Cushing's syndrome is associated with an increased risk for abnormalities of cardiac mass, which ameliorates, but does not fully disappear after remission. Systolic and diastolic functions are largely within the normal range in these patients.
AimsPrevious studies investigating the effect of hypoxia on left ventricle focused on its global function, an approach that may not detect a selective dysfunction of subendocardial layers that are most sensitive to an inadequate oxygen supply. In the HIGHCARE study, aimed at exploring the effects of high altitude hypoxia on multiple biological variables and their modulation by an angiotensin receptor blocker, we addressed the effects of hypobaric hypoxia on both systolic and diastolic left ventricular geometry and function, focusing on echocardiographic assessment of left ventricle twist to indirectly examine subendocardial left ventricular systolic function.
Methods and resultsIn 39 healthy subjects, physiological and echocardiographic variables, including left ventricular twist and a simplified torsion-to-shortening ratio (sTSR), were recorded at sea level, at 3400 m, and at 5400 m altitude (Mount Everest base camp). Both left ventricular twist and sTSR were greater at 5400 m than at sea level (12.68 vs. 9.68 and 0.285 vs. 0.202, P , 0.05 for both), were linearly related to the reduction in arterial oxygen partial pressure (P , 0.01 for both), and were associated with significant changes in LV dimensions and contractility. No effects of angiotensin receptor blockade were observed on these variables throughout the study.
ConclusionOur study, for the first time, demonstrates an increase in left ventricular twist at high altitude in healthy subjects exposed to high altitude hypoxia, suggesting the occurrence of subendocardial systolic dysfunction in such condition.
AimsDiastolic dysfunction in patients with heart failure has prognostic relevance, possibly because of its relationship with worsening haemodynamic status. In the quest for simpler indexes of haemodynamic status in patients, brain natriuretic peptide (BNP) levels have been proposed as a surrogate of diastolic function. To date, the value of combining BNP levels with non-invasive haemodynamic monitoring by transthoracic electric bioimpedance (TEB) for the prediction of diastolic function has not been evaluated.
Methods and resultsWe compared left ventricular diastolic function measured by tissue Doppler imaging (TDI) with TEB results and BNP levels in 120 patients with chronic advanced systolic heart failure on optimal treatment (70 + 9 years, NYHA 2.4 + 0.8, ejection fraction 31 + 5%). Of the TEB variables measured, we only considered thoracic fluid content (TFC). To describe diastolic function, we used the TDI of the velocity of displacement of the mitral annulus (E ′ ) and the ratio E/E ′ . In all patients, E/E ′ was significantly related to TFC and to BNP levels (P , 0.001). Moreover, the combination of BNP ≥ 350 pg/mL and TFC ≥ 35/kV identified patients with diastolic dysfunction (defined as E/E ′ ≥ 15) with high sensitivity and specificity (95 and 94%, respectively).
ConclusionThe combination of transthoracic bioimpedance monitoring and BNP measurement accurately indicated the presence of diastolic dysfunction in most patients. These user-friendly and operator-independent tools may be useful as a screening assessment for diastolic dysfunction, and consequently abnormal central haemodynamic status, either in ambulatory patients or when an adequate echocardiographic evaluation is not readily available.--
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