Scar Burden Research Articles

Appropriateness and diagnostic yield of cardiac magnetic resonance imaging from a tertiary referral center in the Middle East.

Cardiac magnetic resonance imaging (CMRI) is a novel non-invasive modality with many potential indications, and was recently introduced in Lebanon. We sought to assess the appropriateness and diagnostic yield of CMR studies performed at a tertiary referral center from the Middle East since the inception of the program. All patients who underwent CMR studies between January 1(st) 2013 and June 18(th) 2014 were enrolled in this study. CMR reports were retrospectively reviewed. The study indication, clinical history, and findings were extracted and analyzed. The appropriateness of the study was judged according to the 2010 updated Asian Society of Cardiac Imaging guidelines. There were a total of 142 patients [mean age 42.1 (SD: 18) years, 24.6% females] that underwent CMR study. Two-thirds of studies were performed on an outpatient basis, and outside referrals constituted 16.2% of the entire cohort. The cardiologists referred 122 cases (86%) with main contribution from electrophysiology and imaging specialists. Of the 142 cases, 12 (8.4%) were not indicated and added little value. Of the remaining 130 appropriate studies (appropriateness level A8-A9), one-third had an incorrect diagnosis prior to CMR, and 8% had relevant findings that were missed on other studies but captured by CMR. Furthermore, CMR confirmed the diagnosis in 28% of the cases, provided relevant information on scar burden, shunt quantification, and ruled out infiltrative disease in the remaining patients. Also, CMR demonstrated the presence of scar in 45 of patients, among whom 20 (44%) had significant scar volume quantification (>5% of left ventricular myocardium). Finally, 9% of patients had a relevant extra-cardiac finding that needed further investigation. Despite the recent launch of the CMR program at our institution, the majority of studies were appropriately indicated, provided relevant data and were clinically useful. Inappropriate or uncertain studies did not provide relevant data, and should be further minimized to avoid unnecessary costs and downstream testing. Large prospective CMR database with clinical follow-up is needed to provide more insight about cardiovascular disease and outcomes in our population.

(228) - Response to CD34+ Cell Therapy Is Associated With Myocardial Scar Burden in Patients With Ischemic and Non-Ischemic Chronic Heart Failure

s S91 (SFN) by i.p. 1 day prior to surgery to induce Nrf2, with saline as vehicle control (n= 6 per group). After 2 hours of cold ischemia, donor hearts were transplanted into the recipients. Just after transplant, recipients received an additional single injection of SFN or saline. Following 24 hours of reperfusion, echocardiography was performed and donor hearts were harvested. Superoxide dismutase-2 (SOD2) and Caspase-3 activities were measured as markers of the Nrf2 pathway downstream enzyme and apoptosis respectively. P65 and phosphorylated P65 were measured by Western immunoblotting to assess NF-kB activation. Results: Compared to WT-Saline, KO-Saline demonstrated lower SOD2, increased Caspase-3, and increased P65 expression and phosphorylation. Among WT donors, SFN treatment rescued SOD2, decreased Caspase-3, and inhibited P65 phosphorylation compared to saline treatment. These SFN effects were absent on KO donors (Figure A). Echocardiography of donor hearts showed that the fractional area change (FAC) was significantly higher in WT-SFN than WT-Saline. KO-Saline and KO-SFN displayed similarly lower FAC than WT donors (Figure B). Conclusion: Our results suggest the anti-inflammatory potential of Nrf2 through inhibition of NF-kB activity during IRI. The Nrf2 pathway may be a promising pharmacological target to mitigate IRI-mediated inflammation, apoptosis, and impaired cardiac function through the anti-inflammatory property as well as its anti-oxidant nature in heart transplantation.

REPLACEMENT AND INTERSTITIAL FIBROSIS BY CARDIAC MR AND DIASTOLIC DYSFUNCTION IN PATIENTS WITH DILATED CARDIOMYOPATHY

Cardiac MR can be used to determine the extent of both replacement and interstitial fibrosis in patients with cardiomyopathies. We hypothesized that myocardial extracellular volume fraction (ECV) and scar burden by CMR are related to LV diastolic function in patients with dilated cardiomyopathy (DCM

Association of Plasma Thrombospondin-1 Level with Cardiovascular Disease and Mortality in Hemodialysis Patients.

Thrombospondin-1 (TSP-1) is known to be involved in the regulation of angiogenesis, inflammation, and vascular function. Clinical studies have demonstrated its correlation with peripheral artery disease, coronary artery disease, and pulmonary hypertension. In this study, we explored its potential roles in the background of end-stage renal disease (ESRD). A total of 140 ESRD outpatients (ages 61.0 ± 12.4 years) were prospectively followed for 34 ± 7 months. Their TSP-1 levels were analyzed from pre-hemodialysis blood sample. Cardiovascular survey included ankle- brachial index (ABI), echocardiography and Tl-201 dipyridamole single-photon emission computed tomography (SPECT). Plasma TSP-1 levels were higher in those patients with preexisting clinical evidence of cardiovascular disease (CVD) than those without (p = 0.002). TSP-1 concentrations were also correlated with ABI, left ventricular ejection fraction, and scar burden in SPECT. Stepwise logistic regression analysis revealed that TSP-1 level was independently associated with the presence of CVD, with an odds ratio of 1.38 [95% confidence interval (CI), 1.09-1.75, p = 0.008]. In survival analyses, 31 patients (22%) died during the follow-up, 16 (52%) arising from cardiovascular causes. Cox hazards analysis revealed that the patients with TSP-1 levels in the highest tertile had a 5.32- and 6.75-fold higher risk for all-cause and cardiovascular mortality than those in the lowest tertile. This predictive value for all-cause mortality still persisted after multivariate adjustment (hazard ratio, 8.71; 95% CI, 1.36-55.68; p = 0.02). This study hallmarks the association of elevated TSP-1 level with CVD and adverse outcome among hemodialysis patients. Thrombospondin-1; End-stage renal disease; Cardiovascular disease; Mortality.

The Relationship between Time from Myocardial Infarction, Left Ventricular Dyssynchrony, and the Risk for Ventricular Arrhythmia: Speckle-Tracking Echocardiographic Analysis

Differences in arrhythmogenic substrate may explain the variable efficacy of implantable cardioverter-defibrillators (ICDs) in primary sudden cardiac death prevention over time after myocardial infarction (MI). Speckle-tracking echocardiography allows the assessment left ventricular (LV) dyssynchrony, which may reflect the electromechanical heterogeneity of myocardial tissue. The aim of the present study was to evaluate the relationship among LV dyssynchrony, age of MI, and their association with the risk for ventricular tachycardia (VT) after MI. A total of 206 patients (median age, 67 years; 87% men) with prior MIs (median MI age, 6.2 years; interquartile range, 0.66-15 years) who underwent programmed electrical stimulation, speckle-tracking echocardiography, and ICD implantation were retrospectively evaluated. LV dyssynchrony was defined as the standard deviation of time to peak longitudinal systolic strain values using speckle-tracking strain echocardiography. LV scar burden was evaluated by the percentage of segments exhibiting scar (defined as an absolute longitudinal strain of magnitude < 4.5%). Patients were followed up for the occurrence of first monomorphic VT requiring ICD therapy (antitachycardia pacing or shock) for a median of 24 months. In total, 75 individuals experienced the primary end point of monomorphic VT. LV dyssynchrony was independently associated with the occurrence of VT at follow-up (hazard ratio per 10-msec increase, 1.12; 95% confidence interval, 1.07-1.18; P < .001), together with nonrevascularization of the infarct-related artery and VT inducibility. Patients with older (>180 months) MIs had a higher likelihood of VT inducibility (88% vs 63%, P = .003) and greater scar burden (14.7 ± 15.8% vs 10.7 ± 11.4%, P = .03) compared with patients with recent (<8 months) MIs. LV dyssynchrony is independently associated with the occurrence of VT after MI.

Predictive power of late gadolinium enhancement for myocardial recovery in chronic ischaemic heart failure: a HEART sub-study.

The amount of myocardial scar measured by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging predicts regional recovery in wall motion following revascularization. Previous studies have been conducted in patients with a relatively recent myocardial insult and relatively preserved left ventricular (LV) function. In this sub-study of a clinical trial, the predictive value of LGE, and other CMR-derived data, for myocardial recovery in patients with chronic severe ischaemic cardiomyopathy was assessed. Twenty-two patients with severe LV impairment of ischaemic origin were enrolled as a sub-study of a trial that randomly assigned patients to revascularization or not in addition to guideline-indicated pharmacological therapy. Patients underwent a CMR study at baseline and 6 months. Scans were qualitatively and quantitatively assessed for wall motion, rest/stress myocardial perfusion, and LGE. The median duration of heart failure was 13 (inter-quartile range 5-21) months. Patients had severe LV dilatation [end-diastolic volume (EDV) 280 ± 77 mL] and reduction in LV ejection fraction (LVEF) (29 ± 10%). The percentage scar burden by LGE was 17 ± 9%. Patient characteristics of those undergoing revascularization (n = 7) or not (n = 14) were similar. Myocardial perfusion reserve index (MPRI) improved following revascularization (MPRI 1.17 vs. 1.57, P < 0.0001) but not following medical therapy (1.39 vs. 1.32, P = 0.54). However, LVEF improved in patients whether or not they had revascularization. In the revascularization group, 14% of dysfunctional segments with LGE <25% and 22% of dysfunctional segments with LGE <50% had improved contractile function. However, the transmural extent of LGE did not predict contractile recovery following revascularization or pharmacological therapy (P = 0.19, P = 0.42). LVEDV improved overall (280 ± 77 to 269 ± 83 mL, P = 0.05); improvement was associated with heart failure duration (P = 0.04). In patients with chronic severe LV impairment of ischaemic origin, duration of heart failure is a better predictor of recovery than transmural extent of LGE, following medical therapy or successful revascularization. This suggests that the extent of myocardial remodelling is more important for LV recovery than the presence and extent of prior infarction alone and that LGE should not be the sole determinant of treatment method in severe LV systolic dysfunction of ischaemic origin.

Left septal atrial tachycardia after open-heart surgery: relevance to surgical approach, anatomical and electrophysiological characteristics associated with catheter ablation, and procedural outcomes.

Septal atrial tachycardia (AT) can occur in patients without structural heart disease and in patients with previous catheter ablation of atrial fibrillation. We aimed to assess septal AT that occurs after open-heart surgery. This study comprised 20 consecutive patients undergoing catheter ablation of macroreentrant AT after open-heart surgery. Relevance to surgical approach, mechanisms, anatomic and electrophysiological characteristics, and outcomes were assessed. Septal AT was identified in 7 patients who had all undergone mitral valve surgery. All septal ATs were localized in the left atrial septum, whereas 10 of 13 nonseptal ATs originated from the right atrium. Patients with left septal AT had a thicker fossa ovalis (median, 4.0; 25th-75th percentile, 3.6-4.2 versus 2.3; 1.6-2.6 mm; P=0.006) and broader area of low voltage (<0.3 mV) in the septum than patients with nonseptal AT (82; 76-89 versus 31; 28%-36%; P=0.02). Repeated gradual prolongations of the tachycardia cycle length without change of the septal circuit were observed in all patients with septal AT (70; 63-100 versus 15; 10-40 ms; P=0.0008). Although ablation terminated all ATs, recurrence of targeted ATs was more frequent in patients with left septal AT during 30-month follow-up (71 versus 0%; P=0.001). Left septal AT after open-heart surgery was characterized by a thicker septum, more scar burden in the septum, and repeated prolongations of the tachycardia cycle length during ablation. Such an arrhythmogenic substrate may interfere with transmural lesion formation by ablation and may account for higher likelihood of recurrence of left septal AT.

Minimal access laparoscopic surgery for treatment of ulcerative colitis and familial adenomatous polyposis coli in children and adolescents.

Laparoscopic restorative proctocolectomy is standard surgical treatment for patients with ulcerative colitis (UC) and familial adenomatous polyposis coli (FAP). Scar burden can be minimized by reducing the number of laparoscopic ports. The aim of this study is to review the authors' experience with reduced-port laparoscopy in this setting and to compare it with conventional laparoscopy using multiple ports. Charts of pediatric patients undergoing colectomy for UC or FAP between 2009 and 2012 were retrospectively reviewed. Patients who had the operation performed through one or two multichannel ports were assigned to the minimal access (MA) study group. Patients who had four or five single-channel ports with or without an additional small laparotomy were assigned to the LAP group. Twenty-two patients were identified. Ages at first operation were 2-18 years (median, 13.5 years). There were no conversions to laparotomy and no mortality. Mean operative times for the MA and LAP groups, respectively, were 250 and 284 minutes for abdominal colectomy with end ileostomy (P=.15), 198 and 301 minutes for completion proctectomy with diverting loop ileostomy (DLI) (P=.26), and 455 and 414 minutes for proctocolectomy with ileal pouch-anal anastomosis and DLI (P=.72). A major complication requiring laparotomy occurred in 1 patient (9%) in the MA group and in 2 patients (18%) in the LAP group. Minimal access laparoscopic surgery for UC and FAP is safe and feasible. A slightly larger incision at the ostomy site facilitates extraction of the specimen and extracorporeal construction of a J-pouch. Operative times and hospital stay are comparable to those with multiport laparoscopy.

Imaging Challenges in Secondary Mitral Regurgitation

Chronic secondary mitral regurgitation (SMR) is a complex entity that is often clinically underappreciated.1 It complicates either ischemic heart disease or dilated cardiomyopathy; its prevalence varies among series but may reach ≤50% in patients with heart failure.2 When present, SMR may exhibit a broad range of severity and confers an adverse prognosis, which is worse with increasing severity of mitral regurgitation (MR).3,4 The management of SMR poses a unique set of challenges, based partly on the complexity of the valve disorder and the still-evolving adoption of the optimal therapeutic approach.5 Noninvasive imaging and, in particular, echocardiography, plays a critical role for the initial and longitudinal assessment, for individual risk stratification and outcome prediction, and for guiding intervention in patients with chronic SMR.6 SMR develops because of a combination of mitral leaflet tethering secondary to left ventricular (LV) dilatation/deformation with papillary displacement/discoordination, annular dilatation/dysfunction, insufficient LV-generated closing forces attributable to reduction of LV contractility, and global LV/papillary muscle dyssynchrony.1,5 Tethering of the mitral leaflets is the principal lesion of SMR and results in restriction of systolic leaflet motion, namely type IIIb of Carpentier’s classification. SMR does not typically occur in global LV dysfunction without tethering. However, once tethering occurs, leaflet closure is further impaired by LV dysfunction because there is decreased force opposing tethering.6–9 The key event in the pathogenesis of SMR is the distortion of normal LV geometry—regional and global LV remodeling—with subsequent apical and lateral displacement of papillary muscles, which, in turn, draws the chordae tendineae away from the line of coaptation.7,8 The extent of LV systolic dysfunction and dilatation is weakly correlated to the degree of SMR unless accompanied by geometric distortion in the region of the papillary muscles.1,9 …

Atrial structure and function 5 years after successful ablation for persistent atrial fibrillation: an MRI study.

The atrial outcome after extensive ablation is unknown. We sought to quantify atrial structure and function years after successful ablation for persistent atrial fibrillation (PsAF). We studied after 80 ± 15 months 26 patients (54 ± 8 years, 1 woman) with PsAF successfully treated by ablation (2.2 ± 0.7 stepwise approach procedures, cumulative RF duration 126 ± 37 minutes). At follow-up atrial scar burden and atrial outflows were quantified using delayed-enhanced and velocity-encoded MRI, respectively. Cine imaging was used to quantify atrial conduit function (CF), active emptying fraction (AEF), expansion index (EI), and the inter-appendage mechanical activation delay. Patients underwent exercise testing at baseline and follow-up. LA and RA scar extent were 29 ± 6 and 4.3 ± 2.8%, respectively. LA and RA AEF were 10.0 ± 5.3 and 30 ± 8%. Mean inter-appendage delay was 83 ± 47 ms [42-217]. Complete LAA isolation was found in 3 patients. A wave was absent in 9/26 patients. LA scar extent related to the number of procedures (R = 0.58, P = 0.002) and total RF duration (R = 0.56, P = 0.003). Among follow-up characteristics, LA scar extent related to LAAEF (R = -0.73, P < 0.0001), LAEI (R = -0.64, P = 0.0003), A-wave peak (R = -0.72, P < 0.0001), and inter-appendage mechanical delay (R = 0.47, P = 0.02). At multivariable analysis, LA scar extent was independently related to LAAEF and LAEI. LAAEF and LA scar extent correlated with exercise capacity at follow-up (R = 0.44, P = 0.02, and R = -0.40; P = 0.04). LA contractility and compliance are markedly impaired years after successful PsAF ablation. LA dysfunction is closely related to scar burden.

Genomic scars as biomarkers of homologous recombination deficiency and drug response in breast and ovarian cancers.

Poly (ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapies have been found to be particularly effective in tumors that harbor deleterious germline or somatic mutations in the BRCA1 or BRCA2 genes, the products of which contribute to the conservative homologous recombination repair of DNA double-strand breaks. Nonetheless, several setbacks in clinical trial settings have highlighted some of the issues surrounding the investigation of PARP inhibitors, especially the identification of patients who stand to benefit from such drugs. One potential approach to finding this patient subpopulation is to examine the tumor DNA for evidence of a homologous recombination defect. However, although the genomes of many breast and ovarian cancers are replete with aberrations, the presence of numerous factors able to shape the genomic landscape means that only some of the observed DNA abnormalities are the outcome of a cancer cell’s inability to faithfully repair DNA double-strand breaks. Consequently, recently developed methods for comprehensively capturing the diverse ways in which homologous recombination deficiencies may arise beyond BRCA1/2 mutation have used DNA microarray and sequencing data to account for potentially confounding features in the genome. Scores capturing telomeric allelic imbalance, loss of heterozygosity (LOH) and large scale transition score, as well as the total number of coding mutations are measures that summarize the total burden of certain forms of genomic abnormality. By contrast, other studies have comprehensively catalogued different types of mutational pattern and their relative contributions to a given tumor sample. Although at least one study to explore the use of the LOH scar in a prospective clinical trial of a PARP inhibitor in ovarian cancer is under way, limitations that result in a relatively low positive predictive value for these biomarkers remain. Tumors whose genome has undergone one or more events that restore high-fidelity homologous recombination are likely to be misclassified as double-strand break repair-deficient and thereby sensitive to PARP inhibitors and DNA damaging chemotherapies as a result of prior repair deficiency and its genomic scarring. Therefore, we propose that integration of a genomic scar-based biomarker with a marker of resistance in a high genomic scarring burden context may improve the performance of any companion diagnostic for PARP inhibitors.

Is there a role for diastolic function assessment in era of delayed enhancement cardiac magnetic resonance imaging?: A multimodality imaging study in patients with advanced ischemic cardiomyopathy

Cardiac magnetic resonance (CMR) identifies important prognostic variables in ischemic cardiomyopathy (ICM) patients such as left ventricular (LV) volumes, LV ejection fraction (LVEF), peri-infarct zone, and myocardial scar burden (MSB). It is unknown whether Doppler-based diastolic dysfunction (DDF) retains its prognostic value in ICM patients, in the context of current imaging, medical, and device therapies. Diastolic function was evaluated in ICM patients (LVEF ≤ 40% and ≥ 70% stenosis in ≥ 1 coronary artery) who underwent transthoracic echocardiogram and delayed hyperenhancement CMR studies within 7 days. The association of DDF with the combined end point was assessed after risk-adjustment using Cox proportional hazards models. A total of 360 patients with severe LV dysfunction (LVEF = 24 ± 9%) and extensive MSB (31 ± 17%) were evaluated; DDF was present in all patients (stage 1%-44%, stage 2%-25%, stage 3%-31%). There were 130 events (124 deaths and 6 heart transplants) over a median follow-up of 5.8 years (IQR, 3.7-7.4 years). On multivariable analysis, DDF > stage 1 (HR, 1.37; P = .007) was associated with the combined end-point, independent of clinical risk score (HR, 2.40; P < .0001), implantable cardioverter defibrillator implantation (HR, 0.60; P = .009), incomplete revascularization (HR, 1.32; P = .003), mitral regurgitation (HR, 3.37; P = .01), peri-infarct zone area (HR, 1.04; P = 0.02), and MSB (HR, 1.02; P = .01). DDF had incremental prognostic value for the combined end-point (model χ(2) increased from 89 to 95, P = .02). DDF is a powerful predictor of mortality in ICM patients with significant LV dysfunction, independent of clinical and CMR data. DDF assessment provides incremental value, improving risk stratification.

PM086 Assessment of LV scar burden cardiac magnetic resonance and phase analysis gated SPECT and impact on cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected patients with heart failure, but up to one third of patients may not respond to CRT. A transmural postero-lateral (TMPL) wall scar in the left ventricle (LV) or over the LV pacing site may attenuate clinical and echocardiographic response to CRT.We systematically searched PubMed, EMBASE, and Cochrane databases for studies examining the association between Cardiac magnetic resonance (CMR)-determined postero-lateral or LV pacing site scar and clinical and echocardiographic response to CRT. Eleven prospective studies were included. The presence of TMPL scar on pre-implant CMR was associated with a 75% lower chance of echocardiographic response to CRT, and a similarly lower chance of clinical response. Significant scar over LV pacing site on pre-implant CMR was also associated with a 46% lower chance of echocardiographic response to CRT, and a 67% lower chance of clinical response.The presence of transmural postero-lateral scar or significant scar within the LV pacing site detected by pre-implant CMR is associated with a lower rate of clinical or echocardiographic response to CRT.

A prospective evaluation of cardiovascular magnetic resonance measures of dyssynchrony in the prediction of response to cardiac resynchronization therapy

Many patients with electrical dyssynchrony who undergo cardiac resynchronization therapy (CRT) do not obtain substantial benefit. Assessing mechanical dyssynchrony may improve patient selection. Results from studies using echocardiographic imaging to measure dyssynchrony have ultimately proved disappointing. We sought to evaluate cardiac motion in patients with heart failure and electrical dyssynchrony using cardiovascular magnetic resonance (CMR). We developed a framework for comparing measures of myocardial mechanics and evaluated how well they predicted response to CRT. CMR was performed at 1.5 Tesla prior to CRT. Steady-state free precession (SSFP) cine images and complementary modulation of magnetization (CSPAMM) tagged cine images were acquired. Images were processed using a novel framework to extract regional ventricular volume-change, thickening and deformation fields (strain). A systolic dyssynchrony index (SDI) for all parameters within a 16-segment model of the ventricle was computed with high SDI denoting more dyssynchrony. Once identified, the optimal measure was applied to a second patient population to determine its utility as a predictor of CRT response compared to current accepted predictors (QRS duration, LBBB morphology and scar burden). Forty-four patients were recruited in the first phase (91% male, 63.3 ± 14.1 years; 80% NYHA class III) with mean QRSd 154 ± 24 ms. Twenty-one out of 44 (48%) patients showed reverse remodelling (RR) with a decrease in end systolic volume (ESV) ≥ 15% at 6 months. Volume-change SDI was the strongest predictor of RR (PR 5.67; 95% CI 1.95-16.5; P = 0.003). SDI derived from myocardial strain was least predictive. Volume-change SDI was applied as a predictor of RR to a second population of 50 patients (70% male, mean age 68.6 ± 12.2 years, 76% NYHA class III) with mean QRSd 146 ± 21 ms. When compared to QRSd, LBBB morphology and scar burden, volume-change SDI was the only statistically significant predictor of RR in this group. A systolic dyssynchrony index derived from volume-change is a highly reproducible measurement that can be derived from routinely acquired SSFP cine images and predicts RR following CRT whilst an SDI of regional strain does not.

Relationship between CMR derived myocardial extracellular volume and myocardial replacement scarring in non-ischemic cardiomyopathy

Background The measurement of the extent of myocardial replacement fibrosis in non-ischemic cardiomyopathy (NICMP) has been shown to correlate with clinical cardiac outcomes Although delayed enhancement cardiovascular magnetic resonance (DE-CMR) has been established as the reference standard for assessing myocardial replacement fibrosis (RF), this imaging process is unable to identify more subtle diffuse interstitial fibrosis (IF) in the myocardium. Newer T1 mapping after the administration of gadolinium contrast has been shown to adequately assess increases in extracellular volume (ECV) fraction, which occurs in the setting of IF. In this study, we sought to evaluate the relationship between RF and IF in patients with NICMP. Methods Eighty consecutive patients with NICMP underwent DECMR and T1 mapping using a Modified Look-Locker Inversion recovery (MOLLI) technique. RF extent was determined by analysis of the DE-CMR images. The extracellular gadolinium contrast agent in the myocardium was compared to the amount of contrast in the blood in the dynamic steady state in order to estimate the ECV fraction. In order to decrease statistical variance, regions of localized RF detected on imaging were avoided when measuring the ECV. Results There was RF evident in 49 patients (61%). Patients with RF had higher ECV compared to those without RF (36.1 ± 10.7 and 31.9 ± 6.7 respectively; p = 0.04). The left ventricular ejection fraction (LVEF) and stroke volume (SV) were significantly lower in patients with ECV > 30% (p 30 has significantly lower LVEF (p = 0.02). There was a significant increase in ECV for patients with RF of more than 5% of LV myocardium (p 5% had ECV of 32.60 ± 6.20 and 44.70 ± 13.91%, respectively. In linear regression analysis, ECV is positively associated with scar burden (Beta weight = 0.527, p < 0.001). Conclusions The results of this study suggest that there is a positive relationship between increased RF and ECV in patients with NICMP. Our data shows that stroke volume and left ventricular ejection fraction are significantly decreased in patients with RF and in those with an increased ECV. Funding None.

Impaired Hyperemic Myocardial Blood Flow Is Associated With Inducibility of Ventricular Arrhythmia in Ischemic Cardiomyopathy

Risk stratification for ventricular arrhythmias (VAs) is important to refine selection criteria for primary prevention implantable cardioverter defibrillator therapy. Impaired hyperemic myocardial blood flow (MBF) is associated with increased mortality rate in ischemic and nonischemic cardiomyopathy, which may be attributed to electric instability inducing VAs. The aim of this pilot study was to assess whether hyperemic MBF impairment may be related with VA inducibility in patients with ischemic cardiomyopathy. Thirty patients with ischemic cardiomyopathy referred for primary prevention implantable cardioverter defibrillator implantation were prospectively included (26 men; 65±8 years old; left ventricular ejection fraction, 29±6%). [15O]H2O positron-emission tomography was performed to quantify resting MBF, hyperemic MBF, and coronary flow reserve. Left ventricular dimensions, function, and scar burden were assessed with cardiovascular magnetic resonance imaging. An electrophysiological study was performed to test VA inducibility. Positive electrophysiological study patients (n=12) showed reduced hyperemic MBF (1.25±0.30 versus 1.66±0.38 mL·min(-1)·g(-1); P<0.01) and coronary flow reserve (1.59±0.49 versus 2.12±0.48; P<0.01) compared with electrophysiological study negative patients (n=18). In electrophysiological study positive patients, the number of scar segments>75% transmurality was higher (P<0.05), although scar size and border zone did not differ. Receiver-operating characteristic curve analysis indicated that impaired hyperemic MBF (area under the curve, 0.84; 95% confidence intervals [0.69-0.99]) and coronary flow reserve (area under the curve, 0.77; 95% confidence intervals [0.57-0.96]) were associated with VA inducibility. In this pilot study, impaired hyperemic MBF and coronary flow reserve were associated with VA inducibility in patients with ischemic cardiomyopathy. These results are hypothesis generating for a potential role of quantitative positron-emission tomography perfusion imaging in risk stratification for VAs.

Abstract 18808: Relationship Between Myocardial Extracellular Volume and Myocardial Scar in Non-ischemic Cardiomyopathy Patients

Background: Delayed Enhancement (DE) Cardiovascular magnetic resonance (CMR) has been established as the reference standard for assessment of myocardial replacement fibrosis (RF) in ischemic heart disease. However DE-CMR is unable to identify diffuse interstitial fibrosis (IF). Recently, T1 mapping of the myocardium following the administration of gadolinium contrast has been shown to identify increased extracellular volume (ECV) which occurs in the setting of IF. For this study we sought to evaluate the relationship between RF and IF in patients with nonischemic cardiomyopathy (NICMP). Method: We enrolled 80 consecutive patients with NICMP who underwent DE-CMR and T1 mapping using a modified look-locker inversion recovery (MOLLI) technique. The extent of RF was determined by analysis of DE-CMR images. The ECV was estimated from the concentration of extracellular contrast agent in the myocardium relative to the blood in the dynamic steady state. Care was taken to avoid measuring ECV in regions with RF detected on DE-CMR. Results: The cohort consisted of 61.3% of patients with RF. In RF group, the mean scar burden was 7.4±9.9% of left ventricle myocardium. Patients with RF had higher ECV compared to those without RF (36.1±10.7 and 31.9±6.7 respectively; p=0.04). The left ventricular ejection fraction (LVEF) and stroke volume (SV) were significantly lower in patients with increased ECV (p&lt;0.005). Same relation held true for patients with RF (p&lt;0.005). There was a significant increase in ECV for patients with RF of more than 5% of LV myocardium (p&lt;0.001). In linear regression analysis, ECV is positively associated with scar burden (Beta weight=0.527, p&lt;0.001). Conclusion: This study suggests that LVEF and SV are significantly lower in patients with increased ECV and for those with RF. There is a positive relationship between increased ECV and RF in patients with NICMP. There appears to be a threshold effect where the largest increase in IF occurs when there is more than 5% RF.

Impact of scar on SPECT assay of left ventricular contraction dyssynchrony

Many patients presently receiving cardiac resynchronization therapy (CRT) do not respond. A disproportionate number of nonresponders have ischemic cardiomyopathy, with significant left ventricular (LV) scar burden. Current selection criteria, such as electrocardiography or echocardiography, may not reliably portray the magnitude of CRT-remediable LV contraction dyssynchrony. Although phase analysis of gated single photon emission computed tomography (SPECT) image data is increasingly appreciated as a tool for quantifying dyssynchrony, its use in the setting of scar has not been adequately evaluated. Consecutive patients with ischemic (ICM, n = 50) or nonischemic (NICM, n = 39) cardiomyopathy underwent SPECT imaging prior to receiving CRT. In each patient, phase analysis of the raw images was performed to yield a phase standard deviation (PSD), an index which varies directly with the magnitude of dyssynchrony. ICM patient image data were also reanalyzed after scarred segments were stripped away. Raw image analysis demonstrated that PSD was significantly larger among ICM (57 ± 17°) than NICM (35 ± 13°, p < 0.001) patients. Among ICM patients, PSD after stripping of scarred segments was significantly decreased (40 ± 13°, p < 0.001). Signals emanating from scarred segments were of low amplitude and presented a random pattern, suggestive of noise rather than indicating contraction. PSD values may be spuriously increased by scar. These findings may be important when using SPECT in selecting ischemic cardiomyopathy patients for CRT.

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”

HomeCirculation: Cardiovascular ImagingVol. 6, No. 6Letter 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” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter 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” Robin J. Taylor, Fraz Umar and Francisco Leyva Robin J. TaylorRobin J. Taylor Centre for Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom Search for more papers by this author , Fraz UmarFraz Umar Centre for Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom Search for more papers by this author and Francisco LeyvaFrancisco Leyva Centre for Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom Search for more papers by this author Originally published1 Nov 2013https://doi.org/10.1161/CIRCIMAGING.113.001230Circulation: Cardiovascular Imaging. 2013;6:e78To the Editor: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 of the malignant natural history of IDCM with fibrosis.Although we concur with the authors’ view that LGE-cardiovascular MRI is key to the assessment of patients with suspected IDCM, this study did not include patients undergoing cardiac resynchronization therapy (CRT). Therefore, we do not agree with the authors’ view that patients with fibrosis should be selected for CRT at an earlier point. The experience in patients with ischemic cardiomyopathy is that scar burden relates to a poor outcome after CRT.2,3 Moreover, we have recently shown that in patients with IDCM managed with CRT, the presence of midwall fibrosis is associated with unsuccessful reverse remodeling and a dramatically higher risk of cardiovascular mortality (hazard ratio, 18.6).4 This relationship was mediated through both sudden cardiac death and pump failure.The authors also argue that the positive response of patients without LGE to optimal medical therapy should influence the clinician to delay CRT. Clearly, this group of patients has a particularly favorable outcome.4,5 Nevertheless, the authors have not provided information on the outcome in patients who would be appropriate for CRT. It is reported that 59% of patients without LGE underwent reverse left ventricular remodeling, but it would be useful to know the further specific influence of QRS duration on this. Importantly, 14% of the study population were excluded from follow-up analyses because they received device therapy. Arguably, CRT may be paramount to left ventricular reverse remodeling in this subgroup.In essence, Masci et al1 have shown that patients with IDCM and myocardial fibrosis have a worse outcome than patients without fibrosis after medical therapy. However, because the study cohort did not include patients undergoing CRT, no conclusions can be drawn as to the eligibility or timing of CRT.Robin J. Taylor, MBChB, MRCPFraz Umar, MRCPFrancisco Leyva, MBChB, MDCentre for Cardiovascular SciencesUniversity of BirminghamEdgbaston, Birmingham, United KingdomDisclosuresNone.

Myocardial scar burden predicts survival benefit with implantable cardioverter defibrillator implantation in patients with severe ischaemic cardiomyopathy: influence of gender

ObjectiveWe sought to assess the impact of myocardial scar burden (MSB) on the association between implantable cardioverter defibrillator (ICD) implantation and mortality in patients with ischaemic cardiomyopathy (ICM) and left...