Neuromuscular diseases and their cardiac manifestations under the spectrum of cardiovascular imaging.

Neuromuscular diseases (NMDs) include a broad spectrum of disorders that affect motor unit in every possible site, extending from the cell body of peripheral nerves to the muscle. The different lesion sites make this group of inherited disorders difficult to diagnose. Many NMDs, especially those involving skeletal muscles, can present significant cardiovascular complications, ranging from rhythm disturbances to the development of dilated or hypertrophic cardiomyopathy. Heart disease represents a major cause of morbidity and mortality among NMD patients, underlining the vital need for further familiarization with the pathogenesis and assessment of cardiac involvement. Cardiovascular imaging is the cornerstone for the evaluation of heart disorders in NMDs, with conventional echocardiography still offering a portable, affordable, and easily accessible solution. Meanwhile, newer echocardiographic techniques such as speckle tracking imaging in combination with cardiac magnetic resonance add new insights into further substrate characterization. The purpose of this review is to offer a brief presentation of the main NMDs and their cardiovascular complications, as well as the presentation of data that highlight the importance of cardiovascular imaging in early diagnosis, monitoring, and prognosis of these patients. Lastly, the authors provide a simple guide about which clinical features, imaging findings, and follow-up plan to adopt in each myopathic disorder.

Angiographic predictors of aberrant circumflex artery during cardiac catheterization.

OBJECTIVES: To identify angiographic predictors of aberrant left circumflex artery (LCx) by comparing left main (LM) length and bifurcation angle between patients with aberrant LCx and normal anatomy. BACKGROUND: Failure to recognize aberrant LCx during a cardiac catheterization may hamper correct diagnosis, delay intervention in acute coronary syndromes, and result in increased contrast volume, radiation exposure, and infarct size. METHODS: We retrospectively analyzed angiograms of aberrant LCx patients and normal anatomy matched controls, in three-participating centers. LM-length, bifurcation angle between the left anterior descending (LAD) and the first non-LAD branch of the LM, and procedural data were compared. RESULTS: Between 2003 and 2020, 136 patients with aberrant LCx and 135 controls were identified. More catheters (2.4 ± 0.6 vs. 2.2 ± 0.9, p = 0.009), larger contrast volumes (169 ± 94 ml vs. 129 ± 68 ml, p < 0.0005), and prolonged fluoroscopy time (652.9 ± 623.7 s vs. 393.1 ± 332.1 s, p < 0.0005), were required in the aberrant LCx-group compared with controls. Patients with aberrant LCx had a longer LM-length and a more acute bifurcation angle, both in caudal and cranial views, compared with controls (24.7 ± 8.1 vs. 10.8 ± 4.5 mm, p < 0.0005 and 26.7 ± 7.4 vs. 12 ± 5.5 mm, p < 0.0005, respectively, and 45.2° ± 12° vs. 88.8° ± 23°, p < 0.0005 and 51.9° ± 21° vs. 68.2° ± 28.3°, p < 0.0005, respectively). In ROC analysis, LM-length showed the best diagnostic accuracy for detecting aberrant LCx. In multiple logistic regression analysis, a cranially measured LM-length > 17.7 mm was associated with a 5.3 times greater probability of predicting aberrant LCx [95% CI (3.4-8.1), p < 0.0001]. CONCLUSIONS: Our study suggests that a long LM-length and an acute bifurcation angle can indicate the presence of aberrant LCx. We present a practical algorithm for its rapid identification.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment.

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.

Impact of centre volume on atrial fibrillation ablation outcomes in Europe: a report from the ESC EHRA EORP Atrial Fibrillation Ablation Long-Term (AFA LT) Registry.

AIMS: The aim of the study was to investigate differences in clinical outcomes and complication rates among European atrial fibrillation (AF) ablation centres related to the volume of AF ablations performed. METHODS AND RESULTS: Data for this analysis were extracted from the ESC EHRA EORP European AF Ablation Long-Term Study Registry. Based on 33rd and 67th percentiles of number of AF ablations performed, the participating centres were classified into high volume (HV) (≥ 180 procedures/year), medium volume (MV) (<180 and ≥74/year), and low volume (LV) (<74/year). A total of 91 centres in 26 European countries enrolled in 3368 patients. There was a significantly higher reporting of cardiovascular complications and stroke incidence in LV centres compared with HV and MV (P = 0.039 and 0.008, respectively) and a lower success rate after AF ablation (55.3% in HV vs. 57.2% in LV vs. 67.4% in MV centres, P < 0.001), despite lower CHA2DS2-VASc score of patients, enrolled in LVs and less complex ablation techniques used. Adjustments of confounding factors (including type of AF ablation) led to elimination of these differences. CONCLUSION: Low-volume centres tended to present slightly higher cardiovascular complications' and stroke incidence and a lower unadjusted success rate after AF ablation, despite the fact that ablation procedures and patients were of lower risk compared with MV and HV centres. On the other hand, adjusted overall complication and recurrence rates were non-significantly different among different volume centres, a fact reflecting the heterogeneity of patient and procedural profiles, and a counterbalance between expertise and risk level among participating centres.

Right ventricular remodelling after transcatheter pulmonary valve implantation.

OBJECTIVES: To define the optimal timing for percutaneous pulmonary valve implantation (PPVI) in patients with severe pulmonary regurgitation (PR) after Fallot's Tetralogy (ToF) correction. BACKGROUND: PPVI among the aforementioned patients is mainly driven by symptoms or by severe right ventricular (RV) dilatation/dysfunction. The optimal timing for PPVI is still disputed. METHODS: Twenty patients [age 13.9 ± 9.2 years, (range 4.3-44.9), male 70%] with severe PR (≥3 grade) secondary to previous correction of ToF, underwent Melody valve (Medtronic, Minneapolis, MN) implantation, after a pre-stent placement. Full echocardiographic assessment (traditional and deformation analysis) and cardiovascular magnetic resonance evaluation were performed before and at 3 months after the intervention. 'Favorable remodelling' was considered the upper quartile of RV size decrease (>20% in 3 months). RESULTS: After PPVI, indexed RV effective stroke volume increased from 38.4 ± 9.5 to 51.4 ± 10.7 mL/m2 , (P = 0.005), while RV end-diastolic volume and strain indices decreased (123.1 ± 24.1-101.5 ± 18.3 mL/m2 , P = 0.005 and -23.5 ± 2.5 to -21 ± 2.5%, P = 0.002, respectively). After inserting pre-PPVI clinical, RV volumetric and deformation parameters in a multiple regression model, only time after last surgical correction causing PR remained as significant regressor of RV remodelling [R2 = 0.60, beta = 0.387, 95%CI(0.07-0.7), P = 0.019]. Volume reduction and functional improvement were more pronounced in patients treated with PPVI earlier than 7 years after last RV outflow tract (RVOT) correction, reaching close-to-normal values. CONCLUSIONS: Early PPVI (<7 years after last RVOT operation) is associated with a more favorable RV reverse remodelling toward normal range and should be considered, before symptoms or RV damage become apparent. © 2017 Wiley Periodicals, Inc.

Left Ventricular Myocardial Mechanics in Cirrhosis: A Speckle Tracking Echocardiographic Study.

Cirrhosis is commonly associated with impaired left ventricular (LV) myocardial contractile reserve to stress and diastolic dysfunction. The aim of this study was to assess LV systolic performance at rest, using both "standard" echocardiographic indices and novel deformation-rotational parameters, in order to elucidate the pathophysiologic basis of cardiac dysfunction in cirrhosis. Seventy-seven men with cirrhosis (mean age 54.4 ± 9.7) of variable Child-Pugh class (A, B, C) and 20 healthy control subjects were prospectively evaluated by standard as well as speckle tracking echocardiography. Left ventricular ejection fraction (LVEF) was significantly higher in patients with cirrhosis compared to controls (64.6 ± 5.7% in controls vs. 71 ± 9.5%, 71.2 ± 7.1%, and 73 ± 7% in Child-Pugh classes A, B, and C, respectively, P = 0.002). Interestingly, LV systolic function augmentation was not associated with changes in LV longitudinal deformation (LV strain -19 ± 1.9% in controls vs. -20.1 ± 5.3% in class A vs. -21.3 ± 2.6% in class B vs. -21 ± 3.4% in class C, P = NS), but a statistically significant increase in LV apical systolic rotation and accordingly in LV twist was observed (LV twist 13.0 ± 3° in controls vs. 14.9 ± 5° in class A vs. 16.5 ± 2.8° in class B vs. 18.2 ± 2.9° in class C, P < 0.0005). Despite the increase in LV rotation, time to both basal and apical peak systolic rotation was significantly delayed in patients compared to healthy controls (P = 0.015 and P = 0.017 accordingly). Increased EF in cirrhosis could be attributed to increased LV torsion. Despite the "improved" rotation values at rest, there is a significant time delay in succeeding peak systolic rotation, hampering also the consequent untwisting-diastolic period.

Clinical characteristics and natural history of hypertrophic cardiomyopathy with midventricular obstruction.

BACKGROUND: The prevalence, clinical characteristics and natural history of patients with hypertrophic cardiomyopathy (HCM) and midventricular obstruction (MVO) have not been adequately studied. METHODS AND RESULTS: A single-center cohort consisting of 423 patients (mean age, 49.3±17.2 years; 66.2% male) was thoroughly followed up for a median of 84 months (7 years; range, 6-480 months). MVO, characterized by the echocardiographic appearance of midventricular muscular apposition with a simultaneous mid-cavitary gradient ≥30mmHg, was identified in 34 patients (8%). Patients with MVO tended to be more symptomatic during their initial evaluation (>90% presented with NYHA class ≥II) compared to the rest of the HCM cohort. Apical aneurysm formation was identified in more than one-fourth of patients with MVO (26.5%), being a characteristic of the group. On multivariate Cox regression hazard analysis, presence of MVO strongly predicted progression to end-stage (burnt out) HCM and related heart failure (HF) deaths (hazard ratio, [HR], 2.62; 95% confidence interval [CI]: 1.2-8.8; P=0.047), as well as sudden death and associated lethal arrhythmic events (HR, 3.3; 95% CI: 1.26-8.85; P=0.016). CONCLUSIONS: MVO is a distinct phenotype of HCM associated with unfavorable prognosis in terms of end-stage HCM, sudden death and lethal arrhythmic events. The high adverse outcome rate necessitates early recognition of MVO and appropriate therapeutic interventions.

Efficacy of various "classic" echocardiographic and laboratory indices in distinguishing the "gray zone" between athlete's heart and hypertrophic cardiomyopathy: a pilot study.

Left ventricular hypertrophy (LVH) with intraventricular septum thickness (IVST) between 1.2 and 1.5 cm in athletes represents a "gray zone" between physiologic adaptation and mild hypertrophic cardiomyopathy (HCM). Various echo and laboratory parameters have been reported till now in the literature to discriminate the "gray zone" entities. Aim of this study was to assess the efficacy of these "classic" parameters in differentiating physiologic LVH in athletes from mild HCM in a highly selected population. Nine highly trained athletes with IVST (1.28 ± 0.07 cm), 9 patients with mild HCM (1.38 ± 0.11 cm), and 26 athletes without LVH (1.06 ± 0.09 cm; P < 0.0005) underwent echocardiographic study, cardiopulmonary treadmill exercise stress test, and brain natriuretic peptide (BNP) measurement before and after exercise. Among all parameters tested, 7 were found to significantly differ between "gray zone" groups. After bootstrapping analysis, it was found that athletes with left ventricular end-diastolic diameter <4.74 cm, mitral deceleration time >200 ms, isovolumic relaxation time >94 ms, tricuspid E/A < 1.63, septum Em < 9.5 cm/sec, relative wall thickness >0.445, and a BNP value at rest >9.84 pg/mL had a greater possibility for having underlying cardiomyopathy. A 10-point score based on these parameters showed accuracy (area under the curve = 0.958 [95%CI: 0.738-1.0; P = 0.00005, standard error = 0.0342]) for revealing HCM in a gray zone athletic population. Differentiation of adaptive LVH versus HCM in a gray zone population could be facilitated by recognition of certain features referring to LV dimensions, diastolic function, and BNP.

Iron therapy and severe arrhythmias in HFrEF: rationale, study design, and baseline results of the RESAFE-HF trial.

AIMS: The Iron Intravenous Therapy in Reducing the burden of Severe Arrhythmias in HFrEF (RESAFE-HF) registry study aims to provide real-word evidence on the impact of intravenous ferric carboxymaltose (FCM) on the arrhythmic burden of patients with heart failure with reduced ejection fraction (HFrEF), iron deficiency (ID), and implanted cardiac implantable electronic devices (CIEDs). METHODS AND RESULTS: The RESAFE-HF (NCT04974021) study was designed as a prospective, single-centre, and open-label registry study with baseline, 3, 6, and 12 month visits. Adult patients with HFrEF and CIEDs scheduled to receive IV FCM as treatment for ID as part of clinical practice were eligible to participate. The primary endpoint is the composite iron-related endpoint of haemoglobin ≥ 12 g/dL, ferritin ≥ 50 ng/L, and transferrin saturation > 20%. Secondary endpoints include unplanned HF-related hospitalizations, ventricular tachyarrhythmias detected by CIEDs and Holter monitors, echocardiographic markers, functional status (VO2 max and 6 min walk test), blood biomarkers, and quality of life. In total, 106 patients with a median age of 72 years (14.4) were included. The majority were male (84.9%), whereas 92.5% of patients were categorized to New York Heart Association II/III. Patients' arrhythmic burden prior to FCM administration was significant-19 patients (17.9%) received appropriate CIED therapy for termination of ventricular tachyarrhythmia in the preceding 12 months, and 75.5% of patients have frequent, repetitive multiform premature ventricular contractions. CONCLUSIONS: The RESAFE-HF trial is expected to provide evidence on the effect of treating ID with FCM in HFrEF based on real-world data. Special focus will be given on the arrhythmic burden post-FCM administration.

An echocardiographic study of acute, progressive cardiac changes following a 246 km running race.

We describe the case of an ultra-marathon runner who finished first the "Spartathlon", a 246 km running race. The finishing time was the second fastest time ever in "Spartathlon". After finishing the race, the athlete suffered non-cardiac syncope and was administered intravenously 3 L of fluids for 5 hours. He underwent two echocardiographic assessments, one immediately after the finish of the race and the second 5 h later. Post-exercise fluid administration led to an increase in dimensions of all cardiac cavities, accompanied by a decrease in left ventricular (LV) end-diastolic interventricular septum thickness and posterior wall thickness of 0.1 cm. Dimensions and the respiratory profile of inferior vena cava improved after the race, reflecting alleviation of exercise-related hypovolaemia. Additionaly, LV global longitudinal strain improved, but right ventricular (RV) systolic function continued to deteriorate, mainly due to impairment of basal and medial RV free wall longitudinal strain. Study of this case offers a unique model for understanding the successive changes of cardiac structure and function following an ultra-marathon running race.

Brugada syndrome masked by ibutilide treatment in a patient with atrial flutter.

We present a case of Brugada syndrome in a young patient whose typical ECG pattern was 'masked' after ibutilide was administered for atrial flutter cardioversion. Ibutilide, a class III antiarrhythmic agent used for the treatment of atrial fibrillation and flutter, prolongs the action potential duration plateau phase by augmenting the slow component of the inward Na(+) current and by blocking the rapid component of the delayed rectifier potassium current. Insights into the pathophysiology of Brugada syndrome and this first-reported action of ibutilide are supplied, providing a plausible scientific basis for the masking effect of ibutilide. Furthermore, issues concerning the safety of ibutilide administration in patients with Brugada syndrome along with the importance of programmed ventricular stimulation and especially short-long-short sequence protocol in inducing ventricular fibrillation in these patients are also discussed.

Impact of a 246 Km ultra-marathon running race on heart: Insights from advanced deformation analysis.

Although previous studies suggest that prolonged intense exercise such as marathon running transitorily alters cardiac function, there is little information regarding ultramarathon races. Aim of this study was to investigate the acute impact of ultra-endurance exercise (UEE) on heart, applying advanced strain imaging. Echocardiographic assessment was performed the day before and at the finish line of "Spartathlon": A 246 Km ultra-marathon running race. 2D speckle-tracking echocardiography was performed in all four chambers, evaluating longitudinal strain (LS) for both ventricles and atria. Peak strain values and temporal parameters adjusted for heart rate were extracted from the derived curves. Out of 60 participants initially screened, 27 athletes (19 male, age 45 ± 7 years) finished the race in 33:34:27(28:50:38-35:07:07) hours. Absolute values of right (RV) and left ventricular (LV) LS (RVLS -22.9 ± 3.6 pre- to -21.2 ± 3.0% post-, p=0.04 and LVLS -20.9 ± 2.3 pre- to -18.8 ± 2.0 post-, p=0.009) slightly decreased post-race, whereas atrial strain did not change. RV and LV LS decrease was caused mainly by strain impairment of basal regions with apical preservation. Inter-chamber relationships assessed through RV/LV, LV/LA, RV/RA and RA/LA peak values' ratios remained unchanged from pre to post-race. Finally, UEE caused an extension of the systolic phase of cardiac cycle with concomitant diastole reduction (p<0.001 for all strain curves). Conclusively, ventricular LS strain as well as effective diastolic period slightly decreased, whereas atrial strain and inter-chamber relationships remained unchanged after running a 246-km-ultra-marathon race. These changes may be attributed to concomitant pre- and afterload alterations following UEE.

Safety and efficacy of long-term statin treatment for cardiovascular events in patients with coronary heart disease and abnormal liver tests in the Greek Atorvastatin and Coronary Heart Disease Evaluation (GREACE) Study: a post-hoc analysis.

BACKGROUND: Long-term statin treatment reduces the frequency of cardiovascular events, but safety and efficacy in patients with abnormal liver tests is unclear. We assessed whether statin therapy is safe and effective for these patients through post-hoc analysis of the Greek Atorvastatin and Coronary Heart Disease Evaluation (GREACE) study population. METHODS: GREACE was a prospective, intention-to-treat study that randomly assigned by a computer-generated randomisation list 1600 patients with coronary heart disease (aged <75 years, with serum concentrations of LDL cholesterol >2·6 mmol/L and triglycerides <4·5 mmol/L) at the Hippokration University Hospital, Thessaloniki, Greece to receive statin or usual care, which could include statins. The primary outcome of our post-hoc analysis was risk reduction for first recurrent cardiovascular event in patients treated with a statin who had moderately abnormal liver tests (defined as serum alanine aminotransferase or aspartate aminotransferase concentrations of less than three times the upper limit of normal) compared with patients with abnormal liver tests who did not receive a statin. This risk reduction was compared with that for patients treated (or not) with statin and normal liver tests. FINDINGS: Of 437 patients with moderately abnormal liver tests at baseline, which were possibly associated with non-alcoholic fatty liver disease, 227 who were treated with a statin (mainly atorvastatin 24 mg per day) had substantial improvement in liver tests (p<0·0001) whereas 210 not treated with a statin had further increases of liver enzyme concentrations. Cardiovascular events occurred in 22 (10%) of 227 patients with abnormal liver tests who received statin (3·2 events per 100 patient-years) and 63 (30%) of 210 patients with abnormal liver tests who did not receive statin (10·0 events per 100 patient-years; 68% relative risk reduction, p<0·0001). This cardiovascular disease benefit was greater (p=0·0074) than it was in patients with normal liver tests (90 [14%] events in 653 patients receiving a statin [4·6 per 100 patient-years] vs 117 [23%] in 510 patients not receiving a statin [7·6 per 100 patient-years]; 39% relative risk reduction, p<0·0001). Seven (<1%) of 880 participants who received a statin discontinued statin treatment because of liver-related adverse effects (transaminase concentrations more than three-times the upper limit of normal). INTERPRETATION: Statin treatment is safe and can improve liver tests and reduce cardiovascular morbidity in patients with mild-to-moderately abnormal liver tests that are potentially attributable to non-alcoholic fatty liver disease. FUNDING: None.

Prognostic value of right ventricular diastolic function indices in hypertrophic cardiomyopathy.

AIMS: Despite the fact that the role of left ventricular diastolic dysfunction in hypertrophic cardiomyopathy (HCM) patients' prognosis has been established, the effect of increased right ventricular (RV) diastolic filling pressures still remains unclear. The purpose of this study was to determine the prognostic significance of transthoracic echocardiographic indices of RV diastolic function (tricuspid inflow and tricuspid annulus tissue Doppler imaging) in HCM patients. METHODS AND RESULTS: We followed up 386 patients diagnosed with HCM (aged 49.3 ± 17.2 years; 65% male) for a median period of 67 months (interquartile range 26-189 months). Primary endpoints were considered mortality due to heart failure (HF) (13 patients) and total cardiovascular (TC) mortality [HF, sudden cardiac death and its equivalents (35 patients)]. Patients presenting with an increased RV E/E(r) ratio (ratio of tricuspid in flow E wave to E(r) wave obtained by tissue Doppler imaging at the lateral tricuspid annulus) had a 1.6 times greater risk for HF mortality [hazard ratio (HR): 1.6, 95% confidence interval (CI): 1.1-2.4, P = 0.03] while patients with shortened tricuspid E wave deceleration time (DTE) had a 1.1 greater risk for SCD (HR: 1.1, 95% CI: 1.01-1.2, P = 0.03). Following ROC analysis, the optimal RV indices' cut-off values for the recognition of our study endpoints were assessed [E/E(r) = 6.88, sensitivity 75%, specificity 77.4%, area under curve (AUC) 0.847, P = 0.017 for HF mortality and DTE < 239 ms, sensitivity 62.5%, specificity 56.7%, AUC 0.642, P = 0.05 for TC mortality]. CONCLUSION: The establishment of RV restrictive physiology appears to have significant predictive value in HCM, regardless of the presence of other detrimental risk factors.

Carbon dioxide balneotherapy and cardiovascular disease.

Carbon dioxide (CO(2)) balneotherapy is a kind of remedy with a wide spectrum of applications which have been used since the Middle Ages. However, its potential use as an adjuvant therapeutic option in patients with cardiovascular disease is not yet fully clarified. We performed a thorough review of MEDLINE Database, EMBASE, ISI WEB of Knowledge, COCHRANE database and sites funded by balneotherapy centers across Europe in order to recognize relevant studies and aggregate evidence supporting the use of CO(2) baths in various cardiovascular diseases. The three main effects of CO(2) hydrotherapy during whole body or partial immersion, including decline in core temperature, an increase in cutaneous blood flow, and an elevation of the score on thermal sensation, are analyzed on a pathophysiology basis. Additionally, the indications and contra-indications of the method are presented in an evidence-based way, while the need for new methodologically sufficient studies examining the use of CO(2) baths in other cardiovascular substrates is discussed.

Exploring the Anthropometric, Cardiorespiratory, and Haematological Determinants of Marathon Performance.

AIM: We aimed to investigate the main anthropometric, cardiorespiratory and haematological factors that can determine marathon race performance in marathon runners. METHODS: Forty-five marathon runners (36 males, age: 42 ± 10 years) were examined during the training period for a marathon race. Assessment of training characteristics, anthropometric measurements, including height, body weight (n = 45) and body fat percentage (BF%) (n = 33), echocardiographic study (n = 45), cardiopulmonary exercise testing using treadmill ergometer (n = 33) and blood test (n = 24) were performed. We evaluated the relationships of these measurements with the personal best marathon race time (MRT) within a time frame of one year before or after the evaluation of each athlete. RESULTS: The training age regarding long-distance running was 9 ± 7 years. Training volume was 70 (50-175) km/week. MRT was 4:02:53 ± 00:50:20 h. The MRT was positively associated with BF% (r = 0.587, p = 0.001). Among echocardiographic parameters, MRT correlated negatively with right ventricular end-diastolic area (RVEDA) (r = -0.716, p < 0.001). RVEDA was the only independent echocardiographic predictor of MRT. With regard to respiratory parameters, MRT correlated negatively with maximum minute ventilation indexed to body surface area (VEmax/BSA) (r = -0.509, p = 0.003). Among parameters of blood test, MRT correlated negatively with haemoglobin concentration (r = -0.471, p = 0.027) and estimated haemoglobin mass (Hbmass) (r = -0.680, p = 0.002). After performing multivariate linear regression analysis with MRT as dependent variable and BF% (standardised ß = 0.501, p = 0.021), RVEDA (standardised ß = -0.633, p = 0.003), VEmax/BSA (standardised ß = 0.266, p = 0.303) and Hbmass (standardised ß = -0.308, p = 0.066) as independent variables, only BF% and RVEDA were significant independent predictors of MRT (adjusted R2 = 0.796, p < 0.001 for the model). CONCLUSIONS: The main physiological determinants of better marathon performance appear to be low BF% and RV enlargement. Upregulation of both maximum minute ventilation during exercise and haemoglobin mass may have a weaker effect to enhance marathon performance. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier NCT04738877.

Inter-vendor variability in strain measurements depends on software rather than image characteristics.

Despite standardization efforts, vendors still use specific proprietary software algorithms for echocardiographic strain measurements, which result in high inter-vendor variability. Using vendor-independent software could be one solution. Little is known, however, how vendor specific image characteristics can influence tracking results of such software. We therefore investigated the reproducibility, accuracy, and scar detection ability of strain measurements on images from different vendors by using a vendor-independent software. A vendor-independent software (TomTec Image Arena) was used to analyse datasets of 63 patients which were obtained on machines from four different ultrasound machine vendors (GE, Philips, Siemens, Toshiba). We measured the tracking feasibility, inter-vendor bias, the relative test-re-test variability and scar discrimination ability of strain measurements. Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition. Tracking feasibility on vendor datasets were significantly different (p < 0.001). Variability of global longitudinal strain (GLS) measurements was similar among the vendors whereas variability of segmental longitudinal strain (SLS) showed modest difference. Relative test-re-test variability of GLS and SLS showed no relevant differences. No significant difference in scar detection capability was observed. Average GLS and SLS values were similar among vendors. Reproducibility of GLS measurements showed no difference among vendors and was in acceptable range. SLS reproducibility was high but similar for all vendors. No relevant difference was found for identifying regional dysfunction. Tracking feasibility showed a substantial difference among images from different vendors. Our findings demonstrate that tracking results depend mainly on the software used and show little influence from vendor specific image characteristics.