Objectives The aim of this study was to perform direct quantification of myocardial extracellular volume fraction (ECF) with T1-weighted cardiac magnetic resonance (CMR) imaging in patients suspected ...to have infiltrative heart disease. Background Infiltrative heart disease refers to accumulation of abnormal substances within the myocardium. Qualitative assessment of late gadolinium enhancement (LGE) remains the most commonly used method for CMR evaluation of patients suspected with myocardial infiltration. This technique is widely available and can be performed in a reproducible and standardized manner. However, the degree of extracellular matrix expansion due to myocardial infiltration in the intercellular space has, to date, not been amenable to noninvasive quantification with LGE. Methods We performed 3-T CMR in 38 patients (mean age 68 ± 15 years) who were referred for assessment of infiltrative heart disease and also in 9 healthy volunteers as control subjects. The T1 quantification by Look-Locker gradient-echo before and after contrast determined segmental myocardial partition coefficients. The ECF was obtained by referencing the tissue partition coefficient for gadolinium to the plasma volume fraction in blood, derived from serum hematocrit. Cine CMR and LGE imaging in matching locations were also performed. Results Seventeen patients (45%) had cardiac amyloidosis (CA) (biopsy-confirmed or clinically highly probable), 20 (53%) had a non-amyloid cardiomyopathy, and 1 had lysosomal storage disease. Median global ECF was substantially higher in CA patients (0.49) compared with non-amyloid cardiomyopathy patients (0.33, p < 0.0001) and volunteers (0.24, p = 0.0001). The ECF strongly correlated with visually assessed segmental LGE (r = 0.80, p < 0.0001) and LV mass index (r = 0.69, p < 0.0001), reflecting severity of myocardial infiltration. In patients with CA, ECF was highest in segments with LGE, although it remained elevated in segments without qualitative LGE. Conclusions The CMR ECF quantification identified substantial expansion of the interstitial space in patients with CA compared with volunteers. Further studies using this technique for diagnosis and assessment of the severity of myocardial infiltration are warranted.
Right heart failure is poorly understood and treated. In left heart failure, ventricular restraint can reverse pathologic left ventricular remodeling. The effect of restraint in right heart failure, ...however, is not known. We hypothesize that ventricular restraint can be applied selectively to the right ventricle (RV) to promote RV reverse remodeling.
Right heart failure was induced by right coronary artery ligation in a sheep model. Eight weeks later, a saline-filled epicardial balloon was placed around the RV surface for restraint. Restraint level was defined by measuring balloon luminal pressure at end-diastole. Maximum balloon pressure was determined by the amount of balloon pressure required to decrease systemic mean arterial pressure by 10 mm Hg. We determined end-diastolic transmural myocardial pressure, indices of myocardial oxygen consumption, and RV diastolic compliance at 4 different restraint levels.
After coronary ligation, RV ejection fraction (EF) decreased from 0.574±0.04 to 0.362±0.03 (p<0.05). End-diastolic RV volume increased from 70.8 mL/m2±9 to 82.2 mL/m2±7 (p<0.05) by magnetic resonance imaging. After application of restraint to the RV only, RV transmural pressure decreased significantly by 27%. Greater levels of restraint also improved RV EF (0.347±0.06 to 0.473±0.05) but did not change RV end-diastolic volume.
A model of ischemic right heart failure was successfully created. Selective RV restraint results in improved mechanical efficiency, decreased wall stress, and improved EF. The benefits of restraint in right heart failure warrant further investigation.
Objectives The major aim of this study is to test the hypothesis that stress cardiac magnetic resonance (CMR) imaging can provide robust prognostic value in women presenting with suspected ischemia, ...to the same extent as in men. Background Compelling evidence indicates that women with coronary artery disease (CAD) experience worse outcomes than men owing to a lack of early diagnosis and management. Numerous clinical studies have shown that stress CMR detects evidence of myocardial ischemia and infarction at high accuracy. Compared to nuclear scintigraphy, CMR is free of ionizing radiation, has high spatial resolution for imaging small hearts, and overcomes breast attenuation artifacts, which are substantial advantages when imaging women for CAD. Methods We performed stress CMR in 405 patients (168 women, mean age 58 ± 14 years) referred for ischemia assessment. CMR techniques included cine cardiac function, perfusion imaging during vasodilating stress, and late gadolinium enhancement imaging. All patients were followed for major adverse cardiac events (MACE). Results At a median follow-up of 30 months, MACE occurred in 36 patients (9%) including 21 cardiac deaths and 15 acute myocardial infarctions. In women, CMR evidence of ischemia (ISCHEMIA) demonstrated strong association with MACE (unadjusted hazard ratio: 49.9, p < 0.0001). While women with ISCHEMIA(+) had an annual MACE rate of 15%, women with ISCHEMIA(−) had very low annual MACE rate (0.3%), which was not statistically different from the low annual MACE rate in men with ISCHEMIA(−) (1.1%). CMR myocardial ischemia score was the strongest multivariable predictor of MACE in this cohort, for both women and men, indicating robust cardiac prognostication regardless of sex. Conclusions In addition to avoiding exposure to ionizing radiation, stress CMR myocardial perfusion imaging is an effective and robust risk-stratifying tool for patients of either sex presenting with possible ischemia.
Right Ventricular Dysfunction Assessed by Cardiovascular Magnetic Resonance Imaging Predicts Poor Prognosis Late After Myocardial Infarction Eric Larose, Peter Ganz, H. Glenn Reynolds, Sharmila ...Dorbala, Marcelo F. Di Carli, Kenneth A. Brown, Raymond Y. Kwong We investigated whether right ventricular (RV) function late after myocardial infarction (MI) predicts long-term prognosis. Right ventricular ejection fraction (RVEF) was assessed by using cardiovascular magnetic resonance imaging in 147 patients late after MI. A total of 26 deaths occurred during a median follow-up of 17 months. RVEF predicted mortality independently of patient age, left ventricular (LV) infarct size, and LV ejection fraction. Quantitation of RVEF by cardiovascular magnetic resonance imaging is valuable for risk-stratifying patients after MI beyond traditional prognostic factors.
Objectives This study tested whether myocardial extracellular volume (ECV) is increased in patients with hypertension and atrial fibrillation (AF) undergoing pulmonary vein isolation and whether ...there is an association between ECV and post-procedural recurrence of AF. Background Hypertension is associated with myocardial fibrosis, an increase in ECV, and AF. Data linking these findings are limited. T1 measurements pre-contrast and post-contrast in a cardiac magnetic resonance (CMR) study provide a method for quantification of ECV. Methods Consecutive patients with hypertension and recurrent AF referred for pulmonary vein isolation underwent a contrast CMR study with measurement of ECV and were followed up prospectively for a median of 18 months. The endpoint of interest was late recurrence of AF. Results Patients had elevated left ventricular (LV) volumes, LV mass, left atrial volumes, and increased ECV (patients with AF, 0.34 ± 0.03; healthy control patients, 0.29 ± 0.03; p < 0.001). There were positive associations between ECV and left atrial volume (r = 0.46, p < 0.01) and LV mass and a negative association between ECV and diastolic function (early mitral annular relaxation E′, r = −0.55, p < 0.001). In the best overall multivariable model, ECV was the strongest predictor of the primary outcome of recurrent AF (hazard ratio: 1.29; 95% confidence interval: 1.15 to 1.44; p < 0.0001) and the secondary composite outcome of recurrent AF, heart failure admission, and death (hazard ratio: 1.35; 95% confidence interval: 1.21 to 1.51; p < 0.0001). Each 10% increase in ECV was associated with a 29% increased risk of recurrent AF. Conclusions In patients with AF and hypertension, expansion of ECV is associated with diastolic function and left atrial remodeling and is a strong independent predictor of recurrent AF post–pulmonary vein isolation.
Objective Effects of ventricular restraint on the left ventricle are well documented, but effects on the right ventricle are not. We hypothesized that restraint affects the right and left ventricles ...differently. Methods We studied acute effects of restraint on left and right ventricular mechanics in healthy sheep (n = 14) with our previously described technique of adjustable and measurable restraint. Transmural pressure, myocardial oxygen consumption indices, diastolic compliance, and end-systolic elastance were assessed at 4 restraint levels for both ventricles. We then studied long-term effects of restraint for 4 months in an ovine model of ischemic dilated cardiomyopathy (n = 6). Heart failure was induced by coronary artery ligation, and polypropylene mesh was wrapped around the heart to simulate clinical restraint therapy. All subjects were followed up with serial cardiac magnetic resonance imaging to assess left and right ventricular volumes and function. Results Restraint decreased left ventricular transmural pressure ( P < .03) and myocardial oxygen consumption indices ( P < .05) but not left ventricular diastolic compliance ( P = .52). Restraint had no effect on right ventricular transmural pressure ( P = .82) or myocardial oxygen consumption indices ( P = .72) but reduced right ventricular diastolic compliance ( P < .01). In long-term studies, restraint led to reverse left ventricular remodeling with decreased left ventricular end-diastolic volume ( P < .006) but did not affect right ventricular end-diastolic volume ( P = .82). Conclusions Ventricular restraint affects the left and right ventricles differently. Benefits of restraint for right ventricular function are unclear. The left ventricle can tolerate more restraint than the right ventricle. With current devices, the right ventricle may limit overall therapeutic efficacy.
Aims Obesity is associated with the development of atrial fibrillation (AF), and both obesity and AF are independently associated with the development of heart failure with preserved ejection ...fraction. We tested the hypothesis that sleep apnea (SA) would have a body mass index (BMI) independent association with adverse left ventricular (LV) remodeling and clinical outcomes in patients with AF and preserved LV function. Methods and results From 720 consecutive patients with AF, 403 patients without myocardial disease (preserved LV function) were identified and followed up for 3.3 ± 1.5 years. The primary outcome was a combination of all-cause mortality/heart failure hospitalization. Left ventricular mass and LV mass-to-volume ratio were higher in patients with SA and obesity ( P < .0001 for all). Body mass index (β per log = .47; P < .0001) and SA (β = .05; P = .045) were independently associated with LV mass index. Patients with treated SA had a lower LV mass index (but not LV mass-to-volume ratio) compared with untreated ( P = .002). In a best overall multivariable model, SA therapy (β = −.129; P = .001) and BMI (β per log = .373; P = .0007) had opposing associations with LV mass index. Sleep apnea (hazard ratio HR = 2.94; P = .0004) and BMI (HR per 1 kg/m2 = 1.08; P = .004) were associated with clinical outcome in unadjusted analysis. Only SA was associated with clinical outcome in a best overall multivariable model (HR = 2.14; P = .02). Conclusion Sleep apnea and obesity are independently associated with adverse LV remodeling and clinical outcomes in patients with preserved LV function, whereas continuous positive airway pressure therapy is associated with a beneficial effect on LV remodeling. Research investigating SA therapies in patients at high risk for LV remodeling and heart failure is warranted.
...all standard 3-year cardiovascular trainees should receive training that would provide at least a basic understanding of the methods and utility of CMR in the practice of cardiology. Name ...Employment Representation Consultant Speakers Bureau Ownership/Partnership/Principal Personal Research Institutional/Organizational or Other Financial Benefit Expert Witness Richard Kovacs Indiana University, Krannert Institute of Cardiology--QE and Sally Russell Professor of Cardiology Official Reviewer, ACC Board of Trustees None None None None None None Dhanunjaya Lakkireddy Kansas University Cardiovascular Research Institute Official Reviewer, ACC Board of Governors None None None None None None Howard Weitz Thomas Jefferson University Hospital--Director, Division of Cardiology; Sidney Kimmel Medical College at Thomas Jefferson University--Vice Chair, Department of Medicine Official Reviewer, Competency Management Committee Lead Reviewer None None None None None None Warren Manning Beth Israel Deaconess Medical Center, Division of Cardiology--Professor, Medicine and Radiology Organizational Reviewer, SCMR None None None None None None Michael Emery Greenville Health System Content Reviewer, Sports and Exercise Cardiology Section Leadership Council None None None None None None Brian D. Hoit University Hospitals Case Medical Center Content Reviewer, Cardiology Training and Workforce Committee None None None None None None Larry Jacobs Lehigh Valley Health Network, Division of Cardiology; University of South Florida--Professor, Cardiology Content Reviewer, Cardiology Training and Workforce Committee None None None None None None Andrew Kates Washington University School of Medicine Content Reviewer, Academic Cardiology Section Leadership Council None None None None None None Nishant Shah Brigham and Women's Hospital, Harvard Medical School--Cardiovascular Imaging Fellow Content Reviewer, Imaging Council None None None None None None Kim Williams Rush University Medical Center--James B. Herrick Professor and Chief, Division of Cardiology Content Reviewer, Cardiology Training and Workforce Committee None None None None None None Table 4 Core Competency Components and Curricular Milestones for Training in Cardiovascular Magnetic Resonance Add = additional months beyond the 3-year cardiovascular fellowship.
Myocardial extracellular matrix expansion and reduced coronary flow reserve (CFR) occur in patients with type 2 diabetes mellitus without heart failure or coronary artery disease. Because aldosterone ...is implicated in the pathophysiology of cardiac fibrosis and vascular injury, the aim of this study was to test the hypothesis that aldosterone is associated with extracellular matrix expansion and reduced CFR in type 2 diabetes mellitus. Patients with type 2 diabetes mellitus without evidence of coronary artery disease were recruited. Blood pressure, lipid management, and glycemic control were optimized over 3 months. Cardiac magnetic resonance imaging with T1 mapping was used to measure myocardial extracellular volume (ECV). Cardiac positron emission tomography was used to assess CFR. On a liberal, 250 mEq/day sodium diet, 24-hour urinary aldosterone and change in serum aldosterone with angiotensin II stimulation were measured. Fifty-three participants with type 2 diabetes (68% men, mean age 53 ± 7 years, mean body mass index 32.2 ± 4.3 kg/m2 , mean glycosylated hemoglobin 6.8 ± 0.7%, mean systolic blood pressure 126 ± 14 mm Hg) without infarction or ischemia by cardiac magnetic resonance and positron emission tomography were studied. Subjects had impaired CFR (2.51 ± 0.83) and elevated ECV (0.36 ± 0.05), despite normal echocardiographic diastolic function and normal left ventricular function. Myocardial ECV, but not CFR, was positively associated with 24-hour urinary aldosterone excretion (r = 0.37, p = 0.01) and angiotensin II–stimulated aldosterone increase (r = 0.35, p = 0.02). In a best-overall multivariate model (including age, gender, body mass index, glycosylated hemoglobin, and blood pressure), 24-hour urinary aldosterone was the strongest predictor of myocardial ECV (p = 0.004). In conclusion, in patients with type 2 diabetes mellitus without coronary artery disease, aldosterone is associated with myocardial extracellular matrix expansion. These results implicate aldosterone in early myocardial remodeling in type 2 diabetes mellitus.
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