Abstract 9252: Global Longitudinal Strain And Left Atrial Volume Index Predict Appropriate Implantable Cardioverter Defibrillator Therapy In Hypertrophic Cardiomyopathy Patients
Introduction: Accurate predictors of appropriate implantable cardioverter defibrillator (ICD) therapy in hypertrophic cardiomyopathy (HCM) patients have not yet been identified.
Hypothesis: Left ventricular global longitudinal strain (GLS) and indexed left atrial volume (LAVI), indices of systolic and diastolic ventricular function respectively, may be predictive for appropriate ICD therapy in HCM patients.
Methods: LAVI and 2-dimensional speckle tracking-derived GLS were assessed in 92 HCM patients undergoing ICD implantation. Appropriate ICD therapy was defined as occurrence of antitachycardia-pacing/shock for ventricular tachycardia/fibrillation.
Results: Appropriate ICD therapy occurred in 21 (23%) patients during a median follow-up of 4.2 (1.6-7.8) years. Both LAVI and GLS showed higher accuracy for appropriate ICD therapy prediction compared to the presence of ≥1 conventional sudden cardiac death risk factor(s) [area under the ROC curve 0.76 (95%CI:0.65-0.87) and 0.65 (95%CI:0.54-0.77) versus 0.52 (95%CI: 0.43-0.58) respectively, p<0.001]. In particular, the presence of LAVI ≥34 mL/m2 or GLS ≥-14% predicted appropriate ICD therapy with 100% sensitivity. Equally important, the presence of LAVI <34 mL/m2 and GLS <-14% showed a negative predictive value of 100%. Moreover, using these cut-off values, multivariate analysis revealed both LAVI (p=0.03) and GLS (p=0.04), but not the presence of any conventional sudden cardiac death risk factor, as independent predictors of appropriate ICD therapy. Likelihood ratio test (p<0.001) and integrated discrimination improvement index (0.19, p<0.001) showed that LAVI and GLS were of incremental value over conventional sudden cardiac death risk factor(s) to predict appropriate ICD therapy. In addition, net reclassification improvement of 0.45 indicated substantial and adequate reclassification of patients into low probability for appropriate ICD therapy including GLS and LAVI in the risk stratification model (p=0.005).
Conclusion: GLS and LAVI accurately predict appropriate ICD therapy in a high-risk HCM population. In addition to conventional sudden cardiac death risk factors, both parameters may be useful to optimize criteria and timing for ICD implantation in these patients.
- Hypertrophic cardiomyopathy
- Implantable cardioconvert defibrillator
- Atrial function
- Ventricular function
- Ventricular arrhythmia
- © 2012 by American Heart Association, Inc.