Economic impact of contact force sensing in catheter ablation for atrial fibrillation.

AIMS: The TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) clinical trial compared clinical outcomes using a contact force (CF) sensing ablation catheter (TactiCath) with a catheter that lacked CF measurement. This analysis links recorded events in the TOCCASTAR study and a large claims database, IBM MarketScan®, to determine the economic impact of using CF sensing during atrial fibrillation (AF) ablation. METHODS AND RESULTS: Clinical events including repeat ablation, use of antiarrhythmic drugs, hospitalization, perforation, pericarditis, pneumothorax, pulmonary edema, pulmonary vein stenosis, tamponade, and vascular access complications were adjudicated in the year after ablation. CF was characterized as optimal if greater than or equal to 90% lesion was performed with greater than or equal to 10 g of CF. A probabilistic 1:1 linkage was created for subjects in MarketScan® with the same events in the year after ablation, and the cost was evaluated over 10 000 iterations. Of the 279 subjects in TOCCASTAR, 145 were ablated using CF (57% with optimal CF), and 134 were ablated without CF. In the MarketScan® cohort, 9811 subjects who underwent AF ablation were used to determine events and costs. For subjects ablated with optimal CF, total cost was $19 271 ± 3705 in the year after ablation. For ablation lacking CF measurement, cost was $22 673 ± 3079 (difference of $3402, P < .001). In 73% of simulations, optimal CF was associated with lower cost in the year after ablation. CONCLUSION: Compared to ablation without CF, there was a decrease in healthcare cost of $3402 per subject in the first year after the procedure when optimal CF was used.

Electrocardiographic optimization techniques in resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a cornerstone of therapy for patients with heart failure, reduced left ventricular (LV) ejection fraction, and a wide QRS complex. However, not all patients respond to CRT: 30% of CRT implanted patients are currently considered clinical non-responders and up to 40% do not achieve LV reverse remodelling. In order to achieve the best CRT response, appropriate patient selection, device implantation, and programming are important factors. Optimization of CRT pacing intervals may improve results, increasing the number of responders, and the magnitude of the response. Echocardiography is considered the reference method for atrioventricular and interventricular (VV) intervals optimization but it is time-consuming, complex and it has a large interobserver and intraobserver variability. Previous studies have linked QRS shortening to clinical response, echocardiographic improvement and favourable prognosis. In this review, we describe the electrocardiographic optimization methods available: 12-lead electrocardiogram; fusion-optimized intervals (FOI); intracardiac electrogram-based algorithms; and electrocardiographic imaging. Fusion-optimized intervals is an electrocardiographic method of optimizing CRT based on QRS duration that combines fusion with intrinsic conduction. The FOI method is feasible and fast, further reduces QRS duration, can be performed during implant, improves acute haemodynamic response, and achieves greater LV remodelling compared with nominal programming of CRT.

Three-Dimensional Cardiac Mapping Characterizes Ventricular Contractile Patterns during Cardiac Resynchronization Therapy Implant: A Feasibility Study.

BACKGROUND: Electroanatomic mapping systems track the position of electrodes in the heart. We assessed the feasibility of characterizing left ventricular (LV) performance during cardiac resynchronization therapy (CRT) implant utilizing an electroanatomic mapping system to track the motion of CRT lead electrodes, thus deriving ventricular contractility surrogates. METHODS: During CRT implant, atrial, right ventricular (RV), and LV leads were connected to the EnSite NavX™ mapping system (St. Jude Medical Inc., St. Paul, MN, USA). The relative displacement of electrodes was averaged over 10 cardiac cycles during RV, LV, and biventricular (BiV) pacing in DOO mode. Three contractility surrogates indicative of ventricular performance were extracted from the RV-LV distance waveform: systolic slope (SS), time to peak systolic contraction (TPSC), and fractional shortening (FS). RESULTS: In the 20 patients included, there were detectable differences in each of the three contractility surrogates responding to the different pacing configurations. Median SS varied 42%, median TPSC varied 35%, and median FS varied 19% across RV, LV, and BiV pacing interventions. The RV-LV distance waveform showed subtle sensitivity to varying pacing timing cycles when measured in a subset of patients. For all pacing configurations, RV-LV distance waveforms were stable during 2-minute recordings. CONCLUSIONS: Tracking the motion of CRT pacing electrodes with a mapping system to derive contractility surrogates during implant is feasible.

Incidence and Predictors of Pacemaker Implantation in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has emerged as an alternative treatment for patients with symptomatic aortic stenosis who are at high risk for surgical aortic valve replacement. The development of conduction abnormalities is a major complication in the postprocedural period of TAVR. OBJECTIVES: The objective of this study was to investigate the development of postprocedural conduction abnormalities and the requirement of permanent pacemaker (PPM) implantation in patients undergoing TAVR. METHODS: Data from 137 consecutive patients who underwent TAVR (Edwards SAPIEN valve, Edwards Lifesciences, Irvine, CA, USA) between June 2008 and October 2012 were reviewed. Patients with prior history of PPM (n = 27) were excluded. The role of various predictors for pacemaker implantation after TAVR, including the valve index (calculated as [valve size/left ventricular outflow tract diameter] × 100) was investigated. RESULTS: A total of 31/110 (28.2%) patients required implantation of a PPM after TAVR. The median time to implantation of a PPM was 5 days after the procedure. The development of postprocedural complete heart block was the most common indication for implantation of a PPM (16/31; 51.6%). On multivariate analysis, the presence of preexisting right bundle branch block (RBBB) was found to be a strong predictor of PPM implantation after TAVR (adjusted odds ratio: 4.87; 95% confidence interval: 1.29-18.46, P = 0.020). Using the receiver operated curve analysis, a cut-off value of valve index of 128 was found to be a strong predictor for PPM implantation with a sensitivity of 73% and specificity of 61% (c statistic = 0.68). CONCLUSIONS: This study identified the presence of prior RBBB and a valve index of 128 as important risk factors for PPM implantation after TAVR. A larger implanted valve size relative to left ventricular outflow tract diameter leads to a greater compression of the intrinsic conduction system, increasing the need for pacemaker placement.

Single- Versus Dual-Chamber Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death in the United States.

Background Routine addition of an atrial lead during an implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden cardiac death, in patients without pacing indications, was not shown beneficial in contemporary studies. We aimed to investigate the use and safety of single- versus dual-chamber ICD implantations in these patients. Methods and Results Using the National Inpatient Sample database, we identified patients with no pacing indications who underwent primary-prevention ICD implantation in the United States between 2015 and 2019. Sociodemographic and clinical characteristics, as well as in-hospital complications, were analyzed. Multivariable logistic regression was used to identify predictors of in-hospital complications. An estimated total of 15 940 patients, underwent ICD implantation for primary prevention of sudden cardiac death during the study period, 8860 (55.6%) received a dual-chamber ICD. The mean age was 64 years, and 66% were men. In-hospital complication rates in the dual-chamber ICD and single-chamber ICD group were 12.8% and 10.7%, respectively (P<0.001), driven by increased rates of pneumothorax/hemothorax (4.6% versus 3.4%; P<0.001) and lead dislodgement (3.6% versus 2.3%; P<0.001) in the dual-chamber ICD group. Multivariable analyses confirmed atrial lead addition as an independent predictor for "any complications" (odds ratio [OR], 1.1 [95% CI, 1.0-1.2]), for pneumo/hemothorax (odds ratio, 1.1 [95% CI, 1.0-1.4]), and for lead dislodgement (odds ratio, 1.3 [95% CI, 1.1-1.6]). Conclusions Despite lack of evidence for clinical benefit, dual-chamber ICDs are implanted for primary prevention of sudden cardiac death in a majority of patients who do not have pacing indication. This practice is associated with increased risk of periprocedural complications. Avoidance of routine implantation of atrial leads will likely improve safety outcomes.

Left atrial appendage exclusion in atrial fibrillation.

Although oral anticoagulants (OACs) are first-line therapy for stroke prevention in patients with atrial fibrillation (AF), some patients cannot be treated with OACs due to absolute or relative contraindications. Left atrial appendage (LAA) exclusion techniques have been developed over the years as a therapeutic alternative for stroke prevention. In this paper, we review the evolution of surgical techniques, employed as an adjunct to cardiac surgery or as a stand-alone procedure, as well as the recently introduced and widely utilized percutaneous LAA occlusion techniques. Until recently, data on surgical LAAO were limited and based on non-randomized studies. We focus on recently published randomized data which strongly support an add-on surgical LAAO in eligible patients during cardiac surgery and could potentially change current practice guidelines. In recent years, the trans-catheter techniques for LAA occlusion have emerged as another, less invasive alternative for patients who cannot tolerate oral anticoagulation. We review the growing body of evidence from prospective studies and registries, focusing on the two systems which are in widespread clinical use nowadays: the Watchman and Amulet type devices. These data show favorable results for both Watchman and Amulet devices, setting them as an important tool in our arsenal for stroke reduction in AF patients, especially in those who have contraindications for OACs. A better understanding of the different therapeutic alternatives, their specific benefits, and downfalls in different patient populations can guide us in tailoring the optimal therapeutic approach for stroke reduction in our AF patients.

Inpatient vs. elective outpatient cardiac resynchronization therapy device implantation and long-term clinical outcome.

AIMS: It remains unclear whether cardiac resynchronization therapy (CRT) device implantation during inpatient (IP) hospitalization affords the same benefit as elective outpatient (OP) implantation. We hypothesized that IPs undergoing CRT device implantation during acute hospitalization may have worse outcomes compared with elective OP implantation. METHODS AND RESULTS: We retrospectively separated patients undergoing CRT implants at Massachusetts General Hospital into OP (n= 196) and IP (n = 105) cohorts. Long-term outcomes, measured as heart failure (HF) hospitalization, all-cause mortality, ventricular assist device placement, or heart transplant over a 2-year follow-up period, were estimated by the Kaplan-Meier method. Propensity scores were generated to balance the baseline co-morbidities between IP and OP. Baseline age, gender, left ventricular ejection fraction, and aetiology of cardiomyopathy were comparable between OP and IP (66.8 ± 11.8 vs. 67.5 ± 13.4 years, 78 vs. 84% males, 24 vs. 23%, and 39 vs. 50% ischaemic, P = NS). Inpatients had greater burden of diabetes mellitus (40 vs. 27%, P = 0.028), renal insufficiency (47 vs. 25%, P< 0.001), and right ventricular dysfunction (54 vs. 39%, P = 0.026) compared with OPs. At 2-year follow-up, IP implant was associated with greater risk of HF hospitalization (HR 1.6, 95% CI 1.03-2.48, P = 0.038) compared with elective OP implants. After propensity score adjustment, there was no statistically significant difference in HF hospitalization between the IP and OP groups (HR 1.031, 95% CI 0.61-1.78, P = 0.91). CONCLUSION: Compared with OP CRT implants, IPs are at increased risk for recurrent HF hospitalization; however, the increased risk is attributable to greater co-morbidities in the IP population.

Atrial Fibrillation-Mediated Cardiomyopathy.

AF-mediated cardiomyopathy (AMC) is an important reversible cause of heart failure that is likely underdiagnosed in today's clinical practice. AMC describes AF either as the sole cause for ventricular dysfunction or exacerbating ventricular dysfunction in patients with existing cardiomyopathy or heart failure. Studies suggest that irreversible ventricular and atrial remodeling can occur in AMC, making timely diagnosis and intervention critical to optimize clinical outcome. Clinical correlation between AF onset/burden and progression of cardiomyopathy/heart failure symptoms provides strong evidence for the diagnosis of AMC. Cardiac MRI, continuous cardiac monitoring, and biomarkers are important diagnostic tools. From the therapeutic standpoint, early data suggest that AF ablation may improve long-term outcomes in AMC patients compared with medical rate and rhythm control. Patients with more AF burden and less severe underlying structural heart disease are more likely to experience left ventricle function recovery with successful AF ablation. Despite recent advances, significant knowledge gaps exist in our understanding of the epidemiology, mechanisms, diagnosis, management strategies, and prognosis of AMC.

Diagnostic Accuracy of a Novel Mobile Phone Application for the Detection and Monitoring of Atrial Fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in adults, associated with significant morbidity, increased mortality, and rising health-care costs. Simple and available tools for the accurate detection of arrhythmia recurrence in patients after electrical cardioversion (CV) or ablation procedures for AF can help to guide therapeutic decisions. We conducted a prospective, single-center study to evaluate the accuracy of Cardiio Rhythm Mobile Application (CRMA) for AF detection. Patients >18 years of age who were scheduled for elective CV for AF were enrolled in the study. CRMA finger pulse recordings, utilizing an iPhone camera, were obtained before (pre-CV) and after (post-CV) the CV. The findings were validated against surface electrocardiograms. Ninety-eight patients (75.5% men), mean age of 67.7 ± 10.5 years, were enrolled. No electrocardiogram for validation was available in 1 case. Pre-CV CRMA readings were analyzed in 97 of the 98 patients. Post-CV CRMA readings were analyzed for 92 of 93 patients who underwent CV. One patient left before the recording was obtained. The Cardiio Rhythm Mobile Application correctly identified 94 of 101 AF recordings (93.1%) as AF and 80 of 88 non-AF recordings (90.1%) as non-AF. The sensitivity was 93.1% (95% confidence interval [CI] = 86.9% to 97.2%) and the specificity was 90.9% (95% CI = 82.9% to 96.0%). The positive predictive value was 92.2% (95% CI = 85.8% to 95.8%) and the negative predictive value was 92.0% (95% CI = 94.8% to 95.9%). In conclusion, the CRMA demonstrates promising potential in accurate detection and discrimination of AF from normal sinus rhythm in patients with a history of AF.

Effectiveness of a strategy to reduce major vascular complications from catheter ablation of atrial fibrillation.

INTRODUCTION: Vascular access site complications are among the most frequently observed complications after catheter ablation of atrial fibrillation (AF). We sought to determine whether implementation of a three-point strategy would reduce major vascular complications resulting from catheter ablation of atrial fibrillation. METHODS: Three hundred twenty-four consecutive patients undergoing catheter ablation of AF were studied: 162 in each group (with and without the test strategy). The three-point test strategy included the following: (1) performing the procedure on Warfarin with an INR from 2.0 to 3.5 (mean INR of 2.44), rather than stopping Warfarin prior to the procedure and bridging the patient back to Warfarin with low molecular heparin, (2) using a small 21 G needle to obtain femoral vein access rather than a larger 18 G needle, and (3) eliminating the use of femoral arterial access. Major vascular complications were defined as complications requiring either blood transfusion or surgical/percutaneous repair. RESULTS: Major vascular complications were identified in 6/162 (3.7%) of the control patients without the strategy listed above compared to 0/162 (0%) in the test patients with implementations of this strategy (p = 0.03). The frequency of other complications was comparable between the two groups (tamponade requiring drainage: 1/162 control, 1/162 test; pericardial effusion not requiring drainage: 0/162 control, 1/162 test; transient ischemic attack: 1/162 control and 1/162 test; stroke: 1/162 control, 0/162 test): (p = NS for each). CONCLUSIONS: A three-point strategy including performing procedures with therapeutic Warfarin, using a small gauge needle to obtain vascular access and eliminating femoral arterial access significantly reduced major vascular access complications and did not affect other major complications, during catheter ablation of AF. Implementation of this strategy may be useful to reduce groin complications resulting from AF ablation.

Echocardiographic measures of acute haemodynamic response after cardiac resynchronization therapy predict long-term clinical outcome.

AIMS: Although acute haemodynamic improvement in response to cardiac resynchronization therapy (CRT) is reflective of a favourable cardiac contractile response, there is limited information regarding not only its ability to predict long-term clinical outcome but also cardiac-substrate-specific differences in the prognostic value of this measure. METHODS AND RESULTS: Fifty-three heart failure patients (69 +/- 11 years) with low left ventricle ejection fraction (LVEF) (22 +/- 6%), wide QRS (169 +/- 31 ms), and indications for CRT were included. There were no significant differences in age, New York Heart Association (NYHA) class, medications, QRS width, or LVEF between ischaemic (n = 37) and non-ischaemic (n = 16) groups. Echocardiograms were performed within 24 h of implantation with device OFF and ON. Acute haemodynamic response was measured as LV dP/dt derived from the CW Doppler of mitral regurgitation. Percentage change in dP/dt was used to classify patients: high- (HR: DeltadP/dt > 25%) or poor-responders (PR: DeltadP/dt

Three-dimensional anatomy of the left atrium by magnetic resonance angiography: implications for catheter ablation for atrial fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug-refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported. METHODS: Magnetic resonance angiography (MRA) was performed in patients prior to undergoing PVI. Fifty consecutive patients with a RMPV identified by MRA were included in this study. Ridges associated with the left pulmonary veins were examined in an additional 30 patients who did not have a RMPV. Endoluminal views were reconstructed from the gadolinium-enhanced, breath-hold three-dimensional MRA data sets. Measurements were performed using electronic calipers. RESULTS: The width of the ridge separating the LPV from the LAA was found to be 3.7 +/- 1.1 mm at its narrowest point. The segment of this ridge with a width of 5 mm or less was 16.6 +/- 6.4 mm long. The width of the ridges separating the RMPV from the RSPV and the RIPV was found to be 3.0 +/-1.5 mm and 3.1 +/-1.8 mm, respectively. There were no significant differences between LPV ridges for patients with versus without a RMPV. CONCLUSION: The width of the ridges of atrial tissue separating LPV from the LAA and the RMPV from its neighboring veins may explain the technical challenge in obtaining stable catheter positions in these areas. A detailed assessment of the anatomy of these regions may improve the safety and efficacy of catheter ablation at these sites.