Mortality in Patients with Acute Coronary Syndrome-A Prospective 5-Year Follow-Up Study.

Our objective was to compare long-term outcomes in patients with non-ST-elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI) between two time periods in Southern Norway. There are limited contemporary data comparing long-term follow-up after revascularization in the last decades. This prospective follow-up study consecutively included both NSTEMI and STEMI patients during two time periods, 2014-2015 and 2004-2009. Patients were followed up for a period of 5 years. The primary outcome was all-cause mortality after 1 and 5 years. A total of 539 patients with acute myocardial infarction (AMI), 316 with NSTEMI (234 included in 2014 and 82 included in 2007) and 223 with STEMI (160 included in 2014 and 63 included in 2004). Mortality after NSTEMI was high and remained unchanged during the two time periods (mortality rate at 1 year: 3.5% versus 4.9%, p = 0.50; and 5 years: 11.4% versus 14.6%, p = 0.40). Among STEMI patients, all-cause mortality at 1 year was reduced in 2014 compared to 2004 (1.3% versus 11.1%, p < 0.001; and 5 years: 7.0% versus 22.2%, p = 0.004, respectively). Time to coronary angiography in NSTEMI patients remained unchanged between 2014 and 2007 (28.2 h [IQR 18.1-46.3] versus 30.3 h [IQR 18.0-48.3], p = 0.20), while time to coronary angiography in STEMI patients was improved in 2014 compared with 2004 (2.8 h [IQR 2.0-4.8] versus 21.7 h [IQR 5.4-27.1], p < 0.001), respectively. During one decade of AMI treatment, mortality in patients with NSTEMI remained unchanged while mortality in STEMI patients decreased, both at 1 and 5 years.

Increased deformation of the left ventricle during exercise test measured by global longitudinal strain can rule out significant coronary artery disease in patients with suspected unstable angina pectoris.

BACKGROUND: Noninvasive identification of significant coronary artery disease (CAD) in patients with unstable angina pectoris (UAP) is challenging. Exercise stress testing has been used for years in patients with suspected CAD but has low diagnostic accuracy. The use of Global longitudinal strain (GLS) by speckle tracking echocardiography is a highly sensitive and reproducible parameter for detection of myocardial ischemia. Our aim was to study if identification of normal or ischemic myocardium by measurement of GLS immediately after an ordinary bicycle exercise stress testing in patients with suspected UAP could identify or rule out significant CAD. METHODS: Seventy-eight patients referred for coronary angiography from outpatient clinics and the emergency department with chest pain, inconclusive ECG and normal values of Troponin-T was included. All patients underwent echocardiographic examination at rest and immediately after maximum stress by exercise on a stationary bicycle. Significant CAD was defined by diameter stenosis > 90% by coronary angiography. In patients with coronary stenosis between 50-90%, fractional flow reserve (FFR) was measured and defined abnormal < .80. Analysis of echocardiographic data were performed blinded for angiographic data. Patients were discharged diagnosed with CAD (n = 34) or non-coronary chest pain (NCCP, n = 44). RESULTS: In patients with NCCP, GLS at rest was -21.1 ± 1.7% and -25.5 ± 2.6% at maximum stress (P < .01). In patients with CAD, GLS at rest was -16.8 ± 4.0% and remained unchanged at maximum stress (-16.6 ± 4.6%, P = .69). In patients with NCCP, LVEF was 56.1% ± 6.0 and increased to 61.8% 5.2, P < .01. In CAD patients, LVEF at rest was 54.7% ± 8.6 and increased to 58.2% ± 9.5 during stress, P = .16. In NCCP patients, Wall Motion Score index decreased .02 ± .07, P = .03 during stress and was without significant changes in patients with CAD. Area under the curve (AUC) for distinguishing CAD for was .97 (.95-1.00), .63 (.49-.76), and .71 (.59-.83) for GLS, LVEF, and WMSi, respectively. CONCLUSION: In patients with suspected UAP, increased deformation of the left ventricle measured by GLS immediately after exercise stress testing identified normal myocardium without CAD. Reduced LV contractile function by GLS without increase after exercise identified significant CAD.

Strain echocardiography improves prediction of arrhythmic events in ischemic and non-ischemic dilated cardiomyopathy.

BACKGROUND: Recent evidence suggests that an implantable cardioverter defibrillator (ICD) in non-ischemic cardiomyopathy (NICM) may not offer mortality benefit. We aimed to investigate if etiology of heart failure and strain echocardiography can improve risk stratification of life threatening ventricular arrhythmia (VA) in heart failure patients. METHODS: This prospective multi-center follow-up study consecutively included NICM and ischemic cardiomyopathy (ICM) patients with left ventricular ejection fraction (LVEF) <40%. We assessed LVEF, global longitudinal strain (GLS) and mechanical dispersion (MD) by echocardiography. Ventricular arrhythmia was defined as sustained ventricular tachycardia, sudden cardiac death or appropriate shock from an ICD. RESULTS: We included 290 patients (67 ± 13 years old, 74% males, 207(71%) ICM). During 22 ± 12 months follow up, VA occurred in 32(11%) patients. MD and GLS were both markers of VA in patients with ICM and NICM, whereas LVEF was not (p = 0.14). MD independently predicted VA (HR: 1.19; 95% CI 1.08-1.32, p = 0.001), with excellent arrhythmia free survival in patients with MD <70 ms (Log rank p < 0.001). Patients with NICM and MD <70 ms had the lowest VA incidence with an event rate of 3%/year, while patients with ICM and MD >70 ms had highest VA incidence with an event rate of 16%/year. CONCLUSION: Patients with NICM and normal MD had low arrhythmic event rate, comparable to the general population. Patients with ICM and MD >70 ms had the highest risk of VA. Combining heart failure etiology and strain echocardiography may classify heart failure patients in low, intermediate and high risk of VA and thereby aid ICD decision strategies.

Long-term ECG recording: findings and implications. / Funn og konsekvenser ved langtidsregistrering av EKG.

BACKGROUND: Long-term ECG recording is a commonly used test. However, there are no clear guidelines on who should be examined using this method, and we lack an overview of the results of testing and their therapeutic implications. MATERIAL AND METHOD: All long-term ECG recordings performed at Sørlandet Hospital Arendal in the period 2017-18 were included in the study. The tests were identified by searching the medical records system for relevant procedure codes, and all medical records related to the test were subsequently reviewed. Patient characteristics, referrer, indication, results, further assessment, and treatment were recorded. RESULTS: A total of 1 262 long-term ECG recordings were performed at Sørlandet Hospital Arendal in the period 2017-18. The median age of those tested was 60 years, and 48 % of tests were performed in women. A total of 253 (20 %) recordings revealed arrhythmias and 168 (13 %) had therapeutic implications. For patients without known heart disease or a history of stroke (n = 619 (49 %)), the test had therapeutic implications in 32 (5 %) cases. INTERPRETATION: Long-term ECG recording was often used to test patient populations with limited cardiac arrhythmia, and the results rarely had therapeutic implications. The findings of the study may indicate that long-term ECG recording should be used to a greater extent in patients for whom positive findings would have therapeutic and prognostic implications, such as those in whom stroke prophylaxis would be indicated if they were found to have atrial fibrillation.

Global longitudinal strain is a more reproducible measure of left ventricular function than ejection fraction regardless of echocardiographic training.

BACKGROUND: Left ventricular ejection fraction (LVEF) is an established method for evaluation of left ventricular (LV) systolic function. Global longitudinal strain (GLS) by speckle tracking echocardiography seems to be an important additive method for evaluation of LV function with improved reproducibility compared with LVEF. Our aim was to compare reproducibility of GLS and LVEF between an expert and trainee both as echocardiographic examiner and analyst. METHODS: Forty-seven patients with recent Acute Coronary Syndrome (ACS) underwent echocardiographic examination by both an expert echocardiographer and a trainee. Both echocardiographers, blinded for clinical data and each other's findings, performed image analysis for evaluation of intra- and inter- observer variability. GLS was measured using speckle tracking echocardiography. LVEF was calculated by Simpson's biplane method. RESULTS: The trainee measured a GLS of - 19.4% (±3.5%) and expert - 18.7% (±3.2%) with an Intra class correlation coefficient (ICC) of 0.89 (0.74-0.95). LVEF by trainee was 50.3% (±8.2%) and by expert 53.6% (±8.6%), ICC coefficient was 0.63 (0.32-0.80). For GLS the systematic difference was 0.21% (- 4.58-2.64) vs. 4.08% (- 20.78-12.62) for LVEF. CONCLUSION: GLS is a more reproducible method for evaluation of LV function than LVEF regardless of echocardiographic training.

Early assessment of strain echocardiography can accurately exclude significant coronary artery stenosis in suspected non-ST-segment elevation acute coronary syndrome.

BACKGROUND: Many patients with suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) do not have significant coronary artery disease. The current diagnostic approach of repeated electrocardiography and cardiac biomarker assessment requires observation for >6 to 12 hours. This strategy places a heavy burden on hospital facilities. The objective of this study was to investigate whether myocardial strain assessment by echocardiography could exclude significant coronary artery stenosis in patients presenting with suspected NSTE-ACS. METHODS: Sixty-four patients presenting to the emergency department with suspected NSTE-ACS without known coronary artery disease, inconclusive electrocardiographic findings, and normal cardiac biomarkers at arrival were enrolled. Twelve-lead electrocardiography, troponin T assay, and echocardiography were performed at arrival, and all patients underwent coronary angiography. Significant coronary stenosis was defined as >50% luminal narrowing. Global myocardial peak systolic longitudinal strain was measured using speckle-tracking echocardiography. Left ventricular ejection fraction and wall motion score index were calculated. RESULTS: No significant stenosis in any coronary artery was found in 35 patients (55%). Global peak systolic longitudinal strain was superior to conventional echocardiographic parameters in distinguishing patients with and without significant coronary artery stenosis (area under the curve, 0.87). Sensitivity and specificity were calculated as 0.93 and 0.78, respectively, and positive predictive value and negative predictive value as 0.74 and 0.92, respectively. Feasibility of the strain measurements was excellent, with 97% of segments analyzed. CONCLUSIONS: Myocardial strain by echocardiography may facilitate the exclusion of significant coronary artery stenosis among patients presenting with suspected NSTE-ACS with inconclusive electrocardiographic findings and normal cardiac biomarkers.

Strain echocardiography improves risk prediction of ventricular arrhythmias after myocardial infarction.

OBJECTIVES: The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI). BACKGROUND: Prediction of ventricular arrhythmias after MI is challenging. Left ventricular ejection fraction (LVEF) <35% is the main parameter for selecting patients for implantable cardioverter-defibrillator therapy. METHODS: In this prospective, multicenter study, 569 patients >40 days after acute MI were included, 268 of whom had ST-segment elevation MIs and 301 non-ST-segment elevation MIs. By echocardiography, global strain was assessed as average peak longitudinal systolic strain from 16 left ventricular segments. Time from the electrocardiographic R-wave to peak negative strain was assessed in each segment. Mechanical dispersion was defined as the standard deviation from these 16 time intervals, reflecting contraction heterogeneity. RESULTS: Ventricular arrhythmias, defined as sustained ventricular tachycardia or sudden death during a median 30 months (interquartile range: 18 months) of follow-up, occurred in 15 patients (3%). LVEFs were reduced (48 ± 17% vs. 55 ± 11%, p < 0.01), global strain was markedly reduced (-14.8 ± 4.7% vs. -18.2 ± 3.7%, p = 0.001), and mechanical dispersion was increased (63 ± 25 ms vs. 42 ± 17 ms, p < 0.001) in patients with arrhythmias compared with those without. Mechanical dispersion was an independent predictor of arrhythmic events (per 10-ms increase, hazard ratio: 1.7; 95% confidence interval: 1.2 to 2.5; p < 0.01). Mechanical dispersion and global strain were markers of arrhythmias in patients with non-ST-segment elevation MIs (p < 0.05 for both) and in those with LVEFs >35% (p < 0.05 for both), whereas LVEF was not (p = 0.33). A combination of mechanical dispersion and global strain showed the best positive predictive value for arrhythmic events (21%; 95% confidence interval: 6% to 46%). CONCLUSIONS: Mechanical dispersion by strain echocardiography predicted arrhythmic events independently of LVEF in this prospective, multicenter study of patients after MI. A combination of mechanical dispersion and global strain may improve the selection of patients after MI for implantable cardioverter-defibrillator therapy, particularly in patients with LVEFs >35% who did not fulfill current implantable cardioverter-defibrillator indications.

Mean strain throughout the heart cycle by longitudinal two-dimensional speckle-tracking echocardiography enables early prediction of infarct size.

BACKGROUND: Early prediction of infarct size directs therapy in patients with acute myocardial infarction (AMI). Global strain by echocardiography describes myocardial deformation and correlates with infarct size. However, peak strain measures deformation at a single time point, whereas ischemia and necrosis influence deformation throughout the heart cycle. It was hypothesized that the measurement of myocardial deformation throughout the heart cycle by mean strain is a more comprehensive expression of myocardial deformation. The aim of this study was to assess the ability of mean strain to predict infarct size and to identify large infarctions at admission and after revascularization in patients with AMI. METHODS: Seventy-six patients with AMI were included. Echocardiographic measurements were performed at admission and after revascularization. Myocardial strain was calculated using speckle-tracking echocardiography. Infarct size was measured using contrast-enhanced magnetic resonance imaging ≥3 months after revascularization. RESULTS: There were significant correlations between infarct size and longitudinal global mean strain, longitudinal global strain, and left ventricular ejection fraction (P < .0001), both at admission and after revascularization. The correlations improved after revascularization. Longitudinal global mean strain had the best correlation with infarct size and the best ability to discriminate between different infarct size categories. At admission, a cutoff value of -7.6 had 89% sensitivity, 88% specificity, and an area under the receiver operating characteristic curve of 0.92 for the identification of large infarctions. Prediction of infarct size improved for all parameters after revascularization. CONCLUSIONS: Longitudinal global mean strain provides improved early prediction of infarct size in patients with AMI compared with longitudinal global strain and left ventricular ejection fraction.

The advantage of global strain compared to left ventricular ejection fraction to predict outcome after acute myocardial infarction.

The aim of the study was to compare the ability of global strain and left ventricular ejection fraction (LVEF) to predict outcome after acute myocardial infarction (AMI). Left ventricular (LV) function was measured using strain by Doppler and LVEF in 77 patients. Measurements were performed at admission and after 10 ± 5 days. Outcome was measured as the combined end point of cardiac death, reinfarction and hospitalization for heart failure, unstable angina or life threatening arrhythmia. The patients were followed for 3.29 ± 1.59 years (range 0-5.22 years) and 17 cardiac events were registered. The cutoff value of LVEF was 44% for optimal prediction of outcome. We used LVEF ≤ 44% vs. > 44% and the corresponding global strain value ≥ -15.6% vs. < -15.6% to predict cumulative event-free survival. Both methods significantly predicted cardiac combined events at admittance and after 10 days with no difference. After 10 days, however, global strain remained the only significant predictor of outcome in a multivariate logistic regression model (P < 0.0001, odds ratio 1.79). Interobserver reproducibility measured as intraclass correlation was better for global strain than for LVEF (0.92 vs. 0.71). In conclusion, the measurement of global strain in patients with AMI may predict cardiac combined events to the same extent as LVEF in the acute phase and superior to LVEF after 10 days. In addition, global strain demonstrates better interobserver reproducibility and may become an improved bedside tool to evaluate LV function as a prognostic marker after AMI.

Acute coronary occlusion in non-ST-elevation acute coronary syndrome: outcome and early identification by strain echocardiography.

OBJECTIVES: To compare infarct size and left ventricular ejection fraction in patients with non-ST-elevation myocardial infarction (NSTEMI) with and without acute coronary occlusions, and determine if myocardial strain by speckle-tracking echocardiography can identify acute occlusions in patients presenting with non-ST-elevation acute coronary syndrome (NSTE-ACS). METHODS: 111 patients with suspected NSTE-ACS were enrolled shortly after admittance. Echocardiographic measurements were performed a median of 1 h (interquartile range 0.5-4) after admittance, and coronary angiography 36 ± 21 h after onset of symptoms. Territorial longitudinal and circumferential strain was calculated based on the perfusion territories of the three major coronary arteries in a 16-segment model of the left ventricle, and compared with traditional echocardiographic parameters. Long-term follow-up was by echocardiography and contrast-enhanced magnetic resonance imaging (ceMRI). RESULTS: Patients with NSTEMI due to acute coronary occlusion had higher peak troponin T than patients with NSTEMI without acute occlusions (4.9 ± 4.7 vs 0.9 ± 1.1 µg/l, p<0.001), larger infarct size by ceMRI (13 ± 8% vs 3 ± 3%, p<0.001) and poorer left ventricular ejection fraction (48 ± 6% vs 57 ± 6%, p<0.001) at follow-up. Territorial circumferential strain was the best parameter for predicting acute coronary occlusion. A territorial circumferential strain value >-10.0% had 90% sensitivity, 88% specificity and area under the curve=0.93 for identification of acute occlusions. CONCLUSIONS: Patients with NSTEMI due to acute coronary occlusions develop larger infarcts and more impaired left ventricular function than patients with NSTEMI without occlusions, regardless of infarct-related territory. Territorial circumferential strain by echocardiography enables very early identification of acute coronary occlusions in patients with NSTE-ACS and may be used for detection of patients requiring urgent revascularisation.

Changes of myocardial function in patients with non-ST-elevation acute coronary syndrome awaiting coronary angiography.

The optimal timing of coronary angiography in patients with non-ST elevation (NSTE) acute coronary syndromes (ACS) is debated. American Heart Association and American College of Cardiology guidelines recommend an early invasive strategy <12 to 48 hours after the onset of symptoms. The objective of the present study was to determine possible changes in myocardial function in patients with NSTE ACS awaiting coronary angiography. One hundred two patients with suspected NSTE ACS were enrolled, including 56 with NSTE myocardial infarctions (NSTEMIs), 23 with unstable angina pectoris, and 23 with noncoronary chest pain. Global and regional myocardial function was measured as longitudinal and circumferential strain using speckle-tracking echocardiography. Measurements were performed at admission and immediately before coronary angiography (30 + or - 16 hours after admission). In patients with NSTEMIs, there was deterioration in longitudinal global strain from -16.1 + or - 2.6% at admission to -15.0 + or - 2.6% before coronary angiography (p <0.001). This was due to deterioration in longitudinal strain in the territory supplied by the infarct-related artery from -14.2 + or - 4.2% to -12.0 + or - 4.1% (p <0.001). Patients with NSTEMIs due to acute coronary occlusion underwent prominent worsening in longitudinal and circumferential strains (-15.7 + or - 2.9% to -13.9 + or - 3.0%, p = 0.001, and -16.7 + or - 4.0% to -15.0 + or - 3.9%, p = 0.01, respectively) compared to patients with NSTEMIs without occlusions. There were no changes in strain in patients with unstable angina pectoris or noncoronary chest pain. In patients with NSTEMIs without acute coronary occlusions, myocardial function improved after revascularization, whereas patients with acute occlusions demonstrated no improvement. In conclusion, myocardial function deteriorates in patients with NSTEMIs awaiting coronary angiography. Patients with acute coronary occlusions have the most prominent deterioration, and this subgroup shows no recovery of function after revascularization.

Comparison of left ventricular ejection fraction and left ventricular global strain as determinants of infarct size in patients with acute myocardial infarction.

BACKGROUND: The aim was to compare left ventricular ejection fraction (LVEF) and left ventricular (LV) global strain by speckle tracking as predictors of final infarct size. METHODS: LV global strain and LVEF by echocardiography were assessed in the acute phase and after revascularization in 39 patients with ST-elevation myocardial infarction treated with thrombolysis. RESULTS: After revascularization, global strain and LVEF correlated well with infarct size measured by contrast-enhanced cardiac magnetic resonance. A cutoff value of -15.0% for global strain had a sensitivity of 90% and a specificity of 86% to identify myocardial infarcts larger than 20%. Interobserver variability, expressed by intraclass correlation coefficients, for global strain and LVEF was 0.91 and 0.72, respectively. CONCLUSIONS: LV global strain is a more precise diagnostic predictor of large infarcts compared with LVEF and is more reproducible. Global strain measured after revascularization demonstrates advantages over LVEF in the evaluation of LV injury in patients with ST-elevation myocardial infarction.

Diagnostic capability and reproducibility of strain by Doppler and by speckle tracking in patients with acute myocardial infarction.

OBJECTIVES: The objective of the present study was to investigate the ability of strain by Doppler and by speckle tracking echocardiography in the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) to diagnose left ventricular (LV) infarct size. Furthermore, we wanted to study at which time during the cardiac cycle strain should be measured. BACKGROUND: The assessment of regional myocardial dysfunction may be an important diagnostic tool in the evaluation of acute myocardial injury. METHODS: Strain by Doppler and speckle tracking were assessed in the acute phase and after 10 days in 36 patients (61 +/- 11 years) with STEMI treated with thrombolysis. In a 16-segment model of the LV, peak systolic, end systolic, and peak negative strain were validated against the corresponding myocardial segments measured by contrast-enhanced cardiac magnetic resonance. The 16 segments were averaged to assess LV global longitudinal strain. In addition, 6 segments were analyzed from parasternal short-axis recordings at the papillary muscle level to assess circumferential strain. Reproducibility was tested in 20 patients. RESULTS: The different segmental strain assessments separated significantly (p < 0.0001) between the different levels of infarct transmurality regardless of method, with better reproducibility for speckle strain. Circumferential strain separated better than longitudinal strain. With a cutoff value of -13.3% for segmental circumferential strain, sensitivity was 80% and specificity was 74% for prediction of transmural infarction. The LV global strain showed a good correlation with LV infarct size, with the best correlation for LV global peak systolic speckle strain (beta = 0.76, p < 0.0001). CONCLUSIONS: On a segmental level, circumferential strain separated transmural from subendocardial necrosis better than longitudinal strain in the acute phase in patients with STEMI. Our findings suggest that in the acute phase in patients treated with thrombolysis, LV global peak systolic speckle strain should be the preferred method for predicting final LV infarct size.