vendex and Ventricular-Dysfunction--Left

Left ventricular (LV) twist may be a compensatory mechanism to preserve ejection fraction (EF). In patients with hypertension, twist varies depending on the left ventricle's degree of remodeling and systolic function; it is increased in those with hypertension with normal EF (HTNEF) and diminished in those with hypertension with low EF (HTLEF). The ratio of collagen-degradation biomarkers in patients with hypertension is higher in those with low EFs than those with preserved EFs and may contribute to remodeling and systolic dysfunction.. The aim of this study was to evaluate the relationship between these biomarkers and LV twist in 82 patients with hypertension, 41 with EFs < 50% (HTLEF group) and 41 with EFs ≥ 50% (HTNEF group). Net LV twist was measured using speckle-tracking echocardiography. Markers of collagen turnover, including serum concentrations of matrix metalloproteinase-1 (MMP1), tissue inhibitor of MMP1 (TIMP1), and the ratio of MMP1 to TIMP1, were measured.. Log TIMP1, log MMP1, and log MMP1/TIMP1 ratio levels were higher in the HTLEF group than the HTNEF group (12.3 ± 0.3 vs 11.8 ± 0.1 [P < .0001], 9.1 ± 0.3 vs 8.0 ± 0.2 [P < .0001], and -3.3 ± 0.3 vs -3.8 ± 0.2 [P < .0001], respectively). Net LV twist was lower in the HTLEF group than the HTNEF group (3.3 ± 1.1 vs 11.7 ± 0.7, P < .0001). An inverse correlation existed between log MMP1/TIMP1 and net LV twist after adjusting for age, EF, duration of heart failure, systolic blood pressure, LV mass index, and LV sphericity index at end-diastole (r = -0.43, P < .0001).. This inverse correlation between twist and loss of myocardial collagen scaffolding in patients with hypertension with heart failure suggests that the integrity of the extracellular matrix may play an important role in preserving myocardial deformation.

Topics: Collagen; Echocardiography; Female; Heart Failure; Humans; Hypertension; Male; Matrix Metalloproteinase 1; Middle Aged; Reproducibility of Results; Sensitivity and Specificity; Tissue Inhibitor of Metalloproteinase-1; Torque; Ventricular Dysfunction, Left

Left ventricular (LV) twist mechanics are a promising, sensitive tool for assessing pathophysiologic changes in patients with systolic heart failure. Although LV twist is known to be load dependent in healthy volunteers, this has not been examined in patients with "long-standing" dilated cardiomyopathy (DCM). The aim of this study was to determine whether LV twist remains load dependent in the setting of long-standing, nonischemic DCM.. Thirty-four patients with DCM with baseline LV ejection fractions (LVEFs) < 40% and 13 subjects with preserved LVEFs (≥50%) were enrolled. After baseline measurements, pneumatic compression of the lower extremities (Pcom) was used to increase LV afterload. Subsequently, sublingual nitroglycerin (SL-NG) was administered to modify preload. Conventional echocardiographic parameters, LV end-systolic wall stress, net LV twist angle, and apex-to-base-rotation delay (ABRD) were assessed under each condition.. In patients with DCM, although LV end-systolic wall stress significantly increased under Pcom (196.9 ± 64.9 g/m(2) at baseline vs 231.8 ± 78.9 g/m(2) under Pcom, P < .017) and decreased after SL-NG application (231.8 ± 78.9 g/m(2) under Pcom vs 197.4 ± 67.4 g/m(2) after SL-NG, P < .017), net LV twist angle and ABRD showed no significant changes depending on LV loading condition (for LV twist, 7.63 ± 4.47° at baseline vs 7.03 ± 4.13° under Pcom vs 7.35 ± 4.36° after SL-NG, P = 0.65; for ABRD, 16.56 ± 13.81% at baseline vs 17.19 ± 14.81% under Pcom vs 15.95 ± 13.27% after SL-NG, P = .53). Careful examination of individual patient data revealed that LV twist was load independent when patients had LV twist < 12°. ABRD was also found to be load independent, but only in patients with LVEFs < 34%. In contrast, LV twist and ABRD were load dependent in patients with preserved LVEFs.. LV twist and its component, ABRD, had relatively load insensitive properties in patients with long-standing DCM and can be used in future clinical trials as load-independent indexes of LV dyssynchrony.

Topics: Cardiomyopathy, Dilated; Echocardiography; Elastic Modulus; Elasticity Imaging Techniques; Female; Heart Ventricles; Humans; Male; Middle Aged; Myocardial Ischemia; Stroke Volume; Torque; Ventricular Dysfunction, Left

Patients with severe chronic heart failure (CHF) suffer from marked weakness of skeletal muscles. Neuromuscular electrical stimulation (NMES) proved to be an alternative to active strength training. The objective of this study was to test the feasibility and effectiveness of NMES in patients with chronic heart failure. Seven patients (56.0 +/- 5.0 years, CHF for 20 +/- 4 months, left ventricular ejection fraction 20.1 +/- 10.0%) finished an 8 week course of NMES of the knee extensor muscles. The stimulator delivered biphasic, symmetric, constant voltage impulses of 0.7 ms pulse width with a frequency of 50 Hz, 2 s on and 6 s off. No adverse effects occurred. After the stimulation period, the isokinetic peak torque of the knee extensor muscles increased by 13% from 101.0 +/- 8.7 Nm to 113.5 +/- 7.2 Nm (p = 0.004). The maximal isometric strength increased by 20% from 294.3 +/- 19.6 N to 354.14 +/- 15.7 N (p = 0.04). This increased muscle strength could be maintained in a 20 min fatigue test indicating decreased muscle fatigue. These results demonstrate that NMES of skeletal muscles in patients with severe chronic heart failure is a promising method for strength training in this group of patients.

Topics: Chronic Disease; Electric Stimulation Therapy; Evaluation Studies as Topic; Feasibility Studies; Female; Heart Failure; Humans; Isometric Contraction; Knee Joint; Male; Middle Aged; Muscle Contraction; Muscle Fatigue; Muscle Weakness; Neuromuscular Junction; Range of Motion, Articular; Stroke Volume; Torque; Ventricular Dysfunction, Left