Shining Sun1, James Johnson2, Paul Degroot2, Mark L Brown2, Owen Obel1,3. 1. UT Southwestern Medical Center, Dallas, Texas, USA. 2. Medtronic Inc, Minneapolis, Minnesota, USA. 3. VA North Texas Health Care System, Dallas, Texas, USA.
Abstract
BACKGROUND: Analyses from primary prevention trials on implantable cardioverter defibrillator (ICD) therapy have shown an association between shocks and increased mortality. Recent data suggest a similar association with antitachycardia pacing (ATP). OBJECTIVE: The OMNI study is an observational study of pacemaker and ICD use. We aim to examine associations between ICD therapies and mortality in this setting. METHODS: A total of 2,255 OMNI patients with ICDs were included. Treated episodes were classified as appropriate or inappropriate. Patients were assigned into 1 of 3 groups depending on whether the episode required ATP only, single shock, or multiple shocks, and then followed for all-cause mortality. Additionally, we aimed to determine the frequency with which inappropriate ATP precipitated ventricular arrhythmias that led to shock, since this has been suggested as a mechanism of harm. RESULTS: Over a mean follow-up of 39 ± 19 months, there were a total of 470 deaths (21%). Compared to patients with no treated episodes, patients with appropriate therapy had greater risk of death. Hazard ratios were 1.46 (95% confidence interval [CI] 1.05-2.02; P = 0.023) for the ATP-only group, 2.11 (95% CI 1.51-2.96; P < 0.001) for the single-shock group, and 2.55 (95% CI 1.43-4.57; P = 0.002) for the multishock group. There was no significant association between any type of inappropriate therapy and increased mortality. We identified only 7 instances of inappropriate ATP precipitating ventricular arrhythmia resulting in shock. CONCLUSIONS: Patients receiving appropriate therapy of all types had increased mortality compared to those with no episodes. Furthermore, inappropriate ATP rarely precipitates ventricular arrhythmias.
BACKGROUND: Analyses from primary prevention trials on implantable cardioverter defibrillator (ICD) therapy have shown an association between shocks and increased mortality. Recent data suggest a similar association with antitachycardia pacing (ATP). OBJECTIVE: The OMNI study is an observational study of pacemaker and ICD use. We aim to examine associations between ICD therapies and mortality in this setting. METHODS: A total of 2,255 OMNIpatients with ICDs were included. Treated episodes were classified as appropriate or inappropriate. Patients were assigned into 1 of 3 groups depending on whether the episode required ATP only, single shock, or multiple shocks, and then followed for all-cause mortality. Additionally, we aimed to determine the frequency with which inappropriate ATP precipitated ventricular arrhythmias that led to shock, since this has been suggested as a mechanism of harm. RESULTS: Over a mean follow-up of 39 ± 19 months, there were a total of 470 deaths (21%). Compared to patients with no treated episodes, patients with appropriate therapy had greater risk of death. Hazard ratios were 1.46 (95% confidence interval [CI] 1.05-2.02; P = 0.023) for the ATP-only group, 2.11 (95% CI 1.51-2.96; P < 0.001) for the single-shock group, and 2.55 (95% CI 1.43-4.57; P = 0.002) for the multishock group. There was no significant association between any type of inappropriate therapy and increased mortality. We identified only 7 instances of inappropriate ATP precipitating ventricular arrhythmia resulting in shock. CONCLUSIONS:Patients receiving appropriate therapy of all types had increased mortality compared to those with no episodes. Furthermore, inappropriate ATP rarely precipitates ventricular arrhythmias.
Authors: Fahad Almehmadi; Andreu Porta-Sánchez; Andrew C T Ha; Hadas D Fischer; Xuesong Wang; Peter C Austin; Douglas S Lee; Kumaraswamy Nanthakumar Journal: J Am Heart Assoc Date: 2017-08-19 Impact factor: 5.501