocardial–only ablation. Epicardial ablation was performed in 90 (32%) patients. Before ablation, patients failed a median of 2 antiarrhythmic drugs), including amiodarone, in 166 (59%) patients. The median follow-up after the last procedure was 48 (19–67) months. Overall, VT-free survival was 69% at 60-month follow-up. Transplant-free survival was 76% and 68% at 60- and 120-month follow-up, respectively. Among the 58 (21%) patients with VT recurrence, CA still resulted in a significant reduction of VT burden, with 31 (53%) patients having only isolated (1–3) VT episodes in 12 (4–35) months after the procedure. At the last follow-up, 128 (45%) patients were only on &bgr;-blockers or no treatment, 41 (15%) were on sotalol or class I antiarrhythmic drugs, and 62 (22%) were on amiodarone. Conclusions—In patients with nonischemic dilated cardiomyopathy and VT, endocardial and adjuvant epicardial CA is effective in achieving long-term VT freedom in 69% of cases, with a substantial improvement in VT burden in many of the remaining patients.

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

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

Pulmonary Vein Antral Isolation and Nonpulmonary Vein Trigger Ablation Are Sufficient to Achieve Favorable Long-Term Outcomes Including Transformation to Paroxysmal Arrhythmias in Patients With Persistent and Long-Standing Persistent Atrial Fibrillation

Background—Transformation from persistent to paroxysmal atrial fibrillation (AF) after ablation suggests modification of the underlying substrate. We examined the nature of initial arrhythmia recurrence in patients with nonparoxysmal AF undergoing antral pulmonary vein isolation and nonpulmonary vein trigger ablation and correlated recurrence type with long-term ablation efficacy after the last procedure. Methods and Results—Three hundred and seventeen consecutive patients with persistent (n=200) and long-standing persistent (n=117) AF undergoing first ablation were included. AF recurrence was defined as early (⩽6 weeks) or late (>6 weeks after ablation) and paroxysmal (either spontaneous conversion or treated with cardioversion ⩽7 days) or persistent (lasting >7 days). During median follow-up of 29.8 (interquartile range: 14.8–49.9) months, 221 patients had ≥1 recurrence. Initial recurrence was paroxysmal in 169 patients (76%) and persistent in 52 patients (24%). Patients experiencing paroxysmal (versus persistent) initial recurrence were more likely to achieve long-term freedom off antiarrhythmic drugs (hazard ratio, 2.2; 95% confidence interval, 1.5–3.2; P<0.0001), freedom on/off antiarrhythmic drugs (hazard ratio, 2.5; 95% confidence interval, 1.6–3.8; P<0.0001), and arrhythmia control (hazard ratio, 5.2; 95% confidence interval, 2.9–9.2; P<0.0001) after last ablation. Conclusions—In patients with persistent and long-standing persistent AF, limited ablation targeting pulmonary veins and documented nonpulmonary vein triggers improves the maintenance of sinus rhythm and reverses disease progression. Transformation to paroxysmal AF after initial ablation may be a step toward long-term freedom from recurrent arrhythmia.

Long-term Outcomes of Ventricular Tachycardia Ablation in Different Types of Structural Heart Disease

Ventricular tachycardia (VT) often occurs in the setting of structural heart disease and can affect patients with ischaemic or nonischaemic cardiomyopathies. Implantable cardioverter-defibrillators (ICDs) provide mortality benefit and are therefore indicated for secondary prevention in patients with sustained VT, but they do not reduce arrhythmia burden. ICD shocks are associated with increased morbidity and mortality, and antiarrhythmic medications are often used to prevent recurrent episodes. Catheter ablation is an effective treatment option for patients with VT in the setting of structural heart disease and, when successful, can reduce the number of ICD shocks. However, whether VT ablation results in a mortality benefit remains unclear. We aim to review the long-term outcomes in patients with different types of structural heart disease treated with VT ablation.

Comparison of Left Atrial Bipolar Voltage and Scar Using Multielectrode Fast Automated Mapping versus Point‐by‐Point Contact Electroanatomic Mapping in Patients With Atrial Fibrillation Undergoing Repeat Ablation

Bipolar voltage criteria to delineate left atrial (LA) scar have been derived using point‐by‐point (PBP) contact electroanatomical mapping. It remains unclear how PBP‐derived LA scar correlates with multielectrode fast automated mapping (ME‐FAM) derived scar. We aimed to correlate scar and bipolar voltages from LA maps created using PBP versus ME‐FAM.

TPMT genetic variants are associated with increased rejection with azathioprine use in heart transplantation.

Objectives Azathioprine (AZA) is an important immunosuppressant drug used in heart transplantation (HTX). Consensus guidelines recommend that patients with thiopurine S-methyltransferase (TPMT) genetic variants be started on lower AZA dose because of higher active metabolite levels and risk of adverse events. However, in-vitro lymphocyte proliferation assays performed in participants with inactive TPMT alleles have suggested that AZA use may result in decreased immunosuppressant efficacy as compared with wild-type (WT) individuals. The objective of this study was therefore to determine the effect of TPMT genetic variation on AZA efficacy or prevention of rejection in HTX recipients treated with AZA. Participants and methods We genotyped 93 HTX recipients treated with AZA and measured erythrocyte TPMT enzyme activity. Acute rejection was monitored by routine endomyocardial biopsies. Results There were 83 WT and 10 heterozygote (HZ) HTX recipients. TPMT activity level was lower in HZ compared with WT (13.1±2.8 vs. 21±4.5 U/ml red blood cell, P<0.001). Despite similar AZA dose, HZ developed severe rejection earlier (P<0.001), and the total rejection score was higher (P=0.02) than WT. AZA was discontinued more frequently in HZ (P=0.01) because of rejection. The incidence of leukopenia was similar between the groups (40 vs. 43%, P=1.0). Conclusion HTX recipients with TPMT genetic variant alleles who are treated with AZA develop acute rejection earlier, more frequently, and of greater severity. These patients, despite having lower TPMT enzymatic activity, should be monitored carefully for possible increased risk of acute rejection.

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

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.

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

Outflow tract ventricular arrhythmias (OT VAs) are common and catheter ablation is an effective treatment option. We sought to investigate the relationship between age‐related anatomic aortic root changes and QRS morphology during left ventricular outflow tract (LVOT) pace‐mapping using cardiac magnetic resonance (CMR) imaging.

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

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.

Postoperative atrial tachycardias after mitral valve surgery: Mechanisms and outcomes of catheter ablation

BACKGROUND Atrial tachycardias (ATs) including atrial fibrillation are common arrhythmias occurring late after mitral valve (MV) surgery, and their management is challenging. OBJECTIVE The purpose of this study was to determine the electrophysiological mechanisms of ATs in patients with prior MV surgery and the long-term outcomes of catheter ablation. METHODS We studied 67 consecutive patients (mean age 59.4 ± 10.6 years; 41 men [61%]) with prior MV surgery who presented with ATs postoperatively between 2007 and 2015. RESULTS AT was clinically documented before the electrophysiology study in 55 patients, whereas in the remaining 12 patients AT was inducible at the study. A total of 99 ATs (35 spontaneous and 64 inducible) were characterized. Overall, the right atrium (RA) was the chamber of origin in 56%. The underlying mechanism was macroreentry in 91 cases and included typical RA flutter (n = 37), mitral annular flutter (n = 21), incisional right AT (n = 16), roof-dependent reentry (n = 12), and local left atrial reentry (n = 5). Eight focal ATs were also documented: 6 from the left atrium and 2 from the RA. Left-sided ATs were more common in patients with prior Maze procedure (53%), and mitral annular flutter was twice as prevalent in this group (42% vs 21%; P = .05). The ablation was acutely successful in 98.5%. Freedom from atrial arrhythmias was 62% at 12 months, with 42% requiring more than 1 procedure. CONCLUSION Macroreentry is the predominant AT mechanism in patients with prior MV surgery. Circuits are most often localized to the RA, with left-sided ATs more common in patients with prior Maze procedure. Repeat procedures are common and outcomes with 1 year complete AT control good.