Incidence Of Appropriate Implantable Cardioverter-defibrillator Therapy Research Articles

Impact of renal dysfunction on appropriate therapy in implantable cardioverter defibrillator patients with non-ischaemic dilated cardiomyopathy

To examine the effect of renal dysfunction on the occurrence of life-threatening ventricular arrhythmia in patients with non-ischaemic dilated cardiomyopathy and implantable cardioverter defibrillator (ICD). Subjects were 274 consecutive patients with non-ischaemic dilated cardiomyopathy who received ICD implantation. Estimated glomerular filtration rate (eGFR) was calculated using the modification of diet in renal disease formula. Renal dysfunction was defined as eGFR <60 mL/min/1.73 m(2). Differences in survival, appropriate ICD therapy and electrical storm in patients with and without renal dysfunction were compared. The effect of worsening renal function (decrease of eGFR of at least 15 mL/min/1.73 m(2) within 1 year) on appropriate ICD therapy was also evaluated. There was a higher incidence of appropriate ICD therapy in patients with eGFR <60 mL/min/1.73 m(2) than in those with eGFR >or=60 mL/min/1.73 m(2) (P = 0.0001). Patients with eGFR <60 mL/min/1.73 m(2) also showed a significantly higher rate of electrical storm (P = 0.003). Renal dysfunction with eGFR <60 mL/min/1.73 m(2) was an independent predictor of appropriate ICD therapy (HR 1.85, 95% CI 1.24-2.77, P = 0.003). Patients with worsening renal function within 1 year after implantation were at increased risk for appropriate ICD therapy (HR 2.50, 95% CI 1.39-4.52, P = 0.002). Our results suggested that renal dysfunction is an independent risk factor for occurrence of life-threatening arrhythmia even in high-risk patients with non-ischaemic dilated cardiomyopathy.

Renal insufficiency predicts the time to first appropriate defibrillator shock

Indications for implantable cardioverter defibrillator (ICD) implantation are expanding, but many primary and secondary ICD trials have excluded patients with advanced renal insufficiency. We investigated the effect of renal function on the incidence and time to first appropriate ICD shock. We analyzed data from all new ICD implantations at a tertiary care center from July 2001 to December 2002. During a mean follow-up time of 445 +/- 285 days, 29 (13%) of 230 patients (age 63 +/- 14 years, 79% men, 77% white, 75% coronary artery disease, left ventricular ejection fraction 0.28 +/- 0.14) received 41 appropriate shocks. Patients were divided into tertiles according to their serum creatinine level. The 1-year incidence of appropriate ICD shock was 3.8%, 10.8%, and 22.7% in the first, second, and third tertiles, respectively (P = .003). Using the same cut off values of serum creatinine, the 1-year incidence of appropriate ICD therapy (shock and antitachycardia pacing) was 8.8%, 20.8%, and 26.3% (P = .02). After correcting for age, sex, race, left ventricular ejection fraction, indication for ICD implantation, and use of beta-blockers in a Cox regression model, serum creatinine was still an independent predictor of the time to first appropriate ICD shock (hazard ratio 6.0 for the third compared with the first tertile, P = .001). Renal insufficiency is a strong predictor of appropriate ICD shocks. Defibrillator therapy should therefore not be withheld based on the presence of this comorbidity. The mechanisms underlying the relationship between renal function and ventricular arrhythmias deserve further investigation.

Long-term Follow-up of Patients Treated with Implantable Cardioverter Defibrillators in a Danish Centre: Occurrence of ICD Therapy and Patient Survival

The aim of the this prospective follow-up study was to evaluate long-term survival and implantable cardioverter-defibrillator (ICD) therapy for ventricular tachyarrhythmias in patients treated with an ICD in a Danish centre. A total of 140 consecutive patients (112 men), of which 70.7% had coronary artery disease, received an ICD at Skejby University Hospital between March 1989 and October 1996. Mean age was 55.6 ± 14.6 years (range 14–78 years). After implantation, 136 of the patients were followed for a median (range) of 17.7 (0.4–74.1) months. Survival, mode of death and incidence of appropriate ICD therapy and therapy due to potential life-threatening ventricular tachyarrhythmia were the main outcome measures. Kaplan-Meier plots representing total survival, cardiac death, sudden cardiac death and first episode of ICD therapy are presented. After 1, 2, 3 and 4 years, respectively, the cumulative incidences of death were 9, 18, 20 and 24%, of cardiac death 4, 11, 14 and 18%, and of sudden cardiac death 2, 3, 6 and 6%. The cumulative incidences of appropriate therapy after 1, 2, 3 and 4 years were 47, 56, 66 and 80%, respectively. The cumulative incidences of cardiac death after the first episode of appropriate therapy were 9, 11, 15 and 20% after 1, 2, 3 and 4 years, respectively. The occurrence of ICD therapy and patient survival in the present study population treated with ICD at a Danish centre was comparable to results published previously from other larger centres. The rate of sudden cardiac death was low and most of our patients received appropriate ICD therapy during follow-up, indicating correct patient selection and probable benefit of the ICD device.