Susan M. Nelson

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy A Comprehensive Prospective Single-Center Study

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Cardiac troponin T mutation in familial cardiomyopathy with variable remodeling and restrictive physiology

We identified a unique family with autosomal dominant heart disease variably expressed as restrictive cardiomyopathy (RCM), hypertrophic cardiomyopathy (HCM), and dilated cardiomyopathy (DCM), and sought to identify the molecular defect that triggered divergent remodeling pathways. Polymorphic DNA markers for nine sarcomeric genes for DCM and/or HCM were tested for segregation with disease. Linkage to eight genes was excluded, but a cardiac troponin T (TNNT2) marker cosegregated with the disease phenotype. Sequencing of TNNT2 identified a heterozygous missense mutation resulting in an I79N substitution, inherited by all nine affected family members but by none of the six unaffected relatives. Mutation carriers were diagnosed with RCM (n = 2), non‐obstructive HCM (n = 3), DCM (n = 2), mixed cardiomyopathy (n = 1), and mild concentric left ventricular hypertrophy (n = 1). Endomyocardial biopsy in the proband revealed non‐specific fibrosis, myocyte hypertrophy, and no myofibrillar disarray. Restrictive Doppler filling patterns, atrial enlargement, and pulmonary hypertension were observed among family members regardless of cardiomyopathy subtype. Mutation of a sarcomeric protein gene can cause RCM, HCM, and DCM within the same family, underscoring the necessity of comprehensive morphological and physiological cardiac assessment in familial cardiomyopathy screening.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Original articles dyssynchrony indices to predict response to cardiac resynchronization therapy a comprehensive prospective single-center study

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization TherapyClinical Perspective

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.

Dyssynchrony Indices To Predict Response to Cardiac Resynchronization TherapyClinical Perspective: A Comprehensive Prospective Single-Center Study

Background—Whether mechanical dyssynchrony indices predict reverse remodeling (RR) or clinical response to cardiac resynchronization therapy (CRT) remains controversial. This prospective study evaluated whether echocardiographic dyssynchrony indices predict RR or clinical response after CRT. Methods and Results—Of 184 patients with heart failure with anticipated CRT who were prospectively enrolled, 131 with wide QRS and left ventricular ejection fraction <35% had 6-month follow-up after CRT implantation. Fourteen dyssynchrony indices (feasibility) by M-mode (94%), tissue velocity (96%), tissue Doppler strain (92%), 2D speckle strain (65% to 86%), 3D echocardiography (79%), and timing intervals (98%) were evaluated. RR (end-systolic volume reduction ≥15%) occurred in 55% and more frequently in patients without (71%) than in patients with (42%) ischemic cardiomyopathy (P=0.002). Overall, only M-mode, tissue Doppler strain, and total isovolumic time had a receiver operating characteristic area under the curve (AUC) greater than the line of no information, but none of these were strongly predictive of RR (AUC, 0.63 to 0.71). In nonischemic cardiomyopathy, no dyssynchrony index predicted RR. In ischemic cardiomyopathy, M-mode (AUC, 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) -derived indices predicted RR (P<0.05 for all), although the incremental value was modest. No indices predicted clinical response assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption. Conclusions—These findings are consistent with the Predictors of Response to CRT study and do not support use of these dyssynchrony indices to guide use of CRT.