Impact of left ventricular dyssynchrony early on left ventricular function after first acute myocardial infarction

Sphingolipid Metabolism Is Associated with Cardiac Dyssynchrony in Patients with Acute Myocardial Infarction

AIM

Sphingolipids are a class of complex and bioactive lipids that are involved in the pathological processes of cardiovascular disease. Fabry disease is an X-linked storage disorder that results in the pathological accumulation of glycosphingolipids in body fluids and the heart. Cardiac dyssynchrony is observed in patients with Fabry disease and left ventricular (LV) hypertrophy. However, little information is available on the relationship between plasma sphingolipid metabolites and LV remodelling after acute myocardial infarction (AMI). The purpose of this study was to assess whether the baseline plasma sphingomyelin/acid ceramidase (aCD) ratio predicts LV dyssynchrony at 6M after AMI.

METHODS

A total of 62 patients with AMI undergoing primary angioplasty were recruited. Plasma aCD and sphingomyelin were measured prior to primary angioplasty. Three-dimensional echocardiographic measurements of the systolic dyssynchrony index (SDI) were performed at baseline and 6 months of follow-up. The patients were divided into three groups according to the level of aCD and sphingomyelin above or below the median. Group 1 denotes lower aCD and lower sphingomyelin; Group 3 denotes higher aCD and higher sphingomyelin. Group 2 represents different categories of patients with aCD and sphingomyelin. Trend analysis showed a significant increase in the SDI from Group 1 to Group 3. Logistic regression analysis showed that the sphingomyelin/aCD ratio was a significant predictor of a worsening SDI at 6 months.

CONCLUSIONS

AMI patients with high baseline plasma sphingomyelin/aCD ratios had a significantly increased SDI at six months. The sphingomyelin/aCD ratio can be considered as a surrogate marker of plasma ceramide load or inefficient ceramide metabolism. Plasma sphingolipid pathway metabolism may be a new biomarker for therapeutic intervention to prevent adverse remodelling after MI.

Determinants and prognostic implications of left ventricular mechanical dispersion in aortic stenosis

AIMS

The present study aimed at investigating the association between left ventricular (LV) mechanical dispersion measured with speckle tracking echocardiography and severity of aortic stenosis (AS) and its impact on prognosis.

METHODS AND RESULTS

This retrospective study included 630 patients [age 72 (62-78) years, 61.4% men] with various grades of AS (mild AS, 19.8%; moderate AS, 37.0%; severe AS, 43.2%). LV mechanical dispersion (defined as standard deviation of time from Q/R on electrocardiogram to peak longitudinal strain in 17 LV segments) was assessed by speckle tracking echocardiography. Clinical, electrocardiographic, and echocardiographic determinants of increased LV mechanical dispersion were evaluated. During a follow-up of 107 (43-133) months, the independent association between LV mechanical dispersion and all-cause mortality (n = 302, 48%) was evaluated including aortic valve replacement as time-dependent co-variate. LV mechanical dispersion increased significantly with increasing severity of AS (mild AS, 54.5 ± 17.2 ms; moderate AS, 56.7 ± 19.3 ms; severe AS, 70.9 ± 24.3 ms; P < 0.001). Independent determinants of increased mechanical dispersion included older age (β = 0.28; P = 0.003), lower LV ejection fraction (β = -0.24; P = 0.020), smaller aortic valve area (β = -8.55; P = 0.001), larger LV mass index (β = 0.20; P < 0.001), and longer QRS duration (β = 1.12 per each 10 ms increase; P = 0.012). LV mechanical dispersion showed incremental prognostic value for all-cause mortality (hazard ratio 1.10 per each 10 ms increase, 95% confidence interval 1.04-1.15; P < 0.001).

CONCLUSION

LV mechanical dispersion assessed by speckle tracking echocardiography increases significantly with severity of AS and is significantly associated with all-cause mortality.

Left ventricular systolic dyssynchrony in patients with Kawasaki disease: a real-time three-dimensional echocardiography study

The left ventricular (LV) systolic dyssynchrony index (SDI) is an important prognostic indicator for many cardiovascular diseases; however, the characteristics of the SDI in patients with Kawasaki disease (KD) are unknown. In this study, we aimed to identify and quantify the SDI using real-time three-dimensional echocardiography (RT3DE) in KD patients during different phases. In addition, we intended to explore whether the SDI is associated with systolic dysfunction. Seventy consecutive KD patients and seventy age- and sex-matched controls were enrolled. The SDIs (percent of cardiac cycle) of 16 segments (16-SDI%) and 12 segments (12-SDI%) were calculated based on the defined standard deviation of each segment time from end diastole to the minimal systolic volume according to the 17-segment model (apex excluded). In the acute phase, the 16-SDI% and 12-SDI% were significantly higher in KD patients than in controls (4.40 ± 0.14 vs. 1.98 ± 0.12, P = 0.000; 3.55 ± 1.21 vs. 1.67 ± 0.93, P = 0.009, respectively), and patients with coronary artery aneurysm (CAA) exhibited higher 16-SDI% (P = 0.021) and 12-SDI% (P = 0.034) than patients without CAA. In the convalescent phase, patients with CAA still had higher 16-SDI% (P = 0.002) and 12-SDI% (P = 0.031) than controls, while the SDI in patients without CAA recovered to normal. The 16-SDI% was negatively correlated with the LV ejection fraction obtained from RT3DE (r = - 0.845, P = 0.000). Mechanical dyssynchrony is prevalent in KD patients during the acute phase and transient in patients without CAA, while patients with CAA still have impaired synchrony even in the convalescent phase. LV systolic dysfunction is associated with increased dyssynchrony. RT3DE is a valuable modality for identifying and quantifying dyssynchrony in KD patients.

Accuracy of three-dimensional systolic dyssynchrony and sphericity indexes for identifying early left ventricular remodeling after acute myocardial infarction

Objective:

Left ventricle (LV) geometry and dyssynchrony are associated with LV remodeling after acute myocardial infarction (AMI). The aim of this prospective study was to assess the diagnostic value of new three-dimensional echocardiography (3DE) parameters [sphericity (SI) and systolic dyssynchrony indexes (SDI)] for the prediction of LV remodeling after AMI and to compare them with two-dimensional echocardiography (2DE) parameters.

Methods:

2DE and 3DE were performed in 75 patients with AMI within 3 days from the onset of MI and 6 months later. LV remodeling was defined as a ≥15% increase in the LV end-diastolic volume (EDV) at follow-up. 3D SI was calculated by dividing EDV by the volume of a sphere whose diameter was derived from the major end-diastolic LV long axis. SDI was considered as a standard deviation of the time from cardiac cycle onset to minimum systolic volume in 16 LV segments.

Results:

LV remodeling was identified in 34 (45%) patients using the 2DE method and in 22 (29%) patients using the 3DE method. Evaluated 3DE parameters, such as EDV [area under the receiver operating characteristic (ROC) curve (AUC) 0.742, sensitivity 71%, specificity 79%], end-systolic volume (AUC 0.729, sensitivity 69%, specificity 78%), SDI (AUC 0.777, sensitivity 73%, specificity 77%), and SI, had significant prognostic value for LV remodeling. According to the AUC, the highest predictive value had 3D SI (AUC 0.957, sensitivity 90%, specificity 91%).

Conclusion:

3DE parameters, especially 3D SI and SDI, play important roles in the prediction of LV remodeling after AMI and can be used in clinical practice.

Prognostic importance of mechanical dyssynchrony in predicting heart failure development after ST-segment elevation myocardial infarction

The aim of this study is to assess the prognostic value of mechanical dyssynchrony defined as the standard deviation of the time to peak longitudinal strain (SD T2P LS) in predicting the development of heart failure (HF) after an ST-segment elevation myocardial infarction (STEMI). Three hundred and seventy-three patients were admitted with STEMI and treated with primary percutaneous coronary intervention. Left ventricular (LV) mechanical dyssynchrony was examined through speckle tracking echocardiography and defined as SD T2P LS. The association with the outcome of HF hospitalization was assessed using Cox proportional hazard models. During a median follow-up of 5.12 years, 144 patients (38.6%) were admitted due to HF. Worse dyssynchrony was associated with the outcome in unadjusted and multivariable analysis (multivariable hazard ratio 1.05, 95% confidence interval 1.00-1.10, p-value 0.039, per 10 ms increase), but not after further adjustment for LV ejection fraction (LVEF), E/e' and global longitudinal strain (GLS) (hazard ratio 1.01, 95% confidence interval 1.00-1.07, p-value 0.71, per 10 ms increase), nor in a model only adjusting for GLS (hazard ratio 1.01, 95% confidence interval 1.00-1.06, p-value 0.61, per 10 ms increase). These findings were reproduced in a competing risk analysis treating all-cause mortality as a competing risk. LV mechanical dyssynchrony, as assessed by SD T2P LS is not an independent predictor of post-STEMI HF development and mechanical dyssynchrony does not provide independent prognostic information regarding HF when GLS is known.

Prevalence, Correlates, and Prognostic Relevance of Myocardial Mechanical Dispersion as Assessed by Feature-Tracking Cardiac Magnetic Resonance After a First ST-Segment Elevation Myocardial Infarction

Postinfarction mechanical dispersion (MD), that is, the regional heterogeneity of myocardial contraction throughout the cardiac cycle, has detrimental effects on left ventricular (LV) function and is related to the occurrence of heart failure and ventricular arrhythmias. However, its prevalence, pathophysiological determinants, and clinical utility are still unknown. The aim of the present study is to clarify these issues. In total, 130 consecutive patients (mean age 60 ± 12 years, 75% male) with a first ST-segment elevation myocardial infarction (STEMI) were included. Cardiac magnetic resonance (CMR) with late gadolinium enhancement imaging was performed to assess LV function, infarct size, and microvascular obstruction. Feature-tracking analysis was applied to cine-CMR short-axis images to assess MD, defined as the SD of the time-to-peak circumferential strain of the LV segments expressed as percent cardiac cycle. For comparison purpose, 40 control subjects similar in age and gender to the STEMI group were also included. Patients were followed-up for a median of 95 months; the outcome event was defined as a composite of cardiovascular death, aborted sudden cardiac death, and hospitalization for heart failure. STEMI patients had significantly higher MD compared with controls (12.0 ± 5.35% vs 3.85 ± 0.99%, p <0.001). At multivariate analysis, heart rate (β = 0.20, p = 0.008), LV end-systolic volume index (β = 0.37, p <0.001), and infarct size (β = 0.23, p = 0.017) were significantly and independently related to MD. The outcome event occurred in 26 (20%) patients. At multivariate Cox proportional hazards analysis, MD was significantly and independently related to the outcome event (p <0.001). MD provided significant incremental value over the other clinical and CMR variables in predicting the outcome event (p <0.001 for the chi-square change). In conclusion, MD after STEMI is a marker of the extent of myocardial damage; its assessment by feature-tracking CMR provides significant, independent, and incremental long-term prognostic information.

Diastolic Dyssynchrony in Acute ST Segment Elevation Myocardial Infarction and Relationship with Functional Recovery of Left Ventricle

Background

Incidence of diastolic dyssynchrony (DD) and its impact on functional recovery of left ventricle (LV) after ST segment elevation myocardial infarction (STEMI) is not known.

Methods

Consecutive patients with STEMI who underwent successful revascularization were prospectively enrolled. Echocardiography with tissue Doppler imaging was performed within 48 hours of admission and at 6 months. LV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), ejection fraction (EF), and left atrial volume index (LAVI) were calculated. Diastolic delay was calculated from onset of QRS complex to peak of E wave in tissue Doppler image and presented as maximal temporal difference between peak early diastolic velocity of 6 basal segments of LV (TeDiff). Study patients were compared with demographically matched control group.

Results

Forty eight consecutive patients (55 ± 10 years, 88% male) and 24 controls (56 ± 6 years, 88% male) were included. TeDiff was higher in STEMI than in controls (35.9 ± 19.9 ms vs. 26.3 ± 6.8 ms, p = 0.025). Presence of DD was higher in STEMI than controls (58% vs. 33%, p = 0.046) according to calculated cut-off value (≥ 29 ms). There was no correlation between TeDiff and change in EDVI, ESVI, and LAVI at 6 months, however TeDiff and change in EF at 6 months was positively correlated (r = 0.328, p = 0.023). Patients with baseline DD experienced remodeling less frequently compared to patients without baseline DD (11% vs. 38%, p = 0.040) during follow-up.

Conclusion

STEMI disrupts diastolic synchronicity of LV. However, DD during acute phase of STEMI is associated with better recovery of LV thereafter. This suggests that DD is associated with peri-infarct stunned myocardium that is salvaged with primary intervention as well as infarct size.

Reference values for left ventricular systolic synchrony according to phase analysis of ECG-gated myocardial perfusion SPECT

BACKGROUND

The aim of this study was to define reference values for left ventricular systolic synchrony and for the volume parameters of the left ventricle using myocardial perfusion SPECT-derived phase analysis method.

METHODS

We evaluated data of 433 patients who underwent myocardial perfusion SPECT/CT during January 2012-February 2013 in Kuopio University Hospital. The final study population consisted of 52 patients (aged 42-84 years) who met the criteria: (1) no previously diagnosed cardiac disease, (2) normal ECG at rest, (3) no advanced coronary artery disease in CT and 4) normal myocardial perfusion in stress/rest myocardial perfusion SPECT/CT. The severity of mechanical dyssynchrony was assessed by phase analysis of gated myocardial SPECT at stress stage after pharmacological exercise and at rest using Quantitative Gated SPECT (QGS) software. Volume parameters of the left ventricle were also assessed.

RESULTS

The phase histogram bandwidth at rest was 28.0 [63.7] degrees (median [95th percentile]). The standard deviation of phase histogram at rest was 7.8 [26.5] degrees. Entropy at the rest study was 54.0 [63.7] %. All left ventricular dyssynchrony parameters were statistically significantly higher at stress compared to rest. There were no statistically significant differences in dyssynchrony values between men and women. In volume parameters, reference values in male were expectedly higher than in female. Cardiac output did not differ significantly between genders.

CONCLUSION

In subjects without signs of cardiac diseases, the left ventricular systolic function is well synchronized. Phase analysis measurement does not depend on gender, age, BMI or blood pressure, but the values of dyssynchrony parameters increase during pharmacological stress.

Predictors of ventricular remodelling in patients with reperfused acute myocardial infarction and left ventricular dysfunction candidates for bone marrow cell therapy: insights from the BONAMI trial

PURPOSE

Few data are available regarding the relation of left ventricular (LV) mechanical dyssynchrony to remodelling after acute myocardial infarction (MI) and stem cell therapy. We evaluated the 1-year time course of both LV mechanical dyssynchrony and remodelling in patients enrolled in the BONAMI trial, a randomized, multicenter controlled trial assessing cell therapy in patients with reperfused MI.

METHODS

Patients with acute MI and ejection fraction (EF) ≤ 45 % were randomized to cell therapy or to control and underwent thallium single-photon emission computed tomography (SPECT), radionuclide angiography, and echocardiography at baseline, 3 months, and 1 year. Eighty-three patients with a comprehensive 1-year follow-up were included. LV dyssynchrony was assessed by the standard deviation (SD) of the LV phase histogram using radionuclide angiography. Remodelling was defined as a 20 % increase in LV end-systolic volume index (LVESVI) at 1 year.

RESULTS

At baseline, LVEF, wall motion score index, and perfusion defect size were significantly impaired in the 43 patients (52 %) with LV remodelling (all p < 0.001), without significant increase in LV mechanical dyssynchrony. During follow-up, there was a progressive increase in LV SD (p = 0.01). Baseline independent predictors of LV remodelling were perfusion SPECT defect size (p = 0.001), LVEF (p = 0.01) and a history of hypertension (p = 0.043). Bone marrow cell therapy did not affect the time-course of LV remodelling and dyssynchrony.

CONCLUSIONS

LV remodelling 1 year after reperfused MI is associated with progressive LV dyssynchrony and is related to baseline infarct size and ejection fraction, without impact of cell therapy on this process.

Prognostic significance of NT-proBNP, 3D LA volume and LV dyssynchrony in patients with acute STEMI undergoing primary percutaneous intervention

OBJECTIVES

The aim of the present study was to assess the short term prognostic significance of N-terminal pro BNP (NT-proBNP), 3D left atrial volume (LAV) and left ventricular (LV) dyssynchrony in patients of acute ST-elevation myocardial infarction (STEMI) who underwent primary Percutaneous intervention (PCI).

BACKGROUND

NT-proBNP, LV dyssynchrony and LAV in patients with acute coronary syndrome have been associated with PCI outcomes and predict the short and long-term prognosis.

METHODS

This study consisted of 142 patients with a first STEMI who underwent primary PCI. Baseline echocardiographic data was collected at admission and at 6 months follow up. Left ventricular dyssynchrony was measured by tissue Doppler imaging and LAV by real time 3D-echocardiography, plasma NT-proBNP levels were estimated between 72 and 96 h of admission.

RESULTS

During study period 3 patients expired and 4 developed congestive heart failure (CHF). Baseline NT-proBNP and LV dyssynchrony correlated with LV size and LV ejection fraction (LVEF) at baseline and during follow up. Patients with higher NT-proBNP levels and higher LV dyssynchrony showed significant increase in LV size with decrease in LVEF during follow-up. Baseline Left atrial volume index (LAVI) showed significant correlation with LV size but no association with LVEF at baseline and during follow-up.

CONCLUSIONS

Higher levels of NT-proBNP and higher LV dyssynchrony can predict patients with increase in LV size, worsening of LV systolic and diastolic function during follow-up. Patients with higher NT-proBNP levels at baseline developed CHF during follow-up.

Decrease in plasma cyclophilin A concentration at 1 month after myocardial infarction predicts better left ventricular performance and synchronicity at 6 months: a pilot study in patients with ST elevation myocardial infarction

BACKGROUND

Cyclophilin A (CyPA) concentration increases in acute coronary syndrome. In an animal model of acute myocardial infarction, administration of angiotensin-converting-enzyme inhibitor was associated with lower left ventricular (LV) CyPA concentration and improved LV performance. This study investigated the relationships between changes in plasma CyPA concentrations and LV remodeling in patients with ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

We enrolled 55 patients who underwent percutaneous coronary intervention for acute STEMI. Plasma CyPA, matrix metalloproteinase (MMP), interleukin-6 and high-sensitivity C-reactive protein concentrations were measured at baseline and at one-month follow-up. Echocardiography was performed at baseline and at one-, three-, and six-month follow-up. Patients with a decrease in baseline CyPA concentration at one-month follow-up (n = 28) had a significant increase in LV ejection fraction (LVEF) (from 60.2 ± 11.5% to 64.6 ± 9.9%, p < 0. 001) and preserved LV synchrony at six months. Patients without a decrease in CyPA concentration at one month (n = 27) did not show improvement in LVEF and had a significantly increased systolic dyssynchrony index (SDI) (from 1.170 ± 0.510% to 1.637 ± 1.299%, p = 0.042) at six months. Multiple linear regression analysis showed a significant association between one-month CyPA concentration and six-month LVEF. The one-month MMP-2 concentration was positively correlated with one-month CyPA concentration and LV SDI. Conclusions : Decreased CyPA concentration at one-month follow-up after STEMI was associated with better LVEF and SDI at six months. Changes in CyPA, therefore, may be a prognosticator of patient outcome.

Prognostic Value of Speckle Tracking Echocardiography in Patients with ST-Elevation Myocardial Infarction Treated with Late Percutaneous Intervention

BACKGROUND

Left ventricular remodeling (LVr) is common after ST-segment elevation myocardial infarction (STEMI). The aim of this study was to evaluate the prognostic value of speckle tracking echocardiography (STE) for predicting LVr 6-9 months after late percutaneous coronary intervention (PCI) in patients with STEMI.

METHODS

Patients with first STEMI who accepted late PCI were enrolled. Echocardiography was performed within 48 hours of admission. Six to nine months after MI, an echocardiography examination was repeated. LVr was defined as >15% increase in LV end-systolic volume (LVESV) after 6 months.

RESULTS

One hundred and twenty-seven patients were divided into two groups: 86 patients without LVr and 41 patients with LVr. There were significant differences in the global longitudinal strain (GLS), SD of time to peak longitudinal systolic strain (longitudinal Ts-SD), longitudinal postsystolic index, radial strain (RS), and SD of time to peak radial systolic strain (Radial Ts-SD). In multivariate logistic regression analysis, the GLS(odds ratio [OR] = 0.39, 95% confidence interval [CI] = 0.26-0.57, P < 0.01), and RS(OR = 1.07, 95% CI = 1.02-1.13, P = 0.01) were determinants of LVr. A receiver operating characteristic curve showed that the GLS predicted LVr with an optimal cutoff value of -10.85 (sensitivity: 89.7%, specificity: 91.7%). During clinical follow-up for 16.9 ± 1.6 months, death or congestive heart failure developed in 12 patients (9.4%), and the baseline ejection fraction (OR = 1.91, 95% CI = 1.18-3.1, P = 0.009) and GLS (OR = 0.56, 95% CI = 0.34-0.91, P = 0.02) were independent predictors.

CONCLUSION

In patients with STEMI treated with late percutaneous coronary intervention, the GLS as measured by STE is a strong predictor of LVr and adverse events.

The prognostic value of mechanical left ventricular dyssynchrony in patients with acute coronary syndrome

Background

Echocardiography is a well-established tool for risk stratification in patients with acute coronary syndrome (ACS). ACS has significant impact on LV dyssynchrony, and detrimental effects on systolic function and long term outcome. The aims of this study were to determine whether LV dyssynchrony carries any predictive information in an unselected ACS population and to evaluate if it has any incremental value to the information given from conventional echocardiographic measurements.

Methods

The study included 227 consecutive ACS patients. Primary endpoint was the composite of death, new MI, or rehospitalisation due to heart failure. Dyssynchrony was measured as intersegmental variation of time to peak strain, the post systolic index (PSI) and myocardial performance index (MPI) with the standard deviation and difference between lowest and highest value (delta) expressing the amount of dyssynchrony. Septal-lateral delay was also tested. All dyssynchrony parameters were compared with Ejection fraction (EF).

Results

The median follow up time was 53 months. 85 patients reached the combined endpoint. Patients with and without a subsequent combined endpoint differed significantly regarding calculated SD: s and delta-value for PSI, time to peak 2D-strain and MPI but not regarding septal-lateral delay. In ROC-analysis none of the dyssynchrony parameters had larger AUC than EF. When adjusting for traditional risk factors none of the dyssynchrony parameters remained associated with outcome, whereas EF still did.

Conclusion

LV dyssynchrony seem to have significant prognostic information in patient with acute coronary syndrome but in comparison to conventional parameters such as EF there is no incremental value of this information.

Usefulness of real-time 3-dimensional echocardiography to identify and quantify left ventricular dyssynchrony in patients with Kawasaki disease

OBJECTIVES

The role of left ventricular (LV) dyssynchrony in Kawasaki disease is unknown. This study sought to establish values for real-time 3-dimensional (3D) echocardiographically derived LV dyssynchrony parameters and identify and quantify LV dyssynchrony in patients with Kawasaki disease.

METHODS

Forty patients hospitalized for Kawasaki disease were analyzed retrospectively, and 40 sex- and age-matched healthy control volunteers were also enrolled. The systolic dyssynchrony index (percentage of the cardiac cycle) from 16 and 12 LV segments on real-time 3D echocardiography was analyzed to calculate LV dyssynchrony (defined as the standard deviation of the time to reach the minimum systolic volume for 16 LV segments) according to a 17-segment model. We analyzed the 3D LV ejection fraction (LVEF), end-diastolic volume, and end-systolic volume in the patients with Kawasaki disease compared to the controls.

RESULTS

The 16-segment systolic dyssynchrony index ± SD was significantly higher in the patients with Kawasaki disease: 2.73% ± 0.96% compared to 2.01% ± 0.85% in the controls (P < .05). The 12-segment systolic dyssynchrony index in the patients with Kawasaki disease was 2.65% ± 0.93% compared to 1.98% ± 0.81% in the controls (P< .05). Patients with Kawasaki disease and an LVEF of less than 50% had a significantly higher systolic dyssynchrony index compared to patients with an LVEF of 50% or greater (2.89% ± 0.79% versus 2.26% ± 0.73%; P < .05). The LVEF measured by echocardiography was decreased in the patients with Kawasaki disease, and global systolic function was impaired. The LVEF measured by a biplane method was sufficiently related to the LVEF measured by echocardiography.

CONCLUSIONS

Real-time 3D echocardiography is a noninvasive and feasible method for identifying and evaluating LV dyssynchrony in children with Kawasaki disease. Left ventricular dyssynchrony is significantly impaired and related to LV systolic function in patients with Kawasaki disease.

Induced pluripotent stem cell intervention rescues ventricular wall motion disparity, achieving biological cardiac resynchronization post-infarction

Dyssynchronous myocardial motion aggravates cardiac pump function. Cardiac resynchronization using pacing devices is a standard-of-care in the management of heart failure. Post-infarction, however, scar tissue formation impedes the efficacy of device-based therapy. The present study tests a regenerative approach aimed at targeting the origin of abnormal motion to prevent dyssynchronous organ failure. Induced pluripotent stem (iPS) cells harbour a reparative potential, and were here bioengineered from somatic fibroblasts reprogrammed with the stemness factors OCT3/4, SOX2, KLF4, and c-MYC. In a murine infarction model, within 30 min of coronary ligation, iPS cells were delivered to mapped infarcted areas. Focal deformation and dysfunction underlying progressive heart failure was resolved prospectively using speckle-tracking imaging. Tracked at high temporal and spatial resolution, regional iPS cell transplantation restored, within 10 days post-infarction, the contractility of targeted infarcted foci and nullified conduction delay in adjacent non-infarcted regions. Local iPS cell therapy, but not delivery of parental fibroblasts or vehicle, prevented or normalized abnormal strain patterns correcting the decrease in peak strain, disparity of time-to-peak strain, and pathological systolic stretch. Focal benefit of iPS cell intervention translated into improved left ventricular conduction and contractility, reduced scar, and reversal of structural remodelling, protecting from organ decompensation. Thus, in ischaemic cardiomyopathy, targeted iPS cell transplantation synchronized failing ventricles, offering a regenerative strategy to achieve biological resynchronization.

Prevalence of dyssynchrony and relation with long-term outcome in patients after acute myocardial infarction

The impact of left ventricular (LV) dyssynchrony on the long-term outcomes of patients with acute myocardial infarction (AMI) remains unknown. The purpose of the present study was to evaluate the prevalence of LV dyssynchrony after AMI and the potential relation with adverse events. A total of 976 consecutive patients admitted with AMI treated with primary percutaneous coronary intervention were evaluated. Two-dimensional echocardiography was performed <48 hours after admission. LV dyssynchrony was assessed with speckle-tracking imaging and calculated as the time difference between the earliest and latest activated segments. Patients were followed up for the occurrence of all-cause mortality (the primary end point) or the composite secondary end point (heart failure hospitalization and all-cause mortality). Within 48 hours of admission for the index infarction, mean LV dyssynchrony was 61 ± 79 ms, and 14% of the patients demonstrated a ≥130-ms time difference, defined as significant LV dyssynchrony. During a mean follow-up period of 40 ± 17 months, 82 patients (8%) reached the primary end point. In addition, 36 patients (4%) were hospitalized for heart failure. The presence of LV dyssynchrony was associated with an increased risk for all-cause mortality and hospitalization for heart failure during long-term follow-up (adjusted hazard ratio 1.06, 95% confidence interval 1.05 to 1.08, p <0.001, per 10-ms increase). Moreover, LV dyssynchrony provided incremental value over known clinical and echocardiographic risk factors for the prediction of adverse outcomes. In conclusion, LV dyssynchrony is a strong predictor of long-term mortality and hospitalization for heart failure in a population of patients admitted with ST-segment elevation AMI treated with primary percutaneous coronary intervention.