Browsing by Author "McNab, Paul"

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    Cardiac dyssynchrony correlates with left ventricular remodeling after myocardial infarction
    (SOC MEDICA SANTIAGO, 2009) McNab, Paul; Castro, Pablo; Gabrielli, Luigi; Verdejo, Hugo; Carlos Quintana, Juan; Rodriguez, Jose A.; Corbalan, Ramon
    Background: Cardiac dyssynchrony is common in advanced heart failure (HF), but the changes in cardiac synchrony after myocardial infarction (MI) have not been adequately described. Aim: To study the relationship between cardiac synchrony and left ventricular remodeling after acute myocardial infarction. Material and methods: Forty nine patients aged 59+/-10 years (77% men) with a first episode of a ST segment elevation MI were studied. Scintigraphic left ventricular function and synchrony analyses were performed at baseline and after a six months follow-up. Determinations were compared with 33 healthy subjects. Results: At baseline, patients with MI had a decreased left ventricular ejection fraction (LVEF) and significant dyssynchrony, when compared with controls. LVEF was 36.4%+/-10%, left ventricular end-diastolic volume (LVEDV) 127+/-38 mL, interventricular delay (IEV) 29+/-35 milliseconds (ms), and intraventricular delay (IAV), 234+/-89 ms. After 6 months, LVEF significantly improved (38%+/-10%, p = 0.042) without significant changes in LVEDV (129+/-32 mL, p = 0.97), IEV (24+/-17, p = 0.96) or IAV (231 +/- 97, p = 0.34). At baseline there were significant correlations between IAV and LVEF, and between IAV and LVEDV (r = -0.48, p = 0.001 and r = -0.41, p = 0.004, respectively). These correlations remained significant after 6 months. There was a positive correlation between IAV and LVEDV changes at six months (r = 0.403, p = 0.04). Conclusions: The development of cardiac dyssynchrony correlates with adverse left ventricular remodeling after MI (Rev Med Chile 2009; 137: 1457-62).
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    Markedly increased Rho-kinase activity in circulating leukocytes in patients with chronic heart failure
    (MOSBY-ELSEVIER, 2011) Paz Ocaranza, Maria; Gabrielli, Luigi; Mora, Italo; Garcia, Lorena; McNab, Paul; Godoy, Ivan; Braun, Sandra; Cordova, Samuel; Castro, Pablo; Novoa, Ulises; Chiong, Mario; Lavandero, Sergio; Jalil, Jorge E.
    Background The small guanosine triphosphatase Rho and its target Rho-kinase have significant roles in experimental remodeling and ventricular dysfunction, but no data are available on Rho-kinase activation in patients with heart failure (HF). We hypothesized that, in patients with chronic HF, Rho-kinase in circulating leukocytes is activated and related to left ventricular (LV) remodeling and dysfunction.
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    Preload responsiveness-guided fluid removal in mechanically ventilated patients with fluid overload: A comprehensive clinical-physiological study
    (2024) Castro, Ricardo; Born, Pablo; Roessler, Eric; Labra, Christian; McNab, Paul; Bravo, Sebastian; Soto, Dagoberto; Kattan, Eduardo; Hernandez, Glenn; Bakker, Jan
    This study investigated fluid removal strategies for critically ill patients with fluid overload on mechanical ventilation. Traditionally, a negative fluid balance (FB) is aimed for. However, this approach can have drawbacks. Here, we compared a new approach, namely removing fluids until patients become fluid responsive (FR) to the traditional empiric negative balance approach. Twelve patients were placed in each group (n = 24). FR assessment was performed using passive leg raising (PLR). Both groups maintained stable blood pressure and heart function during fluid management. Notably, the FR group weaned from the ventilator significantly faster than negative FB group (both for a spontaneous breathing trial (14 h vs. 36 h, p = 0.031) and extubation (26 h vs. 57 h, p = 0.007); the difference in total ventilator time wasn't statistically significant (49 h vs. 62 h, p = 0.065). Additionally, FR group avoided metabolic problems like secondary alkalosis and potential hypokalemia seen in the negative FB group. FR-guided fluid-removal in fluid overloaded mechanically ventilated patients was a feasible, safe, and maybe superior strategy in facilitating weaning and disconnection from mechanical ventilation than negative FB-driven fluid removal. FR is a safe endpoint for optimizing cardiac function and preventing adverse consequences during fluid removal.