Impact of inter‐vendor variability on evaluation of left ventricular mechanical dispersion

Abstract Background Targeted hypothermia, as used after cardiac arrest, increases electrical and mechanical systolic duration. Differences in duration of electrical and mechanical systole are correlated to ventricular arrhythmias. The electromechanical window (EMW) becomes negative when the electrical systole outlasts the mechanical systole. Prolonged electrical systole corresponds to prolonged QT interval, and is associated with increased dispersion of repolarization and mechanical dispersion. These three factors predispose for arrhythmias. The electromechanical relations during targeted hypothermia are unknown. We wanted to explore the electromechanical relations during hypothermia at 33 °C. We hypothesized that targeted hypothermia would increase electrical and mechanical systolic duration without more profound EMW negativity, nor an increase in dispersion of repolarization and mechanical dispersion. Methods In a porcine model (n = 14), we registered electrocardiogram (ECG) and echocardiographic recordings during 38 °C and 33 °C, at spontaneous and atrial paced heart rate 100 beats/min. EMW was calculated by subtracting electrical systole; QT interval, from the corresponding mechanical systole; QRS onset to aortic valve closure. Dispersion of repolarization was measured as time from peak to end of the ECG T wave. Mechanical dispersion was calculated by strain echocardiography as standard deviation of time to peak strain. Results Electrical systole increased during hypothermia at spontaneous heart rate (p < 0.001) and heart rate 100 beats/min (p = 0.005). Mechanical systolic duration was prolonged and outlasted electrical systole independently of heart rate (p < 0.001). EMW changed from negative to positive value (− 20 ± 19 to 27 ± 34 ms, p = 0.001). The positivity was even more pronounced at heart rate 100 beats/min (− 25 ± 26 to 41 ± 18 ms, p < 0.001). Dispersion of repolarization decreased (p = 0.027 and p = 0.003), while mechanical dispersion did not differ (p = 0.078 and p = 0.297). Conclusion Targeted hypothermia increased electrical and mechanical systolic duration, the electromechanical window became positive, dispersion of repolarization was slightly reduced and mechanical dispersion was unchanged. These alterations may have clinical importance. Further clinical studies are required to clarify whether corresponding electromechanical alterations are accommodating in humans.

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Left ventricular mechanical dispersion in a general population: Data from the Akershus Cardiac Examination 1950 study

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez210 ◽

2019 ◽

Author(s):

Erika N Aagaard ◽

Brede Kvisvik ◽

Mohammad O Pervez ◽

Magnus N Lyngbakken ◽

Trygve Berge ◽

...

Keyword(s):

General Population ◽

Global Longitudinal Strain ◽

Population Data ◽

Left Ventricular ◽

Linear Regression Models ◽

Cross Sectional ◽

Clinical Model ◽

Mechanical Dispersion ◽

Obesity And Diabetes ◽

Increased Risk

Abstract Aims Increased left ventricular mechanical dispersion by 2D speckle tracking echocardiography predicts ventricular arrhythmias in ischaemic heart disease and heart failure. However, little is known about mechanical dispersion in the general population. We aimed to study mechanical dispersion in the general population and in diseases associated with increased risk of cardiovascular disease. Methods and results The present cross-sectional study consists of 2529 subjects born in 1950 included in the Akershus Cardiac Examination (ACE) 1950 study. Global longitudinal strain (GLS) was assessed from 17 strain segments, and mechanical dispersion calculated as the standard deviation of contraction duration of all segments. The cohort was divided according to the median value of mechanical dispersion, and multivariable linear regression models were performed with mechanical dispersion as the dependent variable. The prevalence of coronary artery disease (CAD), hypertension, obesity, and diabetes (P < 0.01 for all) was significantly higher in subjects with supra-median mechanical dispersion. In a multivariable clinical model, CAD (B = 7.05), hypertension (B = 4.15; both P < 0.001), diabetes (B = 3.39), and obesity (B = 1.89; both P < 0.05) were independently associated with increasing mechanical dispersion. When echocardiographic indices were added to the multivariable model, CAD (B = 4.38; P < 0.01) and hypertension (B = 2.86; P < 0.001) remained significant in addition to peak early diastolic tissue velocity e’ (B = −2.00), GLS (B = 1.68), and ejection fraction (B = 0.22; P < 0.001 for all). Conclusion In a general middle-aged population, prevalent CAD and hypertension were associated with increasing mechanical dispersion, possibly indicating elevated risk of fatal arrhythmias and sudden cardiac death. Albeit weaker, systolic and diastolic dysfunction, were also associated with increasing mechanical dispersion.

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4091Mechanical dispersion by speckle tracking echocardiography in fabry disease

European Heart Journal ◽

10.1093/eurheartj/ehz745.0103 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

T F Cianciulli ◽

M C Saccheri ◽

A M Risolo ◽

J A Lax ◽

R J Mendez ◽

...

Keyword(s):

Fabry Disease ◽

Speckle Tracking ◽

Heart Diseases ◽

Systolic Dysfunction ◽

Cross Sectional Study ◽

Left Ventricular ◽

Peak Strain ◽

Cross Sectional ◽

Mechanical Dispersion ◽

Group I

Abstract Background Fabry disease is a rare X-linked storage disorder caused by a deficiency of the lysosomal enzyme α-galactosidase A and generally causes multi-organ dysfunction. Heart disease is the main cause of death, due to severe left ventricular (LV) systolic dysfunction and sudden death. In several heart diseases, the LV systolic dysfunction and ventricular arrhythmias are associated with mechanical dispersion (MD). The presence of MD in patients with FD has not been studied yet. In this cross-sectional study, we investigated the prevalence of MD in patients with FD. Methods Complete echocardiographic and speckle tracking echocardiographic (STE) data were collected. MD is an index of inter-segmental discoordination of contraction which has been used to quantify LV dyssynchrony and was defined as the standard deviation (SD) of time to peak negative strain in 17 left ventricular segments. Patients were divided into two groups according to whether or not they had left ventricular hypertrophy (LVH). MD was defined as an SD >49 msec. Results We studied 108 patients with FD, 24 patients (22%) were excluded due to inadequate imaging quality or presence of comorbidities, so the final study population consisted of 84 patients (mean age 33.3±14.6 years, 60.7% women). LVH in FD appears at older ages than in patients without LVH (48±12.5 y/o vs 27.8±11.1 y/o, p<0.0001). Patients with FD without LVH (Group I) showed normal global longitudinal peak strain (GLPS) (21.2±2.5%) and no MD (32.7±8.8 msec). In Group II (n=23) patients with FD with LVH, 17 (73.9%) had MD >49 msec prolonged mechanical dispersion (73.3±20.7 msec) and reduced GLPS (13.6±4.0%). MD was more pronounced in Fabry patients with LVH than in patients without LVH (63.4±24.7 msec vs. 32.7±8.8 msec, p<0.0001). GLPS was lower in Fabry patients with LVH than in patients without LVH (15.3±4.7% vs 21.2±2.5%, p<0.0001). Figure 1 Conclusions To our knowledge, this is the first study to demonstrate the prevalence of mechanical dispersion in patients with FD. Mechanical dispersion was seen in 73.9% of patients with FD with LVH. This dyssynchrony should be taken into account in patients who develop heart failure or life-threatening ventricular tachyarrhythmias.

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Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

Annals of Medicine ◽

10.1080/07853890.2016.1186826 ◽

2016 ◽

Vol 48 (6) ◽

pp. 417-427 ◽

Cited By ~ 10

Author(s):

Mikko Jalanko ◽

Mika Tarkiainen ◽

Petri Sipola ◽

Pertti Jääskeläinen ◽

Kirsi Lauerma ◽

...

Keyword(s):

Ventricular Tachycardia ◽

Hypertrophic Cardiomyopathy ◽

Left Ventricular ◽

Nonsustained Ventricular Tachycardia ◽

Mechanical Dispersion

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Abstract 16215: Ventricular Dyssynchrony is Associated With Arrhythmic Mitral Prolapse Prior to Chamber Remodeling

Circulation ◽

10.1161/circ.142.suppl_3.16215 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Dimosthenis Pandis ◽

Marc Miller ◽

Ahmed El-Eshmawi ◽

Ioulia A Grapsa ◽

Percy Boateng ◽

...

Keyword(s):

At Risk ◽

Global Longitudinal Strain ◽

Left Ventricular ◽

Lv Function ◽

Study Cohort ◽

Ventricular Ectopy ◽

Myocardial Mechanics ◽

Ventricular Dyssynchrony ◽

Mechanical Dispersion ◽

The Mean

Introduction: Asymptomatic patients on active surveillance for degenerative mitral regurgitation are at risk of ventricular arrhythmia and sudden death. Hypothesis: Abnormal myocardial mechanics may precede ventricular remodeling and may help identify at-risk patients. Methods: Multi-directional myocardial mechanics and LV dyssynchrony were assessed in 204 consecutive patients awaiting surgical mitral repair for severe degenerative MR in a quaternary mitral reference center. Results: The mean age was 58 ±12.5 years and 40% were females. The mean EF was 63% ± 6% and 92% had compensated LV function (EF>60% and LVESD<4cm) and only 24% had elevated LV filling pressures (E/e'≥13). Indexed LV wall stress-to-LVEDD, relative wall thickness and indexed LV mass-to-BSA were similar amongst males-females, although males had higher mean blood pressure (94 Vs. 90, P=0.02) . The peak global longitudinal strain (GLS) was -25.2% ± 3.3% and the mid-ventricular circumferential and radial strains were -33.5%±6.7% and 56%±25% respectively. Ventricular ectopy was present in 24.5% of patients and only 17% had atrial fibrillation (Afib) despite the significantly dilated left atria (mean LAVi 70±26.6 ml/m 2 ). The median LV mechanical dispersion was 40msec (IQR 30.7-56.5) but increased significantly with ventricular ectopy (65msec, P<0.01) and further influenced by concomitant Afib (p=0.001 for 2-factor interaction). Diastolic LV function did not correlate with dispersion (r=0.02 and 0.01 for E/A and E/e', P=NS) but was associated with the duration of LV diastolic filling (mean 502±140msec; r=0.2, P=0.004). Interpapillary radial strain delay was noted in the study cohort (mean delay 52.8msec, range 0-335msec) while intepapillary activation delay was manifested with concomitant ventricular ectopy (mean time-to-peak LS delay 57.5±48msec). Conclusions: Left ventricular dyssynchrony manifested by increased mechanical dispersion and imbalanced interpapillary mechanics are observed prior to overt chamber remodeling in significant degenerative MR and is associated with ventricular ectopy. Further studies are needed to assess the related clinical implications and potential impact on risk stratification in this patient group.

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P321 Cardiotoxicity related to cancer therapy. is the study of mechanical dispersion an additional value?

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez319.174 ◽

2020 ◽

Vol 21 (Supplement_1) ◽

Author(s):

F Privitera ◽

V Losi ◽

I P Monte

Keyword(s):

Ventricular Dysfunction ◽

Myocardial Dysfunction ◽

Global Longitudinal Strain ◽

Treated Group ◽

Left Ventricular ◽

Lv Function ◽

Breast Cancer Chemotherapy ◽

Mechanical Dispersion ◽

Group 2 ◽

Group 1

Abstract Myocardial dysfunction are the most concerning cardiovascular complications of cancer therapies with a poor prognosis, so it’s critical to detect subclinical cardiac abnormalities in order to start cardioprotective therapy early or increased surveillance frequency. Global longitudinal strain (GLS) by echocardiography is an excellent tool for assessing regional and global left ventricular (LV) function. Mechanical dispersion (MD) reflects heterogeneous myocardial contraction, evaluated in many cardiopathies. We evaluated subclinical myocardial dysfunction by GLS and MD using 2D Speckle-tracking Echo, in order to established if MD could be a predictor of ventricular dysfunction in the field of Cardiotoxicity (CTX). Were enrolled 42 women with breast cancer chemotherapy-treated and underwent to Echo evaluation during 3- and 6-months follow-up, compared to evaluation performed before starting chemotherapy (T0). Depending on chemotherapy type were identified 2 groups: Anthracyclines ± Taxol treated (group 1) and Anti-HER2 treated (group 2). CTX diagnosis was made according ESC criteria: LVEF < 50%, LVEF decrease >10% or GLS decrease >15% compared to previous check. At three months, 28% patients (p < 0,009) developed CTX and, in this group, MD was significantly increased compared to T0 (64,4ms ± 18,6 vs 43,48ms ± 7.88 p < 0,001). This finding was consistent regardless treatment group: 65,2 ms ± 5,30 (p < 0.0001) in group 1 and 63,14 ms ± 36,40 (p 0.02) in group 2. Also, GLS was significantly changed: in CTX patients decreased of 9% compared to T0 (p 0.02), but this finding was consistent in group 1 in which GLS decreased of 18% (p 0,01), while in group 2 decrease only of 5% and wasn’t statistically significant compared to T0 (p = 0,3). These patients were treated by beta-blockers or ACE-inhibitors. At six months there was a normalization of MD value (47.7 ± 15.97 ms in CTX group) that was not statistically significant compared to T0 (p = 0,2) and we have interpreted as consequence of positive effect induced by cardioprotective therapy. We believe that MD is a predictor of ventricular dysfunction earlier than GLS during Anti-HER2 treatment, so in this field MD could integrates information obtained from GLS about subclinical dysfunction.

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Left ventricular mechanical dispersion predicts arrhythmic risk in mitral valve prolapse

Heart ◽

10.1136/heartjnl-2018-314269 ◽

2019 ◽

Vol 105 (14) ◽

pp. 1063-1069 ◽

Cited By ~ 13

Author(s):

Simon Ermakov ◽

Radhika Gulhar ◽

Lisa Lim ◽

Dwight Bibby ◽

Qizhi Fang ◽

...

Keyword(s):

Mitral Valve ◽

Ejection Fraction ◽

Myocardial Fibrosis ◽

Mitral Valve Prolapse ◽

Longitudinal Strain ◽

Global Longitudinal Strain ◽

Left Ventricular ◽

Peak Strain ◽

Mechanical Dispersion ◽

Lv Ejection Fraction

ObjectiveBileaflet mitral valve prolapse (MVP) with either focal or diffuse myocardial fibrosis has been linked to ventricular arrhythmia and/or sudden cardiac arrest. Left ventricular (LV) mechanical dispersion by speckle-tracking echocardiography (STE) is a measure of heterogeneity of ventricular contraction previously associated with myocardial fibrosis. The aim of this study is to determine whether mechanical dispersion can identify MVP at higher arrhythmic risk.MethodsWe identified 32 consecutive arrhythmic MVPs (A-MVP) with a history of complex ventricular ectopy on Holter/event monitor (n=23) or defibrillator placement (n=9) along with 27 MVPs without arrhythmic complications (NA-MVP) and 39 controls. STE was performed to calculate global longitudinal strain (GLS) as the average peak longitudinal strain from an 18-segment LV model and mechanical dispersion as the SD of the time to peak strain of each segment.ResultsMVPs had significantly higher mechanical dispersion compared with controls (52 vs 42 ms, p=0.005) despite similar LV ejection fraction (62% vs 63%, p=0.42) and GLS (−19.7 vs −21, p=0.045). A-MVP and NA-MVP had similar demographics, LV ejection fraction and GLS (all p>0.05). A-MVP had more bileaflet prolapse (69% vs 44%, p=0.031) with a similar degree of mitral regurgitation (mostly trace or mild in both groups) (p>0.05). A-MVP exhibited greater mechanical dispersion when compared with NA-MVP (59 vs 43 ms, p=0.0002). Mechanical dispersion was the only significant predictor of arrhythmic risk on multivariate analysis (OR 1.1, 95% CI 1.02 to 1.11, p=0.006).ConclusionsSTE-derived mechanical dispersion may help identify MVP patients at higher arrhythmic risk.

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Antiarrhythmic Effect of Sacubitril-Valsartan: Cause or Consequence of Clinical Improvement?

Journal of Clinical Medicine ◽

10.3390/jcm8060869 ◽

2019 ◽

Vol 8 (6) ◽

pp. 869 ◽

Cited By ~ 2

Author(s):

António Valentim Gonçalves ◽

Tiago Pereira-da-Silva ◽

Ana Galrinho ◽

Pedro Rio ◽

Luísa Moura Branco ◽

...

Keyword(s):

Global Longitudinal Strain ◽

Left Ventricular ◽

Antiarrhythmic Effect ◽

Qtc Interval ◽

Dispersion Index ◽

Time Intervals ◽

Mechanical Dispersion ◽

Before And After ◽

Qrs Duration

Sacubitril/Valsartan (LCZ696) reduced sudden cardiac death in the PARADIGM-HF trial. However, the mechanism by which LCZ696 reduces ventricular arrhythmias remains unclear. The aim of this study was to compare electrocardiographic (ECG) parameters and mechanical dispersion index, assessed by left ventricular (LV) global longitudinal strain (GLS), before and after LCZ696 therapy. We prospectively evaluated chronic Heart Failure (HF) patients with LV ejection fraction ≤40%, despite optimal medical and device therapy, in which LCZ696 therapy was started, while no additional HF treatment was expected to change. ECG and transthoracic echocardiographic data were gathered in the week before starting LCZ696 and at six months of therapy. A semiautomated analysis of LV GLS was performed and mechanical dispersion index was defined as the standard deviation from 16 time intervals corresponding to each LV segment. Of the 42 patients, 35 completed the six month follow-up, since two patients died and five discontinued treatment for adverse events. QTc interval (451.9 vs. 426.0 ms, p < 0.001), QRS duration (125.1 vs. 120.8 ms, p = 0.033) and mechanical dispersion index (88.4 vs. 78.1 ms, p = 0.036) were significantly reduced at six months. LCZ696 therapy is associated with a reduction in QTc interval, QRS duration and mechanical dispersion index as assessed by LV GLS.

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P353 Structural, functional, and electromechanical alterations in patients with paroxysmal atrial fibrillation compared to healthy controls

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jez319.204 ◽

2020 ◽

Vol 21 (Supplement_1) ◽

Author(s):

S Trivedi ◽

L Stefani ◽

P Brown ◽

E Kizana ◽

S Kumar ◽

...

Keyword(s):

Atrial Fibrillation ◽

Paroxysmal Atrial Fibrillation ◽

Inverse Correlation ◽

Left Ventricular ◽

P Value ◽

Healthy Controls ◽

Systolic Volume ◽

Mechanical Dispersion ◽

Lv Mass ◽

Echocardiographic Parameters

Abstract Background and Methods We sought to evaluate the clinical and echocardiographic differences between healthy controls and paroxysmal atrial fibrillation (AF) patients. Clinical and echocardiographic parameters (performed in sinus rhythm) in 46 paroxysmal AF patients were compared with a departmental database of 83 health controls. Results AF patients were older and had increased body size (Table 1). 39/46 (84%) of AF patients had hypertension and 23/46 (50%) had diabetes mellitus. AF patients had increased left ventricular (LV) mass, and reduced diastolic function (lower e’ and increased E/e’ ratio) when compared to healthy controls. Left atrial (LA) volumes were significantly increased in the AF group. All strain parameters – reservoir, conduit, and contractile strain – were impaired in AF patients compared to controls. LA mechanical dispersion (MD) was significantly increased in AF patients. A ratio of indexed LA volume/LA reservoir strain was significantly higher in AF patients over controls. The duration of AF had an inverse correlation with LA reservoir strain (Fig 1) (r=–0.78; p < 0.001). Conclusions Compared to healthy controls, patients with paroxysmal AF have significant structural, functional and electromechanical alterations. LA strain is significantly impaired in paroxysmal AF and correlates with AF duration. Table 1. Echocardiographic parameters Parameter Controls (mean ± SD) AF patients (mean ± SD) P value Age (years) 48 ± 18 58 ± 14 0.001 Body surface area (m2) 1.9 ± 0.2 2 ± 0.2 0.014 LV mass (g) 178 ± 48 223 ± 68 <0.001 Average e’ velocity (cms-1) 10.3 ±2.7 8.1 ± 2.2 <0.001 E/e’ 7.4 ± 1.9 9.3 ± 3.4 0.001 Indexed LA end systolic volume (ml/m2) 27.2 ± 7.1 39.0 ± 11.6 <0.001 LA ejection fraction 55.2 ± 10.4 48.5 ± 14.0 0.007 LA functional index 43.7 ± 14.6 29.8 ± 14.3 <0.001 LA reservoir strain (%) 34.3 ± 6.8 27.9± 8.1 <0.001 LA conduit strain (%) 18.4 ± 6.2 13.5 ± 4.7 <0.001 LA contractile strain (%) 15.9 ± 3.9 14.4 ± 5.5 0.007 LA mechanical dispersion (ms) 25.8 ± 9.6 30.9 ± 11.6 0.018 Indexed LA volume / Reservoir strain ratio 0.8 ± 0.3 1.6 ± 0.9 <0.001 LV = left ventricular; LA = left atrium; SD = standard deviation Abstract P353 Figure. Fig 1. AF duration vs. Reservoir strain

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