Deborah H. Kwon

Extent of left ventricular scar predicts outcomes in ischemic cardiomyopathy patients with significantly reduced systolic function: a delayed hyperenhancement cardiac magnetic resonance study.

OBJECTIVES The objective of the study was to determine whether the extent of left ventricular scar, measured with delayed hyperenhancement cardiac magnetic resonance (DHE-CMR), predicts survival in patients with ischemic cardiomyopathy (ICM) and severely reduced left ventricular ejection fraction (LVEF). BACKGROUND Patients with ICM and reduced LVEF have poor survival. Such patients have a high myocardial scar burden. CMR is highly accurate in delineation of myocardial scar. METHODS We studied 349 patients (76% men) with severe ICM (>or=70% disease in >or=1 epicardial coronary, and mean LVEF of 24%) that underwent DHE-CMR (Siemens 1.5-T scanner, Erlangen, Germany), between 2003 and 2006. Scar (quantified as percentage of myocardium) was defined on DHE-MR images as an intensity >2 standard deviations above the viable myocardium. Transmurality score was semiquantitatively recorded in a 17-segment model as: 0 = no scar, 1 = 1% to 25% scar, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = >75%. The LVEF, demographic data, risk factors, need for cardiac transplantation (CTx), and all-cause mortality were recorded. RESULTS The mean age and follow-up were 65 +/- 11 years and 2.6 +/- 1.2 years (median 2.4 years [1.1, 3.5]), respectively. There were 56 events (51 deaths and 5 CTx). Mean scar percentage and transmurality score were higher in patients with events versus those without (39 +/- 22 vs. 30 +/- 20, p = 0.003, and 9.7 +/- 5 vs. 7.8 +/- 5, p = 0.004). On Cox proportional hazard survival analysis, quantified scar was greater than the median (30% of total myocardium), and female gender predicted events (relative risk 1.75 [95% Confidence Interval: 1.02 to 3.03] and relative risk 1.83 [95% Confidence Interval: 1.06 to 3.16], respectively, both p = 0.03). CONCLUSIONS In patients with ICM and severely reduced LVEF, a greater extent of myocardial scar, delineated by DHE-CMR is associated with increased mortality or the need for cardiac transplantation, potentially aiding further risk-stratification.

Cardiac magnetic resonance detection of myocardial scarring in hypertrophic cardiomyopathy: correlation with histopathology and prevalence of ventricular tachycardia.

OBJECTIVES In hypertrophic cardiomyopathy (HCM) patients undergoing surgical myectomy, we sought to determine the association between pre-operative cardiac magnetic resonance (CMR) findings, small intramural coronary arteriole dysplasia (SICAD) on histopathology, and ventricular tachycardia (VT). BACKGROUND Myocardial scarring (fibrosis) and SICAD are frequently observed on histopathology in HCM patients. CMR measures wall thickness and detects scar. METHODS Sixty symptomatic HCM patients (62% men; mean age 51 +/- 14 years), with preserved ejection fraction (mean 64 +/- 5%) and no angiographic coronary disease underwent CMR (cine and delayed post-contrast) using a Siemens 1.5 T scanner, followed by septal myectomy. Maximal basal septal thickness was recorded on cine CMR. Scar was determined (percentage of total myocardium) on delayed post-contrast CMR images and quantified as none, mild (0% to 25%), moderate (26% to 50%), or severe (>50%). VT was assessed using Holter monitoring. Degree of SICAD was determined (normal, mild, moderate, and severe) on histopathology of surgical specimen. RESULTS SICAD and scar were seen in 45 (75%) and 38 (63%) patients, respectively. In 15 patients without SICAD, 12 (80%) had no scar; 23 (70%) patients with mild SICAD had mild scar on CMR. On multivariate analysis, degree of SICAD was independently associated with scar on CMR (Wald chi-square statistic: 6.8, p < 0.01). Patients with basal septal scar on CMR had higher VT frequency compared with those without (27% vs. 5%, p = 0.03). CONCLUSIONS A strong association exists between degree of SICAD and myocardial scarring seen on CMR.

Association Between Regional Ventricular Function and Myocardial Fibrosis in Hypertrophic Cardiomyopathy Assessed by Speckle Tracking Echocardiography and Delayed Hyperenhancement Magnetic Resonance Imaging

The relationship among myocardial fibrosis, segmental strains, and hypertrophic cardiomyopathy (HCM) in patients with preserved left ventricular ejection fraction is not known. We evaluated this relationship in 39 consecutive patients with HCM with transthoracic echocardiography and delayed hyperenhancement magnetic resonance imaging 20 minutes after injection of 0.2 mmol/kg of gadolinium. Speckle tracking echocardiography was used to assess left ventricle strains. Fibrosis was determined semiautomatically with magnetic resonance imaging, using a 12-segment short-axis left ventricular model. Myocardial fibrosis was detected in 23 of 39 patients with HCM. The mean end-systolic longitudinal strain correlated with the number of fibrotic segments (r = 0.47, P =.002) and total myocardial fibrosis (r = 0.46, P =.003). Fibrosis and wall thickness were both multivariate predictors of lower segmental longitudinal strain (P <.003). Longitudinal, circumferential, and radial strains are decreased in patients with HCM even in the absence of fibrosis. Myocardial fibrosis is associated with depressed longitudinal strain in patients with HCM.

Pericardial delayed hyperenhancement with CMR imaging in patients with constrictive pericarditis undergoing surgical pericardiectomy: a case series with histopathological correlation.

OBJECTIVES The purpose of this study was to examine the prevalence and histopathologic correlates of pericardial delayed hyperenhancement (DHE) seen with cardiac magnetic resonance imaging (CMR) among patients with constrictive pericarditis (CP) undergoing pericardiectomy. BACKGROUND Constrictive pericarditis patients studied by CMR will occasionally demonstrate pericardial DHE following gadolinium contrast administration. METHODS We identified 25 CP patients who underwent pericardiectomy following CMR-gadolinium study. We also assessed 10 control subjects with no evidence of pericardial disease referred for cardiac viability imaging. A novel 14-segment pericardial model was used to determine pericardial DHE score and thickness score. Histopathology of pericardial specimens was reviewed and evaluated semiquantitatively on a 4-point scale for the extent of calcification, fibrosis, inflammation, and neovascularization. RESULTS DHE was present in 12 (48%) CP patients (DHE+ group), and absent in 13 CP patients (DHE- group) and all control patients. The DHE+ group had greater fibroblastic proliferation and neovascularization, as well as more prominent chronic inflammation and granulation tissue. Fibroblastic proliferation and chronic inflammation correlated with DHE presence quantitated by DHE score (Spearman r = 0.578, p < 0.002, and r = 0.590, p < 0.002, respectively), but not with pericardial thickness. Segmental analysis demonstrated no significant difference in the percentage of patients with different pericardial segmental thickness; however, overall, in each segment, the DHE+ group tended to have greater pericardial thickness. CONCLUSIONS The presence of pericardial DHE on CMR is common in patients with CP, and its presence is associated with histological features of organizing pericarditis, which may be a target for future focused pharmacological interventions. Patients with CP without pericardial DHE had more pericardial fibrosis and calcification, as well as lesser degrees of pericardial thickening.

Long-Term Outcomes in High-Risk Symptomatic Patients With Hypertrophic Cardiomyopathy Undergoing Alcohol Septal Ablation

OBJECTIVES We sought to assess outcomes of alcohol septal ablation (ASA) in high-risk patients. BACKGROUND Because surgical myectomy is the preferred treatment in patients with symptomatic hypertrophic obstructive cardiomyopathy (HOCM) at our institution, we perform ASA in patients who are at high risk for surgery. METHODS We studied 55 symptomatic HOCM patients (mean age 63 +/- 13 years, 67% women, mean follow-up 8 +/- 1 years), at high risk for surgery (as the result of age/comorbidities) who had ASA between 1997 and 2000. The following were recorded at baseline, 3 months, and 1 year: septal thickness, maximal (resting or provocable) left ventricular outflow tract gradient, Minnesota living with heart failure questionnaire score, and the presence of a permanent pacemaker. All-cause mortality was recorded. RESULTS No patients died at 48 h, 2 died at 1 year, 7 died at 5 years, and 13 died at 10 years. Only age >65 years at time of ASA predicted long-term mortality (log-rank p = 0.03). Mean maximal left ventricular outflow tract gradient (104 +/- 35 mm Hg vs. 49 +/- 28 mm Hg), septal thickness (2.4 +/- 0.4 cm vs. 1.8 +/- 0.6 cm), and Minnesota living with heart failure score (63 vs. 25) improved at 3 months, compared with baseline (all p < 0.001), with no significant changes at 1 year. New permanent pacemaker was present in 26% of patients. CONCLUSIONS In symptomatic HOCM patients who are at high risk for surgery, ASA is associated with symptomatic improvement and low short-term mortality; with long-term mortality only associated with older age at time of procedure. In symptomatic HOCM patients at high-risk for surgery, ASA is a viable option.

Characteristics and surgical outcomes of symptomatic patients with hypertrophic cardiomyopathy with abnormal papillary muscle morphology undergoing papillary muscle reorientation

OBJECTIVE In patients with hypertrophic cardiomyopathy with bifid hypermobile papillary muscles and a dynamic left ventricular outflow tract gradient, we performed surgical papillary muscle reorientation, fixing the mobile papillary muscle to the posterior left ventricle to reduce mobility. We report the outcomes of patients with hypertrophic cardiomyopathy undergoing surgical papillary muscle reorientation versus those of patients undergoing standard surgical procedures. METHODS We studied 204 consecutive patients with hypertrophic cardiomyopathy undergoing surgical intervention (after consensus decision) for symptomatic left ventricular outflow tract gradient. Preoperative and postoperative maximal (resting/provocable) left ventricular outflow tract gradients were recorded by using echocardiographic analysis. RESULTS The population was divided into 3 groups: (1) isolated myectomy (n = 143; age, 54 +/- 14 years; 48% men), (2) myectomy plus mitral valve repair/replacement (n = 39; age, 54 +/- 13 years; 54% men), and (3) papillary muscle reorientation with or without myectomy (n = 22; age, 50 +/- 14 years; 59% men). The mean preoperative (103 +/- 32, 103 +/- 32, and 114 +/- 36 mm Hg; P = .3) and predischarge (15 +/- 18, 14 +/- 14, and 16 +/- 21 mm Hg; P = .9) maximal left ventricular outflow tract gradients were similar. There were no deaths either in the hospital or at 30 days. At a median follow-up of 166 days (interquartile range, 74-343 days), 21 of 22 patients in group 3 were asymptomatic. One patient in group 3 had a symptomatic left ventricular outflow tract gradient (87 mm Hg) requiring mitral valve replacement. CONCLUSIONS In patients with hypertrophic cardiomyopathy with bifid hypermobile papillary muscles (even with a basal septal thickness <1.5 cm), papillary muscle reorientation reduces the symptomatic left ventricular outflow tract gradient. Long-term outcomes need to be ascertained.

Biventricular Mechanics in Constrictive Pericarditis Comparison With Restrictive Cardiomyopathy and Impact of Pericardiectomy

Background— The aim of our study was to compare myocardial mechanics of constrictive pericarditis (CP) with restrictive cardiomyopathy (RCM), or healthy controls; to assess the impact of pericardial thickening detected by cardiac magnetic resonance on regional myocardial mechanics in CP; and to quantitate the effect of pericardiectomy on myocardial mechanics in CP. Methods and Results— Myocardial mechanics were evaluated by 2-dimensional speckle tracking in 52 consecutive patients with CP who underwent cardiac magnetic resonance examination before pericardiectomy, 35 patients with RCM, and 26 control subjects. CP patients had selectively depressed left ventricular (LV) anterolateral wall strain (LWS) and right ventricular (RV) free wall longitudinal systolic strain (FWS) but preserved LV septal wall systolic strain (SWS). In a comparison of RCM and normals, CP patients had significantly lower regional longitudinal systolic strain ratios (CP versus RCM and normal; LVLWS/LVSWS: 0.8±0.2 versus 1.1±0.2 and 1.0±0.2; P<0.001, RVFWS/LVSWS: 0.8±0.4 vs. 1.4±0.5 and 1.2±0.2; P<0.001). LVLWS/LVSWS was more robust than the LV lateral wall to LV septal wall ratio of early diastolic velocities at the LV base (LE′/SE′) in differentiating CP from RCM (area under the curve=0.91 versus 0.76; P=0.011). There was a significant inverse correlation between pericardial thickness and respective ventricular strains (P=0.001). Pericardiectomy resulted in the improvement of the depressed LVLWS/LVSWS (0.83±0.18–0.95±0.12; P<0.001). Conclusions— Regional longitudinal systolic strain ratios are robust novel diagnostic tools for CP. Regional myocardial mechanics inversely correlates with adjacent pericardial segment thickness detected by cardiac magnetic resonance, and pericardiectomy leads to systolic strain improvement, which is more pronounced in right ventricular and LV free walls.

Myocardial T1 mapping: modalities and clinical applications.

Myocardial fibrosis appears to be linked to myocardial dysfunction in a multitude of non-ischemic cardiomyopathies. Accurate non-invasive quantitation of this extra-cellular matrix has the potential for widespread clinical benefit in both diagnosis and guiding therapeutic intervention. T1 mapping is a cardiac magnetic resonance (CMR) imaging technique, which shows early clinical promise particularly in the setting of diffuse fibrosis. This review will outline the evolution of T1 mapping and the various techniques available with their inherent advantages and limitations. Histological validation of this technique remains somewhat limited, however clinical application in a range of pathologies suggests strong potential for future development.

Abnormally Thickened Papillary Muscle Resulting in Dynamic Left Ventricular Outflow Tract Obstruction: An Unusual Presentation of Hypertrophic Cardiomyopathy

We report the case of a symptomatic 18-year-old patient, gene-positive for hypertrophic cardiomyopathy (HCM), who presented with symptomatic dynamic left ventricular outflow tract (LVOT) obstruction caused by an abnormally thickened papillary muscle in the absence of septal hypertrophy. This was confirmed using multimodality imaging, including echocardiography and magnetic resonance imaging. He successfully underwent surgery for papillary muscle realignment without septal myectomy.

Steep left ventricle to aortic root angle and hypertrophic obstructive cardiomyopathy: study of a novel association using three-dimensional multimodality imaging

Background: Patients with hypertrophic cardiomyopathy (HCM) exhibit a difference in left ventricular outflow tract (LVOT) obstruction, independently of basal septal thickness (BST). Some patients with HCM have a steeper left ventricle to aortic root angle than controls. Objective: To test the predictors of the LV-aortic root angle and the association between LV-aortic root angle and LVOT obstruction using three-dimensional imaging. Patients: 153 consecutive patients with HCM (mean (SD) age 46 (14) years, 68% men) and 62 patients with hypertensive heart disease of the elderly (all >65 years of age, 73 (6) years, 34% men) who underwent whole-heart three-dimensional cardiac magnetic resonance (CMR) angiography (1.5 T) and Doppler echocardiography. Forty-two controls (age 43 (11) years, 38% men) who underwent contrast-enhanced multidetector computed tomography and were free of cardiovascular pathology were also studied. Main outcomes: LV-aortic root angle, BST and maximal non-exercise LVOT gradient were measured in patients with HCM and in hypertensive-elderly patients. Additionally, LV-aortic root angle and BST were measured in controls. Results: The mean (SD) LV-aortic root angle was significantly different (p<0.001) in the three groups: HCM (134 (10)°), hypertensive-elderly (128 (10)°), control (140 (7)°). There was an inverse correlation between age and LV-aortic root angle in the three groups (all p<0.001): HCM (r = −0.56), hypertensive-elderly (r = −0.35), control (r = −0.48). On univariate analysis, in the HCM group, LV-aortic root angle (β = −0.34, p<0.001), age (β = 0.23, p = 0.01) and end-systolic volume index (β = −0.20, p = 0.02), but not BST (β = 0.02, p = 0.8), were associated with LVOT gradient. On multivariate analysis, only LV-aortic root angle was associated with LVOT gradient. Conclusions: Patients with HCM have a steeper LV-aortic root angle than controls. In patients with HCM, a steeper LV-aortic root angle predicts dynamic LVOT obstruction, independently of BST.