Stefan Buchner

Delayed hyperenhancement in magnetic resonance imaging of left ventricular hypertrophy caused by aortic stenosis and hypertrophic cardiomyopathy: visualisation of focal fibrosis

Objective: To compare the extent and distribution of focal fibrosis by gadolinium contrast-enhanced magnetic resonance imaging (MRI; delayed hyperenhancement) in severe left ventricular (LV) hypertrophy in patients with pressure overload caused by aortic stenosis (AS) and with genetically determined hypertrophic cardiomyopathy (HCM). Methods: 44 patients with symptomatic valvular AS (n  =  22) and HCM (n  =  22) were studied. Cine images were acquired with fast imaging with steady-state precession (trueFISP) on a 1.5 T scanner (Sonata, Siemens Medical Solutions). Gadolinium contrast-enhanced MRI was performed with a segmented inversion–recovery sequence. The location, extent and enhancement pattern of hyperenhanced myocardium was analysed in a 12-segment model. Results: Mean LV mass was 238.6 (SD 75.3) g in AS and 205.4 (SD 80.5) g in HCM (p  =  0.17). Hyperenhancement was observed in 27% of patients with AS and in 73% of patients with HCM (p < 0.01). In AS, hyperenhancement was observed in 60% of patients with a maximum diastolic wall thickness ⩾ 18 mm, whereas no patient with a maximum diastolic wall thickness < 18 mm had hyperenhancement (p < 0.05). Patients with hyperenhancement had more severe AS than patients without hyperenhancement (aortic valve area 0.80 (0.09) cm2v 0.99 (0.3) cm2, p < 0.05; maximum gradient 98 (22) mm Hg v 74 (24) mm Hg, p < 0.05). In HCM, hyperenhancement was predominant in the anteroseptal regions and patients with hyperenhancement had higher end diastolic (125.4 (36.9) ml v 98.8 (16.9) ml, p < 0.05) and end systolic volumes (38.9 (18.2) ml v 25.2 (1.7) ml, p < 0.05). The volume of hyperenhancement (percentage of total LV myocardium), where present, was lower in AS than in HCM (4.3 (1.9)% v 8.6 (7.4)%, p< 0.05). Hyperenhancement was observed in 4.5 (3.1) and 4.6 (2.7) segments in AS and HCM, respectively (p  =  0.93), and the enhancement pattern was mostly patchy with multiple foci. Conclusions: Focal scarring can be observed in severe LV hypertrophy caused by AS and HCM, and correlates with the severity of LV remodelling. However, focal scarring is significantly less prevalent in adaptive LV hypertrophy caused by AS than in genetically determined HCM.

Kidney injury molecule-1 and N-acetyl-ß-d-glucosaminidase in chronic heart failure: possible biomarkers of cardiorenal syndrome

Patients with chronic heart failure are often characterized by impaired renal function, also referred to as cardiorenal syndrome (CRS). The aim of this study was to assess whether novel markers of kidney injury are elevated in chronic heart failure and CRS.

Planimetry of aortic valve area in aortic stenosis by magnetic resonance imaging.

Background:The aim of the study was to determine whether noninvasive planimetry of aortic valve area (AVA) by magnetic resonance imaging (MRI) is feasible and reliable in patients with valvular aortic stenosis in comparison to transesophageal echocardiography (TEE) and catheterization. Methods and Results:Planimetry of AVA by MRI (MRI-AVA) was performed on a clinical magnetic resonance system (1.5-T Sonata, Siemens Medical Solutions) in 33 patients and compared with AVA calculated invasively by the Gorlin-formula at catheterization (CATH-AVA, n = 33) as well as to AVA planimetry by multiplane TEE (TEE-AVA, n = 27). Determination of MRI-AVA was possible with an adequate image quality in 82% (27/33), whereas image quality of TEE-AVA was adequate only in 56% (15/27) of patients because of calcification artifacts (P = 0.05). The correlation between MRI-AVA and CATH-AVA was 0.80 (P < 0.0001) and the correlation of MRI-AVA and TEE-AVA was 0.86 (P < 0.0001). MRI-AVA overestimated TEE-AVA by 15% (0.98 ± 0.31 cm2 vs. 0.85 ± 0.3 cm2, P < 0.001) and CATH-AVA by 27% (0.94 ± 0.29 cm2 vs. 0.74 ± 0.24 cm2, P < 0.0001). Nevertheless, a MRI-AVA below 1,3 cm2 indicated severe aortic stenosis (CATH-AVA < 1 cm2) with a sensitivity of 96% and a specificity of 100% (ROC area 0.98). Conclusions:Planimetry of aortic valve area by MRI can be performed with better image quality as compared with TEE. In the clinical management of patients with aortic stenosis, it has to be considered that MRI slightly overestimates aortic valve area as compared with catheterization despite an excellent correlation.

Time course of eosinophilic myocarditis visualized by CMR

We report the diagnostic potential of cardiovascular magnetic resonance (CMR) to visualize the time course of eosinophilic myocarditis upon successful treatment. A 50-year-old man was admitted with a progressive heart failure. Endomyocardial biopsies were taken from the left ventricle because of a white blood cell count of 17000/mm3 with 41% eosinophils. Histological evaluation revealed endomyocardial eosinophilic infiltration and areas of myocyte necrosis. The patient was diagnosed with hypereosinophilic myocarditis due to idiopathic hypereosinophilic syndrome. CMR-studies at presentation and a follow-up study 3 weeks later showed diffuse subendocardial LGE in the whole left ventricle. Upon treatment with steroids, CMR-studies revealed marked reduction of subendocardial LGE after 3 months in parallel with further clinical improvement. This case therefore highlights the clinical importance of CMR to visualize the extent of endomyocardial involvement in the diagnosis and treatment of eosinophilic myocarditis.

High-sensitive troponin T in chronic heart failure correlates with severity of symptoms, left ventricular dysfunction and prognosis independently from N-terminal pro-b-type natriuretic peptide.

Abstract Background: Troponin T is an established marker of myocardial ischemia. We speculated that the role of the new high-sensitive troponin T (hs-cTnT) might expand towards non-ischemic myocardial disease, indicate disease severity and allow for prognostication in chronic heart failure. Methods: Hs-cTnT (Roche Diagnostics, Mannheim, Germany) was assessed in 233 individuals with chronic heart failure (n=149) or healthy controls (n=84). Results: Hs-cTnT was significantly elevated in patients with chronic heart failure [0.018 ng/mL, interquartile range (IQR) 0.009–0.036 ng/mL, vs. controls 0.003 ng/mL, 0.003–0.003 ng/mL, p<0.001] and positively correlated with N-terminal pro-b-type natriuretic peptide (NT-proBNP) (r=0.79, p<0.001). Hs-cTnT increased stepwise and signitificantly according to clinical (NYHA stage) as well as functional (LV ejection fraction, fluid retention) severity (each p<0.001). At a binary cutpoint of 0.014 ng/mL, hs-TropT was a significant predictor of all-cause mortality and all-cause mortality or rehospitalization for congestive heart failure (each p≤0.01). Of note, the prognostic value of hs-TropT was independent and additive to that of NT-proBNP. Conclusions: Hs-cTnT increases stepwise with the severity of symptoms and LV dysfunction and offers important prognostic information in chronic heart failure, independently from and additive to NT-proBNP. The utility of hs-cTnT expands beyond acute myocardial ischemia and towards chronic heart failure.

Variable phenotypes of bicuspid aortic valve disease: classification by cardiovascular magnetic resonance

Background Recently, cardiovascular magnetic resonance (CMR) has been shown to allow accurate visualisation and quantification of aortic valve disease. Although bicuspid aortic valve (BAV) disease is relatively rare in the general population, the frequency is high in patients requiring valve surgery. The aim of the current study was to characterise the different phenotypes of BAV disease by CMR. Methods CMR studies were performed on a 1.5 T scanner in 105 patients with BAV. Results The pattern of BAV phenotypes was as follows: a raphe was identified in 90 patients (86%). Among patients with raphe, 76 patients had fusion between the right and left cusps (RL) and 14 patients had fusion between the right and the non-coronary cusps (RN). There were no significant differences in the aortic dimensions in the different BAV phenotypes. Conclusion CMR allows excellent characterisation of valve phenotype in patients with BAV. The present data demonstrate that a raphe is present in the vast majority of cases and RL fusion is the predominant phenotype of BAV. No significant differences in the aortic dimensions were observed.

Natural course of sleep-disordered breathing after acute myocardial infarction

The aim of this study was to test whether an improvement of left ventricular ejection fraction (EF) in the early phase after acute myocardial infarction is associated with a reduction of the severity of central and obstructive sleep apnoea. 40 consecutive patients with acute myocardial infarction underwent polysomnography and cardiovascular magnetic resonance imaging within 5 days and 12 weeks after the event to assess sleep apnoea and cardiac function. We stratified the sample in patients who improved their left ventricular EF within 12 weeks by ≥5% (improved EF group, &Dgr;EF 9±1%, n=16) and in those who did not (unchanged EF group, &Dgr;EF -1±1%, n=24). Prevalence of sleep apnoea (≥15 apnoea and hypopnoea events·h−1) within ≤5 days after myocardial infarction was 55%. Apnoea and hypopnoea events·h−1 were significantly more reduced in the improved EF group compared with the unchanged EF group (-10±3 versus 1±3 events·h−1; p=0.036). This reduction was based on a significant alleviation of obstructive events (-7±2 versus 4±3 events·h−1; p=0.009), while the reduction of central events was similar between groups (p=0.906). An improvement of cardiac function early after myocardial infarction is associated with an alleviation of sleep apnoea. This finding suggests that re-evaluation of treatment indication for sleep apnoea is needed when a change in cardiac function occurs.

Electrocardiographic diagnosis of left ventricular hypertrophy in aortic valve disease: evaluation of ECG criteria by cardiovascular magnetic resonance

BackgroundLeft ventricular hypertrophy (LVH) is a hallmark of chronic pressure or volume overload of the left ventricle and is associated with risk of cardiovascular morbidity and mortality. The purpose was to evaluate different electrocardiographic criteria for LVH as determined by cardiovascular magnetic resonance (CMR). Additionally, the effects of concentric and eccentric LVH on depolarization and repolarization were assessed.Methods120 patients with aortic valve disease and 30 healthy volunteers were analysed. As ECG criteria for LVH, we assessed the Sokolow-Lyon voltage/product, Gubner-Ungerleider voltage, Cornell voltage/product, Perugia-score and Romhilt-Estes score.ResultsAll ECG criteria demonstrated a significant correlation with LV mass and chamber size. The highest predictive values were achieved by the Romhilt-Estes score 4 points with a sensitivity of 86% and specificity of 81%. There was no difference in all ECG criteria between concentric and eccentric LVH. However, the intrinsicoid deflection (V6 37 ± 1.0 ms vs. 43 ± 1.6 ms, p < 0.05) was shorter in concentric LVH than in eccentric LVH and amplitudes of ST-segment (V5 -0.06 ± 0.01 vs. -0.02 ± 0.01) and T-wave (V5 -0.03 ± 0.04 vs. 0.18 ± 0.05) in the anterolateral leads (p < 0.05) were deeper.ConclusionBy calibration with CMR, a wide range of predictive values was found for the various ECG criteria for LVH with the most favourable results for the Romhilt-Estes score. As electrocardiographic correlate for concentric LVH as compared with eccentric LVH, a shorter intrinsicoid deflection and a significant ST-segment and T-wave depression in the anterolateral leads was noted.

Cardiovascular Magnetic Resonance for Direct Assessment of Anatomic Regurgitant Orifice in Mitral Regurgitation

Background—In patients with mitral regurgitation (MR), assessment of the severity of valvular dysfunction is crucial. Recently, regurgitant orifice area has been proposed as the most useful indicator of the severity of MR. The purpose of our study was to determine whether planimetry of the anatomic regurgitant orifice (ARO) in patients with MR is feasible by cardiovascular magnetic resonance (CMR) and correlates with invasive catheterization and echocardiography effective regurgitant orifice [ECHO-ERO] by proximal isovelocity surface area. Methods and Results—Planimetry of ARO was performed with a 1.5-T CMR scanner using a breath-hold balanced gradient echo sequence true fast imaging with steady state precession (TrueFISP). CMR planimetry of ARO was possible in 35 of 38 patients and was closely correlated with angiographic grading (r=0.84, P<0.0001). In patients with MR grade ≥III on catheterization, CMR-ARO (0.60±0.29 cm2 versus 0.30±0.19 cm2, P<0.0001) as well as ECHO-ERO (0.49±0.17 cm2 versus 0.27±0.10 cm2) were significantly elevated in comparison with MR grade <III. Further, CMR-ARO was closely correlated to CMR regurgitant fraction and volume (r=0.90 and r=0.91, P<0.0001, respectively) and catheterization regurgitant fraction and volume (r=0.86 and 0.83, P<0.0001, respectively). The correlation between CMR-ARO and ECHO-ERO was 0.81 (P<0.0001) and CMR slightly overestimated ECHO-ERO by 0.06 cm2 (P<0.05). As assessed by receiver operating characteristic analysis, CMR-ARO at a threshold of 0.40 cm2 detected MR grade ≥III as defined by catheterization, with a sensitivity and specificity of 94% and 94%, respectively. Conclusion—CMR planimetry of the anatomic mitral regurgitant lesion in patients with MR is feasible and permits quantification of MR with good agreement with the accepted invasive and noninvasive methods. Direct measurement by CMR is a promising new method for the precise assessment of ARO area and the severity of MR.

Assessment of the anatomic regurgitant orifice in aortic regurgitation: a clinical magnetic resonance imaging study

Background: The aim of our study was to determine whether planimetry of the anatomic regurgitant orifice (ARO) in patients with aortic regurgitation (AR) by magnetic resonance imaging (MRI) is feasible and whether ARO by MRI correlates with the severity of AR. Methods and results: Planimetry of ARO by MRI was performed on a clinical magnetic resonance system (1.5 T Sonata, Siemens Medical Solutions) in 45 patients and correlated with the regurgitant fraction (RgF) and regurgitant volume (RgV) determined by MRI phase velocity mapping (PVM; MRI-RgF, MRI-RgV, n = 45) and with invasively quantified AR by supravalvular aortography (n = 32) and RgF upon cardiac catheterisation (CATH-RgF, n = 15). Determination of ARO was possible in 98% (44/45) of the patients with adequate image quality. MRI-RgF and CATH-RgF were modestly correlated (n = 15, r = 0.71, p<0.01). ARO was closely correlated with MRI-RgF (n = 44, r = 0.88, p<0.001) and was modestly correlated with CATH-RgF (n = 14, r = 0.66, p = 0.01). Sensitivity and specificity of ARO to detect moderately severe and severe aortic regurgitation (defined as MRI-RgF ⩾40%) were 96% and 95% at a threshold of 0.28 cm2 (AUC  = 0.99). Of note, sensitivity and specificity of ARO to detect moderately severe and severe AR at catheterisation (defined as CATH-RgF ⩾40% or supravalvular aortography ⩾3+) were 90% and 91% at a similar threshold of 0.28 cm2 (AUC  = 0.95). Lastly, sensitivity and specificity of ARO to detect severe aortic regurgitation (defined as MRI-RgF ⩾50% and/or regurgitant volume ⩾60 ml) were 83% and 97% at a threshold of 0.48 cm2 (AUC  = 0.97). Conclusions: Visualisation and planimetry of the ARO in patients with AR are feasible by MRI. There is a strong correlation of ARO with RgV and RgF assessed by PVM and with invasively graded AR at catheterisation. Therefore, determination of ARO by MRI is a new non-invasive measure for assessing the severity of AR.