Outcomes of fibrinolytic therapy for patients with metastatic cancer and acute pulmonary embolism.

INTRODUCTION: Malignancy is a common cause of morbidity and mortality in the United States and around the world and the second leading cause of death in the United States. There is little data on the impact of metastatic cancer on the risk of hemorrhagic stroke or mortality among patients undergoing fibrinolytic therapy (FT) for acute PE. METHODS: Using the National Inpatient Sample (NIS) database, we extracted admissions with a primary diagnosis of acute pulmonary embolism that underwent FT from 2010 to 2014. We performed a case control matched analysis between patients with and without metastatic cancer. Our primary outcome of interest was Mortality and our secondary outcome of interest was hemorrhagic stroke (HS). RESULTS: Of the 883,183 patients with a primary diagnosis of acute PE between 2010 and 12014, 23,690 patients (2.7%) underwent FT. After exclusion, 22,592 patients were included in the analysis. Of these, 941 patients (4.2%) were reported to have metastatic cancer. There was a higher incidence of cerebrovascular accidents and intubation/mechanical ventilation in the metastatic cancer arm. Mortality was significantly higher in the metastatic cancer arm with no difference in the incidence of HS. In multivariate regression analysis, among all patients that underwent FT for acute PE, metastatic cancer was associated with a significant odds for mortality (OR 1.91, 95% CI 1.11-5.82, p < .001). CONCLUSION: The presence of metastatic cancer in patients undergoing fibrinolytic therapy for acute pulmonary embolism is associated with increase mortality.

Trends in the Incidence and In-Hospital Outcomes of Patients With Atrial Fibrillation Complicated by Non-ST-Segment Elevation Myocardial Infarction.

Atrial fibrillation (AF) can present with non-ST-segment elevation myocardial infarction (NSTEMI). The incidence, characteristics, outcomes, and treatment of this subgroup of patients with AF remains poorly studied. Using data from the National Inpatient Sample database, we (1) compared baseline characteristics of patients with AF with/without NSTEMI, (2) evaluated their outcomes and associated trends over the study period (2004-2013), and (3) evaluated revascularization (by percutaneous coronary intervention or coronary artery bypass graft [CABG]) and the impact on patient outcomes. Of the 3 923 436 patients admitted with a primary diagnosis of AF, 47 785 (1.2%) had a secondary diagnosis of NSTEMI. In this subgroup with AF and NSTEMI, there was a significant trend toward a decrease in mortality ( P = .002), stroke ( P < .001), and gastrointestinal bleeding ( P < .001) during the study period. Compared to unrevascularized patients, revascularized patients were more likely to be younger (72.2 ± 10.2 vs 77.0 ± 11.8 years old, P < .001), male (57.8 vs 42.7%, P < .001), and had a much higher incidence of coronary risk factors. Revascularization was associated with increased survival in multivariable analysis (odds ratio: 0.562, 95% confidence interval: 0.334-0.946, P = .03). In conclusion, among patients admitted with AF, 1.2% were diagnosed with NSTEMI. A minority of patients with AF and NSTEMI underwent revascularization and had better in-hospital outcomes.

Characteristics of and current practice patterns of pacing for high-degree atrioventricular block after transcatheter aortic valve implantation in comparison to surgical aortic valve replacement.

OBJECTIVE: We aimed to investigate the current practice patterns of permanent pacing, especially the timing of implantation, for high-degree AV block (HDAVB) following transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR). BACKGROUND: Comparative data regarding current practice patterns of permanent pacing for HDAVB between TAVI and SAVR is limited. METHODS: Using the National Inpatient Sample database, we identified patients who underwent TAVI or SAVR between 2012 and 2014. The incidence of HDAVB, the rate of permanent pacemaker implantation, and the timing of implantations were compared between TAVI and SAVR groups. RESULTS: We identified 33 690 and 202 110 patients who underwent TAVI and SAVR, respectively. HDAVB occurred in 3480 patients (10.3%) in the TAVI group and 11 405 patients (5.6%) in the SAVR group (P < 0.001). Among the patients who developed HDAVB, patients in the TAVI group were more likely to undergo permanent pacemaker implantation than those in the SAVR group (74.1% vs 64.7%; P < 0.001). The median interval from TAVI to pacemaker implantation was 2 days (interquartile range 1-3 days) vs 5 days (interquartile range 3-7 days) from SAVR to pacemaker implantation (P < 0.001). Among the patients who developed HDAVB, TAVI was associated with higher rates of permanent pacemaker implantation after adjusting for other comorbidities (odds ratio 1.41:95% confidence interval 1.13-1.77; P = 0.003). CONCLUSIONS: HDAVB occurred more commonly after TAVI compared to SAVR. HDAVB after TAVI compared to SAVR was associated with a higher rate of permanent pacemaker implantation at an earlier timing from the index procedure.

Sex differences in complications of catheter ablation for atrial fibrillation: results on 85,977 patients.

PURPOSE: Catheter ablation (CA) is an effective treatment for atrial fibrillation (AF). The differences in complication rates and outcomes between women and men remain poorly studied. We aimed to study the sex differences in morbidity and mortality associated with CA in AF. METHODS: Using weighted sampling from the National Inpatient Sample database, women and men with a primary diagnosis of AF and a primary procedure of CA (2004-2013) were identified. We compared the following outcomes based on the sex: (1) major complications [post-procedure transfusion, cardiac drain or surgery, pulmonary embolism, cerebrovascular accident, major cardiac events, kidney failure requiring dialysis, and sepsis], (2) overall complications (minor and/or major complications), and (3) in-hospital mortality. RESULTS: Among 85,977 patients who underwent CA for AF, 27821 (32.4%) were women. Overall complications were more frequent among women versus among men (12.4% versus 9.0%; p < 0.001), as well as major complications (4.7% versus 2.7%; p < 0.001). However, there was no difference in mortality (0.3% versus 0.2%; p = 0.22). After adjusting for other factors, women were more likely than men to have major complication (odds ratio 1.48, 95% CI 1.21-1.82; p < 0.001). Prior CABG was associated with lower risk of major complications in both sexes (odds ratio in the overall cohort 0.27, 95% CI 0.12-0.61; p = 0.002), mostly driven by the reduction in tamponade and pericardial drain. CONCLUSIONS: Among patients who underwent catheter ablation for AF, the female sex was associated with higher rate of complications compared to male but no difference in mortality. Prior CABG was associated with a significant reduction of major complications in both sexes.

Sex differences in the contemporary management of HIV patients admitted for acute myocardial infarction.

BACKGROUND: Studies have reported sex differences in the management of patients with acute myocardial infarction (AMI) in the general population. This observational study is designed to evaluate whether sex differences exist in the contemporary management of human immunodeficiency virus (HIV) patients admitted for diagnosis of AMI. HYPOTHESIS: There is no difference in management of HIV patients with AMI. METHODS: Using the National Inpatient Sample database, we identified patients with a primary diagnosis of AMI and a secondary diagnosis of HIV. We described baseline characteristics and outcomes using NIS documentation. Our primary areas of interest were revascularization and mortality. RESULTS: Among 2 977 387 patients presenting from 2010 to 2014 with a primary diagnosis of AMI, 10907 (0.4%) had HIV (mean age, 54.1 ± 9.3 years; n = 2043 [18.9%] female). Females were younger, more likely to be black, and more likely to have hypertension, diabetes, obesity, and anemia. Although neither males nor females were more likely to undergo coronary angiography in multivariate analysis, revascularization was performed less frequently in females than in males (45.4% vs 62.7%; P < 0.01), driven primarily by lower incidence of PCI. In a multivariate model, females were less likely to undergo revascularization (OR: 0.59, 95% CI: 0.45-0.78, P < 0.01), a finding driven solely by PCI (OR: 0.64, 95% CI: 0.49-0.83, P < 0.01). All-cause mortality was similar in both groups. CONCLUSIONS: AMI was more common in males than females with HIV. Females with HIV were more likely to be younger and black and less likely to be revascularized by PCI.

Colchicine for prevention of post-cardiac procedure atrial fibrillation: Meta-analysis of randomized controlled trials.

BACKGROUND: Development of atrial fibrillation after certain cardiac procedures is a common medical problem. The inflammatory process plays an important role in the pathogenesis of post-cardiac procedure atrial fibrillation (PCP-AF). Colchicine, a potent anti-inflammatory agent, has been used in several studies to reduce the risk of PCP-AF. This meta-analysis of randomized controlled trials (RCTs) was conducted to assess the efficacy of colchicine in prevention of PC-PAF. METHODS: We searched PubMed, EMBASE, Web of Science, Cochrane Library database and Google Scholar for RCTs, using terms "Atrial fibrillation, atrial, or fibrillation and colchicine". The primary end-point was the occurrence of AF post cardiac procedure, which includes cardiac surgery or pulmonary vein isolation. The safety end point was the occurrence of any side effects. Estimated odds ratios (OR) and 95% confidence intervals (CI) were evaluated. RESULTS: A total of six RCTs were included in this meta-analysis, enrolling a total of 1257 patients. Colchicine significantly reduced the odds of PCP-AF (OR 0.52; 95% CI, 0.40-0.68, P<0.001, I2=0%). However, occurrence of side effects was significantly higher with colchicine when compared to placebo (OR 2.10; 95% CI, 1.34-3.30, P<0.001, I2=0%). The number needed to treat is 7 and the number needed to harm is 11.2. The proportion of patients discontinuing treatment was 16%. CONCLUSION: This meta-analysis shows that colchicine is an effective drug for prevention of PCP-AF. Colchicine could be considered as a prophylaxis to reduce PCP-AF, with some risk of treatment discontinuation due to the poor gastrointestinal tolerance (diarrhea).

Use of adenosine to shorten the post ablation waiting period for cavotricuspid isthmus-dependent atrial flutter.

BACKGROUND: Dormant conduction unmasked by adenosine predicts clinical recurrences of cavotricuspid isthmus (CTI) dependent atrial flutter following catheter ablation. Conventional practice involves a waiting period of 20 to 30 minutes after achievement of a bidirectional line of block (BDB) to monitor for recovery of conduction. OBJECTIVE: Assess whether abolition of dormant conduction with adenosine immediately after CTI ablation and BDB can predict the lack of CTI conduction recovery during the following 30 minutes. METHODS: Consecutive patients undergoing catheter ablation for CTI-dependent atrial flutter were studied. Following the completion of CTI ablation and documentation of BDB, adenosine (≥12 mg IV) was administered immediately. In cases of dormant conduction, the CTI was ablated again until its abolition. After the achievement of BDB without dormant conduction, spontaneous CTI reconnection during the following 30 minutes and dormant conduction with adenosine at 30 minutes were evaluated. RESULTS: A CTI block was achieved in 171 patients. Nine patients (5.3%) had dormant conduction across the CTI immediately after ablation and BDB, and required further ablation. Two patients (1.2%) had subsequent spontaneous time-dependent reconnection within 30 minutes. Two other patients (1.2%) developed late dormant conduction with adenosine at 30 minutes. All 4 patients underwent further ablation. CONCLUSION: A negative adenosine challenge immediately after CTI ablation with bidirectional block, or after abolition of dormant conduction with further ablation, strongly predicted the absence of subsequent spontaneous reconnection within 30 minutes. Based on these results, the conventional waiting period is unnecessary in 97.6% patients without dormant conduction after CTI-dependent flutter ablation.

Acute Effects of Implantable Cardioverter-Defibrillator Shocks on Biomarkers of Myocardial Injury, Apoptosis, Heart Failure, and Systemic Inflammation.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) shocks are potentially associated with myocardial injury, altered hemodynamics, apoptosis, and inflammatory signaling. Their precise cellular impact can be explored after defibrillation testing (DFT) via biomarkers. We evaluated changes in biomarkers after ICD shocks during DFT. METHODS: We prospectively enrolled outpatients presenting for first implantation of a cardiac device. Biomarkers indicative of myocardial injury, inflammation, and apoptosis were measured before and after implantation, and compared between patients receiving DFT (DFT+) to those not (DFT-). RESULTS: Sixty-three patients were enrolled, 40 in the DFT+ group and 23 in the DFT- group. Average levels of troponin I, hsCRP, Calprotectin, N-terminal pro B-type natriuretic peptide (NTproBNP), and sFas increased by >50% after cardiac device implantation compared to baseline. Increase in troponin never exceeded the 50-fold upper limit of normal (2 ng/mL). Troponin trended higher in the DFT+ group at 8 hours (median 0.18 ng/mL, interquartile range [IQR] 0.11-0.48) versus the DFT- group (0.10 ng/mL, IQR 0.06-0.28, P = 0.0501); NTproBNP had a similar trend (P = 0.0581). sFas significantly increased in the DFT+ group from baseline (median 4663 pg/mL, IQR 2908-5679) to 24 hours (5039 pg/mL, IQR 3274-6261; P = 0.0338) but not in the DFT- group (P = 0.4705). CONCLUSION: DFT testing is associated with acutely increased plasma levels of troponin and sFas, a biomarker of apoptosis, along with a trend toward higher NTproBNP.

The cardiomyocyte molecular clock regulates the circadian expression of Kcnh2 and contributes to ventricular repolarization.

BACKGROUND: Sudden cardiac death (SCD) follows a diurnal variation. Data suggest the timing of SCD is influenced by circadian (~24-hour) changes in neurohumoral and cardiomyocyte-specific regulation of the heart's electrical properties. The basic helix-loop-helix transcription factors brain muscle arnt-like1 (BMAL1) and circadian locomotor output control kaput (CLOCK) coordinate the circadian expression of select genes. OBJECTIVE: We sought to test whether Bmal1 expression in cardiomyocytes contributes to K(+) channel expression and diurnal changes in ventricular repolarization. METHODS: We used transgenic mice that allow for the inducible cardiomyocyte-specific deletion of Bmal1 (iCSΔBmal1(-/-)). We used quantitative polymerase chain reaction, voltage clamping, promoter-reporter bioluminescence assays, and electrocardiographic telemetry. RESULTS: Although several K(+) channel gene transcripts were downregulated in iCSΔBmal1(-/-)mouse hearts, only Kcnh2 exhibited a robust circadian pattern of expression that was disrupted in iCSΔBmal1(-/-) hearts. Kcnh2 underlies the rapidly activating delayed-rectifier K(+) current, and the rapidly activating delayed-rectifier K(+) current recorded from iCSΔBmal1(-/-) ventricular cardiomyocytes was ~50% smaller than control ventricular myocytes. Promoter-reporter assays demonstrated that the human Kcnh2 promoter is transactivated by the coexpression of BMAL1 and CLOCK. Electrocardiographic analysis showed that iCSΔBmal1(-/-) mice developed a prolongation in the heart rate-corrected QT interval during the light (resting) phase. This was secondary to an augmented circadian rhythm in the uncorrected QT interval without a corresponding change in the RR interval. CONCLUSION: The molecular clock in the heart regulates the circadian expression of Kcnh2, modifies K(+) channel gene expression, and is important for normal ventricular repolarization. Disruption of the cardiomyocyte circadian clock mechanism likely unmasks diurnal changes in ventricular repolarization that could contribute to an increased risk of cardiac arrhythmias/SCD.

Administration of isoproterenol and adenosine to guide supplemental ablation after pulmonary vein antrum isolation.

BACKGROUND: Pulmonary vein antrum isolation (PVAI) remains associated with atrial fibrillation (AF) recurrence. We administered adenosine and isoproterenol (ISP) after PVAI to uncover non-PV atrial triggers and PV reconnection, potentially increasing ablation success rate. METHODS: One hundred and ninety-two consecutive patients with symptomatic AF presenting for PVAI were prospectively studied (group 1). Following PVAI, adenosine (18-24 mg) and ISP (20-30 mcg/min) were administered intravenously. Supplemental ablation was performed in patients with non-PV triggers that induced AF (group 1A). Other subgroups included patients with (group 1B) or without (group 1C) consistent non-PV atrial foci that did not induce AF. A cohort of 196 matched control patients undergoing PVAI without drug challenge was used for comparison (group 2). RESULTS: A total of 132 atrial non-PV foci were revealed (31 inducing AF). The majority of atrial foci were observed with ISP (113/132, 86%). Less than 5% of patients had persistent PV recovery during the drug challenge. During a mean follow-up of 22 ± 8 months, PVAI was successful in 110/192 (57%, group 1) versus 100/196 (52%, group 2), P = 0.038. Furthermore, the success rate was statistically different between group 1A (25/32, 78%), group 1B (28/83, 34%), and group 1C (57/74, 74%), P < 0.001. CONCLUSION: After PVAI, ablation guided by the administration of adenosine and ISP to target non-PV triggers inducing AF increased AF ablation outcomes. Patients with non-PV foci that did not induce AF had no further ablation, with the lowest ablation success rate. This group may likely benefit from further ablation after PVAI.

Adenosine testing in atrial flutter ablation: unmasking of dormant conduction across the cavotricuspid isthmus and risk of recurrence.

BACKGROUND: Adenosine-induced hyperpolarization may identify pulmonary veins at risk of reconnection following electrical isolation for atrial fibrillation. The potential role of adenosine testing in other arrhythmic substrates, such as cavotricuspid isthmus (CTI)-dependent atrial flutter, remains unclear. We assessed whether dormant conduction across the CTI may be revealed by adenosine after ablation-induced bidirectional block, and its association with recurrent flutter. METHODS AND RESULTS: Patients undergoing catheter ablation for CTI-dependent flutter were prospectively studied. After confirming bidirectional block across the CTI by standard pacing maneuvers, adenosine (≥ 12 mg IV) was administered to assess resumption of conduction, followed by isoproterenol (ISP) bolus. Further CTI ablation was performed for persistent (but not transient) resumption of conduction. Bidirectional block across the CTI was achieved in all 81 patients (63 males), age 61.2 ± 11.0 years. The trans-CTI time increased from 71.9 ± 18.1 milliseconds preablation to 166.2 ± 26.4 milliseconds postablation. Adenosine elicited resumption of conduction across the CTI in 7 patients (8.6%), 2 of whom had transient recovery. No additional patient with dormant conduction was identified by ISP. Over a follow-up of 11.8 ± 8.0 months, atrial flutter recurred in 4 (4.9%) patients, 3/7(42.9%) with a positive adenosine challenge versus 1/74 (1.3%) with a negative response, P = 0.0016 (relative risk 31.7). CONCLUSION: Adenosine challenge following atrial flutter ablation provoked transient or persistent resumption of conduction across the CTI in almost 9% of patients and identified a subgroup at higher risk of flutter recurrence. It remains to be determined whether additional ablation guided by adenosine testing during the index procedure may further improve procedural outcomes.

Mechanistic basis for type 2 long QT syndrome caused by KCNH2 mutations that disrupt conserved arginine residues in the voltage sensor.

KCNH2 encodes the Kv11.1 channel, which conducts the rapidly activating delayed rectifier K+ current (I Kr) in the heart. KCNH2 mutations cause type 2 long QT syndrome (LQT2), which increases the risk for life-threatening ventricular arrhythmias. LQT2 mutations are predicted to prolong the cardiac action potential (AP) by reducing I Kr during repolarization. Kv11.1 contains several conserved basic amino acids in the fourth transmembrane segment (S4) of the voltage sensor that are important for normal channel trafficking and gating. This study sought to determine the mechanism(s) by which LQT2 mutations at conserved arginine residues in S4 (R531Q, R531W or R534L) alter Kv11.1 function. Western blot analyses of HEK293 cells transiently expressing R531Q, R531W or R534L suggested that only R534L inhibited Kv11.1 trafficking. Voltage-clamping experiments showed that R531Q or R531W dramatically altered Kv11.1 current (I Kv11.1) activation, inactivation, recovery from inactivation and deactivation. Coexpression of wild type (to mimic the patients' genotypes) mostly corrected the changes in I Kv11.1 activation and inactivation, but deactivation kinetics were still faster. Computational simulations using a human ventricular AP model showed that accelerating deactivation rates was sufficient to prolong the AP, but these effects were minimal compared to simply reducing I Kr. These are the first data to demonstrate that coexpressing wild type can correct activation and inactivation dysfunction caused by mutations at a critical voltage-sensing residue in Kv11.1. We conclude that some Kv11.1 mutations might accelerate deactivation to cause LQT2 but that the ventricular AP duration is much more sensitive to mutations that decrease I Kr. This likely explains why most LQT2 mutations are nonsense or trafficking-deficient.

Is there an association between external cardioversions and long-term mortality and morbidity? Insights from the Atrial Fibrillation Follow-up Investigation of Rhythm Management study.

BACKGROUND: Cardiac electric therapies effectively terminate tachyarrhythmias. Recent data suggest a possible increase in long-term mortality associated with implantable cardioverter-defibrillator shocks. Little is known about the association between external cardioversion episodes (ECVe) and long-term mortality. We sought to assess the safety of repeated ECVe with regard to cardiovascular mortality and morbidity. METHODS AND RESULTS: We analyzed the data of the 4060 patients from the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial. In particular, associations of ECVe with all-cause mortality, cardiovascular mortality, and hospitalizations after ECVe were studied. Over an average follow-up of 3.5 years, 660 (16.3%) patients died, 331 (8.2%) from cardiovascular causes. A total of 207 (5.1%) and 1697 (41.8%) patients had low ejection fraction and nonparoxysmal atrial fibrillation, respectively; 2460 patients received no ECVe, whereas 1600 experienced ≥ 1 ECVe. Death occurred in 412 (16.7%), 196 (16.5%), 39 (13.5%), and 13 (10.4%) of patients with 0, 1, 2, and ≥ 3 ECVe, respectively. There was no significant association between ECVe and mortality within any of the 4 subgroups defined by ejection fraction and atrial fibrillation type, although myocardial infarction, coronary artery bypass graft, and digoxin were significantly associated with death (estimated hazard ratios, 1.65, 1.59, and 1.62, respectively; P < 0.0001). ECVe were associated with increased cardiac hospitalization reported at the next follow-up visit (39.3% versus 5.8%; estimated odds ratio, 1.39; P < 0.0001). CONCLUSIONS: In the AFFIRM study, there was no significant association between ECVe and long-term mortality, even though ECVe were associated with increased hospitalizations from cardiac causes. Digoxin, myocardial infarction, and coronary artery bypass graft were significantly associated with mortality.

General anesthesia reduces the prevalence of pulmonary vein reconnection during repeat ablation when compared with conscious sedation: results from a randomized study.

BACKGROUND: Radiofrequency catheter ablation of atrial fibrillation can be performed under general anesthesia or conscious sedation at the physician's preference. OBJECTIVE: We randomized a series of consecutive patients with paroxysmal atrial fibrillation (AF) undergoing radiofrequency catheter ablation to either general anesthesia or conscious sedation to assess differences in pulmonary vein (PV) reconnection during redo procedures and impact on success rate. METHODS: A total of 257 consecutive patients with paroxysmal AF undergoing AF ablation were enrolled and randomized to either conscious sedation with fentanyl or midazolam (128 patients, group 1) and general anesthesia (129 patients, group 2). In all patients, a high dosage of isoproterenol up to 30 µg/min was used to disclose PV reconnection or extra PV firings. RESULTS: Baseline clinical characteristics were not significantly different between the 2 groups. At 17 ± 8 month follow-up after the first ablation, 88 (69%) patients in group 1 were free of atrial arrhythmias off all antiarrhythmic drugs (AAD), as compared with 114 (88%) in group 2 (log-rank P <.001). All patients with recurrence had a second procedure. At the repeat procedure, 42% (66 of 158) of PVs in group 1 had recovered PV conduction, compared with 19% (11 of 57) in group 2 (P = .003). Compared with group 1, group 2 had a significantly shorter fluoroscopy time (53 ± 9 min vs. 84 ± 21 min, P <.001) and procedure time (2.4 ± 1.4 h vs. 3.6 ± 1.1 h, P <.001). CONCLUSION: The use of general anesthesia is associated with higher cure rate with a single procedure, and it seems to reduce the prevalence of PV reconnection observed at the time of repeat ablation.

Atrial fibrillation termination as a procedural endpoint during ablation in long-standing persistent atrial fibrillation.

BACKGROUND: Ablation of long-standing persistent atrial fibrillation (AF) remains challenging, with a lower success rate than paroxysmal AF. A reliable ablation endpoint has not been demonstrated yet, although AF termination during ablation may be associated with higher long-term maintenance of sinus rhythm (SR). OBJECTIVE: The purpose of this study was to determine whether the method of AF termination during ablation predicts mode of recurrence or long-term outcome. METHODS: Three hundred six patients with long-standing persistent AF, free of antiarrhythmic drugs (AADs), undergoing a first radiofrequency ablation (pulmonary vein [PV] antrum isolation and complex fractionated atrial electrograms) were prospectively included. Organized atrial tachyarrhythmias (AT) that occurred during AF ablation were targeted. AF termination mode during ablation was studied in relation to other variables (characteristics of arrhythmia recurrence, redo procedures, the use of adenosine/isoproterenol for redo, and comparison of focal versus macroreentrant ATs). Long-term maintenance of SR was assessed during the follow-up. RESULTS: During AF ablation, six of 306 patients converted directly to SR, 172 patients organized into AT (with 38 of them converting in SR with further ablation), and 128 did not organize or terminate and were cardioverted. Two hundred eleven of 306 patients (69%) maintained in long-term SR without AADs after a mean follow-up of 25 +/- 6.9 months, with no statistical difference between the various AF termination modes during ablation. Presence or absence of organization during ablation clearly predicted the predominant mode of recurrence, respectively, AT or AF (P = .022). Among the 74 redo ablation patients, 24 patients (32%) had extra PV triggers revealed by adenosine/isoproterenol. Termination of focal ATs was correlated with higher long-term success rate (24/29, 83%) than termination of macroreentrant ATs (20/35, 57%; P = .026). CONCLUSION: AF termination during ablation (conversion to AT or SR) could predict the mode of arrhythmia recurrence (AT vs. AF) but did not impact the long-term SR maintenance after one or two procedures. AT termination with further ablation did not correlate with better long-term outcome, except with focal ATs, for which termination seems critical.

Relationship between catheter forces, lesion characteristics, "popping," and char formation: experience with robotic navigation system.

INTRODUCTION: Popping, char and perforation are complications that can occur following catheter ablation. We measured the amount of grams (g) applied to the endocardium during ablation using a sensor incorporated in the long sheath of a robotic system. We evaluated the relationship between lesion formation, pressure, and the development of complications. METHODS: Using a robotic navigation system, lesions were placed in the left atrium (LA) at six settings, using a constant duration (40 seconds) and flow rate of either 17 cc/min or 30 cc/min with an open irrigated catheter (OIC). Evidence of complications was noted and lesion location recorded for later analysis at necropsy. RESULTS: Lesions using 30 Watts (W) were more likely to be transmural at higher (>40 g) than lower (<30 g) pressures (75% vs 25%, P < 0.001). Significantly higher number of lesions using >40 g of pressure demonstrated "popping" and crater formation as compared with lesions with 20-30 g of pressure (41% vs 15%, P = 0.008). A majority of lesions placed using higher power (45 W) with higher pressures (>40 g) were associated with char and crater formation (66.7%). No lesions using 10 g of pressure were transmural, regardless of the power. Lesions placed with a power setting less than 35 W were more likely to result in "relative" sparing of the endocardial surface than lesions at a power setting higher than 35 W (62% vs 33.3%, P = 0.02) regardless of the pressure. CONCLUSIONS: When using an OIC, lower power settings (

Pulmonary vein calcification by EBCT in patients with drug refractory nonvalular atrial fibrillation.

INTRODUCTION: Pulmonary veins in patients with atrial fibrillation (AF) have been shown to be highly arrhythmogenic. Calcification in these veins may play an adjunctive role in the pathogenesis of AF. METHODS AND RESULTS: A case control study was performed in patients with drug refractory nonvalvular AF whose preablation computed tomography chest scans demonstrated pulmonary vein (PV) calcification. Eight out of 48 patients with PV calcification were compared to 50 patients without AF who underwent electron beam computed tomography coronary artery calcium scores. These patients were matched for age, gender, coronary artery calcium scores, and the presence of PV calcification. The mean age of the combined group was 57 +/- 9 years and 60% were men. The mean total PV calcium score was significantly higher at 199 +/- 112 in patients with AF compared to 106 +/- 52 in controls (p = 0.018). Men had significantly higher total PV calcium score than women in both groups. CONCLUSION: Total PV calcium score was significantly higher in patients with atrial fibrillation. Increased PV calcification may play an adjunctive role in the pathogenesis in initiating and maintaining AF.