Arun Kanmanthareddy

FREEDOM FROM RECURRENT VENTRICULAR TACHYCARDIA AFTER CATHETER ABLATION IS ASSOCIATED WITH IMPROVED SURVIVAL IN PATIENTS WITH STRUCTURAL HEART DISEASE: AN INTERNATIONAL VT ABLATION CENTER COLLABORATIVE GROUP STUDY

BACKGROUND The impact of catheter ablation of ventricular tachycardia (VT) on all-cause mortality remains unknown. OBJECTIVE The purpose of this study was to examine the association between VT recurrence after ablation and survival in patients with scar-related VT. METHODS Analysis of 2061 patients with structural heart disease referred for catheter ablation of scar-related VT from 12 international centers was performed. Data on clinical and procedural variables, VT recurrence, and mortality were analyzed. Kaplan-Meier analysis was used to estimate freedom from recurrent VT, transplant, and death. Cox proportional hazards frailty models were used to analyze the effect of risk factors on VT recurrence and mortality. RESULTS One-year freedom from VT recurrence was 70% (72% in ischemic and 68% in nonischemic cardiomyopathy). Fifty-seven patients (3%) underwent cardiac transplantation, and 216 (10%) died during follow-up. At 1 year, the estimated rate of transplant and/or mortality was 15% (same for ischemic and nonischemic cardiomyopathy). Transplant-free survival was significantly higher in patients without VT recurrence than in those with recurrence (90% vs 71%, P<.001). In multivariable analysis, recurrence of VT after ablation showed the highest risk for transplant and/or mortality [hazard ratio 6.9 (95% CI 5.3-9.0), P<.001]. In patients with ejection fraction <30% and across all New York Heart Association functional classes, improved transplant-free survival was seen in those without VT recurrence. CONCLUSION Catheter ablation of VT in patients with structural heart disease results in 70% freedom from VT recurrence, with an overall transplant and/or mortality rate of 15% at 1 year. Freedom from VT recurrence is associated with improved transplant-free survival, independent of heart failure severity.

Impact of left atrial appendage exclusion using an epicardial ligation system (LARIAT) on atrial fibrillation burden in patients with cardiac implantable electronic devices

BACKGROUND The left atrial appendage (LAA) is a well-known source of atrial arrhythmia and atrial fibrillation (AF). OBJECTIVE The purpose of this study was to determine whether LAA exclusion using the LARIAT device would decrease AF burden. METHODS A total of 50 patients with AF and cardiac implantable electronic devices who underwent successful LAA exclusion were enrolled in this prospective observational study. AF burden before LAA exclusion (baseline) and 3 and 12 months after exclusion was assessed by device interrogation. RESULTS AF burden at 3-month follow-up (42% ± 34%) was significantly lower compared to baseline (76% ± 33%, P < .0001). The reduction in AF burden was sustained at 12 months (59% ± 26%, P < .001). Subgroup analysis revealed that AF burden at 3-month follow-up was similarly reduced in both paroxysmal AF (n = 19) and nonparoxysmal AF (n = 31). However, there was no reduction in AF burden in patients with paroxysmal AF at 12 months. AF burden in patients with known AF triggers in the LAA (n = 9) was significantly reduced at 3 months (52% ± 35%) and 12 months (42% ± 19%) compared to respective baseline (84 ± 31%, P < .0001). CONCLUSION LAA exclusion appears to reduce AF burden. The presence of AF triggers in the LAA appears to be the strongest predictor of AF reduction. The study underscores the role of the LAA in arrhythmogenesis for AF and highlights the complementary role of LAA exclusion in restoration of normal sinus rhythm.

IMPACT OF LEFT ATRIAL APPENDAGE EXCLUSION ON SYSTEMIC HOMEOSTASIS (THE LAA HOMEOSTASIS STUDY)

Left atrial appendage (LAA) a major source of ANP (atrial natriuretic peptide) which can influence the endocrine axis. The physiologic effects of LAA exclusion on systemic homeostasis have not been previously studied. 37 consecutive patients (7 women (19%)/30 men (81%); age 71±8; CHAD2 2.6±1.1;

Effect of Atrial Fibrillation Ablation on Gastric Motility The Atrial Fibrillation Gut Study

Background—Collateral damage to the vagal nerve and the upper gastrointestinal (UGI) system during atrial fibrillation ablation has not been systematically evaluated. Methods and Results—We performed a prospective, observational study assessing the effect of atrial fibrillation ablation on the function of the vagus nerve/UGI system. All patients underwent esophageal manometry, gastric emptying study, and sham-feeding test (corresponding to esophageal, gastric, and small intestinal function evaluation, respectively) before ablation (baseline) and subsequently at 24 hours, 90 days, and 180 days after the procedure. In addition, UGI symptom assessment using the patient assessment of upper gastrointestinal disorders–symptom severity index (PAGI-SYM) questionnaire was performed at baseline and during each of the subsequent evaluations. Of the 27 patients enrolled in the study, 9 (33%) patients had abnormal UGI function at baseline; defined as at least one of the 3 abnormal tests. At 24 hours after the radiofrequency catheter ablation, 20 (74%) patients had at least 1 new abnormality on the UGI function tests (P<0.001). New onset esophageal dysmotility, delayed gastric emptying time, and abnormal sham-feeding tests were observed in 13 (48%), 13 (48%), and 9 (33%) patients, respectively. Mean PAGI-SYM scores increased from 7.78±6.6 at baseline to 15.56±13.4 (P=0.002) at 24 hours. New onset abnormalities persisted in 9 (33%) patients at 3 months and normalized in all patients at 6 months. Conclusions—Atrial fibrillation ablation results in functional impairment of the UGI system, including the esophagus, stomach, and small intestine. This impairment is transient and is probably mediated by the injury to the components of the vagal nerve. Clinical Trial Registration—URL: http://clinicaltrials.gov. Unique Identifier: NCT01396356.

Initial experience with post Lariat left atrial appendage leak closure with Amplatzer septal occluder device and repeat Lariat application

BACKGROUND Left atrial appendage (LAA) ligation with the Lariat device is a therapeutic option to prevent thromboembolic stoke in patients with nonvalvular atrial fibrillation (AF) at high risk for systemic thromboembolization and bleeding related to use of anticoagulation. In rare cases, this procedure could leave the LAA incompletely ligated with continued risk of stroke. OBJECTIVE The purpose of this study was to investigate the incidence and characteristics of LAA leak following ligation using the Lariat device and the feasibility of leak closure with the Amplatzer septal occluder device or a repeat Lariat application. METHODS Seventy-one consecutive patients who underwent LAA ligation by the Lariat device were followed-up with transesophageal echocardiography to evaluate for the presence of appendage leaks, characterization of the leaks, and the presence of any thrombus. Patients with LAA leaks underwent definite closure of the leak. RESULTS Six patients had LAA leaks with a mean leak size of 4.3 ± 0.6 mm. All leaks were concentric in nature. None of the patients had LAA thrombus. Leaks in 5 of these patients were successfully closed using an Amplatzer septal occluder device (St. Jude Medical); the leak in the sixth patient was closed using a repeat Lariat procedure. CONCLUSION LAA leaks from incomplete ligation of the LAA following the Lariat procedure are not uncommon and could be successfully closed with an Amplatzer septal occluder device or a repeat Lariat procedure.

The Effect of Atrial Fibrillation Ablation on Gastric Motility "The AF Gut Study"

Background—Collateral damage to the vagal nerve and the upper gastrointestinal (UGI) system during atrial fibrillation ablation has not been systematically evaluated. Methods and Results—We performed a prospective, observational study assessing the effect of atrial fibrillation ablation on the function of the vagus nerve/UGI system. All patients underwent esophageal manometry, gastric emptying study, and sham-feeding test (corresponding to esophageal, gastric, and small intestinal function evaluation, respectively) before ablation (baseline) and subsequently at 24 hours, 90 days, and 180 days after the procedure. In addition, UGI symptom assessment using the patient assessment of upper gastrointestinal disorders–symptom severity index (PAGI-SYM) questionnaire was performed at baseline and during each of the subsequent evaluations. Of the 27 patients enrolled in the study, 9 (33%) patients had abnormal UGI function at baseline; defined as at least one of the 3 abnormal tests. At 24 hours after the radiofrequency catheter ablation, 20 (74%) patients had at least 1 new abnormality on the UGI function tests (P<0.001). New onset esophageal dysmotility, delayed gastric emptying time, and abnormal sham-feeding tests were observed in 13 (48%), 13 (48%), and 9 (33%) patients, respectively. Mean PAGI-SYM scores increased from 7.78±6.6 at baseline to 15.56±13.4 (P=0.002) at 24 hours. New onset abnormalities persisted in 9 (33%) patients at 3 months and normalized in all patients at 6 months. Conclusions—Atrial fibrillation ablation results in functional impairment of the UGI system, including the esophagus, stomach, and small intestine. This impairment is transient and is probably mediated by the injury to the components of the vagal nerve. Clinical Trial Registration—URL: http://clinicaltrials.gov. Unique Identifier: NCT01396356.

Early versus late surgical intervention or medical management for infective endocarditis: A systematic review and meta-analysis

Objective Infective endocarditis is associated with high morbidity and mortality and optimal timing for surgical intervention is unclear. We performed a systematic review and meta-analysis to compare early surgical intervention with conservative therapy in patients with infective endocarditis. Methods PubMed, Cochrane, EMBASE, CINAHL and Google-scholar databases were searched from January 1960 to April 2015. Randomised controlled trials, retrospective cohorts and prospective observational studies comparing outcomes between early surgery at 20 days or less and conservative management for infective endocarditis were analysed. Results A total of 21 studies were included. OR of all-cause mortality for early surgery was 0.61 (95% CI 0.50 to 0.74, p<0.001) in unmatched groups and 0.41 (95% CI 0.31 to 0.54, p<0.001) in the propensity-matched groups (matched for baseline variables). For patients who had surgical intervention at 7 days or less, OR of all-cause mortality was 0.61 (95% CI 0.39 to 0.96, p=0.034) and in those who had surgical intervention within 8–20 days, the OR of mortality was 0.64 (95% CI 0.48 to 0.86, p=0.003) compared with conservative management. In propensity-matched groups, the OR of mortality in patients with surgical intervention at 7 days or less was 0.30 (95% CI 0.16 to 0.54, p<0.001) and in the subgroup of patients who underwent surgery between 8 and 20 days was 0.51 (95% CI 0.35 to 0.72, p<0.001). There was no significant difference in in-hospital mortality, embolisation, heart failure and recurrence of endocarditis between the overall unmatched cohorts. Conclusion The results of our meta-analysis suggest that early surgical intervention is associated with significantly lower risk of mortality in patients with infective endocarditis.

The Impact of Atrial Fibrillation and Its Treatment on Dementia

Atrial fibrillation (AF) is a very common tachyarrhythmia and is becoming increasingly prevalent, while dementia is a neurological condition manifested as loss of memory and cognitive ability. Both these conditions share several common risk factors. It is becoming increasingly evident that AF increases the risk of dementia. There are several pathophysiological mechanisms by which AF can cause dementia. AF increases the stroke risk and strokes are strongly associated with dementia. Besides stroke, altered cerebral blood flow in AF and cerebral microbleeds from anticoagulation may enhance the risk of dementia. Maintaining sinus rhythm may therefore decrease this risk. Catheter ablation is emerging as an effective alternative to maintain patients in sinus rhythm. This procedure has also shown promise in decreasing the risk of all types of dementia. Besides maintaining sinus rhythm and oral anticoagulation, aggressive risk factor modification may reduce the likelihood or delay the onset of dementia.

Left atrial thrombus formation after successful left atrial appendage ligation: case series from a nationwide survey.

Percutaneous left atrial appendage (LAA) exclusion can be performed using endocardial occlusion devices or an endoepicardially placed suture delivery device (1-3). Thrombus formation on endocardial occlusion devices (Watchman, Boston Scientific, Marlborough, Massachusetts; or Amplatzer Cardiac Plug [ACP], St. Jude Medical, St. Paul, Minnesota) (1,2) has been attributed to platelet aggregation in the setting of a foreign body in the left atrium (LA). With the percutaneous endoepicardial ligation technique (Lariat, SentreHEART, Redwood City, California), there is no foreign body left behind, and the risk of thrombus formation should be insignificant. This study describes the clinical course of LA thrombi after the Lariat procedure in 19 patients. We conducted a nationwide survey of physicians performing procedures with the Lariat device in the United States to identify patients who developed LA thrombus after the procedure. Our study cohort comprised patients found to have LA thrombus post-procedure. Post-procedure surveillance imaging was not uniform across centers. Most patients underwent transesophageal echocardiogram (TEE)/computed tomography at 1 to 3 months post-procedure. Anticoagulation/antiplatelet therapy was initiated immediately after detection of LA thrombus. We collected demographic, clinical, and pre-procedural imaging characteristics of patients. Procedural variables and clinical course of patients after thrombus detection were recorded. Statistical analyses were performed using SPSS version 19.0 for Windows (SPSS, Inc., Chicago, Illinois). A total of 47 operators participated in the survey. Routine post-procedure imaging was performed by 44 (93.6%) operators. Three (6.4%) operators performed imaging only if clinically indicated. Routine post-procedure follow-up imaging was performed at 1 to 3 months and 3 to 6 months by 80% and 40% of the operators, respectively. Of the 964 patients who underwent the procedure, 19 (2%) had an LA thrombus. Table 1 lists some patient characteristics and includes follow-up data of the 19 patients. TABLE 1 Patient Characteristics and Follow-Up (n = 19) LA thrombus was detected within 90 days in 15 (79%) patients. TEEs performed in the first 6 months were negative for thrombi in 2 patients with clots discovered >200 days after the procedure. Eighteen patients received oral anticoagulants after detection of LA thrombus, whereas 1 patient received antiplatelet therapy. Thrombus remained unchanged at 90 days in the latter patient, requiring a switch to rivaroxaban. Serial TEEs were performed until thrombus resolution. Oral anticoagulation was discontinued in 16 patients after clot resolution, whereas 3 patients with unresolved thrombi remained on anticoagulation (30, 58, and 80 days, respectively). None of the patients had clinical evidence of stroke or peripheral embolism during follow-up. Our study highlights that the risk of LA thrombus formation with the device is low (2%). Most (79%) cases were detected within the first 90 days. Prompt initiation of anticoagulation can lead to thrombus resolution. This is the first investigation to describe the clinical course of LA thrombus post-procedure in a large cohort of patients receiving the Lariat device. In a clinical study involving 89 patients, no case of LA thrombus was detected on the 30-day post-procedure TEE. However, 1 patient had an LA thrombus away from the site of occlusion at 1-year follow-up (3). Our study is consistent in that, although uncommon, an LA thrombus can develop after the procedure. The pathophysiology of LA thrombus formation after the Lariat procedure remains unclear. Focal endocardial damage and inflammation around the LAA orifice secondary to tissue compression from the Lariat suture, causing edema and ischemic necrosis around the ligation site, can increase the propensity for LA thrombus formation. In our study, 17 of 19 (89%) patients developed a thrombus at the ligation site. Currently, there are no clear guidelines on LA thrombus surveillance after LAA ligation. We strongly support a follow-up TEE 30 to 90 days post-procedure. Given that the risk of thrombus formation is greatest during the first 3 months post-procedure, it may be appropriate for patients to receive antiplatelet or anticoagulant therapy during this period. The risk of LA thrombus in the absence of anticoagulation use post-procedure is low and is more frequently seen during the first 3 months after LAA ligation. Periodic imaging studies are essential for early detection of an LA thrombus. With prompt initiation of anticoagulation and close supervision, an LA thrombus can be managed safely.

Impact of gender on outcomes after atrial fibrillation ablation

a Metrohealth Medical Center, Case Western Reserve University, Cleveland, OH, United States b Division of Cardiovascular Diseases, Cardiovascular Research Institute, Mid-America Cardiology, University of Kansas Hospital & Medical Center, Kansas City, KS, United States c Division of Cardiovascular Medicine, State University of New York Downstate Medical Center, NY, United States d Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, United States e Texas Cardiac Arrhythmia Institute, Austin, TX, United States f Department of Biomedical Engineering, University of Texas, Austin, TX, United States g Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, United States