Fraz Umar

Left Ventricular Midwall Fibrosis as a Predictor of Mortality and Morbidity After Cardiac Resynchronization Therapy in Patients With Nonischemic Cardiomyopathy

OBJECTIVES The aim of this study was to determine whether left ventricular (LV) midwall fibrosis, detected by midwall hyperenhancement (MWHE) on late gadolinium enhancement cardiovascular magnetic resonance (CMR) imaging, predicts mortality and morbidity in patients with dilated cardiomyopathy (DCM) undergoing cardiac resynchronization therapy (CRT). BACKGROUND Midwall fibrosis predicts mortality and morbidity in patients with DCM. METHODS Patients with DCM with (+) or without (-) MWHE (n = 20 and n = 77, respectively) as well as 161 patients with ischemic cardiomyopathy (ICM) undergoing CRT (n = 258) were followed up for a maximum of 8.7 years. RESULTS Among patients with DCM, +MWHE predicted cardiovascular mortality (hazard ratio [HR]: 18.6; 95% confidence intervals [CI]: 3.51 to 98.5; p = 0.0008), total mortality or hospitalization for major adverse cardiovascular events (HR: 7.57; 95% CI: 2.71 to 21.2; p < 0.0001), and cardiovascular mortality or heart failure hospitalizations (HR: 9.56; 95% CI: 2.72 to 33.6; p = 0.0004), independent of New York Heart Association class, QRS duration, atrial fibrillation, LV volumes, LV ejection fraction, and a CMR-derived measure of dyssynchrony. Among patients with DCM and ICM, the risk of cardiovascular mortality for DCM +MWHE (adjusted HR: 18.5; 95% CI: 3.93 to 87.3; p = 0.0002) was similar to that for ICM (adjusted HR: 21.0; 95% CI: 5.06 to 87.2; p < 0.0001). Both DCM +MWHE and ICM were predictors of pump failure death as well as sudden cardiac death. LV reverse remodeling was observed in DCM -MWHE and in ICM but not in DCM +MWHE. CONCLUSIONS Midwall fibrosis is an independent predictor of mortality and morbidity in patients with DCM undergoing CRT. The outcome of DCM with midwall fibrosis is similar to that of ICM. This relationship is mediated by both pump failure and sudden cardiac death.

Myocardial strain measurement with feature-tracking cardiovascular magnetic resonance: normal values.

AIMS Myocardial deformation is a key to clinical decision-making. Feature-tracking cardiovascular magnetic resonance (FT-CMR) provides quantification of motion and strain using standard steady-state in free-precession (SSFP) imaging, which is part of a routine CMR left ventricular (LV) study protocol. An accepted definition of a normal range is essential if this technique is to enter the clinical arena. METHODS AND RESULTS One hundred healthy individuals, with 10 men and women in each of 5 age deciles from 20 to 70 years, without a history of cardiovascular disease, diabetes, renal impairment, or family history of cardiovascular disease, and with a normal stress echocardiogram, underwent FT-CMR assessment of LV myocardial strain and strain rate using SSFP cines.Peak systolic longitudinal strain (Ell) was -21.3 ± 4.8%, peak systolic circumferential strain (Ecc) was -26.1 ± 3.8%, and peak systolic radial strain (Err) was 39.8 ± 8.3%. On Bland-Altman analyses, peak systolic Ecc had the best inter-observer agreement (bias 0.63 ± 1.29% and 95% CI -1.90 to 3.16) and peak systolic Err the least inter-observer agreement (bias 0.13 ± 6.41 and 95% CI -12.44 to 12.71). There was an increase in the magnitude of peak systolic Ecc with advancing age, which was greatest in subjects over the age of 50 years (R(2) = 0.11, P = 0.003). There were significant gender differences (P < 0.001) in peak systolic Ell, with a greater magnitude of deformation in females (-22.7%) than in males (-19.3%). CONCLUSION Normal values for myocardial strain measurements using FT-CMR are provided. All circumferential and longitudinal based variables had excellent intra- and inter-observer variability.

Comparison of magnetic resonance feature tracking for systolic and diastolic strain and strain rate calculation with spatial modulation of magnetization imaging analysis

To compare cardiovascular magnetic resonance‐feature tracking (CMR‐FT) with spatial modulation of magnetization (SPAMM) tagged imaging for the calculation of short and long axis Lagrangian strain measures in systole and diastole.

Feature-tracking cardiovascular magnetic resonance as a novel technique for the assessment of mechanical dyssynchrony ☆

BACKGROUND Myocardial tagging using cardiovascular magnetic resonance (CMR) is the gold-standard for the assessment of myocardial mechanics. Feature-tracking cardiovascular magnetic resonance (FT-CMR) has been validated against myocardial tagging. We explore the potential of FT-CMR in the assessment of mechanical dyssynchrony, with reference to patients with cardiomyopathy and healthy controls. METHODS Healthy controls (n=55, age: 42.9 ± 13 yrs, LVEF: 70 ± 5%, QRS: 88 ± 9 ms) and patients with cardiomyopathy (n=108, age: 64.7 ± 12 yrs, LVEF: 29 ± 6%, QRS: 147 ± 29 ms) underwent FT-CMR for the assessment of the circumferential (CURE) and radial (RURE) uniformity ratio estimate based on myocardial strain (both CURE and RURE: 0 to 1; 1=perfect synchrony) RESULTS CURE (0.79 ± 0.14 vs. 0.97 ± 0.02) and RURE (0.71 ± 0.14 vs. 0.91 ± 0.04) were lower in patients with cardiomyopathy than in healthy controls (both p<0.0001). CURE (area under the receiver-operator characteristic curve [AUC]: 0.96), RURE (AUC: 0.96) and an average of these (CURE:RUREAVG, AUC: 0.98) had an excellent ability to discriminate between patients with cardiomyopathy and controls (sensitivity 90%; specificity 98% at a cut-off of 0.89). The time taken for semi-automatically tracking myocardial borders was 5.9 ± 1.4 min. CONCLUSION Dyssynchrony measures derived from FT-CMR, such as CURE and RURE, provide almost absolute discrimination between patients with cardiomyopathy and healthy controls. The rapid acquisition of these measures, which does not require specialized CMR sequences, has potential for the assessment of mechanical dyssynchrony in clinical practice.

Haemodynamic effects of cardiac resynchronization therapy using single-vein, three-pole, multipoint left ventricular pacing in patients with ischaemic cardiomyopathy and a left ventricular free wall scar: the MAESTRO study

AIMS The clinical response to cardiac resynchronization therapy (CRT) is variable. Multipoint left ventricular (LV) pacing could achieve more effective haemodynamic response than single-point LV pacing. Deployment of an LV lead over myocardial scar is associated with a poor haemodynamic response to and clinical outcome of CRT. We sought to determine whether the acute haemodynamic response to CRT using three-pole LV multipoint pacing (CRT3P-MPP) is superior to that to conventional CRT using single-site LV pacing (CRTSP) in patients with ischaemic cardiomyopathy and an LV free wall scar. METHODS AND RESULTS Sixteen patients with ischaemic cardiomyopathy [aged 72.6 ± 7.7 years (mean ± SD), 81.3% male, QRS: 146.0 ± 14.2 ms, LBBB in 14 (87.5%)] in whom the LV lead was intentionally deployed straddling an LV free wall scar (assessed using cardiac magnetic resonance), underwent assessment of LV + dP/dtmax during CRT3P-MPP and CRTSP. Interindividually, the ΔLV + dP/dtmax in relation to AAI pacing with CRT3P-MPP (6.2 ± 13.3%) was higher than with basal and mid CRTSP (both P < 0.001), but similar to apical CRTSP. Intraindividually, significant differences in the ΔLV + dP/dtmax to optimal and worst pacing configurations were observed in 10 (62.5%) patients. Of the 8 patients who responded to at least one configuration, CRT3P-MPP was optimal in 5 (62.5%) and apical CRTSP was optimal in 3 (37.5%) (P = 0.0047). CONCLUSIONS In terms of acute haemodynamic response, CRT3P-MPP was comparable an apical CRTSP and superior to basal and distal CRTSP. In the absence of within-device haemodynamic optimization, CRT3P-MPP may offer a haemodynamic advantage over a fixed CRTSP configuration.

Mechanical effects of midwall fibrosis in non-ischemic dilated cardiomyopathy

Background In patients with non-ischemic dilated cardiomyopathy (NIDCM), mid-wall fibrosis (MWF) is associated with a higher risk of hospitalizations and death from pump failure and sudden cardiac death. The mechanical effects of MWF remain unexplored. Strain measures derived from feature tracking-CMR (FT-CMR) have been validated against myocardial tagging. Methods Patients (n = 84, age: 57.7 ± 14.7 yrs, [mean ± SD], LVEF: 25.7 ± 11.1%) with newly diagnosed NIDCM underwent late gadolinium enhancement CMR (inversion-recovery technique 10 min after the administration of gadolinium-DTPA (0.1 mmol/kg). Peak systolic cir

Letter by Taylor et al Regarding Article, “Myocardial Fibrosis as a Key Determinant of Left Ventricular Remodeling in Idiopathic Dilated Cardiomyopathy: A Contrast-Enhanced Cardiovascular Magnetic Study”

Masci et al1 should be commended for providing new evidence with respect to late gadolinium enhancement (LGE) cardiovascular MRI in patients with idiopathic dilated cardiomyopathy (IDCM). After categorizing patients by LGE status, they demonstrated that every patient remained in the same cohort during the 2 years of follow-up, a novel finding strongly suggestive of 2 distinct phenotypes. The observed progression in myocardial fibrosis, in association with a reduction in left ventricular systolic function, adds to the growing evidence …

101 VALIDATION OF MAGNETIC RESONANCE FEATURE TRACKING FOR LONGITUDINAL SYSTOLIC AND DIASTOLIC STRAIN CALCULATION WITH SPATIAL MODULATION OF MAGNETISATION IMAGING ANALYSIS

Introduction Feature-tracking (FT) analysis offers a novel, fast and practicable method to calculate strain from routinely acquired steady state free precession (SSFP) images without the need to perform additional tagged sequences. There is no validation of this technique, however, against a reference standard myocardial tagging analysis for any strain parameter other than mid-left ventricular whole slice circumferential strain. In an adult study of patients with dilated cardiomyopathy (DCM) and healthy controls, we sought to validate the FT method (TomTec Imaging systems, Munich) against spatial modulation of magnetisation (SPAMM) tissue tagging analysis (Cardiac Image Modelling Package (CIMTag2D), University of Auckland) for the computation of long axis function. Methods We compared measures of global longitudinal strain from the horizontal long axis view using the two techniques in 45 patients (mean age 44±14 years, male 63%). Normal healthy adults (n=35) were identified from an ongoing prospective, observational research study examining the effects of living kidney donation on cardiovascular structure and function (NCT01028703). Consecutive DCM patients (n=10) were identified after undergoing myocardial tagging for clinically indicated scans. Retrospective off-line analysis was performed on matched tagged and SSFP slices by two independent blinded observers (WEM and RJT). After manually drawing endocardial borders in the end-diastolic frame for each image, the FT software automatically propagated the contour and followed its features (brightness gradient at the tissue-cavity interface, dishomogeneties of the tissue, spatial coherence) throughout the remainder of the cardiac cycle to compute longitudinal strain parameters. Results Longitudinal strain (Ell). Peak systolic FT-Ell (−18.1±5.0%) correlated most strongly with CIMTag-Ell values derived from the subendocardium (−16.7±4.8%) with a Pearsons correlation coefficient of 0.70 (p<0.001; figure 1A). A Bland Altman plot (figure 1B) showed good agreement with only a small systematic overestimation from FT (mean difference 1.3±3.8%, p=0.03). Whilst in DCM patients peak systolic global Ell values were not significantly different between the two techniques (−9.7±4.5% vs −8.8±3.9%, p=0.44), among healthy controls there was a small but significant difference in Ell values between FT and tagging image analysis (−19.5±3.5% vs −18.0±3.5%, p=0.04; figure 2). Figure 1 Figure 2 Longitudinal strain rate (SR) There was good agreement between the two techniques for peak systolic global longitudinal SR values but with a small tendency towards higher FT values as compared with tagging (mean difference 0.09±0.26 1/s, p=0.04; r=0.64, p<0.001). The weakest correlation between the two techniques was for early diastolic global longitudinal SR but even this relationship was still highly significant (mean difference 0.09±0.26 1/s; r=0.42, p=0.007). Reproducibility testing Intraobserver and interobserver variability for FT-Ell analysis was small (−0.49±1.83% and 0.22±1.13%, respectively). Timed analysis The average time taken for post-processing strain analysis using FT software was significantly less than that required for CIMTag (5.9±0.8 min vs 23.2±3.5 min, p<0.0001). Conclusions FT based assessment of longitudinal strain correlated highly with values derived from tagged images in a population with a wide range of left ventricular function. Furthermore, FT can be performed without the need for additional imaging and lengthy post-processing times.

002 IMPLANTABLE CARDIOVERTER DEFIBRILLATOR THERAPY OR CARDIAC RESYNCHRONISATION THERAPY WITH DEFIBRILLATION IN PATIENTS WITH LEFT VENTRICULAR DYSFUNCTION: A COST-IMPACT STUDY

Background Increasing evidence from clinical outcomes studies suggest that cardiac resynchronisation therapy with defibrillation (CRT-D) is superior to implantable cardioverter defibrillator (ICD) therapy alone in patients with left ventricular dysfunction. Methods We undertook a retrospective analysis of all ICD and CRT-D implants from April 2006 to July 2012. Cost data was obtained on an individual patient basis, derived from financial records of transactions between payers and the provider. Results A total of 921 patients (aged 63±14 years (mean±SD), 49 (91%) male) underwent device implantation: 486 (53%) de novo CRT-D; 381 (41%) single/dual chamber ICD; and, 54 (6%) upgrade from ICD to CRT-D. In the upgrades from ICD to CRT-D, the median time from ICD to CRT-D implantation was 3.2 years. From the time prior to ICD implantation to prior to CRT-D, the LVEF decreased from 30±9.4% to 22±8.7% (p<0.001), the QRS duration increased from 133±34.9 ms to 158±29.3 ms (p=0.0003) and all patients had progressed to NYHA class III. In this upgrade group, the initial ICD implantation cost £846 864 (34 electives: £511 904; 20 non-electives: £334 960) and the upgrade to CRT-D cost £1 330 614 (44 electives: £1 046 364; 10 non-electives: £284 250), totalling £2 177 478 in implantation costs alone over a median of 3.2 years. If these 54 patients had a CRT-D at the initial implant, it would have cost £1 377 054 (34 electives: £808 554; 20 non-electives: £568 500). Therefore, this approach would have saved £800 424 in implantation costs alone. Conclusions This study indicates that upgrading from ICD to CRT-D is costly. Our findings suggest that implantation of CRT-D in patients with known left ventricular dysfunction may be more cost-effective.