Intramural myocardial shortening in hypertensive left ventricular hypertrophy with normal pump function

Association Between Left Ventricular Relative Wall Thickness and Acute Kidney Injury After Noncardiac Surgery

BACKGROUND

Acute kidney injury (AKI) after major noncardiac surgery is commonly attributed to cardiovascular dysfunction. Identifying novel associations between preoperative cardiovascular markers and kidney injury may guide risk stratification and perioperative intervention. Increased left ventricular relative wall thickness (RWT), routinely measured on echocardiography, is associated with myocardial dysfunction and long-term risk of heart failure in patients with preserved left ventricular ejection fraction (LVEF); however, its relationship to postoperative complications has not been studied. We evaluated the association between preoperative RWT and AKI in high-risk noncardiac surgical patients with preserved LVEF.

METHODS

Patients ≥18 years of age having major noncardiac surgery (high-risk elective intra-abdominal or noncardiac intrathoracic surgery) between July 1, 2016, and June 30, 2018, who had transthoracic echocardiography in the previous 12 months were eligible. Patients with preoperative creatinine ≥2 mg/dL or reduced LVEF (<50%) were excluded. The association between RWT and AKI, defined as an increase in serum creatinine by 0.3 mg/dL from baseline within 48 hours or by 50% within 7 days after surgery, was assessed using multivariable logistic regression adjusted for preoperative covariates. An additional model adjusted for intraoperative covariates, which are strongly associated with AKI, especially hypotension. RWT was modeled continuously, associating the change in odds of AKI for each 0.1 increase in RWT.

RESULTS

The study included 1041 patients (mean ± standard deviation [SD] age 62 ± 15 years; 59% female). A total of 145 subjects (13.9%) developed AKI within 7 days. For RWT quartiles 1 through 4, respectively, 20 of 262 (7.6%), 40 of 259 (15.4%), 39 of 263 (14.8%), and 46 of 257 (17.9%) developed AKI. Log-odds and proportion with AKI increased across the observed RWT values. After adjusting for confounders (demographics, American Society of Anesthesiologists [ASA] physical status, comorbidities, baseline creatinine, antihypertensive medications, and left ventricular mass index), each RWT increase of 0.1 was associated with an estimated 26% increased odds of developing AKI (odds ratio [OR]; 95% confidence interval [CI]) of 1.26 (1.09-1.46; P = .002). After adjusting for intraoperative covariates (length of surgery, presence of an arterial line, intraoperative hypotension, crystalloid administration, transfusion, and urine output), RWT remained independently associated with the odds of AKI (OR; 95% CI) of 1.28 (1.13-1.47; P = .001). Increased RWT was also independently associated with hospital length of stay and adjusted hazard ratio (HR [95% CI]) of 0.94 (0.89-0.99; P = .018).

CONCLUSIONS

Left ventricular RWT is a novel cardiovascular factor associated with AKI within 7 days after high-risk noncardiac surgery among patients with preserved LVEF. Application of this commonly available measurement of risk stratification or perioperative intervention warrants further investigation.

Effects of Race, Cardiac Mass, and Cardiac Load on Myocardial Function Trajectories from Childhood to Young Adulthood: The Augusta Heart Study

Background

The overall goal of this longitudinal study was to determine if the Black population has decreased myocardial function, which has the potential to lead to the early development of congestive heart failure, compared with the White population.

Methods and Results

A total of 673 subjects were evaluated over a period of 30 years including similar percentages of Black and White participants. Left ventricular systolic function was probed using the midwall fractional shortening (MFS). A longitudinal analysis of the MFS using a mixed effect growth curve model was performed. Black participants had greater body mass index, higher blood pressure readings, and greater left ventricular mass compared with White participants (all P<0.01). Black participants had a 0.54% decrease of MFS compared with White participants. As age increased by 1 year, MFS increased by 0.05%. As left ventricular mass increased by 1 g, MFS decreased by 0.01%. As circumferential end systolic stress increased by 1 unit, MFS decreased by 0.04%. The MFS trajectories for race differed from early age to young adulthood.

Conclusions

Changes in myocardial function mirror the race‐dependent variations in blood pressure, afterload, and cardiac mass, suggesting that myocardial function depression occurs early in childhood in populations at high cardiovascular risk such as Black participants.

Early Left Ventricular Diastolic Dysfunction and Abnormal Left Ventricular-left Atrial Coupling in Asymptomatic Patients With Hypertension: A Cardiovascular Magnetic Resonance Feature Tracking Study

PURPOSE

Hypertension (HTN) patients suffer from increased risk of left ventricular (LV) diastolic dysfunction and LV hypertrophy (LVH). Evaluation of early LV diastolic function requires accurate noninvasive diagnostic tools. The aim of this study was to evaluate whether cardiovascular magnetic resonance feature-tracking (CMR-FT) could detect early LV dysfunction and evaluate LV-left atrium (LA) correlation in HTN patients.

MATERIALS AND METHODS

In all, 89 HTN patients and 38 age-matched and sex-matched controls were retrospectively enrolled and underwent CMR examination. HTN patients were divided into LVH (n=38) and non-LVH (n=51) groups. All LV deformation parameters were analyzed in radial, circumferential, and longitudinal directions, including peak strain, peak systolic strain rate and peak diastolic strain rate (PDSR), LA strain and strain rate (SR), including LA reservoir function (εs, SRs), conduit function (εe, SRe), and booster pump function (εa, SRa).

RESULTS

Compared with controls, the LV PDSR in radial, circumferential, and longitudinal directions and the LA reservoir and conduit function were significantly impaired in HTN patients regardless of LVH (all P<0.05). LV longitudinal and radial PDSR were correlated with LA reservoir and conduit function (all P<0.01). Among all LV and LA impaired deformation parameters, the longitudinal PDSR (in LV) and εe (in LA) were the most sensitive parameter for the discrimination between non-LVH and healthy volunteers, with an area under the curve of 0.70 (specificity 79%, sensitivity 55%) and 0.76 (specificity 95%, sensitivity 49%), respectively. The area under the curve reached 0.81 (specificity 82%, sensitivity 75%) combined with the longitudinal PDSR and εe.

CONCLUSION

CMR-FT could detect early LV diastolic dysfunction in HTN patients, which might be associated with LA reservoir and conduit dysfunction.

Left ventricular longitudinal shortening: relation to stroke volume and ejection fraction in ageing, blood pressure, body size and gender in the HUNT3 study

Background

Aims of this cross-sectional study were to assess: the relative contribution of left ventricular (LV) systolic long-axis shortening (mean mitral annular plane systolic excursion, MAPSE) to stroke volume (SV), the mechanisms for preserved ejection fraction (EF) despite reduced MAPSE, the age dependency of myocardial volume and myocardial systolic compression.

Methods

Linear dimensions and longitudinal and cross-sectional M-modes were acquired in 1266 individuals without history of heart disease, diabetes or known hypertension from the third wave of the Nord-Trøndelag Health Study. Measurements were entered into a half-ellipsoid LV model for volume calculations, and volumes were related to age, body size (body surface area, BSA), sex and blood pressure (BP).

Results

Mean BP and proportion with hypertensive values increased with increasing age. MAPSE contributed to 75% of SV, with no relation to age or BSA as both MAPSE and SV decreased with increasing age. LV end-diastolic volume (LVEDV) and SV increased with BSA and decreased with higher age; EF was not related to age or BSA. Myocardial volume increased with higher age and BSA, with an additional gender dependency. The association of age with myocardial volume was not significant when corrected for BP, while both systolic and diastolic BP were significant associated with myocardial volume. Myocardial compression was less than 3%.

Conclusions

MAPSE contributes approximately 75% and short axis shortening 25% to SV. Both decline with age, but their percentage contributions to SV are unchanged. EF is preserved by the simultaneous decrease in LVEDV and SV. Myocardial volume is positively associated with age, but this is only related to higher BP, which may have implications for BP treatment in ageing. The myocardium is near incompressible.

Detection of Functionally Significant Coronary Artery Disease: Role of Regional Post Systolic Shortening

Background:

The main goal of this manuscript was to evaluate the diagnostic value of the global and regional postsystolic shortening (PSS) parameters, assessed by two-dimensional (2D) speckle-tracking echocardiography, at rest and during dobutamine stress for the detection of functionally significant coronary artery stenoses in patients with moderate pretest probability of stable coronary artery disease (CAD).

Methods:

Dobutamine stress echocardiography (DSE) and adenosine stress myocardial perfusion imaging by cardiac magnetic resonance (CMR-MPI) were performed on 83 patients with moderate pretest probability of stable CAD and left ventricle ejection fraction ≥55%. CAD was defined as ≥50% diameter stenoses on invasive coronary artery angiography (CAA) validated as hemodynamically significant by CMR-MPI. According to invasive CAA and CMR-MPI results, patients were divided into two groups: Nonpathologic CAD (−) group: 38 (45.8%) and pathologic CAD (+) group: 45 (54.2%).

Results:

There were no significant differences in clinical characteristics, conventional 2D echocardiography between the two groups at rest and during low dobutamine dose. Regional postsystolic index (PSI) during recovery phase had the highest area under the receiver operating characteristic curve (AUC) (AUC 0.882, sensitivity 87%, specificity 92%) for the detection of functionally significant one-vessel disease. During high dobutamine dose, regional PSI had sensitivity 78% and specificity 81% (AUC 0.78) to detect significant CAD. Regional PSI remained the same tendency remains for the detection of multiple-vessel CAD. Other myocardial deformation parameters were less sensitive and specific during high dobutamine dose and recovery phase.

Conclusions:

PSS parameters showed to be sensitive and specific in detecting hemodynamically significant coronary artery stenosis in patients with stable CAD with moderate pretest probability. The study revealed that the assessment of regional PSI performed during recovery improves the diagnostic accuracy of DSE for the detection of functionally significant CAD.

Left ventricular strain and fibrosis in adults with repaired tetralogy of Fallot: A case-control study

BACKGROUND

Left ventricular (LV) systolic dysfunction and myocardial fibrosis have prognostic implications in repaired tetralogy of Fallot (rTOF), but their relationship with myocardial strain is not well understood. We evaluated systolic strain and fibrosis (extracellular volume fraction, ECV) of the left ventricle (LV) using feature tracking with magnetic resonance and determine their association with each other and clinical outcome.

METHOD

Adults with rTOF and age-matched controls underwent CMR to measure LV-ECV. Feature-tracking was used to quantify radial, circumferential, and longitudinal strain in both 2 and 3 dimensions. Clinical events (death, arrhythmia and heart-failure hospitalization) were obtained through chart review. Associations between strain, ECV and clinical events were explored.

RESULTS

48 rTOF subjects (age 40.5 ± 14.3, 42% female) and 20 healthy controls were included. Both LV 2D and 3D global circumferential strain (GCS) and global longitudinal strain (GLS) were lower in rTOF subjects (p ≤0.01 for all). There was no association between strain and LV-ECV. Strain parameters correlated with ventricular volumes and function. After a median follow-up of 8.5 years (range 1-10.9 years) there were 5 deaths, 6 hospitalizations and 9 new arrhythmias. By multivariate Cox-regression, GLS was an independent predictor of both hospitalization and death, whereas LV-ECV was an independent predictor of arrhythmia.

CONCLUSION

While both LV strain abnormalities and fibrosis are present in rTOF, they are associated with different types of clinical outcome, and not to each other. The findings suggest that these measures reflect different long-term adverse adaptations to abnormal hemodynamics.

Effect of pericardial incision on left ventricular morphology and systolic function in patients during coronary artery bypass grafting

Background

Accurate assessment of left ventricular (LV) systolic function is important after coronary artery bypass grafting (CABG). LV ejection fraction (LVEF) is conventionally used to evaluate LV systolic function; deformation parameters can be used to detect subtle LV systolic dysfunction. It is unclear whether an incised pericardium without sutures during CABG could affect LV morphology and function. We investigated the effect of pericardial incision on LV morphology and systolic function during CABG.

Methods

Intraoperative transesophageal echocardiography was performed in 27 patients during elective off-pump beating heart CABG 5 min before and after pericardial incision. LV longitudinal and mid-cavity transversal diameters, sphericity index, volumes, and LVEF were measured. LV global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), and twist obtained by two-dimensional speckle tracking echocardiography were measured simultaneously.

Results

LV mid-cavity transversal diameter increased, while the LV sphericity index decreased (P < 0.001) immediately after pericardial incision. The GLS, GCS, and twist significantly decreased, while the GRS notably increased (P < 0.001). The LV volumes and LVEF remained unchanged.

Conclusions

Pericardial incision immediately transformed LV morphology from an ellipsoid to sphere, with decreased longitudinal and circumferential strain and twist, and increased radial strain, while LVEF remained unchanged. This should be considered when evaluating LV systolic function in patients after CABG.

The Impact of Basal Septal Hypertrophy on Outcomes after Transcatheter Aortic Valve Replacement

BACKGROUND

The role of basal septal hypertrophy (BSH) on preprocedural transthoracic echocardiography in transcatheter aortic valve replacement (TAVR) is unknown.

METHODS

Medical charts and preprocedural transthoracic echocardiograms of 378 patients who underwent TAVR were examined. The association between BSH and the primary composite outcome of valve pop-out, recapture, embolization, aborted procedure, conversion to open procedure, new conduction disturbance, or need for permanent pacemaker ≤30 days after TAVR was evaluated. Patients with preexisting pacemakers were excluded. Sensitivity analyses were performed varying the definition of BSH.

RESULTS

Of 296 TAVR patients (78.3%) with interpretable images, 55 (18.6%) had BSH at a median of 40 days (interquartile range, 19-62 days) before TAVR. Age and sex were similar among those with and without BSH. BSH patients received postdilation more frequently (BSH+ vs BSH-: 41.8% vs 29.9%, P = .04). A total of 50 individuals (16.9%) received pacemakers within 30 days, and 128 (43.2%) developed conduction disturbances (with left bundle branch block most common), without differences between groups. BSH was unrelated to the primary outcome on multivariate analysis (adjusted odds ratio BSH+ vs BSH-, 0.94; 95% CI, 0.42-2.11; P = .88).

CONCLUSIONS

In this convenience sample of TAVR recipients at a large academic medical center, patients with BSH were more likely to receive postdilation. BSH was not associated with procedural or conduction outcomes after TAVR in patients without preexisting pacemakers.

Recent Advances in Imaging of Hypertensive Heart Disease

PURPOSE OF REVIEW

To review recent advances in the imaging of hypertensive heart disease (HHD) with an emphasis on developments in the imaging of diffuse myocardial fibrosis using cardiac magnetic resonance (CMR).

RECENT FINDINGS

HHD results from long-standing hypertension and is characterized by the development of left ventricular hypertrophy and diffuse interstitial fibrosis. Diffuse fibrosis traditionally required endomyocardial biopsy to diagnose, but recent developments using T1 mapping in CMR allow for noninvasive assessment. Studies using T1 mapping have shown an increase in extracellular volume fraction (ECV) in patients with HHD compared to normal controls, suggesting ECV can be used as a noninvasive marker for fibrosis in HHD. In addition to T1 mapping, other recent advances in HHD imaging include improvements in three-dimensional echocardiography, allowing for accurate real-time volumetric measurements, and the use of speckle tracking echocardiography to detect subclinical systolic dysfunction. Measurement of ECV using T1 mapping in CMR can be used as a noninvasive marker of diffuse myocardial fibrosis in HHD. While further studies are needed to validate this approach with larger patient cohorts, ECV can potentially be used to both monitor disease progression and assess therapeutic interventions in HHD.

Prognostic Implications of Mitral Annular Plane Systolic Excursion in Patients with Hypertension and a Clinical Indication for Cardiac Magnetic Resonance Imaging: A Multicenter Study

OBJECTIVES

This study sought to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived mitral annular plane systolic excursion (MAPSE) in a large multicenter population of patients with hypertension.

BACKGROUND

In patients with hypertension, cardiac abnormalities are powerful predictors of adverse outcomes. Long-axis mitral annular movement plays a fundamental role in cardiac mechanics and is an early marker for a number of pathological processes. Given the adverse consequences of cardiac involvement in hypertension, the authors hypothesized that lateral MAPSE may provide incremental prognostic information in these patients.

METHODS

Consecutive patients with hypertension and a clinical indication for CMR at 4 U.S. medical centers were included in this study (n = 1,735). Lateral MAPSE was measured in the 4-chamber cine view. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between lateral MAPSE and death. The incremental prognostic value of lateral MAPSE was assessed in nested models.

RESULTS

Over a median follow-up period of 5.1 years, 235 patients died. By Kaplan-Meier analysis, risk of death was significantly higher in patients with a lateral MAPSE < median (10 mm) (log-rank; p < 0.0001). Lateral MAPSE was associated with risk of death after adjustment for clinical and imaging risk factors (hazard ratio [HR]: 1.402-per-millimeter decrease; p < 0.001). Addition of lateral MAPSE in this model resulted in significant improvement in the C-statistic (0.735 to 0.815; p < 0.0001). Continuous net reclassification improvement was 0.739 (95% confidence interval: 0.601 to 0.902). Lateral MAPSE remained significantly associated with death even after adjustment for feature tracking global longitudinal strain (HR: 1.192-per-millimeter decrease; p < 0.001). Lateral MAPSE was independently associated with death among the subgroups of patients with preserved ejection fraction (HR = 1.339; p < 0.001) and in those without history of myocardial infarction (HR: 1.390; p < 0.001).

CONCLUSIONS

CMR-derived lateral MAPSE is a powerful, independent predictor of mortality in patients with hypertension and a clinical indication for CMR, incremental to common clinical and CMR risk factors. These findings may suggest a role for CMR-derived lateral MAPSE in identifying hypertensive patients at highest risk of death.

Are Measures of Left Ventricular Longitudinal Shortening Affected by Left Atrial Enlargement?

BACKGROUND

Even though left atrial (LA) size and function are intimately related to left ventricular (LV) diastolic dysfunction, the role of LA with regard to LV systolic function is less clear. Consequently, we examined the potential association that might exist between measures of longitudinal LV systolic shortening and LA dilation using LA volume index (LAVI).

METHODS

In this retrospective analysis, data from 75 echocardiograms (mean age 53 ± 14; range 24 - 89 years; mean body surface area (BSA) 2.0 ± 0.3) were analyzed.

RESULTS

Peak global longitudinal (PGLS) correlated best with LV mass index (LVMI) followed by mitral annular systolic excursion (MAPSE), and age. Similar results were obtained when analyzing the best variables that correlated with LAVI. Finally, MAPSE correlated best with PGLS, then with MA tissue Doppler systolic velocity, BSA, and LAVI in that order. All patients had normal LV ejection fraction (LVEF) and normal sinus rhythm when studied.

CONCLUSIONS

LAVI does not directly affect LV systolic function and longitudinal measures of LV shortening are mainly dependent on LV mass. Additional studies are now required to determine how these associations vary when different degrees of LV dilatation and systolic dysfunction are included in the analysis.

ECG strain pattern in hypertension is associated with myocardial cellular expansion and diffuse interstitial fibrosis: a multi-parametric cardiac magnetic resonance study

Aims

In hypertension, the presence of left ventricular (LV) strain pattern on 12-lead electrocardiogram (ECG) carries adverse cardiovascular prognosis. The underlying mechanisms are poorly understood. We investigated whether hypertensive ECG strain is associated with myocardial interstitial fibrosis and impaired myocardial strain, assessed by multi-parametric cardiac magnetic resonance (CMR).

Methods and results

A total of 100 hypertensive patients [50 ± 14 years, male: 58%, office systolic blood pressure (SBP): 170 ± 30 mmHg, office diastolic blood pressure (DBP): 97 ± 14 mmHg) underwent ECG and 1.5T CMR and were compared with 25 normotensive controls (46 ± 14 years, 60% male, SBP: 124 ± 8 mmHg, DBP: 76 ± 7 mmHg). Native T1 and extracellular volume fraction (ECV) were calculated with the modified look-locker inversion-recovery sequence. Myocardial strain values were estimated with voxel-tracking software. ECG strain (n = 20) was associated with significantly higher indexed LV mass (LVM) (119 ± 32 vs. 80 ± 17 g/m², P < 0.05) and ECV (30 ± 4 vs. 27 ± 3%, P < 0.05) compared with hypertensive subjects without ECG strain (n = 80). ECG strain subjects had significantly impaired circumferential strain compared with hypertensive subjects without ECG strain and controls (−15.2 ± 4.7 vs. −17.0 ± 3.3 vs. −17.3 ± 2.4%, P < 0.05, respectively). In subgroup analysis, comparing ECG strain subjects to hypertensive subjects with elevated LVM but no ECG strain, a significantly higher ECV (30 ± 4 vs. 28 ± 3%, P < 0.05) was still observed. Indexed LVM was the only variable independently associated with ECG strain in multivariate logistic regression analysis [odds ratio (95th confidence interval): 1.07 (1.02–1.12), P < 0.05).

Conclusion

In hypertension, ECG strain is a marker of advanced LVH associated with increased interstitial fibrosis and associated with significant myocardial circumferential strain impairment.

Normal range of myocardial layer-specific strain using two-dimensional speckle tracking echocardiography

Background

Newer 2D strain software has a potential to assess layer-specific strain. However, normal reference values for layer-specific strain have not been established. We aimed to establish the normal ranges of layer-specific longitudinal and circumferential strain (endocardial global longitudinal strain (GLS), transmural GLS, epicardial GLS, endocardial global circumferential strain (GCS), transmural GCS, and epicardial GCS).

Methods and results

We retrospectively analyzed longitudinal and circumferential strain parameters in 235 healthy subjects, with use of layer-specific 2D speckle tracking software (GE). The endocardial strain/epicardial strain (Endo/Epi) ratio was also measured to assess the strain gradient across the myocardium. The endocardial, transmural, and epicardial GLS values and the Endo/Epi ratio in the normal subjects were -23.1±2.3, -20.0±2.0, -17.6±1.9, and 1.31±0.07, respectively. The corresponding values of GCS were -28.5±3.0, -20.8±2.3, -15.3±2.0, and 1.88±0.17, respectively. The layer-specific global strain parameters exhibited no age dependency but did exhibit gender dependency except for endocardial GCS. A subgroup analysis revealed that basal and middle levels of endocardial LS was decreased in the middle and elderly aged group. However, apical endocardial LS was preserved even in the elderly subjects.

Conclusions

We proposed normal reference values for layer-specific strain based on both age and gender. This detailed strain analysis provides layer-oriented information with the potential to characterize abnormal findings in various cardiovascular diseases.

The emerging role of Cardiovascular Magnetic Resonance in the evaluation of hypertensive heart disease

BACKGROUND

Arterial hypertension is the commonest cause of cardiovascular death. It may lead to hypertensive heart disease (HHD), including heart failure (HF), ischemic heart disease (IHD) and left ventricular hypertrophy (LVH).

MAIN BODY

According to the 2007 ESH/ESC guidelines, the recommended imaging technique is echocardiography (echo), when a more sensitive detection of LVH than that provided by ECG, is needed. Cardiovascular Magnetic Resonance (CMR), a non-invasive, non-radiating technique, offers the following advantages, beyond echo: a) more reliable and reproducible measurements of cardiac parameters such as volumes, ejection fraction and cardiac mass b) more accurate differentiation of LVH etiology by providing information about tissue characterisation c) more accurate evaluation of myocardial ischemia, specifically if small vessels disease is present d) technique of choice for diagnosis of renovascular, aortic tree/branches lesions and quantification of aortic valve regurgitation e) technique of choice for treatment evaluation in clinical trials. The superiority of CMR against echocardiography in terms of reproducibility, operator independency, unrestricted field of view and capability of tissue characterization makes the technique ideal for evaluation of heart, quantification of aortic valve regurgitation, aorta and aortic branches.

CONCLUSIONS

CMR has a great potential in early diagnosis, risk stratification and treatment follow up of HHD. However, an international consensus about CMR in HHD, taking under consideration the cost-benefit ratio, expertise and availability, is still warranted.

Left ventricular functional, structural and energetic effects of normal aging: Comparison with hypertension

Objectives

Both aging and hypertension are significant risk factors for heart failure in the elderly. The purpose of this study was to determine how aging, with and without hypertension, affects left ventricular function.

Methods

Cross-sectional study of magnetic resonance imaging and ³¹P spectroscopy-based measurements of left ventricular structure, global function, strains, pulse wave velocity, high energy phosphate metabolism in 48 normal subjects and 40 treated hypertensive patients (though no other cardiovascular disease or diabetes) stratified into 3 age deciles from 50–79 years.

Results

Normal aging was associated with significant increases in systolic blood pressure, vascular stiffness, torsion, and impaired diastolic function (all P<0.05). Age-matched hypertension exacerbated the effects of aging on systolic pressure, and diastolic function. Hypertension alone, and not aging, was associated with increased left ventricular mass index, reduced energetic reserve, reduced longitudinal shortening and increased endocardial circumferential shortening (all P<0.05). Multiple linear regression analysis showed that these unique hypertensive features were significantly related to systolic blood pressure (P<0.05).

Conclusions

1) Hypertension adds to the age-related changes in systolic blood pressure and diastolic function; 2) hypertension is uniquely associated with changes in several aspects of left ventricular structure, function, systolic strains, and energetics; and 3) these uniquely hypertensive-associated parameters are related to the level of systolic blood pressure and so are potentially modifiable.

Magnetic resonance imaging of myocardial strain: A review of current approaches

Contraction of the heart is central to its purpose of pumping blood around the body. While simple global function measures (such as the ejection fraction) are most commonly used in the clinical assessment of cardiac function, MRI also provides a range of approaches for quantitatively characterizing regional cardiac function, including the local deformation (or strain) within the heart wall. While they have been around for some years, these methods are still undergoing further technical development, and they have had relatively little clinical evaluation. However, they can provide potentially useful new ways to assess cardiac function, which may be able to contribute to better classification and treatment of heart disease. This article provides some basic background on the physical and physiological factors that determine the motion of the heart, in health and disease and then reviews some of the ways that MRI methods are being developed to image and quantify strain within the myocardium.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1263-1280.

Increased valvulo-arterial impedance differently impacts left ventricular longitudinal, circumferential, and radial function in patients with aortic stenosis: A speckle tracking echocardiography study

BACKGROUND

In aortic stenosis (AS), the left ventricle (LV) should face an increased afterload that is due to both the stenotic aortic valve and the peripheral vascular resistance (PVR). Valvulo-arterial impedance (ZV_a ) is a recently introduced parameter, which permits the evaluation of global LV afterload in AS. Aim of this study was to assess the influence of increasing ZV_a on the longitudinal, circumferential, and radial components of LV mechanics.

METHODS

A total of 126 patients (mean age: 80.1±12.0 years, males: 47%) with severe AS (aortic surface <1 cm² or <0.6 cm² /m² ) underwent standard echocardiography to characterize aortic valve gradients, LV function, and ZV_a . 2D speckle tracking echocardiography was used to estimate global longitudinal (GLS), circumferential (GCS), and radial (GRS) LV strain.

RESULTS

The population was divided into four groups according to ZV_a quartiles: Q1 (ZV_a ≤3.43 mm Hg/mL/m² ), Q2 (3.43<ZV_a ≤4.1 mm Hg/mL/m² ), Q3 (4.1<ZV_a ≤5.1 mm Hg/mL/m² ), ad Q4 (ZV_a >5.1 mm Hg/mL/m² ). ZV_a increase from Q1 to Q4 was associated with a progressive reduction in GLS and GCS (ANOVA, both P<.0001). GRS was relatively insensitive to ZV_a increase, a significant reduction of GRS appearing only in Q4 patients with respect to Q1 (29.7±16.4 vs 20.7±13.2%, P=.01).

CONCLUSIONS

Left ventricle myocardial fibers show a different response to afterload increase. Subendocardial fibers function is impaired earlier, whereas mid-wall circumferential fibers remain substantially unaffected, providing interesting insights into the mechanisms of LV dysfunction in AS.

Image-Based Investigation of Human in Vivo Myofibre Strain

Cardiac myofibre deformation is an important determinant of the mechanical function of the heart. Quantification of myofibre strain relies on 3D measurements of ventricular wall motion interpreted with respect to the tissue microstructure. In this study, we estimated in vivo myofibre strain using 3D structural and functional atlases of the human heart. A finite element modelling framework was developed to incorporate myofibre orientations of the left ventricle (LV) extracted from 7 explanted normal human hearts imaged ex vivo with diffusion tensor magnetic resonance imaging (DTMRI) and kinematic measurements from 7 normal volunteers imaged in vivo with tagged MRI. Myofibre strain was extracted from the DTMRI and 3D strain from the tagged MRI. We investigated: i) the spatio-temporal variation of myofibre strain throughout the cardiac cycle; ii) the sensitivity of myofibre strain estimates to the variation in myofibre angle between individuals; and iii) the sensitivity of myofibre strain estimates to variations in wall motion between individuals. Our analysis results indicate that end systolic (ES) myofibre strain is approximately homogeneous throughout the entire LV, irrespective of the inter-individual variation in myofibre orientation. Additionally, inter-subject variability in myofibre orientations has greater effect on the variabilities in myofibre strain estimates than the ventricular wall motions. This study provided the first quantitative evidence of homogeneity of ES myofibre strain using minimally-invasive medical images of the human heart and demonstrated that image-based modelling framework can provide detailed insight to the mechanical behaviour of the myofibres, which may be used as a biomarker for cardiac diseases that affect cardiac mechanics.

The Relationship Between Left Ventricular Wall Thickness, Myocardial Shortening, and Ejection Fraction in Hypertensive Heart Disease: Insights From Cardiac Magnetic Resonance Imaging

Hypertensive heart disease is often associated with a preserved left ventricular ejection fraction despite impaired myocardial shortening. The authors investigated this paradox in 55 hypertensive patients (52±13 years, 58% male) and 32 age- and sex-matched normotensive control patients (49±11 years, 56% male) who underwent cardiac magnetic resonance imaging at 1.5T. Long-axis shortening (R=0.62), midwall fractional shortening (R=0.68), and radial strain (R=0.48) all decreased (P<.001) as end-diastolic wall thickness increased. However, absolute wall thickening (defined as end-systolic minus end-diastolic wall thickness) was maintained, despite the reduced myocardial shortening. Absolute wall thickening correlated with ejection fraction (R=0.70, P<.0001). In multiple linear regression analysis, increasing wall thickness by 1 mm independently increased ejection fraction by 3.43 percentage points (adjusted β-coefficient: 3.43 [2.60-4.26], P<.0001). Increasing end-diastolic wall thickness augments ejection fraction through preservation of absolute wall thickening. Left ventricular ejection fraction should not be used in patients with hypertensive heart disease without correction for degree of hypertrophy.

Uncontrolled blood pressure as an independent risk factor of early impaired left ventricular systolic function in treated hypertension

BACKGROUND

Uncontrolled blood pressure (BP) is commonly observed in patients receiving antihypertensive agents. However, its relationship with early left ventricular (LV) dysfunction has not been elucidated.

METHODS

This study enrolled 276 patients with treated hypertension and 85 healthy controls. The 140/90 mm Hg was used to define controlled (HT1 group, n=145) or uncontrolled BP (HT2 group, n=131) according to the concurrent guidelines. LV myocardial function was assessed by two-dimensional speckle tracking imaging, and the circumferential end-systolic wall stress (cESS)-corrected mid-wall fraction shortening (MWFS), systolic longitudinal (εLs-18), circumferential (εCs-18), and radial (εRs-18) strain were measured.

RESULTS

Despite similar ejection fraction, the HT1 and HT2 groups displayed an overall reduction in the cESS-corrected MWFS (13.4±2.7 vs 11.7±1.7 vs 15.5±1.2), εLs-18 (15.6±2.8 vs 13.0±2.2 vs 17.4±2.8), εCs-18 (17.3±3.4 vs 14.1±2.7 vs 18.9±3.3), and εRs-18 (18.4±4.0 vs 14.8±3.1 vs 20.5±4.5) %·cm² /kdyne·10^-2 when compared with the control group (all P<.001). The changes were more obvious in the HT2 group, regardless of LV hypertrophy. Reductions in the cESS-corrected MWFS and εLs-18 were seen in 68 (25%) and 52 (19%) patients, respectively. Uncontrolled BP were 4.365 times (95% CI 2.203-8.648, P<.001) and 3.928 times (1.851-8.337, P<.001) more likely to be associated with the changes.

CONCLUSIONS

Uncontrolled BP in hypertensive patients is associated with further reduction in LV myocardial function detected by advanced echocardiographic techniques, which cannot be explained by the increase in afterload. It might be regarded as a composite risk factor for earlier and faster development of clinical heart failure, therefore, a simplified treatment target.

Recommendations on the Use of Echocardiography in Adult Hypertension: A Report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Left Ventricular Systolic Dysfunction by Longitudinal Strain Is an Independent Predictor of Incident Atrial Fibrillation: A Community-Based Cohort Study

BACKGROUND

The increasing prevalence of atrial fibrillation (AF) represents a public health issue. Identifying new predictors of AF is therefore necessary to plan preventive strategies. We investigated whether left ventricular (LV) systolic dysfunction by global longitudinal strain (GLS), a predictor of cardiovascular events, may predict new-onset AF in a population setting.

METHODS AND RESULTS

Participants (n=675; mean age, 71±9 years; 60% women) in sinus rhythm from the population-based Northern Manhattan Study (NOMAS) underwent 2- and 3-dimensional echocardiography as part of the Cardiac Abnormalities and Brain Lesions (CABL) study. LV systolic function was assessed by LV ejection fraction and speckle-tracking GLS. During a mean follow-up of 63.6±18.7 months, 32 (4.7%) new confirmed cases of AF occurred. Lower GLS (adjusted hazard ratio/unit decrease, 1.22; 95% confidence interval, 1.04-1.43; P=0.015) and increased left atrial volume index (LAVi; adjusted hazard ratio/unit increase, 1.12; 95% confidence interval, 1.07-1.17; P<0.001) were significantly associated with incident AF, whereas LV ejection fraction was not (P=0.176). Abnormal GLS (>-14.7%) was associated with risk of new-onset AF with an adjusted hazard ratio of 3.2 (95% confidence interval, 1.4-7.5; P=0.007). The coexistence of abnormal GLS/abnormal LAVi was associated with a 28.6% incidence of AF (adjusted hazard ratio, 12.1; 95% confidence interval, 3.3-44.8; P<0.001) compared with participants with normal GLS/normal LAVi (AF incidence, 2.0%). AF incidence was intermediate in those with either abnormal GLS or abnormal LAVi (9.3% and 11.1%, respectively). GLS prognostic value for incident AF was incremental over risk factors and LAVi.

CONCLUSIONS

LV systolic dysfunction by GLS was a powerful and independent predictor of incident AF. GLS assessment may improve AF risk stratification in addition to established parameters.

Cumulative Blood Pressure in Early Adulthood and Cardiac Dysfunction in Middle Age: The CARDIA Study

BACKGROUND

Cumulative blood pressure (BP) exposure may adversely influence myocardial function, predisposing individuals to heart failure later in life.

OBJECTIVES

This study sought to investigate how cumulative exposure to higher BP influences left ventricular (LV) function during young to middle adulthood.

METHODS

The CARDIA (Coronary Artery Risk Development in Young Adults) study prospectively enrolled 5,115 healthy African Americans and whites in 1985 and 1986 (baseline). At the year 25 examination, LV function was measured by 2-dimensional echocardiography; cardiac deformation was assessed in detail by speckle-tracking echocardiography. We used cumulative exposure of BP through baseline and up to the year 25 examination (millimeters of mercury × year) to represent long-term exposure to BP levels. Linear regression and logistic regression were used to quantify the association of BP measured repeatedly through early adulthood (18 to 30 years of age) up to middle age (43 to 55 years).

RESULTS

Among 2,479 participants, cumulative BP measures were not related to LV ejection fraction; however, high cumulative exposure to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were associated with lower longitudinal strain rate (both p < 0.001). For diastolic function, higher cumulative exposures to SBP and DBP were associated with low early diastolic longitudinal peak strain rate. Of note, higher DBP (per SD increment) had a stronger association with diastolic dysfunction compared with SBP.

CONCLUSIONS

Higher cumulative exposure to BP over 25 years from young adulthood to middle age is associated with incipient LV systolic and diastolic dysfunction in middle age.

Regional Heterogeneity in 3D Myocardial Shortening in Hypertensive Left Ventricular Hypertrophy: A Cardiovascular CMR Tagging Substudy to the Life Study

BACKGROUND

Increased relative wall thickness in hypertensive left ventricular hypertrophy (LVH) has been shown by echocardiography to allow preserved shortening at the endocardium despite depressed LV midwall circumferential shortening (MWCS). Depressed MWCS is an adverse prognostic indicator, but whether this finding reflects reduced global or regional LV myocardial function, as assessed by three-dimensional (3D) myocardial strain, is unknown.

METHODS AND RESULTS

Cardiac Magnetic Resonance (CMR) tissue tagging permits direct evaluation of regional 3D intramyocardial strain, independent of LV geometry. We evaluated 21 hypertensive patients with electrocardiographic LVH in the LIFE study and 8 normal controls using 3D MR tagging and echocardiography. Patients had higher MR LV mass than normals (116 ± 40 versus 63 ± 6 g/m2, P = 0.002). Neither echocardiographic fractional shortening (32 ± 6 versus 33% ± 3%), LVEF (63% versus 64%) or mean end-systolic stress (175 ± 27 versus 146 ± 28 g/cm2) were significantly different, yet global MWCS was decreased by both echocardiography (13.4 ± 2.8 versus 18.2% ± 1.5%, P < 0.001) and MR (16.8 ± 3.6 versus 21.6% ± 3.0%, P < 0.005). 3D MR MWCS was lower at the base versus apex (P = 0.002) in LVH and greater in lateral and anterior regions versus septal and posterior regions (P < 0.001), contributing to the higher mean global MWCS by MR than echo. MR longitudinal strain was severely depressed in LVH patients (11.0 ± 3.3 versus 16.5% ± 2.5%, P < 0.001) and apical twist was increased (17.5 ± 4.3 versus 13.7 ± 3.7, P < 0.05). Importantly, both circumferential and longitudinal shortening correlated with LV relative wall thickness (R > 0.60, P = 0.001 for both).

CONCLUSIONS

In patients with hypertensive LVH, despite normal LV function via echocardiography or CMR, CMR intramyocardial tagging show depressed global MWCS while 3D MR strain revealed marked underlying regional heterogeneity of LV dysfunction.

Increased extracellular volume and altered mechanics are associated with LVH in hypertensive heart disease, not hypertension alone

OBJECTIVES

The goal of this study was to assess the relationship among extracellular volume (ECV), native T1, and systolic strain in hypertensive patients with left ventricular hypertrophy (HTN LVH), hypertensive patients without LVH (HTN non-LVH), and normotensive controls.

BACKGROUND

Diffuse myocardial fibrosis in HTN LVH patients, as reflected by increased ECV and native T1, may be an underlying mechanism contributing to increased cardiovascular risk compared with HTN non-LVH subjects and controls. Furthermore, increased diffuse fibrosis in HTN LVH subjects may be associated with reduced peak systolic and early diastolic strain rate compared with the other 2 groups.

METHODS

T1 mapping was performed in 20 HTN LVH (mean age, 55 ± 11 years), 23 HTN non-LVH (mean age, 61 ± 12 years), and 22 control subjects (mean age, 54 ± 7 years) on a Siemens 1.5-T Avanto (Siemens Healthcare, Erlangen, Germany) using a previously validated modified look-locker inversion-recovery pulse sequence. T1 was measured pre-contrast and 10, 15, and 20 min after injection of 0.15 mmol/kg gadopentetate dimeglumine, and the mean ECV and native T1 were determined for each subject. Measurement of circumferential strain parameters were performed using cine displacement encoding with stimulated echoes.

RESULTS

HTN LVH subjects had higher native T1 compared with controls (p < 0.05). HTN LVH subjects had higher ECV compared with HTN non-LVH subjects and controls (p < 0.05). Peak systolic circumferential strain and early diastolic strain rates were reduced in HTN LVH subjects compared with HTN non-LVH subjects and controls (p < 0.05). Increased levels of ECV and native T1 were associated with reduced peak systolic and early diastolic circumferential strain rate across all subjects.

CONCLUSIONS

HTN LVH patients had higher ECV, longer native T1 and associated reduction in peak systolic circumferential strain, and early diastolic strain rate compared with HTN non-LVH and control subjects. Measurement of ECV and native T1 provide a noninvasive assessment of diffuse fibrosis in hypertensive heart disease.

Basal septal hypertrophy

A significant clinical problem is patients presenting with exercise-limiting dyspnoea, sometimes with associated chest pain, in the absence of detectable left ventricular (LV) systolic dysfunction, coronary artery disease, or lung disease. Often the patients are older, female, and have isolated basal septal hypertrophy (BSH), frequently on a background of mild hypertension. The topic of breathlessness in patients with clinical heart failure, but who have a normal ejection fraction (HFNEF) has attracted significant controversy over the past few years. This review aims to analyse the literature on BSH, identify the possible associations between BSH and HFNEF, and consequently explore possible pathophysiological mechanisms whereby clinical symptoms are experienced.

Reproducibility of myocardial strain and left ventricular twist measured using complementary spatial modulation of magnetization

PURPOSE

To establish the reproducibility of complementary spatial modulation of magnetization (CSPAMM) tagged cardiovascular MR (CMR) data in normal volunteers.

MATERIALS AND METHODS

Twelve healthy volunteers underwent CMR studies on two separate occasions using an identical CSPAMM pulse sequence with images acquired in three short axis slices. Data were analyzed by two independent observers using harmonic phase analysis (HARP). Lagrangian circumferential and radial strain, rotation, and left ventricular twist were calculated.

RESULTS

The intraobserver reproducibility of circumferential strain (CoV [coefficient of variation] 1.5-4.3%) and LV twist (CoV 1.2-4.4%) was better than radial strain (CoV 10.6-14.8%). For interobserver reproducibility, circumferential strain (CoV 3.5-6.2%) and LV twist (CoV 3.5-7.2%) were more reproducible than radial strain (CoV 11.8-21.8%). Interstudy reproducibility of circumferential strain (CoV 3.7-5.5%) and LV twist (CoV 9.8-12.2%) were good but radial strain (CoV 13.8-23.4%) but showed poorer interstudy reproducibility. Sample size calculations suggested 20 or fewer subjects are needed to detect a 10% change in circumferential strain (power 90%; α error 0.05), whereas for twist, 66 subjects would be required.

CONCLUSION

In normal volunteers, the intraobserver, interobserver, and interstudy reproducibility of circumferential strain and LV twist measured from CSPAMM tagged CMR data are good, but are less so for radial strain.

Subclinical left ventricular dysfunction and silent cerebrovascular disease: the Cardiovascular Abnormalities and Brain Lesions (CABL) study

BACKGROUND

Silent brain infarcts (SBIs) and white matter hyperintensities are subclinical cerebrovascular lesions associated with incident stroke and cognitive decline. Left ventricular ejection fraction (LVEF) is a predictor of stroke in patients with heart failure, but its association with subclinical brain disease in the general population is unknown. Left ventricular global longitudinal strain (GLS) can detect subclinical cardiac dysfunction even when LVEF is normal. We investigated the relationship of LVEF and GLS with subclinical brain disease in a community-based cohort.

METHODS AND RESULTS

LVEF and GLS were assessed by 2-dimensional and speckle-tracking echocardiography in 439 participants free of stroke and cardiac disease from the Cardiovascular Abnormalities and Brain Lesions (CABL) study. SBIs and white matter hyperintensities were assessed by brain MRI. Mean age of the study population was 69±10 years, 61% were women, LVEF was 63.8±6.4%, GLS was -17.1±3.0%. SBIs were detected in 53 participants (12%), white matter hyperintensity volume was 0.63±0.86%. GLS was significantly lower in participants with SBI versus those without (-15.7±3.5% versus -17.3±2.9%, P<0.01), whereas no difference in LVEF was observed (63.3±8.6% versus 63.8±6.0%, P=0.60). In multivariate analysis, lower GLS was associated with SBI (odds ratio/unit decrease=1.18; 95% confidence interval, 1.05-1.33; P<0.01), whereas LVEF was not (odds ratio/unit increase=1.00; 95% confidence interval, 0.96-1.05; P=0.98). Lower GLS was associated with greater white matter hyperintensity volume (adjusted β=0.11, P<0.05), unlike LVEF (adjusted β=-0.04, P=0.42).

CONCLUSIONS

Lower GLS was independently associated with subclinical brain disease in a community-based cohort without overt cardiac disease. GLS can provide additional information on cerebrovascular risk burden beyond LVEF assessment.

Usefulness of speckle tracking echocardiography in hypertensive crisis and the effect of medical treatment

The acute impact of hypertensive crisis, and changes after treatment, on left ventricular (LV) systolic and diastolic function using comprehensive echocardiography, including speckle tracking, has not been well characterized. Thirty consecutive patients admitted to the hospital from the emergency room with hypertensive crisis underwent Doppler echocardiography at baseline and after blood pressure optimization. The mean age of the patients was 54 ± 13 years, with 19 men (63%). The most common presenting symptoms included dyspnea (70%), chest pain (43%), and altered mental status (13%). Mean systolic and diastolic blood pressures at presentation were 198 ± 12 and 122 ± 12 mm Hg, decreasing to 143 ± 15 and 77 ± 12 mm Hg (p <0.001 for both) after treatment. There was no significant change in LV ejection fraction between baseline and follow-up (48 ± 18% vs 46 ± 18%, p = 0.50); however, global longitudinal LV systolic strain (-10 ± 4% to -12 ± 4%, p = 0.01) and global systolic strain rate (-1.0 ± 0.4 vs -1.4 ± 0.6 s(-1), p = 0.01) significantly improved. Mean global early diastolic strain (-7.2 ± 4.0% to -9.4 ± 2.9%, p = 0.004) and early diastolic strain rate (0.3 ± 0.2 to 0.5 ± 0.4 s(-1), p = 0.05) also improved after treatment. On multivariate analysis, the independent predictors of LV longitudinal strain at follow-up were LV ejection fraction (p <0.001), heart rate (p = 0.005), systolic blood pressure (p = 0.04), and left atrial volume index (p = 0.05). In conclusion, as opposed to LV ejection fraction, LV systolic strain and strain rate were depressed during hypertensive crisis and significantly improved after medical treatment. LV diastolic function, assessed using conventional and speckle-tracking parameters, was also depressed and significantly improved after treatment.

Relationship of multidirectional myocardial strain with radial thickening and ejection fraction and impact of left ventricular hypertrophy: a study in a community-based cohort

BACKGROUND

Left ventricular (LV) systolic strain provides additional prognostic value to LV ejection fraction (LVEF) and wall motion analysis. However, the relationship between myocardial multidirectional strain and LVEF, and the effect of LV hypertrophy on this relationship, are not completely understood especially in unselected populations.

METHODS

LV global longitudinal (εL ) and circumferential (εC ) systolic strain analysis was performed by two-dimensional speckle tracking echocardiography in 215 participants from a community-based study. LV radial wall thickening was measured as global radial strain (εR ), and LVEF was assessed by biplane Simpson's method.

RESULTS

εR was significantly associated with εC (β = -0.56, P < 0.01) and with εL (β = -0.18, P < 0.01). The contribution of εL to εR was especially evident in subjects with lower εC and in presence of LV hypertrophy (β = -0.30, P < 0.01). εL and εC were significantly associated with LVEF (β = -0.36 and β = -0.49, both P < 0.01) independent of LV mass and other confounders, and their interaction significantly improved the prediction of LVEF (R(2) -change = 0.14) but not of εR (R(2) -change = 0.002).

CONCLUSIONS

εR is mainly related to εC with a smaller contribution of εL , which becomes especially evident in subjects with lower εC and in presence of LV hypertrophy. Therefore, radial thickening may not detect subclinical LV longitudinal function reduction in normal ventricles and when εC is preserved. While a reduction in εL has a limited impact on εR , it exerts a greater effect on global LVEF, therefore for a more accurate LVEF prediction both εL and εC need to be considered.

Relation of torsion and myocardial strains to LV ejection fraction in hypertension

OBJECTIVES

The goal of this study was to define the mechanism of preserved ejection fraction (EF) despite depressed myocardial strains in hypertension (HTN).

BACKGROUND

Concentric left ventricular (LV) remodeling in HTN may have normal or supranormal EF despite depressed myocardial strains. The reason for such discordance is not clear. The aim of this study was to comprehensively evaluate the LV mechanics in a well-defined HTN population to define underlying reasons for such a paradox.

METHODS

Sixty-seven patients with resistant HTN and 45 healthy control subjects were studied by cardiac magnetic resonance imaging and tissue tagging with 3-dimensional analysis. Amplitude and directional vector of longitudinal (Ell), circumferential (Ecc), and principal strain for maximal shortening (E3) were computed at basal, mid, and distal LV levels, respectively. LV torsion, defined as the rotation angle of apex relative to base, and LV twist, which accounts for the effects of differential LV remodeling on torsion for comparison among the 2 groups, were also calculated.

RESULTS

LV mass index and LV mass/LV end-diastolic volume ratio were significantly higher in the HTN group compared with controls, consistent with concentric LV remodeling. Ell and Ecc were significantly decreased in amplitude with altered directional vector in HTN compared with controls. However, the amplitude of E3 was similar in the 2 groups. Torsion and twist were significantly higher in HTN, which was mainly due to increase in apical rotation. The HTN group demonstrated significantly increased LV wall thickening compared with controls that resulted in greater LVEF in the HTN group compared with controls (70% vs. 65%, p < 0.001, respectively).

CONCLUSIONS

In compensated LV remodeling secondary to HTN, there is increased LV wall thickening with preserved E3 and increased torsion compared with normal controls. This, therefore, contributes to supranormal LVEF in HTN despite depressed longitudinal and circumferential strains.

Left ventricular midwall mechanics at 24 weeks' gestation in high-risk normotensive pregnant women: relationship to placenta-related complications of pregnancy

OBJECTIVES

Most studies during pregnancy have assessed maternal left ventricular (LV) function by load-dependent indices, assessing only chamber function. The aim of this study was to assess afterload-adjusted LV myocardial and chamber systolic function at 24 weeks' gestation and 6 months postpartum in high-risk normotensive pregnant women.

METHODS

A group of 118 high-risk women with bilateral notching of the uterine arteries underwent an echocardiographic examination to evaluate midwall mechanics (midwall shortening (mFS%) and stress-corrected midwall shortening (SCmFS%)) of the LV at 24 weeks' gestation and 6 months postpartum. Patients were followed until delivery and pregnancies were classified retrospectively as uneventful (uncomplicated outcome) or complicated. A control group of 54 low-risk women with uneventful pregnancies without bilateral notching was also enrolled.

RESULTS

The pregnancy was uneventful in 74 (62.7%) women, whereas 44 (37.3%) developed complications. At 24 weeks' gestation, mFS% and SCmFS% were greater in the uncomplicated-outcome compared with the complicated-outcome group (25.9 ± 4.8 vs 18.8 ± 5.0%, P < 0.001 and 107.9 ± 18.4 vs 77.9 ± 20.7%, P < 0.001, respectively). At 6 months postpartum, SCmFS% remained greater in the uncomplicated-outcome compared with the complicated-outcome group (100.4 ± 21.6 vs 87.8 ± 19.1, P < 0.05). In the uncomplicated-outcome group, SCmFS% was higher during pregnancy than it was postpartum, whereas in the complicated-outcome group, it was lower during pregnancy than it was postpartum (P < 0.05).

CONCLUSIONS

Maternal cardiac midwall mechanics appear to be enhanced (SCmFS% increased compared with controls) during pregnancy compared with postpartum in high-risk patients with uncomplicated pregnancy, whereas midwall mechanics are depressed both during pregnancy and postpartum in patients with pregnancy complications.

Assessment of subclinical left ventricular dysfunction in obstructive sleep apnea patients with speckle tracking echocardiography

In this study, our aim was to evaluate the LV (left ventricle) subclinical myocardial dysfunction using the two-dimensional speckle tracking echocardiography (2D-STE) method on obstructive sleep apnea (OSA) patients with preserved left ventricular ejection fraction (LVEF) and without any confounding disease that may result myocardial dysfunction. Twenty-one healthy individuals and 58 OSA patients were enrolled in the study. The patients were categorized into mild, moderate and severe OSA groups according to the apnea-hypopnea index (AHI). Conventional- and tissue Doppler echocardiography imagings were performed in all the individuals besides the 2D-STE. The longitudinal strain (S) and systolic strain rate (SR(S)) values decreased as the severity of disease increased from moderate towards severe OSA. The circumferential S and SR(S) values were observed to be lower in the severe OSA patients. Despite the increase in the radial S and SR(S) in moderate and mild OSA patients, these measurements decreased in those with severe OSA. Although the longitudinal, circumferential and radial early diastolic strain rates (SR(E)) decreased as the severity of disease increased form moderate to severe, the late diastolic strain rates (SR(A)) were observed to increase. In the early stages of OSA, longitudinal systolic LV dysfunction is detected in addition to the diastolic dysfunction. The circumferential mechanics of the LV deteriorate in the later stages of the OSA. Despite a compensatory increase in the radial LV function in the early stages of OSA, in later stages, the LV radial function also deteriorates. The assessment of the myocardial functions using the STE method in patients with OSA with preserved LVEF has the potential to detect the subclinical LV dysfunction and might provide useful information for risk stratification.

Regional left ventricular myocardial dysfunction as a predictor of incident cardiovascular events MESA (multi-ethnic study of atherosclerosis)

OBJECTIVES

We sought to examine the prognostic value of subclinical left ventricular (LV) regional myocardial dysfunction (RMD) measured by magnetic resonance imaging (MRI) among asymptomatic individuals.

BACKGROUND

LV RMD, defined as segmental impairment in systolic wall thickening, predicts adverse events in patients with established cardiovascular disease. MRI is highly accurate for detecting subtle RMD, of which the prognostic significance in a large multiethnic asymptomatic population is not known.

METHODS

We used MRI to evaluate baseline regional LV myocardial function and prospectively followed a multiethnic (African American, Caucasian, Chinese, and Hispanic) population-based sample of 4,510 men and women without cardiovascular disease for a mean of 4.6 years. Regional myocardial dysfunction was defined as the presence of impaired systolic wall thickening (<10th percentile of segment-specific population distribution) in ≥2 contiguous LV segments within any given coronary artery territory.

RESULTS

Baseline prevalence of RMD was 25.6%. Heart failure developed in 34 (1.0%) and 30 (2.6%) participants without and with RMD, respectively (p < 0.001). After adjustment for demographics and traditional risk factors, RMD remained independently associated with incident heart failure (hazard ratio [HR]: 2.62; 95% confidence interval [CI]: 1.56 to 4.39; p < 0.001). The relationship persisted after further adjustment for biomarkers of reported association with cardiovascular disease and indexes of global LV systolic dysfunction and hypertrophy (HR: 1.80; 95% CI: 1.02 to 3.20; p = 0.044). Similarly, RMD independently conferred an increased risk for hard coronary events (myocardial infarction or death from coronary heart disease; HR: 1.75; 95% CI: 1.06 to 2.89; p = 0.029), the composite of hard coronary events and stroke (HR: 1.72; 95% CI: 1.16 to 2.56; p = 0.005), and all atherosclerotic cardiovascular events (HR: 1.50; 95% CI: 1.09 to 2.07; p = 0.012).

CONCLUSIONS

Among an asymptomatic multiethnic American cohort, RMD is an independent predictor beyond traditional risk factors and global LV assessment for incident heart failure and atherosclerotic cardiovascular events. The clinical utility of early recognition of this subclinical phenotype deserves further investigation. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487).

Imaging in hypertensive heart disease

Hypertensive heart disease is the target organ response to arterial hypertension. Left ventricular hypertrophy represents an important predictor for cardiovascular events. Myocardial fibrosis, a common end point in hypertensive heart disease, has been linked to the development of left ventricular hypertrophy and diastolic dysfunction. Echocardiography is clinically useful in the detection of left ventricular hypertrophy and the assessment of diastolic function. Although echocardiography is more widely available, cardiac magnetic resonance has been demonstrated to be more reproducible for the estimation of left ventricular mass. Future developments in cardiac magnetic resonance techniques may facilitate the quantification of diffuse fibrosis that occurs in hypertensive heart disease. Thus, advances in cardiac imaging provide comprehensive, noninvasive tools for imaging left ventricular hypertrophy, diastolic dysfunction, myocardial fibrosis and ischemia observed in hypertensive heart disease. The objective of this article is to summarize the state-of-the-art and the future of multimodality imaging of hypertensive heart disease.

Normal ranges and physiological changes of midwall fractional shortening in healthy korean population

Background and Objectives

Left ventricular (LV) midwall fractional shortening (FSmw) reflects systolic function more accurately than LV endocardial fractional shortening (eFS) in patients with increased LV wall thickness. Although the normal reference ranges of LV-FSmw have been suggested in Western population studies, its reference values and age-related physiological changes in Eastern populations remain unknown.

Subjects and Methods

Conventional echocardiographic parameters, LV-FSmw, and stress-corrected LV-FSmw were assessed in 160 healthy and clinically normal subjects with a mean age of 45 (range, 11-72 years; 104 males, 56 women), all of whom were confirmed to be free of disease, based on laboratory investigations, clinical and physical examination findings and computed tomographic coronary angiographic examinations.

Results

LV-FSmw was higher in women compared to men. However, the differences were without statistical significance (18.2±1.5% for male gender and 19.4±2.5% for female gender, p=0.07). In contrast to LV-eFS that progressively increased with age (p=0.001), LV-FSmw and stress-corrected LV-FSmw was not influenced by changes in age (p=0.88 and 0.29, respectively). The results remained unchanged when analyses were performed adjusting for gender.

Conclusion

The results of this study provide normal reference values for LV-FSmw and stress-corrected LV-FSmw and their natural physiological changes with advancing age. These measures can be used as reference standards for research on LV systolic function in the setting of pressure or volume overload.

A dual-chamber, thick-walled cardiac phantom for use in cardiac motion and deformation imaging by ultrasound

Determination of the mechanical properties of the myocardium is crucial for cardiac diagnosis. Cardiac strain and strain rate imaging may enable such quantification. To further develop these methodologies, an experimental setup allowing the recording of ultrasonic deformation data in a reproducible manner is necessary. Such setup with biventricular polyvinyl alcohol heart phantoms has been built. To test this setup, segmental longitudinal, radial and circumferential displacement, velocity, strain and strain rate in the phantoms were measured using a clinical ultrasound scanner and commercially available deformation imaging algorithms (based on both tissue velocity imaging and speckle tracking). The model deformation was close to that observed in the human left ventricular wall and was highly reproducible (e.g., the average peak longitudinal strain for the mid- and apical phantom segments equals -15.32 +/- 0.53% and -19 +/- 6% for the ventricle wall). The experimental setup is a valuable source of data for the development of algorithms for deformation estimation.