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Y Chandrashekhar

Publications and source records attributed to Y Chandrashekhar.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Relation between major indices of prognosis in patients with chronic congestive heart failure: studies of maximal exercise oxygen consumption, neurohormones and ventricular function.

Peak exercise capacity (Peak VO2), neurohormonal changes, ventricular enlargement and ejection fraction are among the most important determinants of prognosis in congestive heart failure. However, the inter-relation between these parameters is unknown. We, therefore, correlated these indices in patients with hemodynamically severe congestive heart failure (NYHA class II, pulmonary artery wedge pressure 25 +/- 2 mm Hg, cardiac index 2.5 +/- 0.2 l/min/m2, ejection fraction 43 +/- 2% and fractional shortening 19 +/- 1%). Peak VO2 measured directly during exercise by breath to breath expiratory gas analysis using a metabolic cart was 23 ml/min/kg. Plasma epinephrine (E) and norepinephrine (NE) were measured by high performance liquid chromatography (HPLC) and plasma renin activity (PRA), aldosterone (Aldo), cortisol, prolactin, growth hormone, anti-diuretic hormone (ADH) and antinatriuretic peptide (ANP) by radioimmunoassay. Ejection fraction was measured by echocardiography. There was no relation between peak VO2 and any of the neurohormones E: r = -0.43, NE: r = -0.43, ANP: r = -0.49, Cortisol: r = -0.37, ADH: r = -0.07, Aldo: r = -0.45, 2 tail critical value 0.55. PRA showed a modest correlation (r = -0.61). Similarly, there was no relation between ejection fraction or degree of ventricular enlargement and any of the other indices (r = -0.05). We conclude that although peak VO2, neurohormonal profile and ventricular function are important individual prognostic determinants, there seems to be no direct relation between them.

Adult↗
PubMedDate not supplied

Do hemodynamic indices correlate with maximum exercise capacity and oxygen consumption in chronic congestive heart failure?

The mechanism of exercise intolerance in chronic congestive heart failure remains unclear. We correlated resting haemodynamic variables with the peak exercise capacity and maximum oxygen consumption (VO2 max) in patients with congestive heart failure in 27 studies on treadmill exercise testing using the modified Bruce protocol. VO2 max was measured using breath by breath expiratory gas analysis. The patients were in severe congestive heart failure (NYHA class II and III, pulmonary artery wedge pressure 23 +/- 2 mmHg, cardiac index 2.4 +/- 0.21 l/min/m2). VO2 max was 23 +/- 2 ml/kg/min. Fatigue was the commonest symptom limiting the exercise. None of the hemodynamic variables correlated well with VO2 max. [right atrial pressure (r = 0.08), pulmonary artery pressure (r = 0.05), pulmonary artery wedge pressure (r = 0.08), aortic pressure (r = -0.3) & cardiac index (r = 0.29)]. Both uni- and multi-variate analysis failed to show any relation between VO2 max and resting hemodynamic variables. We conclude that unlike the acute heart failure syndromes, resting hemodynamic variables do not correlate with exercise capacity in patients with chronic congestive heart failure. The abnormal resting haemodynamics do not limit exercise in these patients. Peripheral mechanisms may thus be more important.

Cardiac Output, Low↗
PubMedDate not supplied

Can common exercise indices determine peak exercise oxygen consumption and anaerobic threshold during stress testing in patients with chronic congestive heart failure?

Maximal oxygen consumption (VO2 max) is one of the most important predictors of prognosis in chronic heart failure and is now used to define degree of heart failure. While most centres can routinely do treadmill exercise testing (TMT), VO2 max measurements are not widely available. We, therefore, analysed the ability to predict VO2 max from common TMT variables: Peak exercise heart rate, exercise time, and METS achieved in 26 patients with chronic congestive heart failure (NYHA II-III, ejection fraction 43 +/- 2%) in whom exercise VO2 studies were simultaneously done by breath to breath expiratory gas analysis using a metabolic cart. METS achieved during exercise and exercise time correlated reasonably well although not perfectly (r = 0.78 & 0.73 respectively, tail critical value +/-0.41). Resting ejection fraction did not correlate at all (r = 0.0004). The regression equation (2.7) (METS) + 5.8 defined VO2 max with SE of 0.47. Although in unvariate analysis, exercise time, METS achieved & peak heart rate predicted VO2 max, only METS achieved was predictive in step wise regression. None of the parameters predicted the anaerobic threshold accurately although there was a modest relation between AT and peak exercise VO2. We conclude that most exercise variables do not accurately predict VO2 max in patients with chronic congestive heart failure. METS achieved is the best predictor and the VO2 max can be predicted using a regression equation. Anaerobic threshold cannot be predicted without tests involving expiratory gas analysis.

Adult↗