Left Ventricular Mechanical Dispersion for the Better Risk Stratification of Patients With Hypertrophic Cardiomyopathy: Is It Possible?

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Exercise-Induced Cardiac Fatigue in Soldiers Assessed by Echocardiography

Background: Echocardiographic signs of exercise-induced cardiac fatigue (EICF) have been described after strenuous endurance exercise. Nevertheless, few data are available on the effects of repeated strenuous exercise, especially when associated with other constraints as sleep deprivation or mental stress which occur during military selection boot camps. Furthermore, we aimed to study the influence of experience and training level on potential EICF signs.Methods: Two groups of trained soldiers were included, elite soldiers from the French Navy Special Forces (elite; n = 20) and non-elite officer cadets from a French military academy (non-elite; n = 38). All underwent echocardiography before and immediately after exposure to several days of uninterrupted intense exercise during their selection boot camps. Changes in myocardial morphology and function of the 4 cardiac chambers were assessed.Results: Exercise-induced decrease in right and left atrial and ventricular functions were demonstrated with 2D-strain parameters in both groups. Indeed, both atrial reservoir strain, RV and LV longitudinal strain and LV global constructive work were altered. Increase in LV mechanical dispersion assessed by 2D-strain and alteration of conventional parameters of diastolic function (increase in E/e' and decrease in e') were solely observed in the non-elite group. Conventional parameters of LV and RV systolic function (LVEF, RVFAC, TAPSE, s mitral, and tricuspid waves) were not modified.Conclusions: Alterations of myocardial functions are observed in soldiers after uninterrupted prolonged intense exercise performed during selection boot camps. These alterations occur both in elite and non-elite soldiers. 2D-strain is more sensitive to detect EICF than conventional echocardiographic parameters.

Moderate Hypothermia Attenuates Pro-Arrhythmic Electromechanical Relations in the Left Ventricle – A Clinical Study

BackgroundTargeted temperature management is recommended after cardiac arrest, but the beneficial effects are controversial. The recently published TTM2 study reports that arrhythmias causing hemodynamic compromise are more common during moderate hypothermia. The causation is not explored. Experimentally, moderate hypothermia attenuates electromechanical relations with pro-arrhythmic impact. Mechanical systole outlasts the electrical systole to a greater extent giving increased electromechanical window positivity, and dispersion of electrical and mechanical activity are unaltered. In this prospective clinical study, we explored the effect of moderate hypothermia on electromechanical relations in un-insulted left ventricles. We hypothesized that during moderate hypothermia, prolongation of systolic duration would exceed electrical duration without dispersed electrical- or mechanical activity. Methods20 patients with normal left ventricular function, undergoing surgery on the ascending aorta and connected to cardiopulmonary bypass, were included. Measurements were obtained at 36 °C and 32 °C prior to aortic-repair, and at 36 °C after repair at spontaneous and paced heart rate 90 bpm. Comparable loading conditions were ensured and cardiopulmonary bypass was reduced to 20% of estimated maximum during the measurements. Global cardiac function was measured invasively and with echocardiography. Electromechanical window, dispersion of repolarization by ECG and mechanical dispersion by echocardiography, were calculated. ResultsAt moderate hypothermia (32°C), mechanical systolic prolongation exceeded electrical prolongation so that electromechanical window increased (29 ± 30 to 86 ± 50 ms, p <0.001). Dispersion of repolarization and mechanical dispersion remained unchanged. Myocardial function was preserved with maintained strain, fractional shortening and stroke volume. Similar electromechanical relations were present also at comparable increased heart rate during moderate hypothermia. After rewarming to 36°C, electromechanical alterations were reversed. ConclusionModerate hypothermia increased electromechanical window positivity. Dispersion of repolarisation, mechanical dispersion, and myocardial function were unchanged. Moderate hypothermia did not induce adverse electromechanical changes in the left ventricle during standardized conditions, but rather an attenuation of pro-arrhythmic electromechanical relations.

Left atrial appendage function by strain predicts subclinical atrial fibrillation in patients with cryptogenic stroke/TIA

Background Left atrial (LA) function by strain has shown to be promising to predict clinical atrial fibrillation (AF) in patients with cryptogenic stroke/TIA. However, there is little knowledge, if this novel method may prospectively predict subclinical AF (SCAF) and moreover, if left atrial appendage (LAA) function by strain and mechanical dispersion may be more sensitive to improve prediction of SCAF. Purpose The aim of the present study was to investigate if LA and LAA function by strain could improve the prediction of SCAF in patients at risk. Methods In this prospective study (mean follow-up 859±226 days), 185 patients with cryptogenic stroke/TIA, mean age 68±13 years, 33% female and no history of clinical AF or SCAF, were included. All participants underwent 2D and 3D transesophageal and transthoracic echocardiography in sinus rhythm after index cryptogenic stroke/TIA (mean 5±3days). LAA and LA functions by phasic strain, including reservoir strain (Sr), conduit strain (Scd) and contraction strain (Sct) and mechanical dispersion of Sr were assessed. SCAF episodes were detected by cardiac monitoring during follow up (mean 257±273 days). Results LAA function by strain was decreased in those with SCAF (60/32% of all patients) compared to those without: Sr: 19.2±4.5% vs. 25.6±6.5% (p&lt;0.001), Scd: −11.0±3.1% vs. −14.4±4.5% (p&lt;0.001), Sct: −7.9±4.0% vs. −11.2±4% (p&lt;0.001), respectively, while mechanical dispersion by Sr strain was increased, 34±24ms vs. 26±20ms (p=0.02). However, LA function by strain and mechanical dispersion did not differ in patients with SCAF compared to patients without. By ROC analyses, LAA strain and mechanical dispersion were highly significant in prediction of SCAF. LAA reservoir strain showed the best AUC of 0.80 (95% CI 0.73–0.87) with a cut-off value of 22.2%, sensitivity of 80%, and specificity of 73%, p&lt;0.001. (Figure) Conclusions For the first time, we showed, that left atrial appendage function by strain and mechanical dispersion predicts SCAF, as opposed to left atrial function. Left atrial appendage function by strain may be useful in risk prediction in patients at considerable AF risk. FUNDunding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Akershus University Hospital, Oslo/Lørenskog, Norway

Myocardial deformation techniques as potential tools to detect arrhythmogenic cardiomyopathy in early stages of the disease

Introduction Arrhythmogenic Cardiomyopathy (ACM) is a life-threatening entity which predispose to malignant arrhythmias and sudden cardiac death even in early stages of the disease. Deformation techniques obtained by echocardiography are promising tools which can identify subtle pathologic changes in the myocardial wall. Our aim is to investigate how myocardial deformation parameters may be affected throughout ACM spectrum. Methods A cohort of ACM 45 subjects, was characterized using advanced transthoracic echocardiography and divided into groups according to left ventricle ejection fraction (LVEF). Twenty-three healthy volunteers were also included as control group (CG). We analyzed regional wall motion abnormalities and left ventricular myocardial deformation parameters by 2D Speckle Tracking, such as global longitudinal strain (GLS), mechanical dispersion (MD) [standard deviation (SD) and range (delta)]. Results 23 (51,1%) of the ACM cohort were men, with a mean age of 43,13±16,55 years. Next-generation sequencing identified a potential pathogenic mutation in 37 (82,2%) of the patients. Those ACM subjects with low LVEF (ACM-L) presented lower GLS values when compared to those with normal LVEF (ACM-N) (−16,17±2,68% vs. ACM-N −19,39±2,97%; p&lt;0.001) with no significant differences in MD parameters. ACM-N showed no differences in GLS regarding to CG, but significant differences were found when analyzing MD values, with pathological dispersion times in the ACM-N group (ACM-N DMSD 50,50±20,39ms vs. CG 37,35±17,15ms; p=0,016; ACM-N DMDelta 167,4583±75,07ms vs CG 125±49,13ms; p=0,033). Conclusions MD may be an additive tool for identifying ACM patients in early stages of the disease when LVEF is still preserved. FUNDunding Acknowledgement Type of funding sources: None.

Mechanical dispersion identifies patients with extensive electroanatomic abnormalities in Brugada syndrome

Background Brugada syndrome (BrS) was initially described as a pure electrical disorder caused by ion channel abnormalities in the absence of structural heart disease. However, imaging, autopsy and endomyocardial biopsy studies have increasingly demonstrated in patients with BrS the presence of myocardial structural alterations of the right ventricle (RV), particularly in the outflow tract. Indeed, electroanatomic mapping studies identified electroanatomic abnormalities of the RV outflow tract in both unipolar and bipolar maps with a significant correlation between the extension of low-voltage areas and the inducibility of arrhythmias at electrophysiological study or the incidence of malignant arrhythmias during the follow up. New echocardiographic parameters have been proposed to identify subtle myocardial alterations associated with arrhythmic events. Mechanical dispersion (MD) of the left ventricle (LV) has been identified as a prognostic marker in the arrhythmic risk stratification in various cardiac diseases including some cardiomyopathies. Purpose In this study we evaluated MD and global longitudinal strain (GLS) of RV and LV in patients with BrS to identify echocardiographic correlates of the abnormalities detected by electroanatomic mapping. Methods We performed 2D-Echocardiography with speckle tracking analysis of RV and LV in patients with BrS previously submitted to RV electroanatomic mapping. All studies were performed by investigators blind to clinical features and electrophysiological findings. Echocardiographic data were compared with electroanatomic mapping and electrophysiological study findings and with clinical data. Results We enrolled 18 patients (52±11 years, male 44%). Patients with a LV MD value ≥40 ms showed a pathological unipolar area with voltage &lt;5.5 mV significantly more extended than patients with a LV MD value &lt;40 ms (28.49±21.06 vs 10.47±8.22; p=0.03). Patients with LV MD ≥40 ms also showed a trend to greater extension of the unipolar area with voltage &lt;4 mV (13.94±13.11 vs 4.94±3.12; p=0.07), a greater extension of the bipolar area with voltage &lt;1.5 mV (6.24±5.22 vs 2.24±3.15; p=0.07) and higher inducibility at programmed ventricular stimulation (70% vs 37.5%, p=0.34). No correlation was observed between RV MD or GLS values and the extent of the low-voltage areas or with the presence of genetic mutations associated with BrS. Conclusions In patients with BrS a LV MD ≥40 ms is associated with a greater extension of low-voltage areas at unipolar mapping. Echocardiographic evaluation with MD analysis may represent a valuable non-invasive tool to identify electroanatomic alterations prompting further invasive studies including electronatomic mapping and electrophysiological study. Prospective studies on larger series may further clarify the potential role of MD and electroanatomic mapping in the prognostic stratification of patients with BrS. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2

Cardiac magnetic resonance strain and mechanical dispersion assessment in patients with chronic total coronary artery occlusion

Background Chronic total occlusions (CTO) are a frequent angiographic finding. Viability of CTO-subtended myocardium is dependent on the presence of an adequate collateral circulation. At rest, collateral supply may be sufficient to avert ischaemia and maintain normal systolic function. However, it remains unclear whether CTO-subtended myocardium may be considered truly normal, or whether subtle functional abnormalities may be present at rest. Purpose To determine whether, in the absence of infarction and hibernation, CTO-subtended myocardium remains functionally normal or whether abnormalities of strain and/or mechanical dispersion may be present at rest. Methods In a retrospective, single centre, observational study, we studied patients with ≥1 angiographically-diagnosed CTO referred for clinical stress perfusion cardiovascular magnetic resonance (CMR), and compared healthy volunteers (HVs) with a normal stress CMR scan. CMR imaging comprised functional and scar assessment with qualitative [visual] evaluation of infarction and segmental wall motion. Patients with infarction and/or wall motion score index (WMSI) ≥1 were excluded from further analysis. In remaining CTO subjects and HVs, segmental peak systolic longitudinal strain and circumferential strain were analysed (in 3 long-axis planes and 3 short-axis planes, respectively) and mechanical dispersion for both orientations was computed. Image analysis was performed using Medis (QStrain) software blinded to all clinical information. Results From a total of 389 patients with ≥1 angiographically-diagnosed CTO, 68 had normal WMSI and no infarction (63.0±11.7 years, 79.4% male, LVEF 62.6±4.5%). Fifty HVs (61.1±7.0 years, 74.0% males, LVEF 61.1±5.3%) were also studied. The majority of CTO patients had concomitant coronary artery disease in at least one non-CTO vessel (n=37, 54.4%). GLS was lower in CTO patients than HVs (−21.8%±1.5% versus −24.0±1.1%; p&lt;0.0001; Figure 1). By contrast, GCS was greater in CTO patients (−32.7±2.5% versus −28.8±2.1%; p&lt;0.0001). Mechanical dispersion was increased in CTO patients (Figure 2), both longitudinally (90.3±14.6 ms in CTO patients versus 68.6±11.1 ms in HVs; p&lt;0.0001) and circumferentially (66.7±9.1 ms versus 55.3±6.6 ms, respectively; p=0.02). Conclusion Subclinical changes in left ventricular dynamics are present at rest in CTO patients with fully viable myocardium and no evidence of resting regional wall abnormality. Further study is warranted to evaluate the potential association between mechanical dispersion and arrhythmic events in CTO. FUNDunding Acknowledgement Type of funding sources: Other. Main funding source(s): NIHR Clinician Scientist Award (CS-2018-18-ST2-007 to J.R.A.) and Research Professorship award (RP-2017-08-ST2-007 to G.P.M.). Figure 1. Strain analysis. CTO vs HV Figure 2. Mechanical dispersion. CTO vs HV

New score scale for assessing the risk of establishing chronic heart failure with preserved ejection fraction

The aim of the study was to develop a score scale for assessing the high risk of establishing chronic heart failure with preserved ejection fraction (HFpEF), based on echocardiography (EchoCG) evidence.Materials and methods. A clinical and instrumental study of 175 patients, of which 108 (61.7%) women and 67 (38.3%) men, aged 71 [64; 78] years was performed in the 1st City Clinical Hospital in Minsk in 2017–2018. In order to validate the score scale for assessing the risk of HFpEF establishment in 2019–2020 a reproductive clinical and instrumental study of 129 patients was performed at the Minsk Scientific and Practical Center for Surgery, Transplantology and Hematology, of which 55 (42.6%) were men and 74 (57.4%) women aged 65 [58; 70] years. Inclusion criteria: sinus rhythm, essential arterial hypertension, chronic coronary heart disease: atherosclerotic heart disease, past myocardial infarction of left ventricle (LV), after which at least six months have passed, necessary to stabilize the structural and functional parameters of the LV, HFpEF, informed consent of the patient. Exclusion criteria: primary mitral regurgitation, mitral stenosis, mitral valve repair or prosthetics, congenital heart defects, acute and chronic diseases of the kidneys, lungs. EchoCG was performed on ultrasound machines Siemens Acuson S1000 (Germany) and Vivid E9 (GE Healthcare, USA).Results. The developed scale for assessing the risk of establishing HFpEF in a patient with sinus rhythm including the criteria: LV diastolic dysfunction type II – 47 points, deceleration time of peak E of the transmitral blood flow DTE ≤171 ms – 25 points, the speed of early diastolic movement of the septal part of the mitral fibrous ring e'septal ≤7 cm/s – 25 points, LV early diastolic filling index E/е'septal >7.72 – 20 points, index of the end-systolic volume of the left atrium >34.3 ml/m2 – 24 points, has high diagnostic reliability (AUC 0.96, sensitivity (S) 96.6%, specificity (Sp) 83.2%) and reproducibility of results in an examination cohort of patients (AUC 0.99, S 98.8%, Sp 98.0%). A total score > 45 indicates a high probability of HFpEF. If the total score is ≤45, it is recommended to perform 2D Speckle Tracking EchoCG. The leading patho-functional mechanisms for the development of HFpEF are a decrease of LV global systolic longitudinal strain GLSAVG > −18.9% (S 94.9%, Sp 98.0%), GLS of the right ventricle (RV) > −19.9% (S 76.5%, Sp 88.5%), mechanical dispersion with LV mechanical dispersion index > 54.69 ms (S 70.7%, Sp 90.2%), RV mechanical dispersion index > 50.29 msec (S 78.1%, Sp 73.9%) and ventricular dyssynergy with LV global post systolic index >5.59% (S 82.6%, Sp 87.5%), RV global post systolic index > 2.17% (S 84.5%, Sp 69.9%).Conclusions. The use of the developed scale will improve the efficiency of ultrasound imaging of HFpEF.