Identification of 2 Distinct Boundaries Distinguishes Critical From Noncritical Isthmuses in Ablating Atypical Atrial Flutter.

BACKGROUND: Atypical atrial flutters often involve complex circuits. Classic methods of identifying ablation targets, including detailed electroanatomical mapping and entrainment within a well-defined isthmus, may not always be sufficient to allow the critical isthmus to be delineated and ablated, with flutter termination and prevention of reinduction. OBJECTIVES: This study sought a systematic method to classify conduction barriers and isthmuses as critical or noncritical that would improve understanding and ablation success. We also sought a construct unifying single- and dual-loop re-entry. Re-entrant circuits are bounded on 2 sides, although these are not consistently identified. We hypothesized 2 distinct critical boundaries, and a critical isthmus could be consistently defined without requiring entrainment, and ablation connecting these 2 boundaries would terminate tachycardia. METHODS: Activation maps were created electroanatomically. Conduction barriers were classified as noncritical barriers or critical boundaries. Critical boundaries showed sequential activation around the barrier, spanning ≥90% of the cycle length. Noncritical barriers showed nonsequential, parallel, or colliding activation or <90% of the cycle length. Only tissue separating the 2 critical boundaries defined a critical isthmus (CI); all others were considered noncritical. The effect of ablation across a CI was assessed. RESULTS: Complete maps were obtained in 128 cases in 121 patients (28 atypical right atrial, 100 left atrial). In all cases, 2 distinct critical boundaries were identified. Ablation across a CI connecting these critical boundaries terminated tachycardia in 123 of 128 cases (96.1%). Failures were due to inability to achieve block across the isthmus. CONCLUSIONS: Activation mapping of atypical atrial flutter allows consistent identification of 2 critical boundaries. Successful ablation connecting the 2 critical boundaries reliably results in termination of atypical atrial flutter.

Neurologic complications of atrial fibrillation: Pharmacologic and interventional approaches to stroke prevention.

Atrial fibrillation is a common cardiac arrhythmia that carries a risk of stroke. This is commonly stratified with the CHA2DS2-VASc score. Stroke risk can be reduced with anticoagulants or with interventions to close the left atrial appendage, the most common source of left atrial thrombi. While warfarin has been traditionally used as the only oral anticoagulant available, there are several direct oral anticoagulants that compare favorably with respect to both stroke and bleeding risk in randomized controlled trials. Multiple interventional options exist to close the left atrial appendage, but the Watchman device is the only one that compares favorably with warfarin in randomized controlled trials.

Trends and predictors of implantable cardioverter defibrillator implantation after sudden cardiac arrest: Insight from the national inpatient sample.

BACKGROUND: Implantable cardioverter defibrillator (ICD) has a class IA indication in survivors of sudden cardiac arrest (SCA) provided no reversible cause is identified. We sought to determine trends and predictors of ICD implant in SCA patients from a national sample of the United States population. METHODS AND RESULTS: Data were gathered from National Inpatient Sample (NIS) from January 2003 to December 2014. All patients ≥18 years of age with a primary discharge diagnosis of SCA, ventricular fibrillation (VF), ventricular flutter, and ventricular tachycardia (VT) were included. Patients died during hospitalization, had a previous ICD implant, and with a reversible cause of SCA were excluded. Primary outcome of interest was rate of new ICD implant at discharge. Logistic regression analysis was then performed to determine predictors for ICD implantation. A total of 176,876 patients were identified to have SCA, VF, ventricular flutter, and VT. After applying exclusion criteria, we were left with 22,054 patients. Out of this, 6,908 (31%) patients were implanted with an ICD prior to discharge. There was a linear trend toward reduced ICD utilization over our study period (40% in 2003 vs 25% in 2014, P trend = 0.0004). Advanced age, black race, and chronic renal disease are independently associated with low ICD utilization. CONCLUSION: We found low trend of ICD implant in survivors of SCA without any reversible cause. There is a need to identify etiologies behind low ICD utilization in this vulnerable group who are at most risk for a subsequent SCA.

Intracardiac versus transesophageal echocardiography to guide transcatheter closure of interatrial communications: Nationwide trend and comparative analysis.

OBJECTIVES: This study aimed to assess current temporal trends in utilization of ICE versus TEE guided closure of interatrial communications, and to compare periprocedural complications and resource utilization between the two imaging modalities. BACKGROUND: While transesophageal echocardiography (TEE) has historically been used to guide percutaneous structural heart interventions, intracardiac echocardiography (ICE) is being increasingly utilized to guide many of these procedures such as closure of interatrial communications. METHODS: Using the Nationwide Inpatient Sample, all patients aged >18 years, who underwent ASD or PFO closure with either ICE or TEE guidance between 2003 and 2014 were included. Comparative analysis of outcomes and resource utilization was performed using a propensity score-matching model. RESULTS: ICE guidance for interatrial communication closure increased from 9.7% in 2003 to 50.6% in 2014. In the matched model, the primary endpoint of major adverse cardiovascular events occurred less frequently in the ICE group versus the TEE group (11.1% vs 14.3%, respectively, P = 0.008), mainly driven by less vascular complications in the ICE group (0.5% vs 1.3%, P = 0.045). Length of stay was shorter in the ICE group (3 ± 4 vs 4 ± 4 days, P < 0.0001). Cost was similar in the two groups 18 454 ± 17 035$ in the TEE group vs 18 278 ± 15 780$ in the ICE group (P = 0.75). CONCLUSIONS: Intracardiac echocardiogram utilization to guide closure of interatrial communications has plateaued after a rapid rise throughout the 2000s. When utilized to guide interatrial communication closure procedure, ICE is as safe as TEE and does not increase cost or prolonged hospitalizations.