Unrecognized venous injuries after cardiac implantable electronic device transvenous lead extraction.

BACKGROUND: The major complication rate of transvenous lead extraction (TLE) is estimated to be 1%-2%. Laceration of the central veins can be fatal. OBJECTIVES: To define the incidence and extent of venous injuries on a microscopic level after TLE and compare these data with those of clinically documented events of venous laceration. METHODS: We studied all patients who underwent TLE at our tertiary center within 30 months via a variety of techniques. Extracted leads and tissue around them were fixed in formalin. Pathologic examination was standardized to examine the leads identifying the areas covered by tissue cuffs along the length of the lead. The cuffs were removed and sectioned transversely to their longitudinal axis. Microscopic examination was performed using hematoxylin and eosin stains and Movat stains to identify the presence of vein tissue. RESULTS: In all, 861 leads (585 pacemaker and 272 defibrillator leads) were extracted from 461 patients (median age 63 years, standard deviation 15 years), with an average of 1.9 leads per patient and a median lead age of 2546 days. On microscopic review, 80 leads (9.3%) in 72 of 461 patients (15.6%) showed segments of vein, most of which were transmural (venous tissue including adventitia). Despite this finding, only 5 catastrophic complications (1.1%) occurred that required emergent surgical intervention. Risk factors for venous injury included implantable cardioverter defibrillator lead, age of lead, and the use of laser sheath. CONCLUSIONS: Microscopic venous injuries during lead extraction are common but often not recognized clinically.

Factors impacting complication rates for catheter ablation of atrial fibrillation from 2003 to 2015.

Aims: Complications from catheter ablation for atrial fibrillation (AF) are well described. Changing aspects of AF ablation including patient populations referred, institutional experience, and emerging catheter and pharmacological options may impact complication rates. We assessed procedural complication trends in AF ablation patients from 2003­2015 to identify what factors affect adverse event rates. Methods and Results: We evaluated consecutively enrolled patients undergoing initial AF ablation from 2003 through 2015. Statistical analyses were performed to identify predictors of increased risk for major complications, which were defined as death, stroke, atrio-oesophageal fistula, phrenic nerve injury, cardiovascular events requiring blood transfusions or procedural interventions, or non-cardiovascular events requiring intervention. A total of 1475 patients (mean age 59.5 ± 10.5, 82% male) were evaluated. Major complications occurred in 3.9% (n = 58) of cases, including vascular access-site haematoma (1.3%), cardiac tamponade (1.1%), and cerebrovascular accident (CVA) (0.9%). Univariate analysis revealed increased risk of complications associated with hypertension (P = 0.048), CHA2DS2VASc score ≥1 (P = 0.015), and early institutional experience (P = 0.003). Populations with higher CHA2DS2VASc scores underwent AF ablation more frequently over time (P < 0.001). Novel catheters and anticoagulants did not appreciably affect complication rates. Multivariate analysis adjusting for hypertension, CHA2DS2VASc score, and institutional experience showed that higher CHA2DS2VASc score and early institutional experience were independent predictors of adverse events. Conclusion: Patient characteristics reflected in CHA2DS2VASc scoring and early institutional experience predict increased complication rates following AF ablation. Despite more patients with higher CHA2DS2VASc scores undergoing AF ablation, complication rates fell over time as institutional experience increased.

Left Atrial LGE and Arrhythmia Recurrence Following Pulmonary Vein Isolation for Paroxysmal and Persistent AF.

OBJECTIVES: The aims of this study were to: 1) use a novel method of late gadolinium enhancement (LGE) quantification that uses normalized intensity measures to confirm the association between LGE extent and atrial fibrillation (AF) recurrence following ablation; and 2) examine the presence of interaction and effect modification between LGE and AF persistence. BACKGROUND: Recurrent AF after catheter ablation has been reported to associate with the baseline extent of left atrial LGE on cardiac magnetic resonance. Traditional methods for measurement of intensity lack an objective threshold for quantification and interpatient comparisons of LGE. METHODS: The cohort included 165 participants (mean age 60.0 ± 10.2 years, 77% men, 57% with persistent AF) who underwent initial AF ablation. The association of baseline LGE extent with AF recurrence was examined using multivariable Cox proportional hazards models. Multiplicative and additive interactions between AF type and LGE extent were examined. RESULTS: During 10.2 ± 5.7 months of follow-up, 63 patients (38.2%) experienced AF recurrence. Baseline LGE extent was independently associated with AF recurrence after adjusting for confounders (hazard ratio: 1.5 per 10% increased LGE; p < 0.001). The hazard ratio for AF recurrence progressively increased as a function of LGE. The magnitude of association between LGE >35% and AF recurrence was greater among patients with persistent AF (hazard ratio: 6.5 [p = 0.001] vs. 3.6 [p = 0.001]); however, there was no evidence for statistical interaction. CONCLUSIONS: Regardless of AF persistence at baseline, participants with LGE ≤35% have favorable outcomes, whereas those with LGE >35% have a higher rate of AF recurrence in the first year after ablation. These findings suggest a role for: 1) patient selection for AF ablation using LGE extent; and 2) substrate modification in addition to pulmonary vein isolation in patients with LGE extent exceeding 35% of left atrial myocardium.

Association of left atrial function with incident atypical atrial flutter after atrial fibrillation ablation.

BACKGROUND: Symptomatic left atrial (LA) flutter (LAFL) is common after atrial fibrillation (AF) ablation. OBJECTIVE: The purpose of this study was to examine the association of baseline LA function with incident LAFL after AF ablation. METHODS: The source cohort included 216 patients with cardiac magnetic resonance (CMR) before initial AF ablation between 2010 and 2013. Patients who underwent cryoballoon or laser ablation, patients with AF during CMR, and those with suboptimal CMR, or missing follow-up data were excluded. Baseline LA volume and function were assessed by feature-tracking CMR analysis. RESULTS: The final cohort included 119 patients (mean age 58.9 ± 11 years; 76.5% men; 70.6% patients with paroxysmal AF). During a median follow-up of 421 days (interquartile range 235-751 days), 22 patients (18.5%) had incident LAFL. Baseline LA volume was similar between the 2 groups. In contrast, baseline reservoir, conduit, and contractile function of the LA were significantly impaired in patients with incident LAFL. Baseline global peak longitudinal atrial strain (PLAS) <22.65% predicted incident LAFL with 86% sensitivity and 68% specificity (C statistic 0.76). In a multivariable model adjusting for age, heart failure, and LA volume, PLAS (hazard ratio 0.9 per % increase in PLAS; P = .003) and LA linear lesions (hazard ratio 2.94; P = .020) were independently associated with incident LAFL. The coexistence of PLAS <22.65% and linear lesions was associated with 9-fold increased hazard of incident LAFL. CONCLUSION: Baseline LA function and linear lesions were independently associated with incident LAFL after AF ablation. Linear lesions should be limited to selected cases, especially in patients with impaired LA function.

Phrenic nerve injury: An underrecognized and potentially preventable complication of pulmonary vein isolation using a wide-area circumferential ablation approach.

INTRODUCTION: Phrenic nerve injury (PNI) is a well-known, although uncommon, complication of pulmonary vein isolation (PVI) using radiofrequency energy. Currently, there is no consensus about how to avoid or minimize this injury. The purpose of this study was to determine how often the phrenic nerve, as identified using a high-output pacing, lies along the ablation trajectory of a wide-area circumferential lesion set. We also sought to determine if PVI can be achieved without phrenic nerve injury by modifying the ablation lesion set so as to avoid those areas where phrenic nerve capture (PNC) is observed. METHODS AND RESULTS: We prospectively enrolled 100 consecutive patients (age 61.7 ± 9.2 years old, 75 men) who underwent RF PVI using a wide-area circumferential ablation approach. A high-output (20 mA at 2 milliseconds) endocardial pacing protocol was performed around the right pulmonary veins and the carina where a usual ablation lesion set would be made. A total of 30% of patients had PNC and required modification of ablation lines. In the group of patients with PNC, the carina was the most common site of capture (85%) followed by anterior right superior pulmonary vein (RSPV) (70%) and anterior right inferior pulmonary vein (RIPV) (30%). A total of 25% of PNC group had capture in all 3 (RSPV, RIPV, and carina) regions. There was no difference in the clinical characteristics between the groups with and without PNC. RF PVI caused no PNI in either group. CONCLUSION: High output pacing around the right pulmonary veins and the carina reveals that the phrenic nerve lies along a wide-area circumferential ablation trajectory in 30% of patients. Modification of ablation lines to avoid these sites may prevent phrenic nerve injury during RF PVI.