ABSTRACT
AIMS: Antitachycardia pacing (ATP) is an effective treatment for ventricular tachycardia (VT) and can reduce the frequency of shocks in patients with an implantable cardioverter defibrillator (ICD). The association between survival and ATP, as compared to a shock, has not been confirmed in a large patient population. This study aims to determine if patients with an ICD receiving ATP have lower mortality, as compared to those receiving shock. METHODS: Sixty-nine thousand three hundred and sixty-eight patients underwent ICD implantation between October 2008 and May 2013 and were enrolled in the remote monitoring network Merlin.net™ (St. Jude Medical, St. Paul, MN, USA). Patients were categorized into three groups based on the type of ICD therapy received during follow-up: no therapy (N = 47,927), ATP (N = 8,049), and shock (N = 13,392) groups. Survival was determined by linking implant records to the Social Security Death Index. RESULTS: The no therapy (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.56-0.64, P < 0.001) and ATP (HR 0.70, 95% CI 0.64-0.77, P < 0.001) groups were associated with a lower mortality risk than the shock group. These results were unaffected by age, gender, device type, atrial fibrillation (AF) burden, or ventricular rate. ATP was effective in 85% of episodes and ATP effectiveness was dependent on the ventricular rate. CONCLUSIONS: Mortality rates were higher in ICD patients who received only ATP compared to no therapy, but ICD patients who received a shock had higher mortality compared to both groups. Furthermore, the data suggest that age, gender, device type, AF burden, and rate of arrhythmia do not change the trend of higher mortality in patients receiving ICD shock compared to ATP alone.
Subject(s)
Defibrillators, Implantable , Electric Countershock/instrumentation , Tachycardia, Ventricular/therapy , Adolescent , Adult , Aged , Aged, 80 and over , Electric Countershock/adverse effects , Electric Countershock/mortality , Female , Heart Rate , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Proportional Hazards Models , Prosthesis Failure , Retrospective Studies , Risk Factors , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/mortality , Tachycardia, Ventricular/physiopathology , Time Factors , Treatment Outcome , Young AdultABSTRACT
BACKGROUND: Left ventricular lead (LVL) implant success rates have historically ranged between 70.5% and 95.5%. To date, there are few large studies that evaluate LVL implant success utilizing a single family of delivery catheters and leads. The Attain Success study was a prospective nonrandomized multicenter global study with the main objectives of assessing single-system LVL implant success and complication rates. METHODS: Patients undergoing cardiac resynchronization therapy implantation were eligible for enrollment. There was no prespecified level of experience for investigator participation. LVL implant success and complication rates were assessed though 3 months of follow-up. RESULTS: A total of 2,014 patients (69.1 ± 12.0 years, 71% male and 38% atrial fibrillation) were enrolled from 114 centers with a follow-up of 3.5 ± 2.1 months. Coronary sinus cannulation success rate was 96.4% with Attain Family delivery catheters. Implant success rate for Attain Family leads using Attain Family catheters was 94.0%; overall LVL implant success rate was 97.1%. Median procedure time was 4 minutes for cannulation and 9 minutes for LVL placement. Median fluoroscopy time was 17 minutes and median contrast used was 25 cc. There were 55 catheter or LVL-related complications in 53 subjects; the majority were LVL dislodgements (34, 1.7%) and extracardiac stimulation (11, 0.5%). The Kaplan-Meier estimate of the 3-month complication probability was 2.6%. CONCLUSION: This study represents the largest prospective evaluation of LVL implantation to date, revealing a high LVL implant success rate and low complication rate using a single family of leads and delivery catheters.
