This study sought to investigate regional left ventricular (LV) rotation in patients with hypertrophic cardiomyopathy (HCM).
Methods and results:
The study comprised 44 patients with HCM with a typical reverse septal curvature (age 40 ± 14 years, 33 men) and 44 healthy volunteers (age 39 ± 14 years, 32 men) in whom LV rotation could be assessed at the basal and apical LV level with speckle-tracking echocardiography, using the QLAB Advanced Quantification Software version 6.0 (Philips, Best, The Netherlands). In HCM patients, lower values of initial counter-clockwise rotation at the basal LV level (1.5 ± 1.2 vs. 0.6 ± 0.9°, P < 0.001) were seen, in particular in the septal segment (1.7 ± 1.6 vs. 0.4 ± 0.7°, P < 0.001). After this period, the direction of rotation changed to clockwise with a peak basal rotation of -4.8 ± 2.0° in controls vs. -6.1 ± 2.5° in HCM patients (P < 0.05). Peak basal rotation in HCM patients was in particular higher in the anterior (-6.6 ± 3.0 vs. -4.4 ± 2.4°, P < 0.01) and septal (-5.4 ± 2.6 vs. -3.9 ± 1.9°, P < 0.05) segments. The normalized (corrected for peak basal rotation) global back-rotation rate was lower in HCM patients (4.1 ± 3.1 vs. 6.3 ± 4.9 s(-1), P < 0.05), in particular driven by a lower rate in the septal segment (3.8 ± 2.6 vs. 6.4 ± 4.8 s(-1), P < 0.01). At the apical level, changes in rotation and back-rotation were more homogeneous.
Changes in rotation and back-rotation at the LV basal level in HCM patients are mainly caused by regional changes in the basal septal and anterior segments, the segments mostly involved in the hypertrophic process.
[Show abstract][Hide abstract] ABSTRACT: Cardiomyopathies are a heterogeneous group of diseases that can be phenotypically recognized by specific patterns of ventricular morphology and function. The authors summarize recent clinical observations that mechanistically link the multidirectional components of left ventricular (LV) deformation with morphological phenotypes of cardiomyopathies for offering key insights into the transmural heterogeneity of myocardial function. Subendocardial dysfunction predominantly alters LV longitudinal shortening, lengthening and suction performance and contributes to the phenotypic patterns of heart failure (HF) with preserved ejection fraction seen with hypertrophic and restrictive patterns of cardiomyopathy. On the other hand, a more progressive transmural disease results in reduction of LV circumferential and twist mechanics leading to the phenotypic pattern of dilated cardiomyopathy and the clinical syndrome of HF with reduced ejection fraction. A proper characterization of LV transmural mechanics, energetics, and space-time distributions of pressure and shear stress may allow recognition of early functional changes that can forecast progression or reversal of LV remodeling. Furthermore, the interactions between LV muscle and fluid mechanics holds the promise for offering newer mechanistic insights and tracking impact of novel therapies.
[Show abstract][Hide abstract] ABSTRACT: Left ventricular twist is an essential part of left ventricular function. Nevertheless, knowledge is limited in "the cardiology community" as it comes to twist mechanics. Fortunately the development of speckle tracking echocardiography, allowing accurate, reproducible and rapid bedside assessment of left ventricular twist, has boosted the interest in this important mechanical aspect of left ventricular deformation. Although the fundamental physiological role of left ventricular twist is undisputable, the clinical relevance of assessment of left ventricular twist in cardiomyopathies still needs to be established. The fact remains; analysis of left ventricular twist mechanics has already provided substantial pathophysiological understanding on a comprehensive variety of cardiomyopathies. It has become clear that increased left ventricular twist in for example hypertrophic cardiomyopathy may be an early sign of subendocardial (microvascular) dysfunction. Furthermore, decreased left ventricular twist may be caused by left ventricular dilatation or an extensive myocardial scar. Finally, the detection of left ventricular rigid body rotation in noncompaction cardiomyopathy may provide an indispensible method to objectively confirm this difficult diagnosis. All this endorses the value of left ventricular twist in the field of cardiomyopathies and may further encourage the implementation of left ventricular twist parameters in the "diagnostic toolbox" for cardiomyopathies.
World Journal of Cardiology (WJC) 08/2015; 7(8):476-82. DOI:10.4330/wjc.v7.i8.476 · 2.06 Impact Factor
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