Mads Ersbøll

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.

Clinical characteristics and major comorbidities in heart failure patients more than 85 years of age compared with younger age groups

Heart failure (HF) is increasingly prevalent among the growing number of elderly people, but not well studied. We sought to evaluate disease pattern and importance of prognostic factors among very elderly patients with HF.

The role of sarcomere gene mutations in patients with idiopathic dilated cardiomyopathy

We investigated a Danish cohort of 31 unrelated patients with idiopathic dilated cardiomyopathy (IDC), to assess the role that mutations in sarcomere protein genes play in IDC. Patients were genetically screened by capillary electrophoresis single strand conformation polymorphism and subsequently by bidirectional DNA sequencing of conformers in the coding regions of MYH7, MYBPC3, TPM1, ACTC, MYL2, MYL3, TNNT2, CSRP3 and TNNI3. Eight probands carried disease-associated genetic variants (26%). In MYH7, three novel mutations were found; in MYBPC3, one novel variant and two known mutations were found; and in TNNT2, a known mutation was found. One proband was double heterozygous. We find evidence of phenotypic plasticity: three mutations described earlier as HCM causing were found in four cases of IDC, with no history of a hypertrophic phase. Furthermore, one pedigree presented with several cases of classic DCM as well as one case with left ventricular non-compaction. Disease-causing sarcomere gene mutations were found in about one-quarter of IDC patients, and seem to play an important role in the causation of the disease. The genetics is as complex as seen in HCM. Thus, our data suggest that a genetic work-up should include screening of the most prominent sarcomere genes even in the absence of a family history of the disease.

Early diastolic strain rate in relation to systolic and diastolic function and prognosis in acute myocardial infarction: a two-dimensional speckle-tracking study

AIMS Diastolic dysfunction in acute myocardial infarction (MI) is associated with adverse outcome. Recently, the ratio of early mitral inflow velocity (E) to global diastolic strain rate (esr) has been proposed as a marker of elevated LV filling pressure. However, the prognostic value of this measure has not been demonstrated in a large-scale setting when existing parameters of diastolic function are known. We hypothesized that the E/esr ratio would be independently associated with an adverse outcome in patients with MI. METHODS AND RESULTS We prospectively included patients with MI and performed echocardiography with comprehensive diastolic evaluation including E/esr. The relationship between E/esr and the primary composite endpoint (all-cause mortality, hospitalization for heart failure (HF), stroke, and new onset atrial fibrillation) was analysed with Cox models. A total of 1048 patients (mean age 63 ± 12, 73% male) were included and 142 patients (13.5%) reached the primary endpoint (median follow-up 29 months). A significant prognostic value was found for E/esr [hazard ratio (HR) per 1 unit change: 2.36, 95% confidence interval (CI): 2.02-2.75, P < 0.0001]. After multivariable adjustment E/esr remained independently related to the combined endpoint (HR per 1 unit change, 1.50; CI: 1.05-2.13, P = 0.02). The prognostic value of E/esr was driven by mortality (HR per 1 unit change, 2.52; CI: 2.09-3.04, P < 0.0001) and HF admissions (HR per 1 unit change, 2.79; CI: 2.23-3.48, P < 0.0001). CONCLUSION Deformation-based E/esr contributes important information about global myocardial relaxation superior to velocity-based analysis and is independently associated with the outcome in acute MI.

The prognostic value of left atrial peak reservoir strain in acute myocardial infarction is dependent on left ventricular longitudinal function and left atrial size.

Background—Peak atrial longitudinal strain (PALS) during the reservoir phase has been proposed as a measure of left atrium function in a range of cardiac conditions, with the potential for added pathophysiological insight and prognostic value. However, no studies have assessed the interrelation of PALS and left ventricular longitudinal strain (global longitudinal strain) in large-scale populations in regard to prognosis. Methods and Results—We prospectively included 843 patients (mean age 62.1±11.8; 74% male) with acute myocardial infarction and measured global longitudinal strain, left atrium volumes, and PALS within 48 hours of admission. PALS was related to a composite outcome of death and heart failure hospitalization. Reduced PALS was associated with hypertension, diabetes mellitus, and Killip class >1 (P<0.05 for all). Reduced PALS was associated with impairment of all measures of left ventricular systolic and diastolic function, and the correlation between global longitudinal strain and PALS was highly significant (P<0.001; r=–0.71). During follow-up (median 23.0 months Q1–Q3, 16.8–26.0), a total of 76 patients (9.0%) reached the composite end point of which 47 patients died (5.6%), and 29 patients were hospitalized for heart failure (3.4%). PALS was significantly associated with outcome (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.85–0.90; P<0.001); however, no independent effect of PALS (HR, 1.00; 95% CI, 0.94–1.05; P=0.87) was found when adjusting for global longitudinal strain (HR, 1.20; 95% CI, 1.09–1.33; P<0.001), maximum left atrium volume before mitral valve opening (HR, 1.02; 95% CI, 1.01–1.04; P=0.006), and age (HR, 1.06; 95% CI, 1.03–1.08; P<0.001). Conclusions—PALS provides a composite measure of left ventricular longitudinal systolic function and maximum left atrium volume before mitral valve opening, and as such contains no added information when these readily obtained measures are known.

Early Echocardiographic Deformation Analysis for the Prediction of Sudden Cardiac Death and Life-Threatening Arrhythmias After Myocardial Infarction

OBJECTIVES This study sought to hypothesize that global longitudinal strain (GLS) as a measure of infarct size, and mechanical dispersion (MD) as a measure of myocardial deformation heterogeneity, would be of incremental importance for the prediction of sudden cardiac death (SCD) or malignant ventricular arrhythmias (VA) after acute myocardial infarction (MI). BACKGROUND SCD after acute MI is a rare but potentially preventable late complication predominantly caused by malignant VA. Novel echocardiographic parameters such as GLS and MD have previously been shown to identify patients with chronic ischemic heart failure at increased risk for arrhythmic events. Risk prediction during admission for acute MI is important because a majority of SCD events occur in the early period after hospital discharge. METHODS We prospectively included patients with acute MI and performed echocardiography, with measurements of GLS and MD defined as the standard deviation of time to peak negative strain in all myocardial segments. The primary composite endpoint (SCD, admission with VA, or appropriate therapy from a primary prophylactic implantable cardioverter-defibrillator [ICD]) was analyzed with Cox models. RESULTS A total of 988 patients (mean age: 62.6 ± 12.1 years; 72% male) were included, of whom 34 (3.4%) experienced the primary composite outcome (median follow-up: 29.7 months). GLS (hazard ratio [HR]: 1.38; 95% confidence interval [CI]: 1.25 to 1.53; p < 0.0001) and MD (HR/10 ms: 1.38; 95% CI: 1.24 to 1.55; p < 0.0001) were significantly related to the primary endpoint. GLS (HR 1.24; 95% CI: 1.10 to 1.40; p = 0.0004) and MD (HR/10 ms: 1.15; 95% CI: 1.01 to 1.31; p = 0.0320) remained independently prognostic after multivariate adjustment. Integrated diagnostic improvement (IDI) and net reclassification index (NRI) were significant for the addition of GLS (IDI: 4.4% [p < 0.05]; NRI: 29.6% [p < 0.05]), whereas MD did not improve risk reclassification when GLS was known. CONCLUSIONS Both GLS and MD were significantly and independently related to SCD/VA in these patients with acute MI and, in particular, GLS improved risk stratification above and beyond existing risk factors.

Sildenafil and Diastolic Dysfunction After Acute Myocardial Infarction in Patients With Preserved Ejection Fraction The Sildenafil and Diastolic Dysfunction After Acute Myocardial Infarction (SIDAMI) Trial

Background— Diastolic dysfunction is frequently seen after myocardial infarction and is characterized by a disproportionate increase in filling pressure during exercise to maintain stroke volume. We hypothesized that sildenafil would reduce filling pressure during exercise in patients with diastolic dysfunction after myocardial infarction. Methods and Results— Seventy patients with diastolic dysfunction and near normal left ventricular ejection fraction on echocardiography were randomly assigned sildenafil 40 mg thrice daily or matching placebo for 9 weeks. Before randomization and after 9 weeks of treatment patients underwent simultaneous echocardiography and right heart catheterization at rest and during exercise. Primary end point was pulmonary capillary wedge pressure, and secondary end points comprised cardiac index and pulmonary arterial pressure at rest and during exercise after 9 weeks. After 9 weeks there were no differences in pulmonary capillary wedge pressure at rest (13±4 versus 13±3 mm Hg, P=0.25) or at peak exercise (35±8 mm Hg versus 31±7 mm Hg, P=0.07). However, with treatment cardiac index increased at rest (P=0.006) and peak exercise (P=0.02) in the sildenafil group, and systemic vascular resistance index (resting, P=0.0002; peak exercise, P=0.007) and diastolic blood pressure (resting, P=0.005; peak exercise, P=0.02) were lower in the sildenafil group. Resting left ventricular end-diastolic volume index increased (P=0.001) within the sildenafil group but was unchanged in the placebo group. Conclusions— Sildenafil did not decrease filling pressure at rest or during exercise in post–myocardial infarction patients with diastolic dysfunction. However, there were effects on secondary end points, which require further studies. Clinical Trial Registration— URL: http://www.clinicaltrials.gov/ct2/show/NCT01046838. Unique identifier: NCT01046838.

Sex Differences in Platelet Reactivity and Cardiovascular and Psychological Response to Mental Stress in Patients With Stable Ischemic Heart Disease: Insights From the REMIT Study

BACKGROUND Although emotional stress is associated with ischemic heart disease (IHD) and related clinical events, sex-specific differences in the psychobiological response to mental stress have not been clearly identified. OBJECTIVES We aimed to study the differential psychological and cardiovascular responses to mental stress between male and female patients with stable IHD. METHODS Patients with stable IHD enrolled in the REMIT (Responses of Mental Stress-Induced Myocardial Ischemia to Escitalopram) study underwent psychometric assessments, transthoracic echocardiography, and platelet aggregation studies at baseline and after 3 mental stress tasks. Mental stress-induced myocardial ischemia (MSIMI) was defined as the development or worsening of regional wall motion abnormality, reduction of left ventricular ejection fraction (LVEF) ≥8% by transthoracic echocardiography, and/or ischemic ST-segment change on electrocardiogram during 1 or more of the 3 mental stress tasks. RESULTS In the 310 participants with known IHD (18% women, 82% men), most baseline characteristics were similar between women and men (including heart rate, blood pressure, and LVEF), although women were more likely to be nonwhite, living alone (p < 0.001), and unmarried (p < 0.001); they also had higher baseline depression and anxiety (p < 0.05). At rest, women had heightened platelet aggregation responses to serotonin (p = 0.007) and epinephrine (p = 0.004) compared with men. Following mental stress, women had more MSIMI (57% vs. 41%; p < 0.04), expressed more negative (p = 0.02) and less positive emotion (p < 0.001), and demonstrated higher collagen-stimulated platelet aggregation responses (p = 0.04) than men. Men were more likely than women to show changes in traditional physiological measures, such as blood pressure (p < 0.05) and double product. CONCLUSIONS In this exploratory analysis, we identified clear, measurable, and differential responses to mental stress in women and men. Further studies should test the association of sex differences in cardiovascular and platelet reactivity in response to mental stress and long-term outcomes. (Responses of Myocardial Ischemia to Escitalopram Treatment [REMIT]; NCT00574847).

Exercise Hemodynamics in Patients With and Without Diastolic Dysfunction and Preserved Ejection Fraction After Myocardial Infarction

Background—Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress. Methods and Results—Invasive hemodynamic exercise testing was performed in 46 patients with a recent MI and left ventricular ejection fraction >45% and in 10 healthy volunteers. MI patients were enrolled prospectively and divided into those with DD (MI+DD; left atrial volume index >34 mL/m2 and diastolic E/e′ ratio>8; n=35) and those without DD (MI–DD; left atrial volume index <34 mL/m2 and E/e′ ratio<8; n=11). All underwent a supine cycle ergometer test with simultaneous right heart catheterization and echocardiography. At rest, 10 patients in MI+DD (29%) had pulmonary capillary wedge pressure >15 (14±4 mm Hg), whereas none of the MI−DD (10±2 mm Hg) or controls (9±2 mm Hg) displayed pulmonary capillary wedge pressure elevation (P=0.03). During exercise, an abnormal rise in pulmonary capillary wedge pressure (>25 mm Hg) was observed in 94% of MI+DD (36±6 mm Hg) compared with 36% of MI−DD (24±6 mm Hg) and none of the controls (16±6 mm Hg; P<0.0001). Exercise right atrial pressure was the highest in MI+DD followed by MI−DD and control (15±5 versus 9±4 versus 7±5 mm Hg; P<0.001), whereas no difference in cardiac index was found between groups. Conclusions—In post-MI patients with preserved ejection fraction and left ventricular DD, cardiac output with exercise is maintained at the expense of substantially increased filling pressure. DD and loss of diastolic reserve may promote progression from stage B to stage C heart failure after MI.

Sildenafil and Diastolic Dysfunction After Acute Myocardial Infarction in Patients With Preserved Ejection Fraction

Background— Diastolic dysfunction is frequently seen after myocardial infarction and is characterized by a disproportionate increase in filling pressure during exercise to maintain stroke volume. We hypothesized that sildenafil would reduce filling pressure during exercise in patients with diastolic dysfunction after myocardial infarction. Methods and Results— Seventy patients with diastolic dysfunction and near normal left ventricular ejection fraction on echocardiography were randomly assigned sildenafil 40 mg thrice daily or matching placebo for 9 weeks. Before randomization and after 9 weeks of treatment patients underwent simultaneous echocardiography and right heart catheterization at rest and during exercise. Primary end point was pulmonary capillary wedge pressure, and secondary end points comprised cardiac index and pulmonary arterial pressure at rest and during exercise after 9 weeks. After 9 weeks there were no differences in pulmonary capillary wedge pressure at rest (13±4 versus 13±3 mm Hg, P=0.25) or at peak exercise (35±8 mm Hg versus 31±7 mm Hg, P=0.07). However, with treatment cardiac index increased at rest (P=0.006) and peak exercise (P=0.02) in the sildenafil group, and systemic vascular resistance index (resting, P=0.0002; peak exercise, P=0.007) and diastolic blood pressure (resting, P=0.005; peak exercise, P=0.02) were lower in the sildenafil group. Resting left ventricular end-diastolic volume index increased (P=0.001) within the sildenafil group but was unchanged in the placebo group. Conclusions— Sildenafil did not decrease filling pressure at rest or during exercise in post–myocardial infarction patients with diastolic dysfunction. However, there were effects on secondary end points, which require further studies. Clinical Trial Registration— URL: http://www.clinicaltrials.gov/ct2/show/NCT01046838. Unique identifier: NCT01046838.