F. Roosevelt Gilliam

Long-Term Outcome After ICD and CRT Implantation and Influence of Remote Device Follow-Up: The ALTITUDE Survival Study

Background— Outcome data for patients receiving implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) devices treated outside of clinical trials are lacking. No clinical trial has evaluated mortality after device implantation or after shock therapy in large numbers of patients with implanted devices that regularly transmit device data over a network. Methods and Results— Survival status in patients implanted with ICD and CRT devices across the United States from a single manufacturer was assessed. Outcomes were compared between patients followed in device clinic settings and those who regularly transmit remote data collected from the device an average of 4 times monthly. Shock delivery and electrogram analysis could be ascertained from patients followed on the network, enabling survival after ICD shock to be evaluated. One- and 5-year survival rates in 185 778 patients after ICD implantation were 92% and 68% and were 88% and 54% for CRT-D device recipients. In 8228 patients implanted with CRT-only devices, survival was 82% and 48% at 1 and 5 years, respectively. For the 69 556 ICD and CRT-D patients receiving remote follow-up on the network, 1- and 5-year survival rates were higher compared with those in the 116 222 patients who received device follow-up in device clinics only (50% reduction; P<0.0001). There were no differences between patients followed on or off the remote network for the characteristics of age, gender, implanted device year or type, and economic or educational status. Shock therapy was associated with subsequent mortality risk for both ICD and CRT-D recipients. Conclusions— Survival after ICD and CRT-D implantation in patients treated in naturalistic practice compares favorably with survival rates observed in clinical trials. Remote follow-up of device data is associated with excellent survival, but arrhythmias that result in device therapy in this population are associated with a higher mortality risk compared with patients who do not require shock therapy.

Real world evaluation of dual-zone ICD and CRT-D programming compared to single-zone programming: The ALTITUDE REDUCES study

Tachycardia Detection, ICD, CRT‐D Devices, Appropriate and Inappropriate Shock. Introduction: We evaluated the frequency of appropriate and inappropriate shocks and survival in patients using dual‐zone programming versus single‐zone programming.

Noise, artifact, and oversensing related inappropriate ICD shock evaluation: ALTITUDE noise study.

Background: Approximately 12–21% of implantable cardioverter defibrillator (ICD) patients receive inappropriate shocks. We sought to determine the incidence and causes of noise/artifact and oversensing (NAO) resulting in ICD shocks.

Changes in Heart Rate Variability, Quality of Life, and Activity in Cardiac Resynchronization Therapy Patients: Results of the HF-HRV Registry

Background: Cardiac resynchronization therapy (CRT) is a viable therapy in the treatment of heart failure (HF). Heart rate variability (HRV) is a prognostic marker of HF and mortality and is a sign of autonomic dysfunction. Acute improvements in measures of HRV have been demonstrated after CRT in small clinical studies. The purpose of the present study was to evaluate changes in HRV and patient outcomes over time and the relationship between these changes in a large generalized sample of patients who received CRT with defibrillator (CRT‐D).

T‐Wave Oversensing in Implantable Cardiac Defibrillators Is Due to Technical Failure of Device Sensing

The expanded indications for the use of implantable cardioverter defibrillators (ICDs) for primary prevention of sudden cardiac death have increased concerns about inappropriate delivery of therapies. Dual‐chamber systems have improved the capacity of ICDs to differentiate ventricular arrhythmias from supraventricular arrhythmias. Still, T‐wave oversensing is a major source of inappropriate therapy. It is likely the true incidence of T‐wave oversensing is greater than reported as documented events reflect only those stored in a device memory. Reviewing cases of T‐wave oversensing that failed noninvasive correction; we found successful resolution resulted from generator replacement. We conclude that T‐wave oversensing is due to inadequate signal processing by some ICD generators.

Implantable Cardioverter Defibrillator Electrogram Adjudication for Device Registries: Methodology and Observations from ALTITUDE

Background: The increasing use of remote monitoring with the associated large retrievable databases provides a unique opportunity to analyze observations on implantable cardioverter‐defibrillator (ICD) therapies. Adjudication of a large number of stored ICD electrograms (EGMs) presents a unique challenge. The ALTITUDE study group was designed to use the LATITUDE remote monitoring system to evaluate ICD patient outcomes across the United States.

Predictors of early mortality in implantable cardioverter-defibrillator recipients

Aims Multiple trials have shown that implantable cardioverter defibrillators (ICDs) prolong survival in secondary and primary prevention populations. However, in spite of the efficacy of these devices in terminating life-threatening arrhythmias, total mortality remains high. Methods and results We evaluated 1703 patients (mean age: 67 ± 12 years, 82% male) with conventional ICD indications, who were enrolled and followed between 2001 and 2004 at 128 US centres. Patients were followed for up to a year, and vital status was obtained for 1655 patients (97%, median follow-up: 377 days). There were 183 deaths within 1 year of ICD implantation (1-year mortality rate: 16%). Predictors of mortality included a history of atrial fibrillation (AF, P < 0.0001), diabetes (P = 0.0001), failure to use cholesterol-lowering medications (P < 0.001), use of digitalis and derivatives (P < 0.0001), use of diuretics (P < 0.0001), low body mass index (BMI, P < 0.0001), increasing age (P < 0.0001), low left ventricular ejection fraction (P < 0.0001), low activity hours (P < 0.0001), elevated resting heart rate (P = 0.014), low mean arterial pressure (MAP, P = 0.007), and poor functional status (New York Heart Association class, P < 0.0001). In multivariate modelling, AF (P ≤ 0.001), diabetes (P = 0.004), BMI (P = 0.001), MAP (P = 0.040), and functional class (P = 0.006) predicted mortality. Conclusion In this population undergoing ICD implantation, poor functional status, low MAP, diabetes, low BMI, and AF were strongly associated with death within a year.

Long-Term Outcome After ICD and CRT Implantation and Influence of Remote Device Follow-Up

Background— Outcome data for patients receiving implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) devices treated outside of clinical trials are lacking. No clinical trial has evaluated mortality after device implantation or after shock therapy in large numbers of patients with implanted devices that regularly transmit device data over a network. Methods and Results— Survival status in patients implanted with ICD and CRT devices across the United States from a single manufacturer was assessed. Outcomes were compared between patients followed in device clinic settings and those who regularly transmit remote data collected from the device an average of 4 times monthly. Shock delivery and electrogram analysis could be ascertained from patients followed on the network, enabling survival after ICD shock to be evaluated. One- and 5-year survival rates in 185 778 patients after ICD implantation were 92% and 68% and were 88% and 54% for CRT-D device recipients. In 8228 patients implanted with CRT-only devices, survival was 82% and 48% at 1 and 5 years, respectively. For the 69 556 ICD and CRT-D patients receiving remote follow-up on the network, 1- and 5-year survival rates were higher compared with those in the 116 222 patients who received device follow-up in device clinics only (50% reduction; P<0.0001). There were no differences between patients followed on or off the remote network for the characteristics of age, gender, implanted device year or type, and economic or educational status. Shock therapy was associated with subsequent mortality risk for both ICD and CRT-D recipients. Conclusions— Survival after ICD and CRT-D implantation in patients treated in naturalistic practice compares favorably with survival rates observed in clinical trials. Remote follow-up of device data is associated with excellent survival, but arrhythmias that result in device therapy in this population are associated with a higher mortality risk compared with patients who do not require shock therapy.

The buddy wire technique: accessing lateral coronary veins while maintaining coronary sinus position.

There is compelling data to place the coronary sinus lead (CSL) in a lateral or posterolateral tributary. Coronary sinus venography often demonstrates the absence of easily accessible lateral veins or those with sufficient size to accommodate the CSL. The operator may choose to deploy the CSL in the anterior vein but publications and experience highlight the lack of resynchronization benefit when the CSL is deployed in this location. There is often a posterolateral vessel or the middle cardiac vein (MCV) originating from near the coronary sinus (CS) os. These vessels require the operator to pull the CS guide essentially out of the CS to allow successful access. Cannulation of the coronary sinus (CS) is often challenging, and the risk of losing access to the CS may dissuade the implanter from attempting access to a vessel near the CS os. We describe a technique to access vessels near the CS os while maintaining secure position in the main body of the CS.

Impact of shock energy and ventricular rhythm on the success of first shock therapy: The ALTITUDE first shock study

BACKGROUND The efficacy of shock in converting different ventricular tachyarrhythmias has not been well characterized in a large natural-practice setting. OBJECTIVE To determine shock success rate by energy and ventricular rhythm in a large cohort of patients with implantable cardioverter-defibrillators. METHODS Two thousand patients with 5279 shock episodes were randomly sampled for analysis from the LATITUDE remote monitoring system. Within an episode, the rhythm preceding therapy (shock or antitachycardia pacing [ATP]) was adjudicated. Patients who died after unsuccessful implantable cardioverter-defibrillator shocks did not transmit final remote monitoring data and were not included in the study. RESULTS Of 3677 shock episodes for ventricular tachyarrhythmia, 2679 were treated with shock initially and were classified as monomorphic ventricular tachycardia ( n = 1544), polymorphic/monomorphic ventricular tachycardia (n = 371), or ventricular fibrillation (n = 764). The success rate after the first, second, and final shock averaged 90.3%, 96.4%, and 99.8%, respectively. After unsuccessful initial ATP (n = 998), the first, second, and final shock was successful in 84.8%, 92.9%, and 100% of the episodes. The success rate after the first or second shock was significantly lower after failed ATP compared to shock as first therapy (both P<.001). Among episodes treated initially with shock, the success rate for monomorphic ventricular tachycardia (89.2%) when treated with energy level ≤ 20 J was significantly higher than that for ventricular fibrillation (80.8%) (P = .04). The level of shock energy was a significant predictor of the success of the first shock (odds ratio 1.16; 95% confidence interval 1.03-1.30; P = .013). CONCLUSIONS The success rate of first shock as first therapy is approximately 90%, but was lower after failed ATP. Programming a higher level of energy after ATP is suggested.