Strain Analysis by Tissue Doppler Imaging: Comparison of Conventional Manual Measurement with a Semiautomated Approach.

PURPOSE: Myocardial strain and strain rate (SR) can be derived from either tissue Doppler (TDI) information or two-dimensional speckle tracking. As conventional TDI analysis (TDI-manual) is time-consuming with poor reproducibility, we developed a faster semiautomated approach (TDI-ST). We aimed to study the comparability of TDI-ST with TDI-manual, an established method for measuring strain and SR. METHODS: Forty healthy subjects (mean age 38.3 ± 12.8 years) and 16 patients with FHL-1 cardiomyopathy (CMP) (36.8 ± 14.2 years) were analyzed with TDI-manual and TDI-ST. TDI-ST was performed with commercial software, using speckle tracking for myocardial tracking and TDI information to derive longitudinal strain and SR from high frame rate TDI recordings. Measurements of longitudinal systolic strain (S) and global S (GLS) made with the two methods were compared with Bland-Altman plots and Deming regression. Receiver operating characteristics (ROC) curves were used to compare discrimination between healthy individuals and patients. RESULTS: Mean S was -20.11 ± 4.85% (healthy) and -16.12 ± 4.44% (CMP) with TDI-ST and -21.15 ± 5.68% (healthy) and -16.27 ± 6.44 (CMP) with TDI-manual. Using all measured segments, the mean bias was 0.78% strain toward less negative S with TDI-ST; the Deming regression slope was 0.7 for S and 0.9 for GLS. Intra- and inter-observer CVs were 5.4% and 7.0%, respectively. ROC curves showed no significant differences between the methods. CONCLUSION: The described S and SR measurements with TDI-ST are comparable to conventional manual analysis. Thus, using TDI-ST, it is possible to quickly and easily extract high-resolution deformation data.

Cardiac Magnetic Resonance Imaging Right Ventricular Longitudinal Strain Predicts Mortality in Patients Undergoing TAVI.

Background: Right ventricular (RV) function predicts survival in numerous cardiac conditions, including left heart disease. The reference standard for non-invasive assessment of RV function is cardiac magnetic resonance imaging (CMR). The aim of this study was to investigate the association between pre-procedural CMR-derived RV functional parameters and mortality in patients undergoing transcatheter aortic valve implantation (TAVI). Methods: Patients scheduled for TAVI were recruited to undergo pre-procedural CMR. Volumetric function and global longitudinal and circumferential strain (GLS and GCS) of the RV and left ventricle (LV) were measured. The association with the primary endpoint (1-year all-cause mortality) was analyzed with Cox regression. Results: Of 133 patients undergoing CMR, 113 patients were included in the analysis. Mean age was 81.8 ± 5.8 years, and 65% were female. Median follow-up was 3.9 [IQR 2.3-4.7] years. All-cause and cardiovascular mortality was 14 and 12% at 1 year, and 28 and 20% at 3 years, respectively. One-year all-cause mortality was significantly predicted by RV GLS [HR = 1.109 (95% CI: 1.023-1.203); p = 0.012], RV ejection fraction [HR = 0.956 (95% CI: 0.929-0.985); p = 0.003], RV end-diastolic volume index [HR = 1.009 (95% CI: 1.001-1.018); p = 0.025], and RV end-systolic volume index [HR = 1.010 (95% CI: 1.003-1.017); p = 0.005]. In receiver operating characteristic (ROC) analysis for 1-year all-cause mortality, the area under the curve was 0.705 (RV GLS) and 0.673 (RV EF). Associations decreased in strength at longer follow-up. None of the LV parameters was associated with mortality. Conclusions: RV function predicts intermediate-term mortality in TAVI patients while LV parameters were not associated with outcomes. Inclusion of easily obtainable RV GLS may improve future risk scores.

Cardiac involvement in a cross-sectional cohort of myotonic dystrophies and other skeletal myopathies.

AIMS: Cardiac involvement in myopathies that primarily affect the skeletal muscle is variable and may be subtle, necessitating sensitive diagnostic approaches. Here, we describe the prevalence of cardiac abnormalities in a cohort of patients with skeletal muscle disease presenting at a tertiary care neuromuscular centre. METHODS AND RESULTS: We systematically investigated patients with skeletal myopathies and comprehensively analysed their cardiac phenotype including 24 h electrocardiogram, echocardiography with strain analyses, contrast-enhanced cardiac magnetic resonance imaging, and, if at increased risk of coronary artery disease, computed tomography coronary angiography. We prospectively screened 91 patients with diverse skeletal myopathies and enrolled 73 patients. The most pronounced cardiac involvement was present in patients with dystrophic myopathies (cardiac abnormalities in 59% of patients). We analysed myotonic dystrophies (n = 29) in more detail and found prolonged QRS (99.4 ± 15.6 vs. 91.5 ± 10.3 ms; P = 0.027) and QTc times (441.1 ± 28.1 vs. 413.0 ± 23.3 ms; P < 0.001) and increased left atrial size (27.28 ± 3.9 vs. 25.0 ± 3.2 mm/m2 ; P = 0.021) when compared with healthy controls. Left ventricular systolic function was reduced (ejection fraction < 55%) in 31% of myotonic dystrophies, while only 4% had an ejection fraction < 50%. Apical peak systolic longitudinal strain was slightly reduced (P = 0.023). CONCLUSIONS: Screening for cardiac involvement in the skeletal muscle disease seems prudent particularly in patients with dystrophic myopathies. In the subset of myotonic dystrophy patients, QRS and QTc times as well as myocardial strain may be useful parameters. Their potential for predicting cardiac adverse events needs further evaluation.

Elevated Cardiac Troponin T in Patients With Skeletal Myopathies.

BACKGROUND: Cardiac troponins are often elevated in patients with skeletal muscle disease who have no evidence of cardiac disease. OBJECTIVES: The goal of this study was to characterize cardiac troponin concentrations in patients with myopathies and derive insights regarding the source of elevated troponin T measurements. METHODS: Cardiac troponin T (cTnT) and cardiac troponin I (cTnI) concentrations were determined by using high sensitivity assays in 74 patients with hereditary and acquired skeletal myopathies. Patients underwent comprehensive cardiac evaluation, including 12-lead electrocardiogram, 24-h electrocardiogram, cardiac magnetic resonance imaging, and coronary artery computed tomography. cTnT and cTnI protein expression was determined in skeletal muscle samples of 9 patients and in control tissues derived from autopsy using antibodies that are used in commercial assays. Relevant Western blot bands were subjected to liquid chromatography tandem mass spectrometry for protein identification. RESULTS: Levels of cTnT (median: 24 ng/l; interquartile range: 11 to 54 ng/l) were elevated (>14 ng/l) in 68.9% of patients; cTnI was elevated (>26 ng/l) in 4.1% of patients. Serum cTnT levels significantly correlated with creatine kinase and myoglobin (r = 0.679 and 0.786, respectively; both p < 0.001). Based on cTnT serial testing, 30.1% would have fulfilled current rule-in criteria for myocardial infarction. Noncoronary cardiac disease was present in 23%. Using cTnT antibodies, positive bands were found in both diseased and healthy skeletal muscle at molecular weights approximately 5 kDa below cTnT. Liquid chromatography tandem mass spectrometry identified the presence of skeletal troponin T isoforms in these bands. CONCLUSIONS: Measured cTnT concentrations were chronically elevated in the majority of patients with skeletal myopathies, whereas cTnI elevation was rare. Our data indicate that cross-reaction of the cTnT immunoassay with skeletal muscle troponin isoforms was the likely cause.

ST2 predicts survival in patients undergoing transcatheter aortic valve implantation.

OBJECTIVE: To assess soluble suppression of tumorigenicity 2 (sST2) serum concentrations and predict mortality in patients undergoing transcatheter aortic valve implantation (TAVI). METHODS: We prospectively enrolled 74 patients with severe aortic stenosis (AS) who underwent TAVI and matched them to patients without aortic valve disease (n=74). AS patients underwent comprehensive echocardiographic and cardiac magnetic resonance imaging and laboratory examinations. sST2 levels were determined by enzyme-linked immunosorbent assay (ELISA), their association with post procedural mortality was investigated using logistic and Cox regression analyses, and the prognostic performance compared to established risk scores. RESULTS: AS patients had substantially higher sST2 levels than controls (39.5 vs. 17.8ng/mL, p<0.001). sST2 significantly correlated with left and right atrial sizes (r=0.25, p=0.033 and r=0.38, p=0.001). At one and two years, 10 (13.9%) and 18 (25%) patients had died, respectively. sST2 significantly predicted survival in uni- and multivariate Cox regression analyses in our cohort (p=0.005 and p=0.025). sST2 also predicted major adverse cardiovascular events (MACE, p=0.046). Adding sST2 to the established STS score improved prediction of two-year mortality in our cohort (ΔAUC=0.108; 95% CI -0.066-0.281; continuous NRI=0.778; 95% CI: 0.277-1.278 and IDI=0.141; 95% CI: 0.031-0.251), and a model containing both sST2 and the STS score had a negative predictive value of 96.1% and 86.3% regarding one and two-year mortality, respectively. CONCLUSIONS: sST2 is elevated in AS patients and a prognostic marker of survival after TAVI. Implementation of this marker in routine pre-TAVI workup may improve risk prediction and patient selection.

Spongious hypertrophic cardiomyopathy in patients with mutations in the four-and-a-half LIM domain 1 gene.

BACKGROUND: X-linked myopathy with postural muscle atrophy is a novel X-linked myopathy caused by mutations in the four-and-a-half LIM domain 1 gene (FHL1). Cardiac involvement was suspected in initial publications. We now systematically analyzed the association of the FHL1 genotype with the cardiac phenotype to establish a potential cardiac involvement in the disease. METHODS AND RESULTS: Seventeen male patients and 23 female mutation carriers were compared with healthy controls. Every patient underwent a comprehensive clinical and cardiovascular workup. ECG abnormalities occurred frequently in affected males and were less frequent in heterozygous females. Both male and female mutation carriers had increased myocardial mass (affected males=115.1±25.3 g/m(2); heterozygous females=95.1±19.6 g/m(2); controls=89.0±15.6 g/m(2) and 72.6±12.6 g/m(2); respectively) with increased wall thickness (typically midventricular and apical segments) mainly in affected males. Longitudinal systolic function was reduced in affected males (radial systolic strain: affected males=24.6±11.8%; male controls=43.2±14.8%; P=0.002). Diastolic dysfunction occurred in both affected males and heterozygous females. Cardiac MRI revealed a morphological hallmark of X-linked myopathy with postural muscle atrophy; a characteristic spongious structure and replacement fibrosis indicated by late enhancement could be detected in most affected males. X-linked myopathy with postural muscle atrophy was associated with reduced exercise capacity in affected males but not in heterozygous female mutation carriers. CONCLUSIONS: X-linked myopathy with postural muscle atrophy patients consistently showed electrical, functional, and characteristic morphological cardiac abnormalities that translate into reduced exercise capacity. Reduced systolic and diastolic function is associated with a novel type of spongious hypertrophic cardiomyopathy. An unexpected finding was that some cardiac abnormalities were also present in heterozygous female mutation carriers.