Thomas Callahan

Radiofrequency ablation of atrial fibrillation under therapeutic international normalized ratio: A safe and efficacious periprocedural anticoagulation strategy

BACKGROUND The best periprocedural anticoagulation strategy at the time of pulmonary vein isolation (PVI) is not known. Most centers stop administering warfarin (Coumadin) and use bridging with heparin or enoxaparin. OBJECTIVE The purpose of this study was to evaluate the efficacy and safety of PVI under therapeutic international normalized ratio (INR). METHODS Between January 2005 and December 2008, PVI was performed in 3,052 patients with therapeutic INR (> or =1.8) at the time of ablation. All patients were evaluated for ischemic strokes and bleeding complications. RESULTS Mean INR was 2.53 +/- 0.62. Only 3 (0.098%) patients had ischemic strokes. One patient had a hemorrhagic stroke on the third day postablation but recovered completely by 1-week follow-up. Bleeding complications occurred in 34 (1.11%) patients; most were minor (0.79%). Major hemorrhagic complications occurred in 10 (0.33%) patients (tamponade in 5, hematomas requiring intervention in 2, transfusion necessary in 3). CONCLUSION In a large patient population, continuation of Coumadin at a therapeutic INR at the time of PVI without use of heparin or enoxaparin for bridging is a safe and efficacious periprocedural anticoagulation strategy. It is an acceptable and potentially better alternative to strategies that use bridging with heparin or enoxaparin.

Use of dabigatran for periprocedural anticoagulation in patients undergoing catheter ablation for atrial fibrillation

Background—Pulmonary vein isolation (PVI) for atrial fibrillation is associated with a transient increased risk of thromboembolic and hemorrhagic events. We hypothesized that dabigatran can be safely used as an alternative to continuous warfarin for the periprocedural anticoagulation in PVI. Methods and Results—A total of 999 consecutive patients undergoing PVI were included; 376 patients were on dabigatran (150 mg), and 623 patients were on warfarin with therapeutic international normalized ratio. Dabigatran was held 1 to 2 doses before PVI and restarted at the conclusion of the procedure or as soon as patients were transferred to the nursing floor. Propensity score matching was applied to generate a cohort of 344 patients in each group with balanced baseline data. Total hemorrhagic and thromboembolic complications were similar in both groups, before (3.2% versus 3.9%; P=0.59) and after (3.2% versus 4.1%; P=0.53) matching. Major hemorrhage occurred in 1.1% versus 1.6% (P=0.48) before and 1.2% versus 1.5% (P=0.74) after matching in the dabigatran versus warfarin group, respectively. A single thromboembolic event occurred in each of the dabigatran and warfarin groups. Despite higher doses of intraprocedural heparin, the mean activated clotting time was significantly lower in patients who held dabigatran for 1 or 2 doses than those on warfarin. Conclusions—Our study found no evidence to suggest a higher risk of thromboembolic or hemorrhagic complications with use of dabigatran for periprocedural anticoagulation in patients undergoing PVI compared with uninterrupted warfarin therapy.

Natural History and Long-Term Outcomes of Ablated Atrial Fibrillation

Background—Atrial fibrillation (AF) ablation is increasingly used in clinical practice. We aimed to study the natural history and long-term outcomes of ablated AF. Methods and Results—We followed 831 patients after pulmonary vein isolation (PVI) performed in 2005. We documented clinical outcomes using our prospective AF registry with most recent update on this group of patients in October 2009. In the first year after ablation, 23.8% had early recurrence. Over long-term follow-up (55 months), only 8.9% had late arrhythmia recurrence defined as occurring beyond the first year after ablation. Repeat ablations in patients with late recurrence revealed conduction recovery in at least 1 of the previously isolated PVs in all of them and right-sided triggers with isoproterenol testing in 55.6%. At last follow-up, clinical improvement was 89.9% (79.4% arrhythmia-free off antiarrhythmic drugs and 10.5% with AF controlled with antiarrhythmic drugs). Only 4.6% continued to have drug-resistant AF. It was possible to safely discontinue anticoagulation in a substantial proportion of patients with no recurrence in the year after ablation (CHADS score ⩽2, stroke incidence of 0.06% per year). The procedure-related complication rate was very low. Conclusions—Pulmonary vein isolation is safe and efficacious for long-term maintenance of sinus rhythm and control of symptoms in patients with drug-resistant AF. It obviates the need for antiarrhythmic drugs, negative dromotropic agents, and anticoagulants in a substantial proportion of patients.

Clinical predictors of adverse patient outcomes in an experience of more than 5000 chronic endovascular pacemaker and defibrillator lead extractions

BACKGROUND It is difficult to predict adverse patient outcomes associated with transvenous lead extraction (TLE) procedures. OBJECTIVE The purpose of this study was to examine the safety and efficacy of chronic endovascular pacemaker and implantable cardioverter-defibrillator (ICD) lead extraction and risk factors associated with adverse patient outcomes. METHODS Consecutive patients undergoing TLE at the Cleveland Clinic between August 1996 and August 2011 were included in the analysis. Univariate and multivariable logistic regression analyses were performed to evaluate for associations with outcomes. Continuous data are given as median (25th, 75th percentile). Categorical data are given as number (percentage). RESULTS In total, 5521 leads (4137 [74.9%] pacemaker, 1384 [25.1%] ICD) were extracted during 2999 TLE procedures (patient age 67.2 [55.2, 76.2] years, 30.2% female). Lead implant duration was 4.7 (2.4, 8.3) years, and 2.0 (1.0, 2.0) leads were extracted per procedure. Powered sheaths were used in 74.9% of procedures. Overall, there was 95.1% complete procedural success, 98.9% clinical success, and 1.1% failure, with 3.6% minor complications and 1.8% major complications. All-cause mortality within 30 days of TLE was 2.2%. Multivariable predictors of major complications included cerebrovascular disease, ejection fraction ≤15%, lower platelet count, international normalized ratio ≥1.2, mechanical sheaths, and powered sheaths. Multivariable predictors of all-cause mortality within 30 days of TLE included body mass index <25 kg/m(2), end-stage renal disease, higher New York Heart Association functional class, lower hemoglobin, higher international normalized ratio, lead extraction for infection, and extraction of a dual-coil ICD lead. CONCLUSION TLE in this single-center experience was highly successful. Risk factors associated with adverse patient outcomes were identified.

Plasma B-Type Natriuretic Peptide Levels and Recurrent Arrhythmia After Successful Ablation of Lone Atrial Fibrillation

Background— Plasma B-type natriuretic peptide (BNP) is abnormally elevated in patients with lone atrial fibrillation (AF). The exact significance and prognostic implications of this elevation have yet to be determined. Little is known about BNP in lone AF patients undergoing arrhythmia ablation. We sought to determine the relationship between BNP levels and the risk of recurrent arrhythmia after ablation of lone AF. Methods and Results— We followed up 726 patients with lone AF undergoing first-time arrhythmia ablation. All had BNP levels measured on the day of ablation with of the point-of-care Triage Meter assay (Biosite Diagnostics, San Diego, CA). At baseline, factors associated with elevated BNP levels in multivariable linear regression analysis (with log BNP being the dependent variable) were older age (&bgr; regression coefficient for +1-year change, 0.025; P<0.0001), longer duration of AF (&bgr; for +1-year change, 0.031; P=0.01), nonparoxysmal AF (versus paroxysmal; &bgr;, 0.52; P<0.0001), and larger left atrial size (&bgr; for +1-cm2 change, 0.040; P<0.0001). The BNP levels were strongly associated with arrhythmia recurrence in univariate- (hazard ratio for +1-log-BNP change, 2.32; 95% confidence interval, 2.11 to 2.74; P<0.001) and covariate- (hazard ratio for +1-log-BNP change, 2.13; 95% confidence interval, 2.06 to 2.38; P<0.001) adjusted Cox proportional hazards analysis. The covariate-adjusted hazard ratios for recurrent arrhythmia were 1.6, 2.7, 4.3, and 5.7 for the second, third, fourth, and fifth quintiles, respectively, compared with patients in the lowest quintile (P for trend across quintiles <0.001). Conclusions— B-type natriuretic peptide levels correlate with AF burden (chronicity, altered hemodynamics, and anatomic remodeling) in patients with lone AF and are strong predictors of recurrent arrhythmia after ablation. Elevated BNP levels may reflect increased cardiac chamber wall stress and/or intrinsic atrial disease, thus increasing the risk of arrhythmia recurrence.

Prognostic Value of Electrocardiographic Measurements Before and After Cardiac Resynchronization Device Implantation in Patients With Heart Failure due to Ischemic or Nonischemic Cardiomyopathy

Postimplant QRS narrowing may predict clinical response after cardiac resynchronization therapy (CRT), but identification of nonresponders remains difficult. We studied the predictive value of electrocardiographic characteristics for mortality or cardiac transplantation in patients after CRT. Patients who had electrocardiograms available for review from before and after CRT device implantation were identified from a clinical database. Bivariate and multivariate Cox regression analyses were performed for the end point of death or transplantation. Of 337 patients (age 65+/-12 years, 76% men, left ventricular ejection fraction 22+/-12%, pre-QRS 175+/-30 ms), 84 died and 7 underwent transplantation during a follow-up of 27+/-15 months. Variables predictive of death or transplantation included QRS increase after CRT (45% vs 32%, p=0.03), older age, higher New York Heart Association class, lower left ventricular ejection fraction, and higher tertile of postimplant QRS (p=0.04), but not preimplant rhythm, QRS duration, or QRS morphology. After adjusting for confounding variables, independent predictors of mortality were older age (hazard ratio [HR] 1.03, 95% confidence interval [CI] 1.00 to 1.05, p=0.04), lack of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (HR 2.17, 95% CI 1.16 to 4.08, p<0.02), and longer postimplant QRS by tertile (HR 1.50, 95% CI 1.09 to 2.05, p=0.01). In conclusion, wider QRS after CRT device implantation is an independent predictor of mortality or transplantation. In patients with increased QRS durations despite CRT, closer follow-up or reassessment for alternative management strategies may be warranted.

Transvenous extraction of implantable cardioverter-defibrillator leads under advisory—A comparison of Riata, Sprint Fidelis, and non-recalled implantable cardioverter-defibrillator leads

BACKGROUND Comparative safety and efficacy associated with transvenous lead extraction (TLE) of recalled and non-recalled implantable cardioverter-defibrillator (ICD) leads has not been well characterized. OBJECTIVES To compare the indications, techniques, and procedural outcomes of recalled vs non-recalled ICD lead extraction procedures. METHODS TLE procedures performed at our institution from June 2002 to June 2012 in which Riata, Sprint Fidelis, or non-recalled ICD leads were extracted were included in the analysis. RESULTS ICD lead extraction procedures were performed in 1079 patients, including 430 patients with recalled leads (121 Riata, 308 Sprint Fidelis, and 1 Riata and Sprint Fidelis) and 649 patients with non-recalled ICD leads. A total of 2056 chronic endovascular leads were extracted, of which 1215 (59.1%) were ICD leads. Overall, there was 96.8% complete procedural success, 99.1% clinical success, and 0.9% failure, with 3.9% minor complications and 1.5% major complications. Procedural outcomes for Riata and Sprint Fidelis TLE procedures were no different. Lead implant duration was significantly less in recalled than in non-recalled ICD lead TLE procedures. Complete procedural success was higher in recalled (424 of 430 [98.6%]) than in non-recalled (621 of 649 [95.7%]; P = .007) ICD lead TLE procedures. Minor complications were lower in recalled (10 of 430 [2.3%]) than in non-recalled (32 of 649 [5.0%]; P = .030) ICD lead TLE procedures. Rates of clinical success, failure, and major complications were no different in the recalled and non-recalled ICD lead TLE procedures. CONCLUSION In our experience, recalled ICD leads were extracted with safety and efficacy comparable to that of non-recalled ICD leads.

Radiofrequency ablation of atrial fibrillation in patients with mechanical mitral valve prostheses safety, feasibility, electrophysiologic findings, and outcomes.

OBJECTIVES The purpose of this study was to evaluate the feasibility, safety, and outcomes of radiofrequency ablation of atrial fibrillation (AF) in patients with mechanical mitral valve replacement (MVR). BACKGROUND The role of ablative therapy in patients with MVR is not yet established, with safety concerns and very few outcome data. METHODS Between January 2003 and December 2008, we followed up 81 patients with MVR undergoing first-time AF ablation (compared with 162 age- and sex-matched controls). Arrhythmia recurrences were identified by symptoms with documentation, event monitoring, Holter monitoring, and electrocardiograms. RESULTS All MVR and control patients underwent ablation under therapeutic international normalized ratio. No entrapment of catheters or stroke occurred. There were no differences in terms of procedure-related complications between the groups (p = NS). Patients with MVR had larger atria (p < 0.0001), lower left ventricular ejection fractions (p = 0.0001), and more concomitant atrial flutter at baseline (p < 0.0001). Over a 24-month follow-up, they had higher recurrence rates compared with controls (49.4% vs. 27.7% after a single ablation, p = 0.0006). The creation of flutter lines significantly reduced recurrences in patients with any history of atrial flutter (16.7% vs. 60.9%, p = 0.009). At last follow-up, 82.7% of MVR patients had their arrhythmia controlled (69.1% not receiving antiarrhythmic drugs). CONCLUSIONS Radiofrequency ablation is feasible and safe for patients with MVR. It allowed restoration of sinus rhythm in a substantial proportion of patients undergoing ablation. An abnormal atrial substrate underlies recurrences in these patients. The ablation procedure needs to be further refined with a focus on extra pulmonary vein triggers and concomitant flutters to improve outcomes.

Radiofrequency Ablation of Persistent Atrial Fibrillation Diagnosis-to-Ablation Time, Markers of Pathways of Atrial Remodeling, and Outcomes

Background—Various ablation strategies of persistent atrial fibrillation (PersAF) have had disappointing outcomes, despite concerted clinical and research efforts, which could reflect progressive atrial fibrillation–related atrial remodeling. Methods and Results—Two-year outcomes were assessed in 1241 consecutive patients undergoing first-time ablation of PersAF (2005–2012). The time intervals between the first diagnosis of PersAF and the ablation procedures were determined. Patients had echocardiograms and measures of B-type natriuretic peptide and C-reactive protein before the procedures. The median diagnosis-to-ablation time was 3 years (25th–75th percentiles 1–6.5). With longer diagnosis-to-ablation time (based on quartiles), there was a significant increase in recurrence rates in addition to an increase in B-type natriuretic peptide levels (P=0.01), C-reactive protein levels (P<0.0001), and left atrial size (P=0.03). The arrhythmia recurrence rates over 2 years were 33.6%, 52.6%, 57.1%, and 54.6% in the first, second, third, and fourth quartiles, respectively (Pcategorical<0.0001). In Cox Proportional Hazard analyses, B-type natriuretic peptide levels, C-reactive protein levels, and left atrial size were associated with arrhythmia recurrence. The diagnosis-to-ablation time had the strongest association with the ablation outcomes which persisted in multivariable Cox analyzes (hazard ratio for recurrence per +1Log diagnosis-to-ablation time 1.27, 95% confidence interval 1.14–1.43; P<0.0001; hazard ratio fourth versus first quartile 2.44, 95% confidence interval 1.68–3.65; Pcategorical<0.0001). Conclusions—In patients with PersAF undergoing ablation, the time interval between the first diagnosis of PersAF and the catheter ablation procedure had a strong association with the ablation outcomes, such as shorter diagnosis-to-ablation times were associated with better outcomes and in direct association with markers of atrial remodeling.

Outcomes of nonpharmacologic treatment of atrial fibrillation in patients with hypertrophic cardiomyopathy

BACKGROUND Limited data exist regarding the outcome of atrial fibrillation (AF) surgery and catheter ablation in patients with hypertrophic cardiomyopathy (HCM). OBJECTIVE The purpose of this study was to evaluate the safety and efficacy of nonpharmacologic treatment of AF in HCM. METHODS One hundred forty-seven patients (46 female, age 55 ± 11 years, ejection fraction [EF] 58% ± 8%) with symptomatic paroxysmal (58%), persistent (31%), and long-standing persistent AF (11%) refractory to antiarrhythmic drugs who presented for their first catheter ablation (n = 79) or AF surgery (n = 68) were included. RESULTS After follow-up of 35 months (interquartile range 13, 60), 29% of patients who underwent catheter ablation and 51% of those who had undergone AF surgery had no documented recurrent atrial arrhythmia after a single procedure. Repeat ablation was performed in 55% of patients with recurrent arrhythmia in the catheter group and 24% in the surgery group, increasing the success rate to 39% and 53%, respectively, after 1 or more procedures. Predictors of success after the first procedure in a multivariable setting included higher baseline EF and male gender. Persistent or long-standing AF and log of AF duration were associated with lower success. Major complications occurred in 6% of the catheter ablation group and 18% of the AF surgery group. During follow-up, 16 patients died (9 in catheter group, 7 in surgery group) and 1 underwent heart replacement. Lower baseline EF and older age were independently associated with death. CONCLUSION Catheter ablation and AF surgery are associated with symptomatic improvement in HCM patients. However, long-term success is lower and complications are higher than previously reported.