Geographic variation in the use of continuous outpatient inotrope infusion therapy and beta blockers

Background: Continuous outpatient inotrope infusion therapy (COIIT) can be used as palliative or interim treatment in patients with advanced heart failure (AHF). Despite widespread use, there is a relative lack of data informing best practices. This study aimed to examine whether patterns of COIIT use differed by region and to explore whether observed differences influenced clinical outcomes. Methods: Retrospective study of AHF patients receiving COIIT from May 2009 through June 2016. The primary outcome was regional difference, the secondary outcome was persistence (duration) on therapy. Cox proportional hazards model was used to calculate hazard ratios for treatment regimens. Results: There were 3,286 patients, mean (SD) age 61.9 (14.4) years and 74.0% (2,433) male. Inotrope selection and beta blocker use varied by region by chi square (χ2 (21) = 166.9, p < 0.001). Persistence was greater on milrinone compared to dobutamine (HR (for discontinuation) 0.54, CI 0.41–0.70, p < 0.001). Concurrent beta-blocker was associated with greater persistence for patients receiving milrinone (HR 0.13, CI 0.08–0.20, p < 0.001) and dobutamine (HR 0.36, CI 0.18–0.71, p < 0.001). Conclusions: Patterns of COIIT use varied by region, and variations in use were associated with differences in clinical outcomes. © 2021Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Female gender as independent risk factor of torsades de pointes during acquired atrioventricular block

PubMed ID: 27650425Background Female gender increases the risk of torsades de pointes (TdP) in the long QT syndrome, and this increased risk is assumed to be due to their longer QT interval. Objective The purpose of this study was to study the interplay between gender, duration of the QT interval, and risk of TdP during AV block. Methods We studied 250 patients (48% women) with AV block. QT interval was measured at the time of most severe bradycardia. We then constructed different receiver operating characteristic curves for the QTc of males and females for predicting TdP. Results As expected, patients with TdP had longer QTc intervals than did patients with uncomplicated AV block (564 ± 81 ms vs 422 ± 62 ms, P <.001). This correlation between longer QTc and higher risk of TdP was true for both genders. However, the QT of females with TdP was shorter than the respective value for males with TdP. Despite similar severity of bradycardia, the QT was shorter for females (QT 672 ± 88 ms vs 727 ± 57 ms for females with TdP vs males with TdP, P =.022). The QTc/TdP risk curve for females was shifted to the left in comparison to the pertinent graph for males. Female gender was an independent predictor of TdP. Conclusion Women are at increased risk for developing TdP during AV block, but this increased risk is independent of their longer QT interval. Females develop TdP with QT intervals that are not necessarily arrhythmogenic for males. © 2016 Heart Rhythm Societ

Combined Echocardiographic and Cardiopulmonary Exercise to Assess Determinants of Exercise Limitation in Chronic Obstructive Pulmonary Disease

Item does not contain fulltextBACKGROUND: Current methods do not allow a thorough assessment of causes associated with limited exercise capacity in patients with chronic obstructive pulmonary disease (COPD). METHODS: Twenty patients with COPD and 20 matched control subjects were assessed using combined cardiopulmonary and stress echocardiographic testing. Various echocardiographic parameters (left ventricular [LV] volumes, right ventricular [RV] area, ejection fraction, stroke volume, S', and E/e' ratio) and ventilatory parameters (peak oxygen consumption [Vo(2)] and A-Vo(2) difference) were measured to evaluate LV and RV function, hemodynamics, and peripheral oxygen extraction (A-VO(2) difference). RESULTS: Significant differences (both between groups and for group-by-time interaction) were seen in exercise responses (LV volume, RV area, LV volume/RV area ratio, S', E/e' ratio, tricuspid regurgitation grade, heart rate, stroke volume, and Vo(2)). The major mechanisms of reduced exercise tolerance in patients with COPD were bowing of the septum to the left in 12 (60%), abnormal increases in E/e' ratio in 12 (60%), abnormal stroke volume reserve in 16 (80%), low peak A-Vo(2) difference in 10 (50%), chronotropic incompetence in 13 (65%), or a combination of several mechanisms. Patients with COPD and poor exercise tolerance showed attenuated increases in stroke volume, heart rate, and A-Vo(2) difference and exaggerated changes in LV/RV ratio and LV compliance (ratio of LV volume to E/e' ratio) compared with patients with COPD with good exercise tolerance. CONCLUSIONS: Combined cardiopulmonary and stress echocardiographic testing can be helpful in determining individual mechanisms of exercise intolerance in patients with COPD. In patients with COPD, exercise intolerance is predominantly the result of chronotropic incompetence, limited stroke volume reserve, exercise-induced elevation in left filling pressure, and peripheral factors and not simply obstructive lung function. Limited stroke volume is related to abnormal RV contractile reserve and reduced LV compliance introduced through septal flattening and direct ventricular interaction