Impaired Longitudinal Strain Research Articles

The year in cardiology 2014: imaging.

Non-invasive cardiac imaging is pivotal for the diagnosis and decision making of patients with cardiovascular diseases. Recent innovations in echocardiography, nuclear imaging, computed tomography, and cardiac magnetic resonance have provided novel pathophysiological insights that may impact on the clinical management of patients. The current review provides a summary of selected articles on technological innovations in imaging and emerging clinical applications. In 2014, many articles were published on the use of non-invasive cardiovascular imaging, including echocardiography, nuclear imaging, computed tomography (CT), and cardiac magnetic resonance (CMR) imaging. A selection of these articles is presented here. The focus is on technical innovations and emerging applications in clinical cardiology. Accumulating data have demonstrated the role of speckle tracking echocardiography (STE) in characterization left ventricular (LV) mechanics and risk stratification of patients with various cardiac diseases. Geske et al .1 demonstrated that LV septal morphology rather than genetic basis is the main determinant of regional LV strain abnormalities in patients with hypertrophic cardiomyopathy (HCM). Genotype-positive HCM patients ( n = 51) were more likely to have reverse curve morphology of the interventricular septum (59%) whereas genotype-negative patients ( n = 80) had more frequently sigmoidal septal curvature (49%). Interestingly, while global LV strain (GLS) was not significantly different between groups, regional strain analysis revealed that genotype-positive HCM patients had significantly more impaired longitudinal strain in the mid inferoseptal, basal inferoseptal, and basal anteroseptal regions compared with genotype-negative patients. When patients were divided according to genotype and LV septal morphology, LV GLS was significantly more impaired among genotype-positive HCM patients with a reverse septal curvature than in genotype-negative HCM patients with a sigmoid septal morphology ( Figure 1 ). Figure 1 Speckle tracking echocardiography …

0347: Structural myocardial dysfunction in bicuspid aortic valve disease - a speckle tracking study

of the study is to compare the longitudinal strain values in patients with bicuspid aortic valve (BAV) disease in comparison to degenerative aortic stenosis and regurgitation, and control population. Patients with BAV and tricuspid degenerative aortic valve were selected in the absence of 1) left ventricular (LV) dysfunction, 2) history of myocardial infarction and 3) atrial fibrillation. The study included 48 patients with isolated BAV (54±19 years, 25% [n=12] with significant aortic stenosis), 30 isolated degenerative aortic stenosis or regurgitation (77±11 years, 26% [n=8] with significant aortic stenosis and 30 healthy control subjects (48±15 years). Patient global longitudinal strain was computed from apical views using speckle tracking analysis (EchoPAC, GE). Left ventricular ejection fraction was similar in BAV (62±6%), degenerative (63±6%) and control groups (62±3%). In contrast, longitudinal global strain was more impaired in BAV (-19±2%) than in degenerative (-20±2%, P=0.04) and control groups (-21±2, P<0.001), even in BAV patients without significant aortic valve disease (-19±2% for BAV vs. -20±2% for degenerative, P=0.01). Interestingly, longitudinal global strain was similar between degenerative group without significant aortic stenosis and control (-20±2% vs. -21±2%, P=0.5) Impaired longitudinal strain in BAV patients is observed independently of the presence of significant aortic valve disease while in degenerative group longitudinal strain is only impaired in the presence of significant aortic stenosis. These results suggest the presence of a structural myocardial disease in BAV disease.

Assessment of cardiovascular physiology using dobutamine stress cardiovascular magnetic resonance reveals impaired contractile reserve in patients with cirrhotic cardiomyopathy.

BackgroundLiver cirrhosis has been shown to affect cardiac performance. However cardiac dysfunction may only be revealed under stress conditions. The value of non-invasive stress tests in diagnosing cirrhotic cardiomyopathy is unclear. We sought to investigate the response to pharmacological stimulation with dobutamine in patients with cirrhosis using cardiovascular magnetic resonance.MethodsThirty-six patients and eight controls were scanned using a 1.5 T scanner (Siemens Symphony TIM; Siemens, Erlangen, Germany). Conventional volumetric and feature tracking analysis using dedicated software (CMR42; Circle Cardiovascular Imaging Inc, Calgary, Canada and Diogenes MRI; Tomtec; Germany, respectively) were performed at rest and during low to intermediate dose dobutamine stress.ResultsWhilst volumetry based parameters were similar between patients and controls at rest, patients had a smaller increase in cardiac output during stress (p = 0.015). Ejection fraction increase was impaired in patients during 10 μg/kg/min dobutamine as compared to controls (6.9 % vs. 16.5 %, p = 0.007), but not with 20 μg/kg/min (12.1 % vs. 17.6 %, p = 0.12). This was paralleled by an impaired improvement in circumferential strain with low dose (median increase of 14.4 % vs. 30.9 %, p = 0.03), but not with intermediate dose dobutamine (median increase of 29.4 % vs. 33.9 %, p = 0.54). There was an impaired longitudinal strain increase in patients as compared to controls during low (median increase of 6.6 % vs 28.6 %, p < 0.001) and intermediate dose dobutamine (median increase of 2.6%vs, 12.6 % p = 0.016). Radial strain response to dobutamine was similar in patients and controls (p > 0.05).ConclusionCirrhotic cardiomyopathy is characterized by an impaired cardiac pharmacological response that can be detected with magnetic resonance myocardial stress testing. Deformation analysis parameters may be more sensitive in identifying abnormalities in inotropic response to stress than conventional methods.

Relation of Biventricular Strain and Dyssynchrony in Repaired Tetralogy of Fallot Measured by Cardiac Magnetic Resonance to Death and Sustained Ventricular Tachycardia

Ventricular strain and dyssynchrony can be measured in patients with repaired tetralogy of Fallot (TOF), but their effect on clinical outcomes is poorly understood. The purpose of this study was to investigate if ventricular strain and dyssynchrony measured by cardiac magnetic resonance feature tracking are associated with death and sustained ventricular tachycardia. Patients with TOF who died or had ventricular tachycardia (TOF case, n = 16) were compared with age-matched patients with TOF with no adverse outcome (TOF control, n = 32). For each patient, midventricular short-axis and 4-chamber cine steady-state free precession images were analyzed using cardiac magnetic resonance feature-tracking software. Peak left ventricular (LV) and right ventricular (RV) global circumferential and longitudinal strain and indexes of dyssynchrony were compared between groups. Compared with the TOF control group, median strain values were significantly lower for the TOF case group for both the LV (circumferential: 17% vs 23%, p = 0.003; longitudinal: 13% vs 18%, p <0.001) and the RV (circumferential: 10% vs 16%, p = 0.001; longitudinal: 11% vs 18%, p <0.001). In a multivariate model including strain and dyssynchrony parameters, RV and LV longitudinal strain were strongly associated with the adverse outcome (p = 0.003 and 0.04, respectively; area under the curve = 0.92). No differences in ventricular dyssynchrony were identified between the groups. In conclusion, patients with TOF in this cohort who experienced adverse outcomes had lower values of all strain parameters than those who did not, and impaired longitudinal strain of both ventricles was strongly associated with adverse clinical outcomes.

Abstract 16989: Impaired Systolic Function Assessed by Strain Imaging Predicts Cardiovascular Morbidity and Mortality in Heart Failure with Preserved Ejection Fraction

Introduction: Left ventricular (LV) systolic function by strain imaging is impaired in heart failure with preserved ejection fraction (HFpEF) but its prognostic relevance is not known. Hypothesis: We hypothesized that worse longitudinal strain (LS) is independently associated with adverse outcomes. Methods: LS was assessed by 2D speckle-tracking echocardiography in a blinded core laboratory at baseline in 447 patients with HFpEF (left ventricular ejection fraction [LVEF] ≥45%) enrolled in the Treatment Of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial and was related to the primary composite outcome of cardiovascular (CV) death, HF hospitalization, or aborted cardiac arrest, and its components. Results: At a median follow-up of 2.6 (IQR 1.5-3.9) years, 115 patients experienced the primary outcome. Impaired LS, defined as an absolute LS &lt; 15.8%, was present in 53% of patients and was associated with the composite outcome (adjusted HR 2.14, 95% CI 1.26-3.66; p=0.005), CV death alone (adjusted HR 3.20, 95% CI 1.44-7.12; p=0.004), and HF hospitalization alone (adjusted HR 2.23, 95% CI 1.16-4.28; p=0.016) after adjusting for age, gender, race, randomization strata (prior HF hospitalization vs elevated B-type natriuretic peptide level), region of enrollment (Americas vs Russia or Georgia), randomized treatment assignment, history of atrial fibrillation, heart rate, New York Heart Association class, history of stroke, creatinine, hematocrit, LVEF, mass, end-systolic volume index, and E/E’ ratio. These findings were similar in the subgroup of 354 patients with LVEF ≥55%. Conclusions: Among HFpEF patients enrolled in TOPCAT, impaired LV systolic function, measured by LS, is predictive of adverse CV outcomes independent of clinical and conventional echocardiographic predictors. Impaired LS represents a novel imaging biomarker to identify HFpEF patients at particularly high risk for CV morbidity and mortality.

Regional myocardial dysfunction assessed by two-dimensional speckle tracking echocardiography in systemic sclerosis patients with fragmented QRS complexes

BackgroundThe aim of the study was to explore the relation between regional myocardial dysfunction and fragmented QRS (fQRS) complexes in systemic sclerosis (SSc). MethodsFifty-three SSc patients and 26 controls were included. All subjects underwent speckle tracking echocardiography for evaluation of left ventricular (LV) function and ECG to check for fQRS complexes. ResultsSSc patients had significantly lower LV global longitudinal, radial and circumferential strain and twist compared to controls. Thirteen SSc patients had fQRS (DII, DIII, aVF leads in eleven patients and V1 to V5 leads in two patients) and they had significantly lower global longitudinal and circumferencial strain compared to SSc patients with normal QRS. The SSc patients with fQRS in DII, DIII, and aVF leads had impaired longitudinal strain and delay in time to peak longitudinal strain in inferior LV segments compared to those with normal QRS. ConclusionfQRS is associated with lower strain measures in SSc patients indicating impairment in LV function.

Impaired Endocardial Radial Strain in Hypertensive Patients with Electrocardiographic Strain Pattern on Twodimensional Speckle-Tracking Echocardiography

Background: Strain ST-T changes on Electrocardiography (ECG) is a well-recognized marker of the presence and severity of Left Ventricular (LV) hypertrophy, which is usually associated with subendocardial dysfunction. However, the relationship between ST-T change and subendocardial dysfunction in hypertensive patients is unknown. Recently, two-dimensional speckle-tracking echocardiography has been used to define myocardial deformation parameters of the LV segment. Herein, we assessed subendocardial dysfunction patients with strain ST-T changes on electrocardiogram using two-dimensional speckle-tracking echocardiography. Methods: Parasternal short-axis and apical long-axis views of the LV were acquired in 42 controls and 69 essential hypertensive patients. Patients were divided into two groups according to presence (n = 29) or absence (n = 40) of strain ST-T changes. Radial, circumferential and longitudinal strain in subendocardial and subepicardial layers were calculated. Results: No significant intergroup differences in circumferential strain in the subendocardial and subepicardial layers were observed. Longitudinal strain was decreased in hypertensive patients with strain ST-T changes versus patients without strain ST-T changes or control subjects (antero-septal: p < 0.0001; posterior: p < 0.005). Although epicardial radial strain was similar between patients with and without strain ST-T changes, endocardial radial strain was reduced in strain ST-T change group versus the no ST-T change group (antero-septal : 19.3 ± 14.5 vs. 31.9 ± 15.8, p < 0.01; posterior : 25.4 ± 14.9 vs. 34.5 ± 11.4, p < 0.05). Conclusions: Hypertensive patients with strain ST-T changes exhibit impaired longitudinal strain and endocardial radial strain, with preserved circumferential strain and epicardial radial strain. The impairment of endocardial radial strain in hypertensive patients with strain ST-T changes suggests a possible link between strain ST-T changes and subendocardial dysfunction.

Outcome prediction in sepsis: speckle tracking echocardiography based assessment of myocardial function.

IntroductionSpeckle tracking echocardiography (STE) is a relatively novel and sensitive method for assessing ventricular function and may unmask myocardial dysfunction not appreciated with conventional echocardiography. The association of ventricular dysfunction and prognosis in sepsis is unclear. We sought to evaluate frequency and prognostic value of biventricular function, assessed by STE in patients with severe sepsis or septic shock.MethodsOver an eighteen-month period, sixty patients were prospectively imaged by transthoracic echocardiography within 24 hours of meeting severe sepsis criteria. Myocardial function assessment included conventional measures and STE. Association with mortality was assessed over 12 months.ResultsMortality was 33% at 30 days (n = 20) and 48% at 6 months (n = 29). 32% of patients had right ventricle (RV) dysfunction based on conventional assessment compared to 72% assessed with STE. 33% of patients had left ventricle (LV) dysfunction based on ejection fraction compared to 69% assessed with STE. RV free wall longitudinal strain was moderately associated with six-month mortality (OR 1.1, 95% confidence interval, CI, 1.02-1.26, p = 0.02, area under the curve, AUC, 0.68). No other conventional echocardiography or STE method was associated with survival. After adjustment (for example, for mechanical ventilation) severe RV free wall longitudinal strain impairment remained associated with six-month mortality.ConclusionSTE may unmask systolic dysfunction not seen with conventional echocardiography. RV dysfunction unmasked by STE, especially when severe, was associated with high mortality in patients with severe sepsis or septic shock. LV dysfunction was not associated with survival outcomes.

Prognostic implications of left ventricular regional function heterogeneity assessed with two-dimensional speckle tracking in patients with ST-segment elevation myocardial infarction and depressed left ventricular ejection fraction

The aim of the current study was to evaluate the prognostic implications of myocardial tissue heterogeneity assessed with two-dimensional speckle-tracking echocardiography in patients three months after first ST-segment elevation myocardial infarction (STEMI) with left ventricular ejection fraction (LVEF) ≤35 %. For this purpose, a total of 79 patients with first STEMI and LVEF ≤35 % at three months postinfarction were evaluated. Based on left ventricular (LV) speckle-tracking longitudinal strain echocardiography, the infarct core, border zone, and remote zone at baseline and three months' follow-up were defined. Patients were followed for the occurrence of the composite end point of appropriate implantable cardioverter-defibrillator (ICD) therapy and/or cardiac mortality. During a median follow-up of 46 months, 13 patients (17 %) reached the composite end point. At baseline, patients with and without events showed comparable values of LV longitudinal strain at the infarct, border, and remote zones. However, at three months' follow-up, patients with events showed significantly more impaired longitudinal strain at the border zone (-6.8 ± 3.1 % vs. -10.5 ± 4.9 %, P = 0.002), whereas LVEF was comparable (28 ± 6 % vs. 31 ± 4 %, P = 0.09). The median three-month LV longitudinal strain at the border zone was -9.4 %. Multivariate Cox regression analysis demonstrated that three-month longitudinal strain >-9.4 % at the border zone was independently associated with the composite end point (hazard ratio 3.94, 95 % confidence interval 1.05-14.70; P = 0.04). In conclusion, regional longitudinal strain at the border zone three months post-STEMI is associated with appropriate ICD therapy and cardiac mortality.

Longitudinal Strain Impairment as a Marker of the Progression of Heart Failure with Preserved Ejection Fraction in a Rat Model

Recent advances in very high frame rate use of ultrasonography have enabled the application of two-dimensional speckle-tracking echocardiography (STE) to small animal cardiac functional assessments. In this study, two-dimensional STE was applied to a rat model of hypertensive heart failure with preserved ejection fraction to clarify consequences of left ventricular (LV) wall deformation in the progression of heart failure with preserved ejection fraction. STE was performed every 2 weeks in Dahl salt-sensitive rats fed a 0.3% (control group) or 8% (hypertension [HT] group) sodium chloride diet from 6 to 14 weeks of age. Longitudinal, radial, and circumferential global strain and strain rate were measured, and the time courses of these parameters were observed. Deterioration of longitudinal strain occurred in the early phase of the progression of LV hypertrophy and continued to worsen until congestive heart failure developed (longitudinal strain in the HT group: 25 ± 3% at 10 weeks, 21 ± 4% at 12 weeks, and 18 ± 2% at 14 weeks; longitudinal strain in controls was preserved during the experimental period). At 12 weeks, radial strain (HT group, 35 ± 7%; controls, 41 ± 10%) had deteriorated at the late stage of manifest diastolic dysfunction. Throughout the experiments, circumferential strain was preserved (HT group, 35 ± 6%; control group, 35 ± 5%), and no significant increase in short-axis function was observed. STE is applicable to the small animal heart and detected LV wall long-axis dysfunction preceding short-axis dysfunction or overt congestive heart failure in the progression of hypertensive LV hypertrophy in a rat model.

Impaired myocardial perfusion in moderate asymptomatic aortic stenosis relates to longitudinal strain but not non-contrast T1 values

Background Myocardial perfusion and strain (in particular longitudinal strain- LS) are reduced in severe aortic stenosis (AS). It is thought that reduced perfusion occurs in the subendocardium secondary to increased LV pressure, leading to fibrosis and reduced LS. This relationship between perfusion, diffuse fibrosis and multidirectional myocardial strain has not been previously investigated in moderate (or severe) AS. We hypothesized that impaired myocardial perfusion occurs in patients with moderate AS, leading to a degree of diffuse fibrosis (reflected in increased non-contrast T1 values) and impaired longitudinal strain. Methods 32 patients with moderate AS (by echo criteria) and 12 age and sex-matched normal controls were recruited. All subjects underwent CMR scanning at 1.5T including valve assessment, stress and rest perfusion, tagging, and non-contrast T1-mapping using the ShMOLLI (Shortened Modified Look-Locker Inversion recovery) sequence, which was previously shown to have a good correlation with histological quantification of diffuse fibrosis. Myocardial perfusion reserve index (MPRI) and strain values were derived from analysis of the perfusion and tagging sequences respectively. Results Despite being well matched for age and sex, there were significant differences between patients with moderate AS and normal controls in longitudinal strain, MPRI and LV mass (p<0.0001, Table 1). There were no significant differences in circumferential strain and T1 values between the two groups. In AS patients there was a moderate correlation with MPRI and LS (r = -0.4, p<0.05), but not circumferential strain (CS). In AS patients T1 values correlated

Myocardial dysfunction in patients with type 2 diabetes mellitus: role of endothelial progenitor cells and oxidative stress

BackgroundEndothelial progenitor cells (EPCs) are responsible for angiogenesis and maintenance of microvascular integrity, the number of EPCs is correlated with oxidative stress. Their relation to myocardial dysfunction in patients with type 2 diabetes mellitus (T2DM) is nonetheless unknown.MethodsEighty-seven patients with T2DM and no history of coronary artery disease were recruited. Transthoracic echocardiography and detailed evaluation of left ventricular (LV) systolic function by 2-dimensional (2D) speckle tracking derived strain analysis in 3 orthogonal directions was performed. Four subpopulations of EPCs, including CD34+, CD133+, CD34+/kinase insert domain-containing receptor (KDR) + and CD133+/KDR + EPCs, were measured by flow cytometry. Oxidative stress was assessed by superoxide dismutase (SOD).ResultsThe mean age of the patients was 62 ± 9 years and 39.6% were male. Those with an impaired longitudinal strain had a lower number of CD34+ EPCs (2.82 ± 1.87% vs. 3.74 ± 2.12%, P < 0.05) than those with preserved longitudinal strain. When compared with those with preserved circumferential strain, patients with an impaired circumferential strain had a lower number of CD34+ EPCs (2.63 ± 1.80% vs. 3.87 ± 2.10%, P < 0.01) and SOD level (0.13 ± 0.06U/ml vs. 0.20 ± 0.08U/ml, P < 0.01). Patients with an impaired radial strain nonetheless had a lower number of CD34+ EPCs (2.62 ± 2.08% vs. 3.69 ± 1.99%, P < 0.05). Multivariate analysis demonstrated that only impaired global circumferential strain remained significantly associated with CD34 + EPCs and SOD.ConclusionsLV global circumferential strain was independently associated with number of CD34+ EPCs and SOD. These findings suggest that myocardial dysfunction in patients with T2DM is related to depletion of EPCs and increased oxidative stress.

Global longitudinal strain for predicting outcome after mitral repair or cardiac surgery: here to stay?

Speckle tracking two-dimensional (2D) strain echocardiography is a novel and promising technique with multiple emerging clinical applicabilities.1,2 In most patients, the method is easy to perform during routine transthoracic echocardiography by the acquisition of the regular 2D gray-scale images, which can then be evaluated offline by the use of work stations. Strain echocardiography has been demonstrated to be useful for assessing and monitoring left ventricular (LV) systolic function in several cardiac disease entities. A major advantage of speckle tracking echocardiography is its angle-independency in comparison with tissue Doppler (TDI) which enables regional and global analysis of myocardial velocities and deformation parameters such as strain or strain rate by the use of an image-processing algorithm of the grey scale pixels. In principle, strain measures the myocardial fibre contraction magnitude, and therefore may detect subtle subclinical LV dysfunction in an early stage. LV function presents a well-established prognostic factor strongly influencing outcome in valve disease and is included in the EuroSCORE preoperative risk calculation for cardiac surgery.3 However, the echocardiographic assessment of the LV ejection fraction (EF) faces several major limitations, including load dependency and imaging quality for endocardial border delineation.1 Importantly, it has been repeatedly observed, that despite apparently preserved ‘normal’ LV EF, myocardial contractility may already be reduced, reflected by impaired longitudinal 2D strain.1,2. In the setting of severe mitral regurgitation, compensatory LV dilatation and geometry changes may sustain a normal stroke volume at rest, although myocardial contractile reserve may already deteriorate even in asymptomatic patients. Therefore, careful assessment of the LV function including longitudinal strain in …

Multidirectional myocardial systolic function in hemodialysis patients with preserved left ventricular ejection fraction and different left ventricular geometry

Multidirectional myocardial strain analysis can provide mechanistic insight into the ventricular systolic function and pathophysiology. The aim of this study was to assess the multidirectional systolic function of the left ventricle (LV) and its relationship to LV geometry in hemodialysis patients with preserved left ventricular ejection fraction (LVEF). A total of 98 end-stage renal disease patients (age 46 ± 10 years, 60% men) with preserved LVEF (≥50%) on a maintenance hemodialysis program and 18 healthy volunteers were enrolled. The patients were divided into non-hypertrophic groups (classified as normal LV geometry and concentric remodeling) and hypertrophy groups (classified as eccentric and concentric hypertrophy) according to their LV geometries assessed from LV mass/height(2.7) and relative wall thickness in combination. Multidirectional strain analysis was performed by two-dimensional speckle tracking echocardiography. Myocardial systolic strain (longitudinal and circumferential) and stress-corrected midwall fraction shorting (sc-MWFS) were lower in the hypertrophy groups compared with non-hypertrophic groups. Longitudinal strain and strain rate were even lower in the concentric hypertrophy group than the eccentric hypertrophy group (-15.5 ± 2.2% versus -17.8 ± 2.6%, P = 0.001; -0.7 ± 0.2 versus -0.9 ± 0.2s(-1), P = 0.016). Impaired longitudinal strain correlated with higher LV mass index (LVMI), relative wall thickness, pre-dialysis systolic blood pressure (SBP), calcium-phosphate product and lower sc-MWFS (all P < 0.0001) and weakly correlated with higher interdialytic weight gain (P = 0.004). Using multivariate linear regression, the independent predictors of LV longitudinal strain were pre-dialysis SBP, LVMI, relative wall thickness and sc-MWFS. There were no differences in LVEF and myocardial function in radial direction among all groups. In hemodialysis patients with LV hypertrophy, myocardial function was impaired not only in longitudinal direction but also in circumferential direction despite preserved LVEF. Low longitudinal strain is related to LV hypertrophy, concentric geometry and pre-dialysis blood pressure.

Strain, Strain Rate, and the Force Frequency Relationship in Patients with and without Heart Failure

The aim of this study was to examine the effect of heart rate (HR) on indices of deformation in adults with and without heart failure (HF) who underwent simultaneous high-fidelity catheterization of the left ventricle to describe the force-frequency relationship. Right atrial pacing to control HR and high-fidelity recordings of left ventricular (LV) pressure were used to inscribe the force-frequency relationship. Simultaneous two-dimensional echocardiographic imaging was acquired for speckle-tracking analysis. Thirteen patients with normal LV function and 12 with systolic HF (LV ejection fraction, 31 ± 13%) were studied. Patients with HF had depressed isovolumic contractility and impaired longitudinal strain and strain rate. HR-dependent increases in LV+dP/dt(max), the force-frequency relationship, was demonstrated in both groups (normal LV function, baseline to 100 beats/min: 1,335 ± 296 to 1,564 ± 320 mm Hg/sec, P < .0001; HF, baseline to 100 beats/min: 970 ± 207 to 1,083 ± 233 mm Hg/sec, P < .01). Longitudinal strain decreased significantly (normal LV function, baseline to 100 beats/min: 18.0 ± 3.5% to 10.8 ± 6.0%, P < .001; HF: 9.4 ± 4.1% to 7.5 ± 3.4%, P < .01). The decrease in longitudinal strain was related to a decrease in LV end-diastolic dimensions. Strain rate did not change with right atrial pacing. Despite the inotropic effect of increasing HR, longitudinal strain decreases in parallel with stroke volume as load-dependent indices of ejection. Strain rate did not reflect the modest HR-related changes in contractility; on the other hand, the use of strain rate for quantitative stress imaging is also less likely to be confounded by chronotropic responses.

Early detection of isolated left ventricular diastolic dysfunction in high-risk differentiated thyroid carcinoma patients on TSH-suppressive therapy

L-Thyroxine-suppressive therapy benefits high-risk differentiated thyroid cancer patients by decreasing recurrence rates and cancer-related mortality. However, fully suppressed serum thyroid-stimulating hormone (TSH) implies a state of subclinical hyperthyroidism (SCH) with associated adverse cardiac effects. Because left ventricular (LV) diastolic dysfunction may be the first manifestation of more severe LV failure, and to balance the risks from thyroid cancer recurrence with risks of cardiac failure, the purpose of this study was to analyse new parameters of LV function in asymptomatic patients with exogenous SCH. Case-control study with 24 patients on TSH-suppressive therapy of short duration (≤ 4 years) after thyroid ablative therapy for differentiated thyroid carcinoma and 20 age- and sex-matched subjects. LV function [LV global strain and strain rate (SR) curves] was assessed by speckle tracking imaging echocardiography in each subject. Patients and controls do not differ in body mass index, systolic blood pressure and heart rate. No significant differences were observed in LV morphology (LV mass and relative wall thickness), cardiac output and parameters of LV systolic function between patients on suppressive therapy and controls. When compared with controls, patients with exogenous SCH had a significantly impaired longitudinal protodiastolic strain, SR and strain diastolic index but preserved radial strain and SR function. In subjects with SCH at the early phase of TSH-suppressive therapy, evidence of isolated longitudinal LV diastolic dysfunction was observed, despite a normal LV morphology. Further prospective studies to clarify the prognosis of picking-up early diastolic dysfunction in asymptomatic patients are needed before serial measurements could be recommended.

Longitudinal mechanics of the periinfarct zone and ventricular tachycardia inducibility in patients with chronic ischemic cardiomyopathy

Quantification of segmental left ventricular (LV) strain by speckle-tracking echocardiography can identify transmural infarcts in patients with chronic ischemic cardiomyopathy. The aim of the study was to explore the relationship between the LV longitudinal peak systolic strain (LPSS) of the infarct, periinfarct, and remote zones and monomorphic ventricular tachycardia (VT) inducibility on electrophysiologic (EP) study. A total of 134 patients with chronic ischemic cardiomyopathy scheduled for EP study were included. The protocol consisted of clinical, electrocardiographic, and echocardiographic evaluation, including LV longitudinal strain analysis using speckle-tracking echocardiography, immediately before EP study. An infarct segment was defined as a longitudinal strain value of greater than -5%, and a periinfarct segment was defined as immediately adjacent to an infarct segment. The infarct zone had the most impaired longitudinal strain (-0.5% ± 3.0%), whereas the periinfarct and remote zones had more preserved longitudinal strain (-10.8% ± 1.9% and -14.5% ± 3.0%, respectively; analysis of variance, P < .001). Seventy-two (54%) patients had inducible monomorphic VT on EP study. There was no significant difference in LV ejection fraction (31% ± 9% vs 32% ± 11%, P = .29) between inducible and noninducible patients. Longitudinal peak systolic strain of the periinfarct zone was more impaired in inducible patients (-9.8% ± 1.5% vs -11.0% ± 2.1%, P = .001), but no differences in LPSS of the infarct (-0.5% ± 3.2% vs -0.4% ± 2.7%, P = .75) and remote (-14.6% ± 2.8% vs -14.5% ± 3.4%, P = .92) zones were observed. Only LPSS of the periinfarct zone (OR 1.43, 95% CI 1.15-1.78, P = .001) was independently related to monomorphic VT inducibility on multiple logistic regression. Longitudinal strain analysis may be a useful imaging tool to risk stratify ischemic patients for malignant ventricular arrhythmia.