Appropriate Implantable Cardioverter-defibrillator Therapy In Patients Research Articles

Predictors of appropriate therapies delivered by the implantable cardioverter-defibrillator in patients with coronary artery disease during long-term period.

This prospective study aimed to investigate the ability of cardiac autonomic nervous system (CANS) activity assessment to predict appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with coronary artery disease (CAD) during long-term follow-up period. We enrolled patients with CAD and ICD implantation indications that included both secondary and primary prevention of sudden cardiac death. Before ICD implantation CANS was assessed by using heart rate variability (HRV), myocardium scintigraphy with 123I-meta-iodobenzylguanidine (123I-MIBG) and erythrocyte membranes β-adrenoreactivity (EMA). The study's primary endpoint was the documentation of appropriate ICD therapy. Of 45 (100.0%) patients, 15 (33.3%) had appropriate ICD therapy during 36 months follow-up period. Patients with appropriate ICD therapy were likely to have a higher summed 123I-MIBG score delayed (p < 0.001) and lower 123I-MIBG washout rate (p = 0.008) indicators. These parameters were independently associated with endpoint in univariable and multivariable logistic regression. We created a logistic equation and calculated a cut-off value. The resulting ROC curve revealed a discriminative ability with AUC of 0.933 (95% confidence interval 0.817-0.986; sensitivity 100.00%; specificity 93.33%). Combined CANS activity assessment is useful in prediction of appropriate ICD therapy in patients with CAD during long-term follow-up period after device implantation.

Prediction of cardiac events with non-contrast magnetic resonance feature tracking in patients with ischaemic cardiomyopathy.

AimsThe aim of this study was to evaluate the prognostic value of feature tracking (FT) derived cardiac magnetic resonance (CMR) strain parameters of the left ventricle (LV)/right ventricle (RV) in ischaemic cardiomyopathy (ICM) patients treated with an implantable cardioverter‐defibrillator (ICD). Current guidelines suggest a LV‐ejection fraction ≤35% as major criterion for ICD implantation in ICM, but this is a poor predictor for arrhythmic events. Supplementary parameters are missing.Methods and resultsIschaemic cardiomyopathy patients (n = 242), who underwent CMR imaging prior to primary and secondary implantation of ICD, were classified depending on EF ≤ 35% (n = 188) or >35% (n = 54). FT parameters were derived from steady‐state free precession cine views using dedicated software. The primary endpoint was a composite of cardiovascular mortality (CVM) and/or appropriate ICD therapy. There were no significant differences in FT‐function or LV‐/RV‐function parameters in patients with an EF ≤ 35% correlating to the primary endpoint. In patients with EF > 35%, standard CMR functional parameters, such as LV‐EF, did not reveal significant differences. However, significant differences in most FT parameters correlating to the primary endpoint were observed in this subgroup. LV‐GLS (left ventricular‐global longitudinal strain) and RV‐GRS (right ventricular‐global radial strain) revealed the best diagnostic performance in ROC curve analysis. The combination of LV‐GLS and RV‐GRS showed a sensitivity of 85% and a specificity of 76% for the prediction of future events.ConclusionsThe impact of FT derived measurements in the risk stratification of patients with ICM depends on LV function. The combination of LV‐GLS/RV‐GRS seems to be a predictor of cardiovascular mortality and/or appropriate ICD therapy in patients with EF > 35%.

Left ventricular sphericity index analysis for the prediction of appropriate implantable cardioverter-defibrillator therapy.

Implantable cardioverter-defibrillator (ICD) is the most effective therapy currently available to prevent sudden cardiac death (SCD) in patients with left ventricular (LV) dysfunction. Although LV ejection fraction (LVEF) is an excellent marker of SCD in these patients, determining other predictors might help to identify patients who will be benefit more from device implantation. The purpose of this study was to determine whether abnormal LV sphericity index (SI) in transthoracic echocardiography is associated with appropriate ICD therapy in these patients. A total of 140 patients with primary ICD implantation (mean age 62.59±11.36years; 98 [70%] male) were included. The patients were classified into "no ICD therapy" or "ICD therapy" group according to the information of their devices for a maximum of 2 previous years. In four-chamber view image of transthoracic echocardiography, SI was calculated by dividing the major-axis dimension to minor-axis dimension of LV in both groups. Compared with patients with no ICD therapy, patients in ICD therapy group had lower LVEF (31.36±9.58vs 23.24±6.03, P=0.0001) and lower SI (1.79±0.29vs 1.57±0.32, P=0.0001). In multivariant logistic regression analysis, the SI of ≤1.58 was associated with fourfold increase of appropriate ICD therapy, even after adjusting for LVEF (odds ratio, 4.08; 95% confidence interval, 1.71-9.75; P=0.02). Simple echocardiographic sphericity dimension index as a marker of cardiac remodeling may be an important predictor of appropriate ICD therapy in patients with primary prevention ICDs and may provide additive risk stratification in patients with LV systolic dysfunction.

Effect of Sleep-Disordered Breathing on Appropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Heart Failure: A Systematic Review and Meta-Analysis.

Patients with heart failure and reduced ejection fraction are at increased risk of malignant ventricular arrhythmias. Implantable cardioverter-defibrillator (ICD) is recommended to prevent sudden cardiac death in some of these patients. Sleep-disordered breathing (SDB) is highly prevalent in this population and may impact arrhythmogenicity. We performed a systematic review and meta-analysis of prospective studies that assessed the impact of SDB on ICD therapy. Relevant prospective studies were identified in the Ovid MEDLINE, EMBASE, and Google Scholar databases. Weighted risk ratios of the association between SDB and appropriate ICD therapies were estimated using random effects meta-analysis. Nine prospective cohort studies (n=1274) were included in this analysis. SDB was present in 52% of the participants. SDB was associated with a 55% higher risk of appropriate ICD therapies (45% versus 28%; risk ratio, 1.55; 95% confidence interval, 1.32-1.83). In a subgroup analysis based on the subtypes of SDB, the risk was higher in both central (risk ratio, 1.50; 95% confidence interval, 1.11-2.02) and obstructive (risk ratio, 1.43; 95% confidence interval, 1.01-2.03) sleep apnea. SDB is associated with an increased risk of appropriate ICD therapy in patients with heart failure and reduced ejection fraction.

Impact of Improved Left Ventricular Systolic Function on the Recurrence of Ventricular Arrhythmia in Heart Failure Patients With an Implantable Cardioverter-Defibrillator.

Data are lacking on the relationship between improved left ventricular ejection fraction (LVEF) and the incidence of ventricular arrhythmia in patients with an implantable cardioverter-defibrillator (ICD) for secondary prevention. The aim of this study was to evaluate the incidence and predictors of improvement in left ventricular (LV) function and determine the impact of improved LVEF on the occurrence of appropriate ICD therapy in patients with reduced LVEF and ICD for secondary prevention. In this study, 93 patients who received ICDs for secondary prevention, had an LVEF of < 45%, and underwent echocardiographic follow-up assessment after receiving an ICD were enrolled. The mean patient age was 56.9 ± 13.1 years, the median time of repeat LVEF assessment was 19.7 (10.4-29.7) months, and the mean LVEF was 30.6 ± 8.5%. Of the patients, 58 (62.4%) had nonischemic cardiomyopathy. LV function improved after ICD implantation in 24 (25.8%) of 93 patients. Multivariable logistic regression revealed a short duration from the time of diagnosis of heart failure to ICD implantation and the presence of ventricular fibrillation as significant predictors of improved LV function. The incidence of appropriate ICD therapy was lower in the patients with than in those without LV function improvement. The composite endpoint of all-cause mortality or heart transplant was lower in the patients with than in those without LV function improvement. Overall survival was better and the recurrence of ventricular arrhythmia was lower in the patients with improved LV function.

0470: Implantable cardioverter defibrillator in primary prevention for chronic heart failure: incidence and predictors of appropriate therapy

Implantable cardioverter defibrillator (ICD) has been shown to be associated with a significant reduction in the risk of sudden cardiac death. The aim of this study was to assess the prevalence and to identify the clinical predictors of appropriate ICD therapy in patients with chronic heart failure following implantation of an ICD for primary prevention. A monocenter retrospective analysis was performed and all consecutive patients undergoing implantation of ICD for primary prevention were included. Device interrogations were performed and appropriate therapies were recorded. The endpoint follow-up was the last available device interrogation in our center. Of 317 primary prevention patients undergoing ICD implantation, 203 (64%) had ischemic cardiomyopathy (ICM) and 114 had non-ischemic dilated cardiomyopathy (NIDCM). After a mean follow-up time 760±599 days, 56 (17.7%) had received appropriate ICD therapies. Mean LVEF was 26±6%. By univariate comparison, LVDD≥65mm (p=0.035) and lack of diuretic (p=0.024) were predictors for ICD therapy. Absence of cardiac resynchronization therapy device (CRTD) was close to be significant (p=0.055). ICM and NIDCM patients benefit from ICD implantation did not differ (p=0.941). By multivariate analysis, elderly patients ≥65y (HR 1.92, p=0.032), LVDD≥65mm (HR 2.01, p=0.022) and lack of diuretic (HR 0.31, p<0.001) were all significant independent predictors for ICD therapy. Overall, the absence of CRTD device was close to be significant (H 0.53, p=0.062), but was significant in NIDCM population (p=0.007). During follow-up, the onset of atrial fibrillation (p=0.027) and hospitalization for acute heart failure (p=0.002) were significantly associated with ICD-delivered therapy. ICD therapy occurred in 17.7% of primary prevention patients without any difference between ICM and NIDCM. Older age, LV dilatation and absence of diuretic were predictive factors for ICD therapy. Presence of CRTD was close to be significant (figure next page). Abstract 0470 – Figure

Left ventricular sphericity independently predicts appropriate implantable cardioverter-defibrillator therapy

Whether echocardiographic markers of remodeling are associated with ventricular tachyarrhythmias is unknown. The purpose of this study was to determine whether a transthoracic echocardiographic (TTE) marker of spherical left ventricular (LV) remodeling is associated with appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with primary prevention ICDs. From TTE images, we calculated sphericity index (SI), the ratio of biplane LV end-diastolic volume to the volume of a hypothetical sphere with a diameter of the LV end-diastolic length, and examined the relation between SI and therapy for ventricular tachyarrhythmias in 278 patients with primary prevention ICDs and in 50 controls without structural heart disease or ventricular arrhythmias. SI in normal healthy adult subjects and in subjects receiving ICDs was 0.44 ± 0.02 and 0.65 ± 0.04, respectively (P <.001). Median time to first appropriate ICD therapy was significantly shorter in ICD patients with SI in the upper vs lower 50% of SI values (1.40 vs 2.38 years, P = .02 for conventional ICD patients; 1.54 vs 2.65 years, P = .02 for cardiac resynchronization therapy-defibrillator [CRT-D] patients). In multivariable Cox regression analysis, SI in the upper 50% was independently associated with appropriate ICD therapy after multivariable adjustment (hazard ratio 2.2, P = .03 for ICD cohort; hazard ratio 4.4, P = .01 for CRT-D cohort). SI was not associated with total mortality in either cohort. SI is associated with appropriate ICD therapy, but not total mortality, in patients receiving primary prevention ICDs. These observations suggest spherical LV remodeling may predispose to ventricular arrhythmias. Furthermore, SI appears to add predictive accuracy for appropriate ICD therapy in patients with reduced ejection fraction.

Scar extent evaluated by late gadolinium enhancement CMR: a powerful predictor of long term appropriate ICD therapy in patients with coronary artery disease.

BackgroundCoronary artery disease (CAD) patients are at risk for life-threatening ventricular arrhythmias (VA) related to scar tissue. Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately identify myocardial scar extent. It has been shown that scar extent, particularly scar transmurality, percent scar and scar mass, are associated with the occurrence of appropriate implantable cardioverter-defibrillator (ICD) therapy. However, quantification of transmurality extent has never been studied. The purpose of our study was to evaluate whether different methods quantifying scar transmurality, percent scar and scar mass (assessed with LGE-CMR) can predict appropriate ICD therapy in CAD patients with a long term follow-up period.Methods and resultsWe enrolled retrospectively 66 patients with chronic CAD referred for primary or secondary preventive ICD implantation and LGE-CMR before ICD implantation. Using LGE-CMR, scar extent was assessed by measuring scar mass, percent scar and transmural scar extent using four different methods. The median follow-up duration was 41.5 months (interquartile range 22–52). The endpoint was the occurrence of appropriate device therapy and occurred in 14 patients. Pre-ICD revascularization and transmural scar extent were significantly associated with the study endpoint but the latter was especially highly dependent on the method used. Patients with appropriate device therapy had also larger scar mass (29.6 ± 14.5 g vs 17.1 ± 8.8 g, p = 0.004), and larger percent scar (15.1 ± 8.2% vs 9.9 ± 5.6%, p = 0.03) than patients without appropriate device therapy. In multivariate analysis, scar extent variables remained significantly associated with the study end-point.ConclusionsIn this study of CAD patients implanted for primary or secondary preventive ICD, pre-ICD revascularization and scar extent studied by LGE-CMR were significantly associated with appropriate device therapy and can identify a subgroup of CAD patients with an increased risk of life-threatening VA. Depending of the method used, transmural scar extent may vary significantly and needs further studies to obtain a validated and consensual study method.

Influence of the vectorcardiogram synthesis matrix on the power of the electrocardiogram-derived spatial QRS-T angle to predict arrhythmias in patients with ischemic heart disease and systolic left ventricular dysfunction

Background and Purpose Several studies have demonstrated that the spatial mean QRS-T angle (SA) predicts cardiac events and mortality. Spatial mean QRS-T angle is a vectorcardiographic variable. Because in clinical practice, 12-lead standard electrocardiograms (ECGs) are recorded rather than vectorcardiograms (VCGs) according to Frank, VCGs are commonly obtained by synthesizing them from 12-lead ECGs, by using a VCG synthesis matrix. Hence, the thus computed SA is an estimate of the real SA measured in the Frank VCG. Recent studies have shown that Kors VCG synthesis matrix yields better estimates of SA than the inverse Dower VCG synthesis matrix. Our current study aims to compare the predictive power of these SA variants for the occurrence of potentially lethal arrhythmias. Methods The study group consisted of patients with ischemic heart disease and left ventricular systolic dysfunction who received an implantable cardioverter-defibrillator (ICD) for primary prevention. During follow-up, the occurrence of appropriate device therapy (occurrence of ventricular arrhythmia) was noted. Alternative SAs were computed in VCGs synthesized from standard 12-lead ECGs by using either the inverse Dower matrix (SA-Dower) or the Kors matrix (SA-Kors). Comparison of the predictive power of SA-Dower and SA- Kors was performed by receiver operating characteristic analysis, by Kaplan-Meier analysis, and by univariate and multivariate Cox regression analysis, using every 10th percentile of SA as a cutoff value. Results The study group consisted of 412 patients (361 men; mean ± SD age 63 ± 11 years), in which 56 patients had appropriate ICD therapy during follow-up. Receiver operating characteristic analysis revealed that the area under the curve of SA-Kors was significantly larger than area under the curve of SA-Dower (0.646 vs 0.607, P = .043). The discriminative power of SA-Kors for the absence/presence of appropriate ICD therapy in patients during follow-up was generally superior to SA-Dower over a wide range of cutoff values in the Kaplan-Meier analysis and generally yielded stronger hazard ratios in the univariate and multivariate Cox regression analyses. Conclusion If there is no specific reason to use the inverse Dower matrix, VCG synthesis from standard 12-lead ECGs should preferably be done by using the Kors matrix. It is likely to assume that already published studies in which the predictive value of SA-Dower was demonstrated would yield stronger results if the SA-Dower angles were substituted by SA-Kors angles.

Renal Dysfunction, Recovery Time Dispersion and Ventricular Arrhythmias in Heart Failure Patients Receiving Cardiac Resynchronization Therapy Defibrillator

Introduction: The aim of this study is to evaluate the influence of renal dysfunction and recovery time dispersion on the occurrence of arrhythmic events in HF patients receiving Cardiac resynchronization therapy (CRT)-implantable cardioverter defibrillator (ICD) devices (CRT-D) without a history of cardiac arrest or sustained ventricular tachycardia. Methods: We studied 80 HF patients who underwent CRT-D implantation from 2007 to 2010 and had indications for ICD for primary prevention of sudden cardiac death. Renal dysfunction was defined as eGFR<60 mL/min/1.73 m2. 187-ch repolarization interval-difference mapping electrocardiograph (187-ch RIDM-ECG) were performed after the implantation and the inter-lead difference between corrected T peak to T end intervals (Tp-e) were analyzed. Results: During mean follow-up time of 13±7 months, 16 patients (20%) experienced appropriate ICD therapy. There was a significantly higher incidence of appropriate ICD therapy in patients with renal dysfunction than without (35% vs. 12%, p<0.05). Among patients with renal dysfunction, there was a significantly higher inter-lead difference between Tp-e (82±30 vs 63±30 msec, p<0.05) in patients with appropriate ICD therapy than without. Conclusion: Both renal dysfunction and recovery time dispersion were associated with a higher incidence ICD therapy in HF patients receiving CRT-D.

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.

ST-segment depression as a risk factor in hypertrophic cardiomyopathy

From the spectrum of electrocardiogram (ECG) changes that may occur in hypertrophic cardiomyopathy (HCM), there is no criterion reported to be useful for risk stratification. We sought to determine whether there was a relationship between the resting ECG findings and prognosis in patients with HCM. We retrospectively analysed data on 173 consecutive patients admitted to our centre with a diagnosis of HCM. The 12-lead ECGs were assessed for underlying rhythm, PR interval, QRS voltages, QRS width, corrected QT interval, ST-segment deviation, T-wave inversion, and left atrial enlargement (LAE). During a mean follow-up of 50 months, 6.4% of patients had a combined endpoint [sudden death or appropriate implantable cardioverter-defibrillator (ICD) therapy]. The frequency of the combined endpoint was greater in patients with syncope, non-sustained ventricular tachycardia, maximal left ventricular (LV) wall thickness >or=30 mm, and ST-segment depression in the high lateral leads (all P < 0.05). Other ECG findings (LV hypertrophy, LAE, abnormal Q wave, abnormal ST-T changes, and underlying rhythm), family history of sudden death, and LV outflow obstruction were not related to the combined endpoint. The results of our multivariate analysis demonstrated that ST-segment depression in the high lateral leads (OR: 20.0, 95% CI: 12.7-27.5; P = 0.0001) and syncope (OR: 19.0, 95% CI: 11.7-26.9; P = 0.0001) were the predictors of sudden death or appropriate ICD therapy in patients with HCM. The results of this study indicated that, in addition to generally accepted risk factors, ST-segment depression in the high lateral leads could be of prognostic significance in HCM patients.

Appropriate ICD Therapy in Patients With Idiopathic Dilated Cardiomyopathy Long-Term Follow-Up

The implantable cardioverter defibrillator (ICD) has proved effective in preventing sudden death and decreasing mortality in randomised secondary prevention trials. Some nonrandomized studies have reported different incidences and predictors of appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy (DCM). The antiarrhythmic and other medical therapies were different between the published studies and it was reported that not using beta-blockers was a predictor of appropriate ICD therapy. In the present study, we report on our long-term experience with ICD therapy in patients with DCM, the majority of whom were treated with beta-blockers and amiodarone. The study population consisted of 25 patients with DCM who underwent initial transvenous ICD implantation between December 1995 and May 2005. Indications for ICD implantation were monomorphic sustained ventricular tachycardia (VT) in 16 patients (64%), cardiac arrest in 8 patients (32%), and syncope plus inducible VT in one patient. Twenty-four patients underwent an electrophysiologic study (EPS). In 18 patients, the ICDs were programmed to only shocks and in 7 patients an additional antitachycardia pacing program was performed. One patient was lost to follow-up and 24 patients were followed-up primarily in our ICD pacemaker outpatient clinic. Appropriate ICD therapy was defined as antitachycardia pacing therapy or shock for tachyarrhythmia determined by evaluation of the clinical information and by device diagnostics to be either ventricular fibrillation or ventricular tachycardia. The mean follow-up was 39.29 +/- 30.59 months after ICD implantation. At follow-up, 17 patients were using a beta-blocker and 16 patients amiodarone. Appropriate ICD therapy was observed in 14 patients (58%). The detected arrhythmias were VT in 12 patients, ventricular fibrillation (VF) in one, and VT and VF in one patient. The time to first ICD therapy was 15.93 +/- 18.45 (range, 1-74) months. Using the Kaplan-Meier method, the percent survival free of appropriate ICD therapy was 82%, 72%, 66%, and 55% at 1, 2, 3, and 4 years follow-up, respectively. The clinical, echocardiographic, and electrophysiologic characteristics did not differ between those who did and did not receive appropriate ICD therapy. However, the mean QRS duration was significantly longer in patients who received appropriate ICD therapies. Cox regression analysis did not reveal any factors that predicted appropriate ICD therapy. Five patients (21%) died during follow-up. Four deaths were classified as cardiac and one as noncardiac. The cumulative survival from total death was 94%, 82%, 82%, and 69%, and the cumulative survival from cardiac death was 94%, 82%, 82%, and 76% during 1, 2, 3, and 4 years of follow-up, respectively. In summary, in this selected patient population with DCM, the majority of patients were unresponsive to beta-blocker and antiarrhythmic therapy. Most of these patients received appropriate ICD therapy during follow-up. Cox regression analysis did not identify any factors that predicted appropriate ICD therapy. Additional trials with larger patient populations are needed to detect the predictors of appropriate ICD therapy in patients with DCM.