title: Outcomes After Implantable Cardioverter-Defibrillator Generator Replacement for Primary Prevention of Sudden Cardiac Death.
abstract: BACKGROUND
  The effectiveness of implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden death in patients with an ejection fraction (EF) ≤ 35% and clinical heart failure is well established. However, outcomes after replacement of the ICD generator in patients with recovery of EF to >35% and no previous therapies are not well characterized.
  
  
  RESULTS
  Between 2001 and 2011, generator replacement was performed at 2 tertiary medical centers in 253 patients (mean age, 68.3 ± 12.7 years; 82% men) who had previously undergone ICD placement for primary prevention but subsequently never received appropriate ICD therapy. EF had recovered to > 35% in 72 of 253 (28%) patients at generator replacement. During median (quartiles) follow-up of 3.3 (1.8-5.3) years after generator replacement, 68 of 253 (27%) experienced appropriate ICD therapy. Patients with EF ≤ 35% were more likely to experience ICD therapy compared with those with EF > 35% (12% versus 5% per year; hazard ratio, 3.57; P = 0.001). On multivariable analysis, low EF predicted appropriate ICD therapy after generator replacement (hazard ratio, 1.96 [1.35-2.87] per 10% decrement; P = 0.001). Death occurred in 25% of patients 5 years after generator replacement. Mortality was similar in patients with EF ≤ 35% and > 35% (7% versus 5% per year; hazard ratio, 1.10; P = 0.68). Atrial fibrillation (3.24 [1.63-6.43]; P < 0.001) and higher blood urea nitrogen (1.28 [1.14-1.45] per increase of 10 mg/dL; P < 0.001) were associated with mortality.
  
  
  CONCLUSIONS
  Although approximately one fourth of patients with a primary prevention ICD and no previous therapy have EF >35% at the time of generator replacement, these patients continue to be at significant risk for appropriate ICD therapy (5% per year). These data may inform decisions on ICD replacement.
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA. madhavan.malini@mayo.edu.
authors.forename: Malini
authors.initials: M
authors.lastname: Madhavan
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Waks
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Kramer
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Buxton
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Noseworthy
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Ramila A
authors.initials: RA
authors.lastname: Mehta
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Angela Y
authors.initials: AY
authors.lastname: Higgins
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Webster
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Chance M
authors.initials: CM
authors.lastname: Witt
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.affiliation: From the Department of Cardiovascular Diseases (M.M., P.A.F., P.A.N., T.L.W., C.M.W., Y.-M.C., B.J.G.), Department of Health Sciences Research (R.A.M., D.O.H.), Mayo Clinic, Rochester, MN; and Cardiovascular Diseases, Department of Medicine (J.W.W., D.B.K., A.E.B.), Department of Medicine (A.Y.H.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Gersh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001900:Boston; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D020878:Device Removal; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D015999:Multivariate Analysis; D011322:Primary Prevention / Q000295:instrumentation* / Q000379:methods; D016016:Proportional Hazards Models; D020127:Recovery of Function; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D062606:Tertiary Care Centers; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left
keywords: cardiomyopathy; death, sudden; defibrillators, implantable; follow-up studies; left ventricular ejection fraction; primary prevention; shock