Detecting Atrial Fibrillation in the Emergency Department in Patients with Cardiac Implantable Electronic Devices.

BACKGROUND: Clinical guidelines emphasize identifying atrial fibrillation (AF) as a strategy to reduce stroke risk. Cardiac implantable electronic device (CIED) interrogation at the point of care may facilitate AF detection, increasing opportunities to identify patients at high risk for stroke. OBJECTIVES: This study sought to quantify AF prevalence and assess stroke risk in patients with a CIED who presented to the emergency department (ED). METHODS: This noninterventional, retrospective observational study included adult patients who presented at a single facility ED that incorporated device interrogation as a routine standard practice for all patients with a CIED. Interrogations were conducted in 494 unique patients, and relevant demographic/clinical information was captured from electronic medical records. RESULTS: AF was detected via CIED interrogation in 54.8% (271/494) of the unique patient population that presented to the ED. Device interrogation detected the presence of AF in 110 patients without a documented past history or current diagnosis of AF, representing 22.3% (110/494) of total unique patients. Based on CHA2DS2-VASc (Congestive heart failure, Hypertension, Age > 75 years, Diabetes mellitus, prior Stroke or transient ischemic attack or thromboembolism, Vascular disease, Age 65-74 years, Sex category [female]) risk scoring methodology, over three-quarters of these newly detected AF patients (78.2%, 86/110) were classified in a high stroke risk category that reflected a > 2.2% annualized risk, and over half (57.3%, 63/110) presented to the ED for reasons unrelated to cardiac/dysrhythmia problems. CONCLUSIONS: The use of technology-assisted device interrogation of CIEDs at the point of care has promise in identifying patients with asymptomatic AF. Results suggest consideration of routine device interrogation of CIEDs in the ED, regardless of reason for admission or history of AF.

Inductionless or limited shock testing is possible in most patients with implantable cardioverter- defibrillators/cardiac resynchronization therapy defibrillators: results of the multicenter ASSURE Study (Arrhythmia Single Shock Defibrillation Threshold Testing Versus Upper Limit of Vulnerability: Risk Reduction Evaluation With Implantable Cardioverter-Defibrillator Implantations).

BACKGROUND: Implantable cardioverter-defibrillators and cardiac resynchronization therapy defibrillators have relied on multiple ventricular fibrillation (VF) induction/defibrillation tests at implantation to ensure that the device can reliably sense, detect, and convert VF. The ASSURE Study (Arrhythmia Single Shock Defibrillation Threshold Testing Versus Upper Limit of Vulnerability: Risk Reduction Evaluation With Implantable Cardioverter-Defibrillator Implantations) is the first large, multicenter, prospective trial comparing vulnerability safety margin testing versus defibrillation safety margin testing with a single VF induction/defibrillation. METHODS AND RESULTS: A total of 426 patients receiving an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator underwent vulnerability safety margin or defibrillation safety margin screening at 14 J in a randomized order. After this, patients underwent confirmatory testing, which required 2 VF conversions without failure at < or = 21 J. Patients who passed their first 14-J and confirmatory tests, irrespective of the results of their second 14-J test, had their devices programmed to a 21-J shock for ventricular tachycardia (VT) or VF > or = 200 bpm and were followed up for 1 year. Of 420 patients who underwent 14-J vulnerability safety margin screening, 322 (76.7%) passed. Of these, 317 (98.4%) also passed 21-J confirmatory tests. Of 416 patients who underwent 14-J defibrillation safety margin screening, 343 (82.5%) passed, and 338 (98.5%) also passed 21-J confirmatory tests. Most clinical VT/VF episodes (32 of 37, or 86%) were terminated by the first shock, with no difference in first shock success. In all observed cases in which the first shock was unsuccessful, subsequent shocks terminated VT/VF without complication. CONCLUSIONS: Although spontaneous episodes of fast VT/VF were limited, there was no difference in the odds of first shock efficacy between groups. Screening with vulnerability safety margin or defibrillation safety margin may allow for inductionless or limited shock testing in most patients.

Outcomes in Patients With Congenital Heart Disease Receiving the Subcutaneous Implantable-Cardioverter Defibrillator: Results From a Pooled Analysis From the IDE Study and the EFFORTLESS S-ICD Registry.

OBJECTIVES: This study was conceived to determine the safety and efficacy of the subcutaneous implantable cardioverter-defibrillator (S-ICD) in patients with congenital heart disease (CHD). BACKGROUND: The S-ICD is a treatment option for patients with CHD in which a transvenous device is contraindicated due to anatomic considerations. However, efficacy in this group has not been determined. METHODS: A pooled analysis of 865 patients in the EFFORTLESS (Evaluation of Factors Affecting the Clinical Outcome and Cost-Effectiveness) registry (an international observational database) and a U.S. Investigational Device Exemption study were reviewed. RESULTS: Nineteen CHD patients versus 846 non-CHD patients with a median follow-up of 567 days and 639 days, respectively, were included. There were no deaths and no appropriate shocks for ventricular tachycardia/ventricular fibrillation in the CHD cohort, versus 26 deaths (3.1%, p = 0.42) and 111 appropriate shocks in 59 patients (7.1%) in the non-CHD cohort (p = 0.23). There were similar complication rates for the CHD versus non-CHD groups (10.5 vs. 9.6% [p = 0.89]), with inappropriate shocks for T-wave oversensing as the only complication in the CHD group (n = 2). The rate of inappropriate shocks was similar for both groups (10.5% vs. 10.9% [p = 0.96]). Successful defibrillation testing at 80J was comparable for the CHD versus non-CHD groups (100% vs. 98.5%). CONCLUSIONS: The overall analysis of the CHD cohort from the pooled data of the Investigational Device Exemption study and the EFFORTLESS registry shows that the S-ICD is a safe option in CHD patients deemed to be at high risk for sudden cardiac death who do not have pacing indications. Further research to accurately define sudden cardiac death risk in the diverse anatomic substrates of CHD patients is warranted.

Multicenter experience with extraction of the Riata/Riata ST ICD lead.

BACKGROUND: In November 2011, the Food and Drug Administration issued a class I recall of Riata and Riata ST implantable cardioverter-defibrillator leads. Management recommendations regarding the recall have remained controversial. OBJECTIVE: Data regarding the safety and feasibility of extraction of Riata implantable cardioverter-defibrillator leads are limited. METHODS: We performed a retrospective study of patients undergoing extraction of Riata/Riata ST leads at 11 centers. RESULTS: Between July 2003 and April 2013, 577 Riata/Riata ST leads were extracted from 577 patients (Riata 467, [84%]; Riata ST 89, [16%]). Complete procedural success achieved in 99.1%. The cohort was 78% men, with a mean age of 60 years and a mean left ventricular ejection fraction of 34% ± 14%. The mean implant duration was 44.7 months (range 0-124.6 months). The majority of leads extracted were for infection (305 [53.0%]) and 220 (35.7%) for lead malfunction. Evaluation for lead integrity was performed in 295 cases. Of these, 34.9% were found to have externalized cables. Implant duration was significantly longer in leads with externalized cables (P < .0001). No difference in lead integrity was noted between Riata and Riata ST leads (11.7% vs. 17.7% failure; P = .23). Among leads in which cable externalization was noted, laser sheaths were used more frequently (P = .01). Major complications included 3 superior vena cava/right ventricular perforations requiring surgical intervention with 1 death 12 days after the procedure and 1 pericardial effusion requiring percutaneous drainage (0.87%). CONCLUSION: Extraction of the Riata/Riata ST leads can be challenging, and leads with externalized cables may require specific extraction techniques. Extraction of the Riata/Riata ST leads can be performed safely by experienced operators at high-volume centers with a complication rate comparable to published data.

Improved extraction of ePTFE and medical adhesive modified defibrillation leads from the coronary sinus and great cardiac vein.

BACKGROUND: Permanent leads with shocking coils for defibrillation therapy are sometimes implanted in the coronary sinus (CS) and great cardiac vein (GCV). These shocking coils, as documented by pathologic examination of animal investigations, often become tightly encapsulated by fibrosis and can be very difficult to remove. METHODS: One of three configurations of the Guidant model 7109 Perimeter coronary sinus shocking lead was implanted into the distal portion of the GCV of 24 sheep for up to 14 months. Group 1 had unmodified coils (control), group 2 had coils backfilled with medical adhesive (MA), and Group 3 had coils coated with expanded polytetrafluoroethylene (ePTFE). Eighteen leads, three from each group at 6 and 14 months were transvenously extracted from the left jugular vein. The remaining six animals were not subject to extraction. All animals were euthanized for pathological and microscopic examination. RESULTS: All six of the control, three of the MA, and one of the ePTFE leads required the use of an electrosurgical dissection sheath (EDS) for extraction. Five control, two MA, and none of the ePTFE leads had significant fibrotic attachments to the shocking coils. Significant trauma was observed at necropsy for those leads requiring the use of the EDS for extraction. CONCLUSIONS: Tissue ingrowth is a major impediment to the removal of defibrillation leads implanted in the CS and GCV of sheep. Reduction of tissue ingrowth by coating the shocking coils with ePTFE or by backfilling with MA facilitates transvenous lead removal with reduced tissue trauma.