Three-dimensional-guided and ICE-guided transseptal puncture for cardiac ablations: A propensity score match study.

INTRODUCTION: Transseptal puncture (TSP) is routinely performed for left atrial ablation procedures. The use of a three-dimensional (3D) mapping system or intracardiac echocardiography (ICE) is useful in localizing the fossa ovalis and reducing fluoroscopy use. We aimed to compare the safety and efficacy between 3D mapping system-guided TSP and ICE-guided TSP techniques. METHODS: We conducted a prospective observational study of patients undergoing TSP for left atrial catheter ablation procedures (mostly atrial fibrillation ablation). Propensity scoring was used to match patients undergoing 3D-guided TSP with patients undergoing ICE-guided TSP. Logistic regression was used to compare the clinical data, procedural data, fluoroscopy time, success rate, and complications between the groups. RESULTS: Sixty-five patients underwent 3D-guided TSP, and 151 propensity score-matched patients underwent ICE-guided TSP. The TSP success rate was 100% in both the 3D-guided and ICE-guided groups. Median needle time was 4.00 min (interquartile range [IQR]: 2.57-5.08) in patients with 3D-guided TSP compared to 4.02 min (IQR: 2.83-6.95) in those with ICE-guided TSP (p = .22). Mean fluoroscopy time was 0.2 min (IQR: 0.1-0.4) in patients with 3D-guided TSP compared to 1.2 min (IQR: 0.7-2.2) in those with ICE-guided TSP (p < .001). There were no complications related to TSP in both group. CONCLUSIONS: Three-dimensional mapping-guided TSP is as safe and effective as ICE-guided TSP without additional cost.

A comparison of clinical outcomes and cost of radiofrequency catheter ablation for atrial fibrillation with monitored anesthesia care versus general anesthesia.

INTRODUCTION: Monitored anesthesia care (MAC) or general anesthesia (GA) can be used during catheter ablation (CA) of atrial fibrillation (AF). However, each approach may have advantages and disadvantages with variability in operator preferences. The optimal approach has not been well established. The purpose of this study was to compare procedural efficacy, safety, clinical outcomes, and cost of CA for AF performed with MAC versus GA. METHODS: The study population consisted of 810 consecutive patients (mean age: 63 ± 10 years, paroxysmal AF: 48%) who underwent a first CA for AF. All patients completed a preprocedural evaluation by the anesthesiologists. Among the 810 patients, MAC was used in 534 (66%) and GA in 276 (34%). Ten patients (1.5%) had to convert to GA during the CA. RESULTS: Although the total anesthesia care was longer with GA particularly in patients with persistent AF, CA was shorter by 5 min with GA than MAC (p < 0.01). Prevalence of perioperative complications was similar between the two groups (4% vs. 4%, p = 0.89). There was no atrioesophageal fistula with either approach. GA was associated with a small, ~7% increase in total charges due to longer anesthesia care. During 43 ± 17 months of follow-up after a single ablation procedure, 271/534 patients (51%) in the MAC and 129/276 (47%) patients in the GA groups were in sinus rhythm without concomitant antiarrhythmic drug therapy (p = 0.28). CONCLUSION: With the participation of an anesthesiologist, and proper preoperative assessment, CA of AF using GA or MAC has similar efficacy and safety.

Efficacy and tolerability of quinidine as salvage therapy for monomorphic ventricular tachycardia in patients with structural heart disease.

INTRODUCTION: Quinidine is an effective therapy for a subset of polymorphic ventricular tachycardia and ventricular fibrillation (VF) syndromes; however, the efficacy of quinidine in scar-related monomorphic ventricular tachycardia (MMVT) is unclear. METHODS AND RESULTS: Between 2009 and 2020 a single VT referral center, a total of 23 patients with MMVT and structural heart disease (age 66.7 ± 10.9, 20 males, 15 with ischemic cardiomyopathy, mean LVEF 22.2 ± 12.3%, 9 with left ventricular assist device [LVAD]) were treated with quinidine (14 quinidine gluconate; 996 ± 321 mg, 8 quinidine sulfate; 1062 ± 588 mg). Quinidine was used in combination with other antiarrhythmics (AAD) in 19 (13 also on amiodarone). All patients previously failed >1 AAD (amiodarone 100%, mexiletine 73%, sotalol 32%, other 32%) and eight had prior ablations (median of 1.5). Quinidine was initiated in the setting of VT storm despite AADs (6), inability to tolerate other AADs (4), or recurrent VT(12). Ventricular arrhythmias recurred despite quinidine in 13 (59%) patients at a median of 26 (4-240) days after quinidine initiation. In patients with recurrent MMVT, VT cycle length increased from 359 to 434 ms (p = .02). Six (27.3%) patients remained on quinidine at 1 year with recurrence of ventricular arrhythmias in all. The following adverse effects were seen: gastrointestinal side effects (6), QT prolongation (2), rash (1), thrombocytopenia (1), neurologic side effects (1). One patient discontinued due to cost. CONCLUSION: Quinidine therapy has limited tolerability and long-term efficacy when used in the management of amiodarone-refractory scar-related MMVT.

Lead damage after cardiac implantable device replacement procedure: Comparison between electrical plasma tool and electrocautery.

BACKGROUND: Lead damage is a complication caused by lead manipulation or heating damage from conventional electrocautery (EC) after cardiovascular implantable electronic device (CIED) replacement. Application of electrical plasma (PEAK PlasmaBlade) is a new technology that reportedly reduces this risk. OBJECTIVES: This study was designed to compare the effect of EC versus PEAK PlasmaBlade on lead parameters and complications after generator replacement procedures. METHODS: We retrospectively studied 410 consecutive patients (840 leads) who underwent CIED replacement using EC (EC group) and 410 consecutive patients (824 leads) using PEAK PlasmaBlade (PlamaBlade group). Pacing lead impedance, incidence of lead damage, and complications were compared between both groups. RESULTS: Lead impedance increased in 393 leads (46.8%) in the EC group versus 282 leads (34.2%) in the PlasmaBlade group (p < .01) with average percent changes of 6.7% and 4.0% (p < .01), respectively. Lead impedance decreased in 438 leads (52.1%) in the EC group versus 507 leads (61.5%) in the PlasmaBlade group (p < .01) with average percent changes of -5.7% and -7.1% (p < .01), respectively. Lead damage requiring lead revision occurred in five leads (0.6%) or after five procedures (1.2%) in the EC group compared to three leads (0.4%, p = .50) or after three procedures (0.7%, p = .48) in the PlasmaBlade group. There were no significant differences in the procedural-related complications between the EC group (nine patients, 2.2%) and the PlasmaBlade group (five patients, 1.2%, p = .28). CONCLUSION: Conventional electrocautery can potentially damage lead insulations. However, this study shows that when used carefully electrocautery is as safe as the PEAK PlasmaBlade™.

Effect of metformin on outcomes of catheter ablation for atrial fibrillation.

BACKGROUND: Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF). The effect of antidiabetic medications on AF or the outcomes of catheter ablation (CA) has not been well described. We sought to determine whether metformin treatment is associated with a lower risk of atrial arrhythmias after CA in patients with DM and AF. METHODS AND RESULTS: A first CA was performed in 271 consecutive patients with DM and AF (age: 65 ± 9 years, women: 34%; and paroxysmal AF: 51%). At a median of 13 months after CA (interquartile range: 6-30), 100/182 patients (55%) treated with metformin remained in sinus rhythm without antiarrhythmic drug therapy, compared with 36/89 patients (40%) not receiving metformin (p = .03). There was a significant association between metformin therapy and freedom from recurrent atrial arrhythmias after CA in multivariable Cox hazards models (hazard ratio [HR]: 0.66; ±95% confidence interval [CI]: 0.44-0.98; p = .04) that adjusted for age, sex, body mass index, AF type (paroxysmal vs. nonparoxysmal), antiarrhythmic medication, obstructive sleep apnea, chronic kidney disease, coronary artery disease, left ventricular ejection fraction, and left atrial diameter. A Cox model that also incorporated other antidiabetic agents and fasting blood glucose demonstrated a similar reduction in the risk of recurrent atrial arrhythmias with metformin treatment (HR: 0.63; ±95% CI: 0.42-0.96; p = .03). CONCLUSIONS: In patients with DM, treatment with metformin appears to be independently associated with a significant reduction in the risk of recurrent atrial arrhythmias after CA for AF. Whether this effect is due to glycemic control or pleiotropic effects on electroanatomical mechanisms of AF remains to be determined.

Baseline and decline in device-derived activity level predict risk of death and heart failure in patients with an ICD for primary prevention.

BACKGROUND: Implanted defibrillators are capable of recording activity data based on company-specific proprietary algorithms. This study aimed to determine the prognostic significance of baseline and decline in device-derived activity level across different device companies in the real world. METHODS: We performed a retrospective cohort study of patients (n = 280) who underwent a defibrillator implantation (Boston, Medtronic, St. Jude, and Biotronik) for primary prevention at the University of Michigan from 2014 to 2016. Graphical data obtained from device interrogations were retrospectively converted to numerical data. The activity level averaged over a month from a week postimplantation was used as baseline. Subsequent weekly average activity levels (SALs) were standardized to this baseline. SAL below 59.4% was used as a threshold to group patients. All-cause mortality and death/heart failure were the primary end-points of this study. RESULTS: Fifty-six patients died in this study. On average, they experienced a 50% decline in SAL prior to death. Patients (n = 129) who dropped their SAL below threshold were more likely to be older, male, diabetic, and have more symptomatic heart failure. They also had a significantly increased risk of heart failure/death (hazard ratio [HR] 3.6, 95% confidence interval [95% CI] 2.3-5.8, P < .0001) or death (HR 4.2, 95% CI 2.2-7.7, P < .0001) compared to those who had sustained activity levels. Lower baseline activity level was also associated with significantly increased risk of heart failure/death and death. CONCLUSION: Significant decline in device-derived activity level and low baseline activity level are associated with increased mortality and heart failure in patients with an ICD for primary prevention.

Atrioventricular conduction in patients undergoing pacemaker implant following self-expandable transcatheter aortic valve replacement.

BACKGROUND: Heart block requiring a pacemaker is common after self-expandable transcatheter aortic valve replacement (SE-TAVR); however, conduction abnormalities may improve over time. Optimal device management in these patients is unknown. OBJECTIVE: To evaluate the long-term, natural history of conduction disturbances in patients undergoing pacemaker implantation following SE-TAVR. METHODS: All patients who underwent new cardiac implantable electronic device (CIED) implantation at Michigan Medicine following SE-TAVR placement between January 1, 2012 and September 25, 2017 were identified. Electrocardiogram and device interrogation data were examined during follow-up to identify patients with recovery of conduction. Logistic regression analysis was used to compare clinical and procedural variables to predict conduction recovery. RESULTS: Following SE-TAVR, 17.5% of patients underwent device placement for new atrioventricular (AV) block. Among 40 patients with an average follow-up time of 17.1 ± 8.1 months, 20 (50%) patients had durable recovery of AV conduction. Among 20 patients without long-term recovery, four (20%) had transient recovery. The time to transient conduction recovery was 2.2 ± 0.2 months with repeat loss of conduction at 8.2 ± 0.9 months. On multivariate analysis, larger aortic annular size (odds ratio: 0.53 [0.28-0.86]/mm, P = 0.02) predicted lack of conduction recovery. CONCLUSIONS: Half of the patients undergoing CIED placement for heart block following SE-TAVR recovered AV conduction within several months and maintained this over an extended follow-up period. Some patients demonstrated transient recovery of conduction before recurrence of conduction loss. Larger aortic annulus diameter was negatively associated with conduction recovery.

Ablation of paroxysmal atrial fibrillation using a second-generation cryoballoon catheter or contact-force sensing radiofrequency ablation catheter: A comparison of costs and long-term clinical outcomes.

INTRODUCTION: Although noninferiority of cryoballoon ablation (CBA) and radiofrequency catheter ablation for antral pulmonary vein isolation (APVI) has been reported in patients with paroxysmal atrial fibrillation (PAF), it is not clear whether contact force sensing (CF-RFA) and CBA with the second-generation catheter have similar procedural costs and long-term outcomes. The objective of this study is to compare the long-term efficacy and cost implications of CBA and CF-RFA in patients with PAF. METHODS AND RESULTS: A first APVI was performed in 146 consecutive patients (age: 63 ± 10 years, men: 95 [65%], left atrial diameter: 42 ± 6 mm) with PAF using CBA (71) or CF-RFA (75). Clinical outcomes and procedural costs were compared. The mean procedure time was significantly shorter with CBA than with CF-RFA (98 ± 39 vs. 158 ± 47 minutes, P < 0.0001). Despite a higher equipment cost in the CBA than the CF-RFA group, the total procedure cost was similar between the two groups (P = 0.26), primarily driven by a shorter procedure duration that resulted in a lower anesthesia cost. At 25 ± 5 months after a single ablation procedure, 51 patients (72%) in the CBA, and 55 patients (73%) in the CF-RFA groups remained free from atrial arrhythmias without antiarrhythmic drug therapy (P = 0.84). CONCLUSIONS: The procedure duration was approximately 60 minutes shorter with CBA than CF-RFA. The procedural costs were similar with both approaches. At 2 years after a single procedure, CBA and CF-RFA have similar single-procedure efficacies of 72-73%.

Dosimetric review of cardiac implantable electronic device patients receiving radiotherapy.

A formal communication process was established and evaluated for the management of patients with cardiac implantable electronic devices (CIEDs) receiving radiation therapy (RT). Methods to estimate dose to the CIED were evaluated for their appropriateness in the management of these patients. A retrospective, institutional review board (IRB) approved study of 69 patients with CIEDs treated with RT between 2005 and 2011 was performed. The treatment sites, techniques, and the estimated doses to the CIEDs were analyzed and compared to estimates from published peripheral dose (PD) data and three treatment planning systems(TPSs) - UMPlan, Eclipse's AAA and Acuros algorithms. When measurements were indicated, radiation doses to the CIEDs ranged from 0.01-5.06 Gy. Total peripheral dose estimates based on publications differed from TLD measurements by an average of 0.94 Gy (0.05-4.49 Gy) and 0.51 Gy (0-2.74 Gy) for CIEDs within 2.5 cm and between 2.5 and 10 cm of the treatment field edge, respectively. Total peripheral dose estimates based on three TPSs differed from measurements by an average of 0.69 Gy (0.02-3.72 Gy) for CIEDs within 2.5 cm of the field edge. Of the 69 patients evaluated in this study, only two with defibrillators experienced a partial reset of their device during treatment. Based on this study, few CIED-related events were observed during RT. The only noted correlation with treatment parameters for these two events was beam energy, as both patients were treated with high-energy photon beams (16 MV). Differences in estimated and measured CIED doses were observed when using published PD data and TPS calculations. As such, we continue to follow conservative guidelines and measure CIED doses when the device is within 10 cm of the field or the estimated dose is greater than 2 Gy for pacemakers or 1 Gy for defibrillators.

An Ethical Analysis of Withdrawal of Therapy in Patients with Implantable Cardiac Electronic Devices: Application of a Novel Decision Algorithm.

Patients with cardiovascular implantable electronic devices (CIEDs), which include pacemakers and implantable cardioverter-defibrillators (ICDs), may request deactivation of their devices as they approach the end of life. The Heart Rhythm Society (2010) has stated that "ethically, and legally, there are no differences between refusing CIED therapy and requesting withdrawal of CIED therapy." On the basis of the principle that there is no ethical distinction between withholding and withdrawing treatment, this professional organization has suggested that both the antibradycardia and antitachycardia features of these devices may be disabled at the patient's request. We argue that disabling ICD shocks is analogs to a do-not-resuscitate order and is ethically permissible whereas withdrawing pacing from a pacemaker-dependent patient is an act of intentionally hastening death and not morally licit.

Effect of catheter ablation on progression of paroxysmal atrial fibrillation.

OBJECTIVE: The objective was to determine the effect of radiofrequency catheter ablation (RFA) on progression of paroxysmal atrial fibrillation (AF). BACKGROUND: Progression to persistent AF may occur in up to 50% of patients with paroxysmal AF receiving pharmacological therapy. Hypertension, age, prior transient ischemic event, chronic obstructive pulmonary disease, and heart failure (HATCH score) have been identified as independent risk factors for progression of AF. METHODS: RFA was performed in 504 patients (mean age: 58 ± 10 years) to eliminate paroxysmal AF. A repeat RFA procedure was performed in 193 patients (38%). Clinical variables predictive of outcome and their relation to progression of AF after RFA were assessed using multivariate analysis. RESULTS: At a mean follow-up of 27 ± 12 months after RFA, 434/504 patients (86%) were in sinus rhythm; 49/504 patients (9.5%) continued to have paroxysmal AF; and 14 (3%) were in atrial flutter. Among the 504 patients, 7 (1.5%) progressed to persistent AF. In patients with recurrent AF after RFA, paroxysmal AF progressed to persistent AF in 7/56 (13%, P < 0.001). The progression rate of AF was 0.6% per year after RFA (P < 0.001 compared to 9% per year reported in pharmacologically treated patients). Age >75 years, duration of AF >10 years and diabetes were independent predictors of progression to persistent AF. The HATCH score was not significantly different between patients with paroxysmal AF who did and did not progress to persistent AF (0.7 ± 0.8 vs 1.0 ± 0.5, P = 0.3). CONCLUSIONS: Compared to a historical control group of pharmacologically treated patients with paroxysmal AF, RFA appears to reduce the rate of progression of paroxysmal AF to persistent AF. Age, duration of AF, and diabetes are independent risk factors for progression to persistent AF after RFA.

Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly.

INTRODUCTION: Factors associated with cerebrovascular events (CVEs) after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF) have not been well defined in elderly patients (≥65 years). The purpose of this study was to determine the prevalence and predictors of CVEs after RFA in patients with AF ≥65 years old, in comparison to patients <65 years, and with or without AF. METHODS AND RESULTS: This study included 508 consecutive patients ≥65 years old (mean age: 70 ± 4 years), who underwent RFA for paroxysmal (297) or persistent (211) AF. A stratified group of 508 patients < 65 years old who underwent RFA for AF served as a control group. All patients were anticoagulated with warfarin for ≥3 months after RFA. A perioperative CVE (≤4 weeks after RFA) occurred in 0.8% and 1% of patients ≥65 and <65 years old, respectively (P = 1). Among the patients ≥65 years old who remained in sinus rhythm after RFA, warfarin was discontinued in 60% and 56% of the patients with a CHADS(2) score of 0 and ≥1, respectively. Paroxysmal AF, no history of CVE, and successful RFA were independent predictors of discontinuing warfarin. During a mean follow-up of 3 ± 2 years, a late CVE (>4 weeks after the RFA) occurred in 15 of 508 (3%) of patients ≥65 years old (1% per year) and in 5 of 508 (1%) patients <65 years old (0.3% per year, P = 0.03). Among patients ≥65 years old, age >75 years old (OR = 4.9, ±95% CI: 3.3-148.5, P = 0.001) was the only independent predictor of a CVE. Among patients <65 years old, body mass index was the only independent predictor of a late CVE (OR = 1.2, ±95% CI: 1.03-1.33, P = 0.02). CONCLUSIONS: The risk of a periprocedural CVE after RFA of AF is similar among patients ≥65 and <65 years old. Late CVEs after RFA are more prevalent in older than younger patients with AF, and age >75 years old is the only independent predictor of late CVEs regardless of the rhythm, anticoagulation status, or the CHADS(2) score (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes mellitus and prior Stroke or transient ischemic attack).

Clinical characteristics and long-term outcomes of catheter ablation in young adults with atrial fibrillation.

PURPOSE: We aim to describe the long-term safety and efficacy of catheter ablation (CA) in young patients (<30 years) with atrial fibrillation (AF). METHODS: This was a retrospective study of patients aged 18-30 who underwent CA for AF, and clinical characteristics and long-term outcomes are reported. Survival analyses were performed between the study group and a propensity-matched older cohort (>30 years, mean age: 58±10 years). RESULTS: From January 2000 to January 2019, a 1st CA (radiofrequency energy n=72, cryoballoon n=10), was performed in 82 patients (mean age 26±4 years, paroxysmal n=61, persistent n=14, longstanding persistent n=7), among 6336 consecutive patients with AF. During a follow-up of 5±5 years, 56% and 30% of the patients with paroxysmal and non-paroxysmal AF were arrhythmia free without antiarrhythmic drug (AAD) therapy after a single CA (P=0.02). After 1.5±0.8 CA procedures, 76% and 75% of the patients with paroxysmal AF and non-paroxysmal AF were arrhythmia free without AADs (P=0.54). Compared to a propensity-matched group of older patients, young patients were as likely to remain in sinus rhythm after CA (P=0.47), however after fewer repeat CAs (1.5±0.8 vs 1.9±0.9, P<0.009). There were no long-term adverse outcomes associated with CA. CONCLUSIONS: CA is a safe and effective treatment of AF in young patients with comparable outcomes to the older patients, however after fewer procedures.

Randomized comparison of cavotricuspid isthmus ablation for atrial flutter using an open irrigation-tip versus a large-tip radiofrequency ablation catheter.

BACKGROUND: Large-tip (10 mm) catheters (LTCs) and open-irrigation-tip catheters (OITCs), both capable of creating large lesions, are more effective than conventional catheters for cavotricuspid isthmus (CTI) ablation. However, it is not clear whether complete CTI block can be achieved more efficiently using an LTC or an OITC. The purpose of this study was to compare the efficiency of radiofrequency catheter ablation (RFA) of the CTI using LTC versus OITC to eliminate atrial flutter (AFL). METHODS AND RESULTS: Sixty consecutive patients (age = 62 ± 10 years) with typical AFL were randomized to undergo RFA of CTI using an LTC (10 mm) or an OITC. If complete CTI block was not achieved by ≤30 minutes of RFA, patients were allowed to cross over to ablation with the other catheter. A 3-dimensional electroanatomical mapping system was used for catheter navigation only with the OITC. The mean duration of RFA to achieve CTI block in 50% of the patients was 6.8 ± 2.2 minutes with an LTC and 11.7 ± 2.7 minutes with an OITC (P = 0.001). After 30 minutes of RFA, CTI block was achieved in 26/30 (87%) and 25/30 patients (83%) using an LTC and an OITC, respectively (P = 1.0). After crossover, CTI block was achieved in 4/5 (80%) and in 4/4 patients (100%) with an LTC and OITC, respectively (P = 1.0). LTC was associated with a lower volume of intravenous fluid administration (388 ± 365 mL versus 865 ± 451 mL, P = 0.0001) and a trend for shorter procedure duration (95 ± 31 minutes versus 114 ± 50 minutes, P = 0.09) than the OITC. At 6 ± 3 months, 30/30 patients (100%) in the LTC and 27/30 patients (90%) in the OITC groups remained free from AFL, respectively (P = 0.24). Except for one inconsequential steam-pop during RFA with the OITC, there were no complications. CONCLUSIONS: Complete CTI block is achieved more rapidly using an LTC than an OITC, and with a similar clinical efficacy.

Time- and frequency-domain characteristics of atrial electrograms during sinus rhythm and atrial fibrillation.

BACKGROUND: Complex fractionated atrial electrograms (CFAE) have been considered to be helpful during catheter ablation of atrial fibrillation (AF). The purpose of this study was to analyze the characteristics of CFAEs recorded during sinus rhythm (SR) and AF, and to determine their relationship to perpetuation of AF and clinical outcome. METHODS AND RESULTS: Antral pulmonary vein isolation (APVI) was performed in 34 consecutive patients (age = 59 ± 10 years) with paroxysmal AF who presented in SR. Time- and frequency-domain characteristics of electrograms recorded from the same sites in the coronary sinus (CS) were analyzed during SR and AF, before and during isoproterenol infusion. There was a modest correlation in fractionation index (FI: change in the direction of depolarization, r = 0.40, P = 0.001) and complexity index (CI: change in the polarity of depolarization, r = 0.41, P = 0.001), but not in the dominant frequency (DF) between SR and AF. There was no relationship between the DF and CI or FI during AF. Isoproterenol was associated with an increase in DF during AF (6.6 ± 0.9 vs 5.1 ± 0.6 Hz, P < 0.001) but had no effect on CI or FI (P = 0.6). A higher CI (58.3 ± 21.0/s vs 38.0 ± 21.0/s, P < 0.01), and FI (123.5 ± 44.8/s vs 75.6 ± 44.6/s, P < 0.01) during AF were associated with a lower likelihood of termination of AF during APVI and a higher probability of recurrent AF after ablation. Ratio of FI during AF to SR was also higher when AF persisted than terminated after APVI (29.7 ± 12.4 vs 19.1 ± 9.7, P = 0.002). However, time- or frequency-domain parameters during SR were not predictive of termination or clinical outcome. CONCLUSIONS: Structural and functional properties of the atrial myocardium during AF contribute to electrogram complexity, which may indicate the presence of extra-PV mechanisms of AF that are not eliminated by APVI. Mapping of complex electrograms in SR is not likely to be sufficient to identify drivers of AF.

Prevalence and predictors of complications of radiofrequency catheter ablation for atrial fibrillation.

INTRODUCTION: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF. METHODS AND RESULTS: The subjects were 1,295 consecutive patients (age = 60 ± 10 years) who underwent RFA (n = 1,642) for paroxysmal (53%) or persistent AF (47%) from January 2007 to January 2010. A complication occurred in 57 patients (3.5%); a vascular access complication in 31 (1.9%); pericardial tamponade in 20 (1.2%); a thromboembolic event in 4 (0.2%); deep venous thrombosis in 1 (<0.01%); and pulmonary vein stenosis in 1 patient (<0.01%). There were no procedure-related deaths. On multivariate analysis, female gender (OR = 2.27; ±95% CI: 1.31-2.57, P < 0.01) and procedures performed in July or August (OR = 2.10; ±95% CI: 1.16-3.80, P = 0.01) were independent predictors of any complication. For vascular complications, treatment with clopidogrel (OR = 4.40; ±95% CI: 1.43-13.53, P = 0.01), female gender (OR = 3.65; ±95% CI: 1.72-7.75, P < 0.01) and performing RFA in July or August (OR = 2.71; ±95% CI: 1.25-5.87, P = 0.01) were independent predictors. The only predictor of cardiac tamponade was prior RFA (OR = 3.32; ±95% CI: 0.95-11.61; P < 0.05). CONCLUSION: Prevalence of perioperative complications for RFA of AF is 3.5% and vascular access complications constitute the majority. The need for clopidogrel therapy should be carefully considered prior to RFA. At teaching institutions close supervision should be exercised during vascular access early in the year. Improvements in ablation technology and elimination of the need for repeat procedures may decrease the risk of pericardial tamponade.