Abstract
Aims
Non-invasive left ventricular (LV) pressure–strain loop (PSL) provides a novel method of quantifying myocardial work (MW) with potential advantages over conventional global longitudinal ...strain (GLS) by incorporating measurements of myocardial deformation and LV pressure. We investigated different patterns of LV PSL and global MW index (GWI) in patients with hypertension (HTN) and dilated cardiomyopathy (CMP).
Methods and results
Seventy-four patients underwent transthoracic echocardiography and strain analysis before coronary angiography. Patients were divided into three groups: control, HTN, and CMP. GWI was calculated as the area of the LV PSL as a product of strain × systolic blood pressure. MW efficiency (GWE) is derived from the percentage ratio of constructive work (GCW) to sum of constructive work (GCW) and wasted work (GWW). Influences of HTN and LV function on its relationship with MW were evaluated. GLS and LV ejection fraction were preserved in the HTN group with no difference from controls. GWI was significantly higher in moderate to severe HTN patients (P = 0.004) as a compensatory mechanism to preserve LV contractility and function against an increase in afterload. GWE was preserved in HTN patients due to the proportional increase in GCW and GWW. GLS, GWI, and GWE were significantly reduced in CMP (P < 0.05), with a trend in rightward shift and reduction in the LV PSL.
Conclusion
GWI is a potential new technique that allows better understanding of the relationship between LV remodelling and increased wall stress under different loading conditions.
Noninvasive detection of functionally significant coronary artery disease (CAD) by echocardiography remains challenging, with the need to perform stress imaging to detect ischemia. The aim of this ...study was to determine whether global myocardial work (MW), derived from noninvasive left ventricular (LV) pressure-strain loops at rest, can predict significant CAD in patients without regional wall motion abnormalities and preserved LV ejection fraction (EF).
One hundred and fifteen patients referred for coronary angiography who had EF ≥ 55%, no resting regional wall motion abnormalities, and no chest pain were assessed using echocardiography. Global MW was derived from noninvasive LV pressure-strain loops constructed from speckle-tracking echocardiography indexed to brachial systolic blood pressure. Global constructive work represented the sum of positive work due to myocardial shortening during systole and negative work due to lengthening during isovolumic relaxation. Global wasted work represented energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation. Global MW efficiency was derived from the percentage ratio of constructive work to the sum of constructive work and wasted work.
Patients with significant CAD demonstrated a significantly reduced global MW (P < .001) compared with those without CAD. Global longitudinal strain was significantly reduced (P < .001) in patients with multivessel CAD but not those with single-vessel CAD (P = .47). Receiver operating characteristic curve analysis demonstrated that global MW was the most powerful predictor of significant CAD (area under the curve = 0.786) and was superior to global longitudinal strain (area under the curve = 0.693). The optimal cutoff global MW value to predict significant CAD was 1,810 mm Hg% (sensitivity, 92%; specificity, 51%).
Noninvasive global MW derived using LV pressure-strain loops at rest is a more sensitive index than global longitudinal strain to detect significant CAD in patients with no regional wall motion abnormalities and normal EF. This is a potential valuable clinical tool to assist in the early diagnosis of CAD.
Despite the already well-known role the right side of the heart plays in many diseases, right ventricular (RV) function has only recently been carefully considered. Echocardiography is the first-line ...diagnostic technique for the assessment of the right ventricle and right atrium, whereas cardiac magnetic resonance is considered the gold standard but is limited by cost and availability. According to the current guidelines, systolic RV function should be assessed by several conventional measurements, but the efficacy of these parameters as diagnostic and prognostic tools has been questioned by many authors. The development in recent years of myocardial deformation imaging techniques and their application to the right heart chambers has allowed deeper evaluation of the importance of RV function in the pathophysiology of a large number of cardiovascular conditions, but the real value of this new tool has not been completely clarified. The aim of this review is to provide a wide and careful analysis of findings available in the literature about the assessment of RV systolic function by strain measurements, comparing them with conventional parameters and evaluating their role in several clinical settings.
Purpose of Review
Echocardiography is a valuable tool for management of patients with a left ventricular assist device (LVAD). We present an updated review on the practical applications of the role ...of echocardiography for pre- and postoperative evaluation of patients selected.
Recent Findings
The LVAD is a temporary or permanent option for patients with advanced heart failure who are unresponsive to other therapy. Use of the device has its own risks, and implantation remains a complex procedure. Transthoracic and transesophageal echocardiography are useful tools for patient evaluation and monitoring both peri- and postoperatively, as we previously presented. Assessment of left and right ventricular function, complications such as thrombus formation or intracardiac shunting, and valvular disease are all important in this assessment. This also aids in predicting postoperative complications. Placement of the device is confirmed intraoperatively, and subsequent ramp studies are used to determine optimal device settings.
Summary
Right ventricular (RV) failure is the most common postoperative complication and preoperative evaluation of its function is crucial. Studies suggest that tricuspid annular plane systolic excursion, RV fractional area change, and RV global longitudinal strain are strong predictors of RV failure; LV ejection fraction, size, and end-diastolic diameter are also important markers. Aortic regurgitation and mitral stenosis must always be corrected prior to LVAD placement. However, direct visualization before and after implantation, especially to rule out potential contraindications such as thrombi, cannot be overemphasized. Ramp studies remain an integral part of device optimization and may result in greater myocardial recovery than previously realized.
Until recently the left atrium had been subordinate to the left ventricle, but cardiologists now recognize that left atrial (LA) function is indispensable to normal circulatory performance. ...Transthoracic two-dimensional (2D) and Doppler echocardiography can elucidate parameters of LA function non-invasively. Yet, with the advent of 2D speckle-tracking echocardiography, we are able to detect early LA dysfunction even before structural changes occur. This is pivotal in some common disease states, such as atrial fibrillation, hypertension, and heart failure, in which LA deformation parameters can influence clinical management. However, a unique standardized technique to investigate LA deformation needs to be validated.
Left ventricular (LV) twist or torsion represents the mean longitudinal gradient of the net difference in clockwise and counterclockwise rotation of the LV apex and base, as viewed from LV apex. ...Twist during ejection predominantly deforms the subendocardial fiber matrix, resulting in storage of potential energy. Subsequent recoil of twist deformation is associated with the release of restoring forces, which contributes to LV diastolic relaxation and early diastolic filling. Noninvasive techniques such as magnetic resonance imaging and echocardiography are useful for understanding LV twist dynamics in clinical settings, and data regarding their relative merits and pitfalls are rapidly accumulating. This review is a focused update on the current and evolving applications of LV twist mechanics in clinical cardiology. First, the theoretical framework for understanding the physiological sequence of LV twist during a cardiac cycle is presented. Second, variations in LV twist encountered in different experimental and clinical situations are discussed. Finally, the review presents an algorithm for routine application of LV twist in clinical differentiation of patterns of LV dysfunction encountered in day-to-day practice.
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