Hybrid venous recanalization and cardiac implantable electronic device lead revision procedures: A single-center retrospective analysis of 38 patients.

PURPOSE: The purpose of this study was to describe the safety and efficacy of hybrid recanalization procedures in a series of patients with obstructed central veins requiring cardiac implantable electronic device (CIED) revision. METHODS: Between 2008 and 2016, 38 consecutive patients (24 M; age 60.5 ±â€¯16.2 years; range 25-87 years) with central venous obstruction underwent 42 recanalization interventions performed in conjunction with CIED revision or extraction. Fifty percent of patients (19/38) presented with veno-occlusive symptoms, and 13% (5/38) of patients had CIED leads with an ipsilateral upper extremity dialysis conduit. RESULTS: Ninety-one percent (38/42) of all procedures resulted in successful recanalization and CIED revision. Twenty-four percent (9/38) of all patients required secondary procedures due to recurrent stenosis, and 78% (7/9) of those requiring secondary procedures had indwelling dialysis conduits and/or clinical symptoms related to venous occlusion before the initial procedure. There were complications in 2 patients related to recanalization, and in 3 related to CIED revision. CONCLUSIONS: Recanalization of central venous stenosis/occlusion in patients with CIED can be technically challenging but is successful in most patients. Symptomatic patients and those with dialysis conduits often require more aggressive revascularization interventions and may be at increased risk of complication or need for secondary interventions.

Long-Term Evaluation of Biotronik Linox and Linox(smart) Implantable Cardioverter Defibrillator Leads.

INTRODUCTION: Expert consensus holds that post-market, systematic surveillance of ICD leads is essential to ensure confirmation of adequate lead performance. GALAXY (NCT00836589) and CELESTIAL (NCT00810264) are ongoing multicenter, prospective, non-randomized registries conducted to confirm the long-term safety and reliability of Biotronik leads. METHODS AND RESULTS: ICD and CRT-D patients are followed for Linox and Linox(smart) ICD lead performance and safety for 5 years post-implant. All procedural and system-related adverse events (AEs) were assessed at each follow-up, along with lead electrical parameters. An independent CEC of EPs adjudicated AEs to determine AE category and lead relatedness. The analysis used categories of lead observations per ISO 5841-2 (Third edition). A total of 3,933 leads were implanted in 3,840 patients (73.0% male, mean age 67.0 ± 12.2 years) at 146 US centers. The estimated cumulative survival probability was 96.3% at 5 years after implant for Linox leads and 96.6% at 4 years after implant for Linox(smart) leads. A comparison of the Linox and Linox(smart) survival functions did not find evidence of a difference (P = 0.2155). The most common AEs were oversensing (23, 0.58%), conductor fracture (14, 0.36%), failure to capture (13, 0.33%), lead dislodgement (12, 0.31%), insulation breach (10, 0.25%), and abnormal pacing impedance (8, 0.20%). CONCLUSIONS: Linox and Linox(smart) ICD leads are safe, reliable and infrequently associated with lead-related AEs. Additionally, estimated cumulative survival probability is clinically acceptable and well within industry standards. Ongoing data collection will confirm the longer-term safety and performance of the Linox family of ICD leads.

Ampere Hour as a Predictor of Cardiac Resynchronization Defibrillator Pulse Generator Battery Longevity: A Multicenter Study.

BACKGROUND: Cardiac resynchronization defibrillator (CRT-D) devices improve survival for New York Heart Association classes II-IV systolic heart failure patients with QRS > 120 ms and left ventricular ejection fraction < 35%. A limitation of 100% CRT pacing is excess battery depletion and pulse generator (PG) replacement compared to VVI or dual-chamber systems. Ampere hour (Ah) measures PG battery capacity and may predict CRT-D device longevity. METHODS: We performed a multicenter retrospective study of all CRT-D devices implanted at our centers from August 1, 2008 to December 31, 2010. Analysis was performed for survival to elective replacement indicator (ERI) between 1.0 Ah, 1.4 Ah, and 2.0 Ah devices, per manufacturers' specifications. RESULTS: One thousand three hundred and two patients were studied through December 31, 2014. Patients were followed for an average of 3.0 ± 1.3 years (794 1.0 Ah, 322 2.0 Ah, and 186 1.4 Ah devices under study). CRT-D generator ERI occurred in 13.5% of 1.0 Ah systems (107 out of 794), versus 3.8% in 1.4 Ah (seven out of 186), and 0.3% in 2.0 Ah devices (one out of 322) over mean follow-up of 3.0 years. Odds ratio (OR) for reaching ERI with 1.0 Ah device versus 1.4 Ah or 2.0 Ah was 9.73, P < 0.0001. Univariate predictors for ERI included 1.0 Ah device and LV pacing output >3V @ 1 ms (OR: 3.74, P < 0.001). LV impedance >1,000 ohms predicted improved device survival (OR: 0.38, P = 0.0025). CONCLUSIONS: CRT-D battery capacity measured by Ah is a strong predictor of survival to ERI for modern systems. Further study on cost and morbidity associated with early PG change in 1.0 Ah systems is warranted.

Value of Cardiac Magnetic Resonance Imaging in Patients With Failed Ablation Procedures for Ventricular Tachycardia.

BACKGROUND: Ventricular tachycardia (VT) in patients with cardiomyopathy originates in scar tissue. Intramural or epicardial scar may result in ineffective ablation if mapping and ablation are limited to the endocardium. The purpose of this study was to investigate whether preprocedural magnetic resonance imaging (MRI) is beneficial in patients with failed endocardial VT ablations in determining an appropriate ablation strategy. METHODS AND RESULTS: A cardiac MRI was performed in 20 patients with a failed ablation procedure and cardiomyopathy (nonischemic n = 12, ischemic n = 8). A subsequent ablation strategy was determined by a delayed enhanced MRI (DE-MRI) and an epicardial subxyphoid access was planned only in patients with epicardial or intramural free-wall scar. MRIs were performed in all patients with or without an implanted cardioverter defibrillator (ICD). The location of scar tissue in the MRI predicted the origin of VT in all patients. In 9/20 patients an epicardial procedure was performed based on the result of the MRI. An endocardial procedure was performed in the remaining 11 patients who had either endocardial or septal scarring and one patient in whom the MRI only showed artifact. Five patients remained inducible postablation and four patients had VT recurrence within a follow-up period of 17 ± 22 months. All of the latter patients had an intramural scar pattern. CONCLUSIONS: Imaging with DE-MRI prior to VT ablation in patients with previously failed endocardial ablation procedures is beneficial in identifying an ablation strategy, helps to focus on an area of interest intraprocedurally, and provides valuable outcomes information.

Percutaneous Extraction of Embolized Intracardiac Inferior Vena Cava Filter Struts Using Fused Intracardiac Ultrasound and Electroanatomic Mapping.

This report describes the percutaneous extraction of embolized intracardiac inferior vena cava (IVC) filter struts using fluoroscopy and fused intracardiac echocardiography and three-dimensional electroanatomic mapping. Six patients with indwelling IVC filters placed at outside institutions 5 months to 14 years previously presented with cross-sectional imaging of the chest demonstrating fractured IVC filter struts embolized to the myocardial free wall (four patients) or interventricular septum (two patients). All embolized filter struts were successfully retrieved, and open heart surgery was avoided.

Occult obstructive sleep apnea and clinical outcomes of radiofrequency catheter ablation in patients with atrial fibrillation.

BACKGROUND: Recurrent atrial fibrillation (AF) after successful cardioversion can be predicted by obstructive sleep apnea (OSA) diagnosed by polysomnography. However, it is not known whether the validated STOP-BANG questionnaire can predict AF recurrence after radiofrequency ablation (RFA). Our objective is to determine the prevalence of unrecognized OSA in patients with AF and its relation to freedom from AF after RFA. METHODS: Validated surveys were administered to 247 consecutive AF patients following radiofrequency ablation from January to October 2011. OSA status was assessed at baseline RFA. Clinical follow up occurred at 3-6 month intervals. RESULTS: OSA had been previously diagnosed in 94/247 (38%). Among 153 patients without prior diagnosis of OSA, 121 (79%) had high risk STOP-BANG scores for OSA. Probability of maintaining sinus rhythm after RFA was similar among patients with known OSA (66/94, 70%) and high risk OSA scores (95/124, 77%) and higher than among patients with low risk OSA scores (29/32, 91%, P=0.03). Among patients without prior OSA, a high risk STOP-BANG score did predict recurrent AF (OR = 3.7, 95 % CI 1.4-11.4, P = 0.0005). Multivariate analysis showed a higher risk of atrial arrhythmia recurrence for non-paroxysmal AF patients (OR = 3.1, ± 95 % CI 1.4-7.1, P = 0.005). CONCLUSIONS: The majority of AF patients undergoing RFA have high risk OSA scores, suggesting that OSA is vastly underdiagnosed in this population. STOP-BANG independently predicted recurrent AF in patients without a prior diagnosis of OSA.

Recurrence of PVCs in patients with PVC-induced cardiomyopathy.

BACKGROUND: The natural history of premature ventricular complex (PVC)-induced cardiomyopathy is incompletely understood. OBJECTIVE: The purpose of this study was to assess long term follow-up data in patients who underwent successful PVC ablation for PVC-induced cardiomyopathy. METHODS: The subjects of this study were 60 patients (17 women; mean age 52.5 ± 16.8 years; ejection fraction [EF] 37.3 ± 8.5%, median 40%, interquartile range [IQR] 15) with PVC-induced cardiomyopathy who underwent successful ablation of their predominant PVCs between 2005 and 2012. Patients were followed up for a mean of 23.6 ± 17.2 months. EF improved to 57.2 ± 4.7% (median 55%, IQR 5; P = .0001) within 9.6 ± 8.4 months of the ablation procedure. During follow-up, 10 of 60 patients (16.7%) had recurrent frequent PVCs and 50 patients (83.3%) did not. Patients underwent repeat assessment of EF and PVC burden. RESULTS: During follow-up of 23.6 ± 17.2 months, 10 patients had recurrent frequent PVCs, with an increase of their PVC burden from 1.4 ± 0.9% (median 1.05%, IQR 1.59) after the initial ablation to 27.2 ± 8.8% (median 26.0%, IQR 18.2; P = .018). Their EF decreased from 55.7 ± 3.4% (median 55%, IQR 5.8) after the initial ablation to 40.2 ± 5.1% (median 40%, IQR 15; P = .005). In the remaining patients with PVC-induced cardiomyopathy, EF and PVC burden remained unchanged during follow-up. Patients with PVC recurrence had a higher number of pleomorphic PVC morphologies during initial presentation (4.7 ± 2.2 vs 2.5 ± 2.8, P = .002). CONCLUSION: Recurrence of frequent PVCs in patients with a history of PVC cardiomyopathy can result in recurrence of cardiomyopathy. Follow-up in patients with PVC-induced cardiomyopathy is important, especially if patients were asymptomatic from the PVCs and have pleomorphic PVCs.

Effect of ablation of frequent premature ventricular complexes on left ventricular function in patients with nonischemic cardiomyopathy.

BACKGROUND: Frequent idiopathic premature ventricular complexes (PVCs) can result in PVC-induced cardiomyopathy. Frequent PVCs can also aggravate ischemic cardiomyopathy. OBJECTIVE: The purpose of this study was to investigate the impact of frequent PVCs on nonischemic cardiomyopathy. METHODS: This was a consecutive series of 30 patients (mean age 59.1 ± 12.1; 18 men; mean ejection fraction [EF] 38% ± 15%) with structurally abnormal hearts based on the presence of scar on cardiac magnetic resonance imaging and/or a history of cardiomyopathy before the presence of frequent PVCs who were referred for ablation of frequent PVCs. RESULTS: Ablation was successful in 18 of 30 patients (60%), resulting in an increase of mean EF from 33.9% ± 14.5% to 45.7% ± 17% (P < .0001) during mean follow-up of 30 ± 28 months. The PVC burden in these patients was reduced from 23.1% ± 8.8% to 1.0% ± 0.9% (P < .0001). Mean EF did not change in patients with a failed ablation procedure (44.4 ± 16 vs 43.5 ± 21, P = .85). The PVC site of origin was in scar tissue in 14 of 18 patients with a successful ablation procedure. Mean New York Heart Association functional class improved from 2.3 ± 0.6 to 1.1 ± 0.2 (P < .0001) in patients with a successful outcome and remained unchanged in patients with an unsuccessful outcome (1.9 ± 0.9 vs 1.9 ± 0.7, P = 1). CONCLUSION: In patients with frequent PVCs and nonischemic cardiomyopathy, EF and functional class can be improved but not always normalized by successful PVC ablation. In most patients with an effective ablation, the arrhythmogenic substrate was located in scar tissue.

Mortality and cerebrovascular events after radiofrequency catheter ablation of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with a significant increase in the risk of stroke and mortality. It is unclear whether maintaining sinus rhythm (SR) after radiofrequency ablation (RFA) is associated with an improvement in stroke risk and survival. OBJECTIVE: The purpose of this study was to determine whether SR after RFA of AF is associated with an improvement in the risk of cerebrovascular events (CVEs) and mortality during an extended 10-year follow-up. METHODS: RFA was performed in 3058 patients (age 58 ± 10 years) with paroxysmal (n = 1888) or persistent AF (n = 1170). The effects of time-dependent rhythm status on CVEs and cardiac and all-cause mortality were assessed using multivariable Cox models adjusted for baseline and time-dependent variables during 11,347 patient-years of follow-up. RESULTS: Independent predictors of a higher arrhythmia burden after RFA were age (estimated beta coefficient [ß] = 0.017 per 10 years, 95% confidence interval [CI] 0.006-0.029, P = .003), left atrial (LA) diameter (ß = 0.044 per 5-mm increase in LA diameter, 95% CI 0.034-0.055, P <.0001), and persistent AF (ß = 0.174, 95% CI 0.147-0.201, P <.0001). CVEs and cardiac and all-cause mortality occurred in 71 (2.3%), 33 (1.1%), and 111 (3.6%), respectively. SR after RFA was associated with a significantly lower risk of cardiac mortality (hazard ratio [HR] 0.41, 95% CI 0.20-0.84, P = .015). There was not a significant reduction in all-cause mortality (HR 0.86, 95% CI 0.58-1.29, P = .48) or CVEs (HR 0.79, 95% CI 0.48-1.29, P = .34) in patients who remained in SR after RFA. CONCLUSION: Maintenance of SR after RFA is associated with a reduction in cardiovascular mortality in patients with AF.

Predictors of outcome after catheter ablation of premature ventricular complexes.

BACKGROUND: The purpose of this study was to assess how well acute procedural outcomes predict the clinical outcome of catheter ablation of premature ventricular complexes (PVCs). METHODS: A consecutive series of 50 patients (28 women, age: 51 ± 13 years) with frequent PVCs was referred for PVC ablation. Acute failure was defined as inability to eliminate the predominant PVC or recurrence of the predominant PVC within 12 hours. The PVC burden was reassessed 3 months after the ablation procedure. A successful procedure was defined as reduction of the PVC burden at 3 months by ≥80% of the initial burden. RESULTS: The procedure was acutely effective in 37 patients (74%) and at 3 months in 40 patients (80%). The presence or absence of the predominant PVC in the 12 hours postablation had the highest accuracy for outcome at 3 months (accuracy: 90%). From among the 13/50 patients (26%) with evidence of acute failure, 4 had a PVC reduction of ≥80% at 3 months and 10 had a PVC reduction of >50% resulting in symptomatic improvement at 3 months. CONCLUSION: The presence or absence of the predominant PVC within 12 hours postablation best correlated with the 3-month-efficacy data. Recurrence of the predominant PVC shortly after ablation did not indicate a procedural failure and the necessity for a repeat procedure. The majority of these patients had a significant, clinically meaningful reduction in their PVC burden. Acute predictors for procedural outcome at 3 months have a high positive but rather low negative predictive value.

Characteristics of intramural scar in patients with nonischemic cardiomyopathy and relation to intramural ventricular arrhythmias.

BACKGROUND: Ventricular arrhythmias have been described to originate from intramural locations. Intramural scar can be assessed by delayed-enhanced MRI, but MRIs cannot be performed on every patient. The objective of this study was to assess the value of voltage mapping to detect MRI-defined intramural scar and to correlate the scar with ventricular arrhythmias. METHODS AND RESULTS: In 15 consecutive patients (3 women; age 55±16 years; ejection fraction, 49±13%) with structural heart disease, intramural scar was detected by delayed-enhanced MRI. All patients underwent endocardial unipolar and bipolar voltage mapping guided by the registered intramural scar. Scar volume by MRI was 11.7±8 cm3 with a scar thickness of 4.6±0.7 mm and a preserved endocardial/epicardial rim of 3.3±1.6 and 4.8±2.6 mm, respectively. Endocardial bipolar voltage was 1.6±1.73 mV at the scar, 2.12±2.15 mV in a 1 cm perimeter around the scar, and 2.83±3.39 mV in remote myocardium without scar. The corresponding unipolar voltage was 4.94±3.25, 6.59±3.81, and 8.32±3.39 mV, respectively (P<0.0001). Using receiver-operator characteristic curves, a unipolar cut-off value of 6.78 mV (area under the curve, 0.78) and a bipolar cut-off value of 1.55 mV (area under the curve, 0.69) best separated endocardial measurements overlying scar as compared with areas not overlying a scar. At least 1 intramural ventricular arrhythmia was eliminated in all but 2 patients in this series. CONCLUSIONS: Intramural scar can be detected by unipolar and bipolar voltage, unipolar voltage being more useful. Mapping and ablation of intramural arrhythmias originating from an intramural focus can be accomplished.

Reasons for failed ablation for idiopathic right ventricular outflow tract-like ventricular arrhythmias.

BACKGROUND: The right ventricular outflow tract (RVOT) is the most common site of origin of ventricular arrhythmias (VAs) in patients with idiopathic VAs. A left bundle branch block, inferior axis morphology arrhythmia is the hallmark of RVOT arrhythmias. VAs from other sites of origin can mimic RVOT VAs, and ablation in the RVOT typically fails for these VAs. OBJECTIVE: To analyze reasons for failed ablations of RVOT-like VAs. METHODS: Among a consecutive series of 197 patients with an RVOT-like electrocardiographic (ECG) morphology who were referred for ablation, 38 patients (13 men; age 46 ± 14 years; left ventricular ejection fraction 47% ± 14%) in whom a prior procedure failed within the RVOT underwent a second ablation procedure. ECG characteristics of the VA were compared to a consecutive series of 50 patients with RVOT VAs. RESULTS: The origin of the VA was identified in 95% of the patients. In 28 of 38 (74%) patients, the arrhythmia origin was not in the RVOT. The VA originated from intramural sites (n = 8, 21%), the pulmonary arteries (n = 7, 18%), the aortic cusps (n = 6, 16%), and the epicardium (n = 5, 13%). The origin was within the RVOT in 10 (26%) patients. In 2 (5%) patients, the origin could not be identified despite biventricular, aortic, and epicardial mapping. The VA was eliminated in 34 of 38 (89%) patients with repeat procedures. The ECG features of patients with failed RVOT-like arrhythmias were different from the characteristics of RVOT arrhythmias. CONCLUSIONS: In patients in whom ablation of a VA with an RVOT-like appearance fails, mapping of the pulmonary artery, the aortic cusps, the epicardium, the left ventricular outflow tract, and the aortic cusps will help identify the correct site of origin. The 12-lead ECG is helpful in differentiating these VAs from RVOT VAs.

The optimal range of international normalized ratio for radiofrequency catheter ablation of atrial fibrillation during therapeutic anticoagulation with warfarin.

BACKGROUND: Uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation is associated with a lower risk of periprocedural complications than when warfarin is temporarily discontinued. However, the optimal international normalized ratio (INR) levels during RFA have not been defined. METHODS AND RESULTS: In this retrospective analysis, RFA was performed in 1133 consecutive patients (mean age, 61±10 years) with paroxysmal (550) or persistent atrial fibrillation (583). Patients were grouped based on the INR on the day of RFA. There was a quadratic relationship between the INR and bleeding and vascular complications (P<0.001). Complications were less prevalent when INR was ≥2.0 and ≤3.0 (5% [31/572]) than when INR was <2.0 (10% [49/485]; P=0.004) and >3.0 (12% [9/76]; P=0.03). The prevalence of pericardial tamponade (1%) was similar at all INRs. From the quadratic model, the optimal range of INR was calculated as 2.1 to 2.5. INRs<2.0 and >3.0 were associated with a >2-fold increase in complications, with a further steep rise beyond an INR>3.5. Concomitant clopidogrel use was associated with a significant increase in complications at all INRs (odds ratio=3.1; ±95% confidence interval, 1.4-7.4). Unfractionated heparin requirements to maintain a therapeutic activated clotting time during RFA was reduced by 50% in patients with an INR>2.0. CONCLUSIONS: The optimal INR range during uninterrupted periprocedural anticoagulation using warfarin is narrow. Therefore, INR levels should be carefully monitored in preparation for RFA of atrial fibrillation.

Endocardial ablation of postinfarction ventricular tachycardia with nonendocardial exit sites.

BACKGROUND: Most infarct-related ventricular tachycardias (VTs) have an exit site that can be targeted by endocardial ablation. However, some VT reentry circuits have an exit site that is intramural or epicardial. Even these circuits may have an endocardial component that can be endocardially ablated. OBJECTIVE: To assess the prevalence of postinfarction VTs with a nonendocardial exit site that can be successfully eliminated by endocardial ablation. METHODS: Twenty-eight consecutive patients with postinfarction VT (27 men, age 69 ± 8 years, ejection fraction 0.25% ± 0.15%) were referred for VT ablation. A total of 213 VTs were inducible (cycle length 378 ± 100 ms). Pace mapping was performed throughout the scar, and critical sites were identified for 137 VTs (64.5%). Critical sites identified by entrainment mapping and/or pace mapping were divided into exit and nonexit sites depending on the stimulus-QRS/VT cycle length ratio (S-QRS/VT CL ≤ 0.3 vs>0.3). RESULTS: Endocardial exit sites (S-QRS/VTCL ≤ 0.3) were identified for 100 of 137 VTs. Only critical nonexit sites were identified for 37 of 137 (27%) VTs. Nonexit sites were confined to a smaller area within the endocardium (1.81 ± 1.7 cm(2)) and were located within dense scar (0.28 ± 0.24 mV) further away from the border zone (2.05 ± 2.79 cm) than did the VT exit sites. Exit sites had a larger area of matching pace maps (3.86 ± 1.9 cm(2); P<.01) and were at a closer distance to the border zone (0.93 ± 1.06 cm; P<.01). A total of 133 of 137 VTs were ablated. The success rate was similar for VTs in which exit sites were targeted (n = 90 of 100) and VTs in which only nonexit sites were targeted (n = 36 of 37) (P = .83). CONCLUSIONS: In about one-third of postinfarction VTs for which critical sites were identified, the exit site was not endocardial. Critical nonexit sites that are effective for ablation are often within dense scar at a distance from the border zone and can be missed if only the border zone is targeted.

Characteristics of atrial tachycardia due to small vs large reentrant circuits after ablation of persistent atrial fibrillation.

BACKGROUND: While macroreentrant atrial tachycardias (ATs) have been reasonably well described, little is known about small reentrant circuits. OBJECTIVE: To compare characteristics of large and small reentrant circuits after ablation of persistent atrial fibrillation. METHODS: Seventy-seven patients (age 61±10 years; left atrium 46±6 mm; ejection fraction 0.52±0.13) underwent a procedure for postablation AT. The p-wave duration, circuit size, electrogram characteristics, and conduction velocity were determined. RESULTS: AT was due to macroreentry in 62 (80%) patients, a small reentrant circuit in 13 (17%), and a focal mechanism in 2 (3%). The p-wave duration during small reentrant ATs was shorter than that during macroreentry (174±12 ms vs 226±22 ms; P<.0001). The duration of fractionated electrograms at the critical site was longer in small vs large circuits (167±43 ms vs 98±38 ms, respectively; P<.0001) and accounted for a greater percentage of the tachycardia cycle length (59%±18% vs 38%±14%, respectively; P<.0001). The mean diameters of macroreentrant and small reentrant circuits were 44±7 and 26±11 mm, respectively (P<.0001). The mean conduction velocity along the small circuits was lower (0.5±0.2 m/s vs 1.2±0.3 m/s; P<.0001). Catheter ablation eliminated the AT in all 77 patients. CONCLUSIONS: AT due to a small reentrant circuit after ablation of atrial fibrillation may be distinguished from macroreentry by a shorter p-wave duration and the presence of long-duration electrograms at the critical site owing to extremely slow conduction. These features may aid the clinician in the mapping of postablation ATs.

Reasons for recurrent ventricular tachycardia after catheter ablation of post-infarction ventricular tachycardia.

OBJECTIVES: The purpose of this study was to assess the determinants of ventricular tachycardia (VT) recurrence in patients who underwent VT ablation for post-infarction VT. BACKGROUND: The factors that predict recurrence of VT after catheter ablation in patients with prior infarctions are not well described. METHODS: Catheter ablation was performed in 98 consecutive patients (88 males [90%]; mean age 67 ± 10 years; ejection fraction 27 ± 13%) with post-infarction VT. Electrograms from the implantable cardioverter-defibrillator were analyzed, and VTs were classified as clinical, nonclinical, or new clinical. RESULTS: A total of 725 VTs were induced during the ablation procedure. All VTs were targeted. In 76 patients, 105 clinical VTs were inducible. Critical sites were identified with entrainment mapping and pace-mapping (≥10 of 12 matching leads) for 75 of 105 clinical VTs (71%) and for 278 of 620 nonclinical VTs (45%). Post-ablation, the clinical VT was not inducible in any patient, and all VTs were rendered noninducible in 63% of the patients. Over a mean follow-up period of 35 ± 23 months, 65 of 98 patients (66%) had no recurrent VTs and 33 (34%) had VT recurrence. A new VT occurred in 26 of 33 patients (79%), and a prior clinical VT recurred in 7 patients (21%). Patients with recurrent VT had a larger scar area as assessed by electroanatomic mapping compared with patients without recurrent VTs (93 ± 40 cm(2) vs. 69 ± 30 cm(2); p = 0.002). In patients with repeat procedures, the majority of inducible VTs for which a critical area could be identified were at a distance of 6 ± 3 mm to the prior ablation lesions. CONCLUSIONS: Patients with recurrent VTs have a larger scar as assessed by electroanatomic mapping. Most recurrent VTs were new, and the majority of these VTs were mapped to the vicinity of prior ablation lesions in patients with repeat procedures.

Recovery from left ventricular dysfunction after ablation of frequent premature ventricular complexes.

BACKGROUND: Patients with frequent premature ventricular complexes (PVCs) and PVC-induced cardiomyopathy usually have recovery of left ventricular (LV) dysfunction postablation. The time course of recovery of LV function has not been described. OBJECTIVE: To describe the time course and predictors of recovery from LV dysfunction after effective ablation of PVCs in patients with PVC-induced cardiomyopathy. METHODS: In a consecutive series of 264 patients with frequent idiopathic PVCs referred for PVC ablation, LV dysfunction was present in 87 patients (mean ejection fraction 40%±10%). The PVC burden was reduced to<20% of the initial PVC burden in 75 patients. In these patients, echocardiography was repeated 3-4 months postablation. If LV function did not normalize after 3-4 months, a repeat echocardiogram was performed every 3 months until there was normalization or stabilization of LV function. RESULTS: The ejection fraction normalized at a mean of 5±6 months postablation. The majority of patients (51 of 75, 68%) with PVC-induced LV dysfunction had a recovery of LV function within 4 months. In 24 (32%) patients, recovery of LV function took more than 4 months (mean 12±9 months; range 5-45 months). An epicardial origin of PVCs was more often present (13 of 24, 54%) in patients with delayed recovery of LV function than in patients with early recovery of LV function (2 of 51, 4%; P<.0001). The PVC-QRS width was significantly longer in patients with delayed recovery than in patients with recovery within 4 months (170±21 ms vs 159±16 ms; P = .02). In multivariate analysis, only an epicardial PVC origin was predictive of delayed recovery of LV function in patients with PVC-induced cardiomyopathy. CONCLUSIONS: PVC-induced cardiomyopathy resolves within 4 months of successful ablation in most patients. In about one-third of the patients, recovery is delayed and can take up to 45 months. An epicardial origin predicts delayed recovery of LV function.

Dabigatran vs warfarin for radiofrequency catheter ablation of atrial fibrillation.

BACKGROUND: It is not clear whether dabigatran is as safe and effective as uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). OBJECTIVE: To compare the safety and efficacy of dabigatran by using a novel administration protocol and uninterrupted anticoagulation with warfarin for periprocedural anticoagulation in patients undergoing RFA of AF. METHODS: In this case-control analysis, 763 consecutive patients (mean age 61±10 years) underwent RFA of AF using dabigatran (N = 191) or uninterrupted warfarin (N = 572) for periprocedural anticoagulation. In all patients, anticoagulation was started≥4 weeks before RFA. Dabigatran was held after the morning dose on the day before the procedure and resumed 4 hours after vascular hemostasis was achieved. RESULTS: A transesophageal echocardiogram performed in all patients receiving dabigatran did not demonstrate an intracardiac thrombus. There were no thromboembolic complications in either group. The prevalence of major (4 of 191, 2.1%) and minor (5 of 191, 2.6%) bleeding complications in the dabigatran group were similar to those in the warfarin group (12 of 572, 2.1%; P = 1.0 and 19 of 572, 3.3%; P = .8, respectively). Pericardial tamponade occurred in 2 of 191 (1%) patients in the dabigatran group and in 7 of 572 (1.2%) patients in the warfarin group (P = 1.0). All patients who had a pericardial tamponade, including 2 in the dabigatran group, had uneventful recovery after perdicardiocentesis. On multivariate analysis, international normalized ratio (odds ratio [OR] 4.0; 95% confidence interval [CI] 1.1-15.0; P = .04), clopidogrel use (OR 4.2; 95% CI 1.5-12.3; P = .01), and CHA2DS2-VASc score (OR 1.4; 95% CI 1.1-1.8; P = .01) were the independent risk factors of bleeding complications only in the warfarin group. CONCLUSIONS: When held for approximately 24 hours before the procedure and resumed 4 hours after vascular hemostasis, dabigatran appears to be as safe and effective as uninterrupted warfarin for periprocedural anticoagulation in patients undergoing RFA of AF.

Effect of radiation therapy on permanent pacemaker and implantable cardioverter-defibrillator function.

BACKGROUND: Radiation therapy's (RT's) effects on cardiac implantable electronic devices (CIEDs) such as implantable cardioverter-defibrillators (ICDs) and pacemakers (PMs) are not well established, leading to device removal or relocation in preparation for RT. OBJECTIVE: To determine the effect of scattered RT on CIED performance. METHODS: We analyzed 69 patients--50 (72%) with PMs and 19 (28%) with ICDs--receiving RT at the University of Michigan. Collected data included device model, anatomic location, and treatment beam energies, treatment type, and estimated dose to the device. Patients were treated with either high-energy (16-MV) and/or low-energy (6 MV) photon beams with or without electron beams (6-16 MeV). The devices were interrogated with pre- and post-RT and/or weekly with either in-treatment or home interrogation, depending on the patient's dependence on the device and the estimated or measured delivered dose. Outcomes analyzed were inappropriate ICD therapies, device malfunctions, or device-related clinical events. RESULTS: The PMs were exposed to 84.4 ± 99.7 cGy of radiation, and the ICDs were exposed to 92.1 ± 72.6 cGy of radiation. Two patients with ICDs experienced a partial reset of the ICD with the loss of historic diagnostic data after receiving 123 and 4 cGy, respectively. No device malfunction or premature battery depletion was observed at 6-month follow-up from RT completion. CONCLUSIONS: CIED malfunction due to indirect RT exposure is uncommon. Regular in-treatment or home interrogation should be done to detect and treat these events and to ensure that diagnostic data are preserved.