Randomized Trial of Stand-Alone Use of the Antimicrobial Envelope in High-Risk Cardiac Device Patients.

BACKGROUND: Cardiac implantable electronic device (CIED) infection has a high mortality. Previous investigations showed reduced postoperative infections using skin preparation with chlorhexidine, preoperative intravenous antibiotics, and a TYRX-a antibacterial envelope. The additional benefit of antibiotic pocket wash and postoperative antibiotics has not been systematically studied. METHODS: The ENVELOPE trial (A Randomized trial of Stand-Alone Use of the Antimicrobial Envelope in High-Risk Cardiac Device Patients) was a prospective, multicenter, randomized, controlled trial enrolling patients undergoing CIED procedures with ≥2 risk factors for infection. The control arm received standard chlorhexidine skin preparation, intravenous antibiotics, and the TYRX-a antibiotic envelope. The study arm received pocket wash (500 mL antibiotic solution) and postoperative antibiotics for 3 days along with the prophylactic control measures. The primary end point was CIED infection and system removal at 6 months. RESULTS: One thousand ten subjects (505 per arm) were enrolled and randomized. Patients were seen in person for a wound check with digital photo 2 weeks postimplant and at 3 and 6 months. CIED infection rate was low in both groups (1.0% control arm and 1.2% study arm, P=0.74). In the 11 subjects with infection and system removal, the time to study end point was 107±92 days with a PADIT (Prevention of Arrhythmia Device Infection Trial) score of 7.4 and a 64% 1-year mortality. Prior history of CIED infection independently predicted CIED system removal at 6 months in all subjects (odds ratio, 9.77, P=0.004). Of 11 infections requiring system removal, 5 were in the setting of pocket hematoma. CONCLUSIONS: The use of antibiotic pocket irrigation and postoperative oral antibiotics provides no additional benefit to the prophylactic measures of chlorhexidine skin preparation, preoperative intravenous antibiotics, and an antibiotic envelope in reducing CIED infection. Postoperative hematoma is a major risk factor for infection, driven by the use of antiplatelet and anticoagulant medications. The strongest predictor of CIED removal at 6 months, regardless of intervention, was prior CIED infection. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02809131.

Ampere Hour as a Predictor of Cardiac Resynchronization Defibrillator Pulse Generator Battery Longevity: A Multicenter Study.

BACKGROUND: Cardiac resynchronization defibrillator (CRT-D) devices improve survival for New York Heart Association classes II-IV systolic heart failure patients with QRS > 120 ms and left ventricular ejection fraction < 35%. A limitation of 100% CRT pacing is excess battery depletion and pulse generator (PG) replacement compared to VVI or dual-chamber systems. Ampere hour (Ah) measures PG battery capacity and may predict CRT-D device longevity. METHODS: We performed a multicenter retrospective study of all CRT-D devices implanted at our centers from August 1, 2008 to December 31, 2010. Analysis was performed for survival to elective replacement indicator (ERI) between 1.0 Ah, 1.4 Ah, and 2.0 Ah devices, per manufacturers' specifications. RESULTS: One thousand three hundred and two patients were studied through December 31, 2014. Patients were followed for an average of 3.0 ± 1.3 years (794 1.0 Ah, 322 2.0 Ah, and 186 1.4 Ah devices under study). CRT-D generator ERI occurred in 13.5% of 1.0 Ah systems (107 out of 794), versus 3.8% in 1.4 Ah (seven out of 186), and 0.3% in 2.0 Ah devices (one out of 322) over mean follow-up of 3.0 years. Odds ratio (OR) for reaching ERI with 1.0 Ah device versus 1.4 Ah or 2.0 Ah was 9.73, P < 0.0001. Univariate predictors for ERI included 1.0 Ah device and LV pacing output >3V @ 1 ms (OR: 3.74, P < 0.001). LV impedance >1,000 ohms predicted improved device survival (OR: 0.38, P = 0.0025). CONCLUSIONS: CRT-D battery capacity measured by Ah is a strong predictor of survival to ERI for modern systems. Further study on cost and morbidity associated with early PG change in 1.0 Ah systems is warranted.

Atrial tachyarrhythmias temporally precede fluid accumulation in implantable device patients.

BACKGROUND: The complex relationship between heart failure and atrial tachyarrhythmias (AT/atrial fibrillation [AF]) is not well understood. We examined the temporal association between changes in intrathoracic impedance, suggesting thoracic fluid accumulation, and AT/AF occurrence in cardiac resynchronization therapy-defibrillator and implantable cardioverter defibrillator (ICD) patients. METHODS: A retrospective analysis was conducted on stored implantable device data to identify patients with automatic monitoring of daily AT/AF burden and intrathoracic impedance. Daily population trends in AT/AF burden before and after a fluid index threshold crossing (FIC) were determined. RESULTS: A total of 73,018 patients (68 ± 12 years, 51% ICD, 75% male) were evaluated over 18.6 ± 11.5 months. Kaplan-Meier analysis indicated a significantly higher probability of FIC events in the first month following the onset of persistent AT/AF when compared to a matched group without persistent AT/AF (hazard ratio [HR] 1.65, 95% confidence interval [CI] [1.58, 1.72], P < 0.001). Conversely, patients were significantly more likely to experience an episode of persistent AF in the first month after the FIC event (HR 1.32, 95% CI [1.08, 1.63], P = 0.008). The probability of a fluid index crossing within 30 days of the onset of persistent AT/AF was significantly lower in a subgroup of patients with adequate rate control (35.8% [34.3-37.4%] vs 42.0% [39.6-44.6%]; HR 1.24 [1.13-1.36]). CONCLUSION: Thoracic fluid accumulation, as indicated by decreasing intrathoracic impedance, was more likely to occur immediately after the onset of persistent AT/AF, especially in the presence of inadequate rate control. Likewise, the onset of persistent AT/AF was more likely following a decrease in intrathoracic impedance.

Uncovering interim clinical events at the time of clinical encounter by reviewing intrathoracic impedance threshold crossings.

BACKGROUND: Acute decreases in intrathoracic impedance monitored by implanted devices have been shown to precede heart failure exacerbations, although there is still debate regarding its clinical utility in predicting and preventing future events. However, the usefulness of such information to direct patient encounter and enhance patient recall of relevant preceding clinical events at the point of care has not been carefully examined. METHODS AND RESULTS: In this multicenter study, we interviewed 326 patients with heart failure who received an implanted device with intrathoracic impedance-monitoring capabilities both before and after device information was reviewed. We compared the self-reported clinically relevant events (including heart failure hospitalizations, signs and symptoms of worsening heart failure, changes in diuretic therapy, or other fluid-related events) obtained before and after device interrogation, and then examined the relationship between such events with impedance trends documented by the devices. Over 333 ± 96 days of device monitoring, 215 of 326 patients experienced 590 intrathoracic impedance fluid index threshold-crossing events at the nominal threshold value (60 Ω-d). Review of device-derived information led to the discovery of 221 (37%) previously unreported clinically relevant events in 138 subjects. This included 60 subjects not previously identified as having had clinically relevant events (or 35% of the 171 subjects who did not report events). CONCLUSIONS: Our data demonstrated that reviewing device-derived intrathoracic impedance trends at the time of clinical encounter may help uncover self-reporting of potential clinically relevant events.