Christian Zwicker

Dependency of cardiac resynchronization therapy on myocardial viability at the LV lead position.

OBJECTIVES This study sought to analyze the effectiveness of cardiac resynchronization therapy (CRT) related to the viability in the segment of left ventricular (LV) lead position defined by myocardial deformation imaging. BACKGROUND Echocardiographic myocardial deformation analysis allows determination of LV lead position as well as extent of myocardial viability. METHODS Myocardial deformation imaging based on tracking of acoustic markers within 2-dimensional echo images (GE Ultrasound, GE Healthcare, Horton, Norway) was performed in 65 heart failure patients (54 ± 6 years of age, 41 men) before and 12 months after CRT implantation. In a 16-segment model, the LV lead position was defined based on the segmental strain curve with earliest peak strain, whereas the CRT system was programmed to pure LV pacing. Nonviability of a segment (transmural scar formation) was assumed if the peak systolic circumferential strain was >-11.1%. RESULTS In 47 patients, the LV lead was placed in a viable segment, and in 18 patients, it was placed in a nonviable segment. At 12-month follow-up there was greater decrease of LV end-diastolic volumes (58 ± 13 ml vs. 44 ± 12 ml, p = 0.0388) and greater increase of LV ejection fraction (11 ± 4% vs. 5 ± 4%, p = 0.0343) and peak oxygen consumption (2.5 ± 0.9 ml/kg/min vs. 1.7 ± 1.1 ml/kg/min, p = 0.0465) in the viable compared with the nonviable group. The change in LV ejection fraction and the reduction in LV end-diastolic volumes at follow-up correlated to an increasing peak systolic circumferential strain in the segment of the LV pacing lead (r = 0.61, p = 0.0274 and r = 0.64, p = 0.0412, respectively). Considering only patients with ischemic heart disease, differences between viable and nonviable LV lead position group were even greater. CONCLUSIONS Preserved viability in the segment of the CRT LV lead position results in greater LV reverse remodeling and functional benefit at 12-month follow-up. Deformation imaging allows analysis of viability in the LV lead segment.

Myocardial Deformation Imaging by Two-Dimensional Speckle-Tracking Echocardiography for Prediction of Global and Segmental Functional Changes after Acute Myocardial Infarction: A Comparison with Late Gadolinium Enhancement Cardiac Magnetic Resonance

BACKGROUND Myocardial deformation analysis by speckle-tracking echocardiography (STE) has been shown to accurately predict viability in patients with chronic ischemic left ventricular (LV) dysfunction. The aim of this study was to evaluate two-dimensional STE for the prediction of global and segmental LV functional changes after acute myocardial infarction (AMI) in comparison with late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR). METHODS In 93 patients (mean age, 60 ± 11 years) with first AMIs (55 with ST-segment elevation myocardial infarctions and 38 with non-ST-segment elevation myocardial infarctions) treated with acute percutaneous coronary intervention, global peak longitudinal strain was determined to describe global function by STE, and peak systolic circumferential and longitudinal strain was determined for segmental function analysis. LGE CMR was performed to define the amounts of global and segmental myocardial scar. STE and LGE CMR were performed within 48 hours of AMI. At 6-month follow-up, transthoracic echocardiography was repeated to determine global und segmental LV recovery and adverse LV remodeling (increase in end-systolic volume > 15%). RESULTS Accuracy to predict global functional improvement as well as LV remodeling at 6-month follow-up after AMI was similar for STE and LGE CMR (areas under the curve, 0.715 vs 0.729 [P = .8830] and 0.806 vs 0.824 [P = .7141], respectively). Peak systolic circumferential strain < -14.2% had sensitivity of 71.6% and specificity of 58.1% to predict segmental functional improvement. Compared with LGE CMR, the predictive accuracy of transmural STE for segmental functional improvement at 6-month follow-up was lower (area under the curve, 0.788 vs 0.668; P = .0001). Predictive accuracy for segmental functional improvement could be improved by analysis of endocardial circumferential strain (area under the curve, 0.700 vs 0.668 for transmural speckle-tracking echocardiographic analysis; P = .0023). CONCLUSIONS Two-dimensional STE allows the prediction of global functional recovery as well as LV remodeling after AMI with accuracy comparable with that of LGE CMR. Accuracy to predict segmental functional recovery using transmural deformation analysis by two-dimensional STE is inferior compared with LGE CMR but can be improved by a layer-specific analysis of endocardial deformation.

Layer-specific analysis of myocardial deformation for assessment of infarct transmurality: comparison of strain-encoded cardiovascular magnetic resonance with 2D speckle tracking echocardiography

AIMS Separate analysis of endocardial and epicardial myocardial layer deformation has become possible using strain-encoded cardiovascular magnetic resonance (SENC) and 2D-dimensional speckle tracking echocardiography (Echo). This study evaluated and compared both modalities for the assessment of infarct transmurality as defined by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR). METHODS AND RESULTS In 29 patients (age 62.4 ± 11.7 years, 23 male) with ischaemic cardiomyopathy, SENC using 1.5 T CMR and Echo were performed. Peak circumferential systolic strain of the endocardial and the epicardial layer of 304 myocardial segments was assessed by SENC and by Echo. The segmental transmurality of myocardial infarction was determined as relative amount of LGE (0%: no infarction; 1-50%: non-transmural infarction; 51-100%: transmural infarction). Endocardial and epicardial strain defined by SENC and by Echo differed significantly between segments of different infarct transmurality determined by CMR. Endocardial layer circumferential strain analysis by Echo and by SENC allowed distinction of segments with non-transmural infarction from non-infarcted segments with similar accuracy [area under the curve (AUC) 0.699 vs. 0.649, respectively, P = 0.239]. Epicardial layer circumferential strain analysis by Echo and by SENC allowed distinction of transmural from non-transmural myocardial infarction defined by LGE CMR with similar accuracy (AUC 0.721 vs. 0.664, respectively, P = 0.401). Endocardial strain by SENC correlated moderately with endocardial strain by Echo (r = 0.50; standard error of estimate = 5.2%). CONCLUSION Layer-specific analysis of myocardial deformation by Echo and by SENC allows discrimination between different transmurality categories of myocardial infarction with similar accuracy. However, accuracy of both methods is non-optimal, indicating that further tools for improvement should be evaluated in the future.