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We recently showed more severe diastolic dysfunction at the time of myectomy in female compared to male patients with obstructive hypertrophic cardiomyopathy. Early recognition of aberrant cardiac contracility using cardiovascular magnetic resonance (CMR) imaging may identify women at risk of cardiac dysfunction. To define myocardial function at an early disease stage, we studied regional cardiac function using CMR imaging with tissue tagging in asymptomatic female gene variant carriers. CMR imaging with tissue tagging was done in 13 MYBPC3, 11 MYH7 and 6 TNNT2 gene carriers and 16 age-matched controls. Regional peak circumferential strain was derived from tissue tagging images of the basal and midventricular segments of the septum and lateral wall. Left ventricular wall thickness and global function were comparable between MYBPC3, MYH7, TNNT2 carriers and controls. MYH7 gene variant carriers showed a different strain pattern as compared to the other groups, with higher septal peak circumferential strain at the basal segments compared to the lateral wall, whereas MYBPC3, TNNT2 carriers and controls showed higher strain at the lateral wall compared to the septum. Only subtle gene-specific changes in strain pattern occur in the myocardium preceding development of cardiac hypertrophy. Overall, our study shows that there are no major contractile deficits in asymptomatic females carrying a pathogenic gene variant, which would justify the use of CMR imaging for earlier diagnosis.

Background: In hypertrophic cardiomyopathy (HCM), autopsy studies revealed both increased focal and diffuse deposition of collagen fibers. Late gadolinium enhancement imaging (LGE) detects focal fibrosis, but is unable to depict interstitial fibrosis. We hypothesized that with T1 mapping, which is employed to determine the myocardial extracellular volume fraction (ECV), can detect diffuse interstitial fibrosis in HCM patients., Methods: T1 mapping with a modified Look-Locker Inversion Recovery (MOLLI) pulse sequence was used to calculate ECV in manifest HCM (n = 16) patients and in healthy controls (n = 14). ECV was determined in areas where focal fibrosis was excluded with LGE., Results: The total group of HCM patients showed no significant changes in mean ECV values with respect to controls (0.26 ± 0.03 vs 0.26 ± 0.02, p = 0.83). Besides, ECV in LGE positive HCM patients was comparable with LGE negative HCM patients (0.27 ± 0.03 vs 0.25 ± 0.03, p = 0.12)., Conclusions: This study showed that HCM patients have a similar ECV (e.g. interstitial fibrosis) in myocardium without LGE as healthy controls. Therefore, the additional clinical value of T1 mapping in HCM seems limited, but future larger studies are needed to establish the clinical and prognostic potential of this new technique within HCM.

Background: Left ventricular segmental wall motion analysis is important for clinical decision making in cardiac diseases. Strain analysis with myocardial tissue tagging is the non-invasive gold standard for quantitative assessment, however, it is time-consuming. Cardiovascular magnetic resonance myocardial feature-tracking (CMR-FT) can rapidly perform strain analysis, because it can be employed with standard CMR cine-imaging. The aim is to validate segmental peak systolic circumferential strain (peak SCS) and time to peak systolic circumferential strain (T2P-SCS) analysed by CMR-FT against tissue tagging, and determine its intra and inter-observer variability., Methods: Patients in whom both cine CMR and tissue tagging has been performed were selected. CMR-FT analysis was done using endocardial (CMR-FTendo) and mid-wall contours (CMR-FTmid). The Intra Class Correlation Coefficient (ICC) and Pearson correlation were calculated., Results: 10 healthy volunteers, 10 left bundle branch block (LBBB) and 10 hypertrophic cardiomyopathy patients were selected. With CMR-FT all 480 segments were analyzable and with tissue tagging 464 segments.Significant differences in mean peak SCS values of the total study group were present between CMR-FTendo and tissue tagging (-23.8 ± 9.9% vs -13.4 ± 3.3%, p<0.001). Differences were smaller between CMR-FTmid and tissue tagging (-16.4 ± 6.1% vs -13.4 ± 3.3%, p=0.001). The ICC of the mean peak SCS of the total study group between CMR-FTendo and tissue tagging was low (0.19 (95%-CI-0.10-0.49), p=0.02). Comparable results were seen between CMR-FTmid and tissue tagging. In LBBB patients, mean T2P-SCS values measured with CMR-FTendo and CMR-FTmid were 418 ± 66 ms, 454 ± 60 ms, which were longer than with tissue tagging, 376 ± 55 ms, both p<0.05. ICC of the mean T2P-SCS between CMR-FTendo and tissue tagging was 0.64 (95%-CI-0.36-0.81), p<0.001, this was better in the healthy volunteers and LBBB group, whereas the ICC between CMR-FTmid and tissue tagging was lower.The intra and inter-observer agreement of segmental peak SCS with CMR-FTmid was lower compared with tissue tagging; similar results were seen for segmental T2P-SCS., Conclusions: The intra and inter-observer agreement of segmental peak SCS and T2P-SCS is substantially lower with CMR-FTmid compared with tissue tagging. Therefore, current segmental CMR-FTmid techniques are not yet applicable for clinical and research purposes.

Background: Patients with Brugada syndrome (BrS) and a spontaneous type 1 ECG are considered to be at greater increased risk for sudden cardiac death than are patients with an abnormal ECG only after administration of sodium channel blockers and therefore represent a more severe phenotype. Thus, it can be hypothesized that in the presence of a more severe electrical phenotype, structural and functional changes are more likely expected because electrical changes can play a causal role in producing structural changes., Objective: The purpose of this study was to investigate whether the different ECG manifestations in patients with BrS are associated with structural changes detected by cardiovascular magnetic resonance imaging., Methods: Cardiovascular magnetic resonance imaging was performed on 69 consecutive patients with proven BrS and 30 healthy controls. Twenty-six patients had a spontaneous diagnostic type 1 BrS ECG; the remainder had a type 1 response to ajmaline provocation. Left and right ventricular volumes and dimensions were assessed and compared with respect to ECG pattern., Results: The right ventricular outflow tract area was significantly enlarged in patients with a spontaneous type 1 ECG compared to patients with a nondiagnostic resting ECG or controls (11 cm(2), 9 cm(2), and 9 cm(2), respectively, P < .05). Patients with a spontaneous type 1 BrS ECG revealed significantly lower left ventricular ejection fraction than did patients with a nondiagnostic resting ECG and controls (56 ± 5 vs 59 ± 5 vs 60 ± 4, respectively, P < .05) and significantly lower right ventricular ejection fraction (54 ± 5 vs 59 ± 5, P = .001) as well as end-systolic volumes compared to controls (34 ± 9 mL/m(2) vs 28 ± 79 mL/m(2), P = .02)., Conclusion: Patients with a spontaneous type 1 BrS ECG reveal significantly functional and morphological alterations in both the left and right ventricles compared to patients with basal nondiagnostic ECG or controls., (Copyright © 2010. Published by Elsevier Inc.)

Background: Clinical data on myocardial function in HCM mutation carriers (carriers) is sparse but suggests that subtle functional abnormalities can be measured with tissue Doppler imaging before the development of overt hypertrophy. We aimed to confirm the presence of functional abnormalities using cardiovascular magnetic resonance (CMR), and to investigate if sensitive functional assessment could be employed to identify carriers., Results: 28 carriers and 28 controls were studied. Global left atrial (LA) and left ventricular (LV) dimensions, segmental peak systolic circumferential strain (SCS) and peak diastolic circumferential strain rate (DCSR), as well as the presence of late Gadolinium enhancement (LGE) were determined with CMR. Septal and lateral myocardial velocities were measured with echocardiographic tissue Doppler imaging. LV mass and volumes were comparable between groups. Maximal septal to lateral wall thickness ratio (SL ratio) was larger in carriers than in controls (1.3+/-0.2 versus 1.1+/-0.1, p<0.001). Also, LA volumes were larger in carriers compared to controls (p<0.05). Both peak SCS (p<0.05) and peak DCSR (p<0.01) were lower in carriers compared to controls, particularly in the basal lateral wall. Focal LGE was present in 2 carriers and not in controls. The combination of a SL ratio>1.2 and a peak DCSR<105%.s-1 was present in 45% of carriers and in none of the controls, yielding a positive predictive value of 100%. Two carriers and 18 controls had a SL ratio<1.2 and peak DCSR>105%.s-1, yielding a negative predictive value of 90%. With multivariate analysis, HCM mutation carriership was an independent determinant of reduced peak SCS and peak DCSR., Conclusions: HCM mutation carriership is an independent determinant of reduced peak SCS and peak DCSR when LV wall thickness is within normal limits, and is associated with increased LA volumes and SL ratio. Using SL ratio and peak DCSR has a high accuracy to identify carriers. However, since carriers also display structural abnormalities and focal LGE, we advocate to also evaluate morphology and presence of LGE when screening for carriers.

Objectives: We sought to evaluate the relation between atrial fibrillation (AF) and the extent of myocardial scarring together with left ventricular (LV) and atrial parameters assessed by late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM)., Background: AF is the most common arrhythmia in HCM. Myocardial scarring is also identified frequently in HCM. However, the impact of myocardial scarring assessed by LGE CMR on the presence of AF has not been evaluated yet., Methods: 87 HCM patients underwent LGE CMR, echocardiography and regular ECG recordings. LV function, volumes, myocardial thickness, left atrial (LA) volume and the extent of LGE, were assessed using CMR and correlated to AF. Additionally, the presence of diastolic dysfunction and mitral regurgitation were obtained by echocardiography and also correlated to AF., Results: Episodes of AF were documented in 37 patients (42%). Indexed LV volumes and mass were comparable between HCM patients with and without AF. However, indexed LA volume was significantly higher in HCM patients with AF than in HCM patients without AF (68 +/- 24 ml.m-2 versus 46 +/- 18 ml.m-2, p = 0.0002, respectively). The mean extent of LGE was higher in HCM patients with AF than those without AF (12.4 +/- 14.5% versus 6.0 +/- 8.6%, p = 0.02). When adjusting for age, gender and LV mass, LGE and indexed LA volume significantly correlated to AF (r = 0.34, p = 0.02 and r = 0.42, p < 0.001 respectively). By echocardiographic examination, LV diastolic dysfunction was evident in 35 (40%) patients. Mitral regurgitation greater than II was observed in 12 patients (14%). Multivariate analysis demonstrated that LA volume and presence of diastolic dysfunction were the only independent determinant of AF in HCM patients (p = 0.006, p = 0.01 respectively). Receiver operating characteristic curve analysis indicated good predictive performance of LA volume and LGE (AUC = 0.74 and 0.64 respectively) with respect to AF., Conclusion: HCM patients with AF display significantly more LGE than HCM patients without AF. However, the extent of LGE is inferior to the LA size for predicting AF prevalence. LA dilation is the strongest determinant of AF in HCM patients, and is related to the extent of LGE in the LV, irrespective of LV mass.

Purpose: To investigate whether mechanical dyssynchrony (regional timing differences) or heterogeneity (regional strain differences) in myocardial function should be used to predict the response to cardiac resynchronization therapy (CRT)., Materials and Methods: Baseline mechanical function was studied with MRI in 29 patients with chronic heart failure. Using myocardial tagging, two mechanical dyssynchrony parameters were defined: the standard deviation (SD) in onset time (T onset) and in time to first peak (T peak,first) of circumferential shortening. Electrical dyssynchrony was described by QRS width. Further, two heterogeneity parameters were defined: the coefficient of variation (CV) in end-systolic strain and the difference between peak septal and lateral strain (DiffSLpeakCS). The relative increase in maximum rate of left ventricle pressure rise (dP/dt max) quantified the acute response to CRT., Results: The heterogeneity parameters correlated better with acute response (CV: r = 0.58, DiffSLpeakCS: r = 0.63, P < 0.005) than the mechanical dyssynchrony parameters (SD(T onset): r = 0.36, SD(T peak,first) r = 0.47, P = 0.01, but similar to electrical dyssynchrony (r = 0.62, P < 0.001). When a heterogeneity parameter was combined with electrical dyssynchrony, the correlation increased (r > 0.70, P incr < 0.05)., Conclusion: Regional heterogeneity in myocardial shortening correlates better with response to CRT than mechanical dyssynchrony, but should be combined with electrical dyssynchrony to improve prediction of response beyond the prediction from electrical dyssynchrony only., ((c) 2007 Wiley-Liss, Inc.)

Background: The effect of a left bundle branch block (LBBB) on cardiac function and remodeling in patients at different stages of heart failure (HF) is unknown. We used cardiac magnetic resonance imaging (CMR) to evaluate the effect of LBBB on left ventricular (LV) remodeling, mechanical dyssynchrony, functional mitral regurgitation (FMR) and deformation of the mitral valve apparatus (MVA) in LBBB patients at different stages of HF., Methods: In 12 LBBB patients with HF, 4 patients with isolated LBBB, and 4 controls, cine CMR was performed to measure LV remodeling, FMR grade and deformation of the MVA. CMR tagging was used to measure septal-to-lateral onset of shortening delay and coefficient of circumferential strain variation (CV) to quantify dyssynchrony., Results: LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were largest in LBBB patients with HF. Patients with isolated LBBB tended to have a larger LVESV and smaller LV ejection fraction compared to controls, (56 +/- 22 ml/m2 versus 45 +/- 9 ml/m2, P = ns, 42 +/- 9% versus 53 +/- 4 %, P = ns). QRS duration and septal-to-lateral-onset-of-shortening delay were comparable between LBBB patients with HF and isolated LBBB patients, CV was larger (98 +/- 45 versus 40 +/- 4, P < 0.05). MVA tenting and FMR were present both in LBBB patients with HF and patients with isolated LBBB and were not observed in controls., Conclusion: The presence of a LBBB in asymptomatic patients is related to mechanical dyssynchrony and deformation of the MVA and may be associated with LV remodeling. If confirmed, close monitoring or even timely initiation of therapy may be warranted in patients with isolated LBBB. This advocates to conduct a longitudinal CMR follow-up study on the clinical course in patients with isolated LBBB.

The response to cardiac resynchronization therapy (CRT), which is applied to patients with heart failure (HF) and left bundle-branch block (LBBB), can be predicted from the mechanical dyssynchrony measured on circumferential strain. Circumferential strain can be assessed by either 2D or 3D strain analysis. In this study was evaluated the difference between 2D and 3D circumferential strain using MR tagging with high temporal resolution (14 ms). Six healthy volunteers and five patients with LBBB were evaluated. We compared the 2D and 3D circumferential strains by computing the mechanical dyssynchrony and the cross correlation (r) between 2D and 3D strain curves, and by quantifying the differences in peak circumferential shortening, time to onset, and time to peak of shortening. The obtained maximum r(2) values were 0.97 +/- 0.03 and 0.87 +/- 0.16 for the healthy and LBBB populations, respectively, and thus showed a good similarity between 2D and 3D strain curves. No significant difference was observed between 2D and 3D in time to onset, time to peak, or peak circumferential shortening. Thus, to measure dyssynchrony, 2D strain analysis will suffice. Since 2D analysis is easier to implement than 3D analysis, this finding brings the application of MRI tagging and strain analysis closer to the clinical routine.