Dyspnea in Heart Failure with a Preserved Ejection Fraction
thesisposted on 2013-10-24, 00:00 authored by Karen M. Vuckovic
Dyspnea is a common, debilitating symptom of heart failure. African Americans, despite having the highest mortality rates for heart failure, have been underrepresented in clinical trials. To our knowledge there is limited information about dyspnea in African American patients with reduced ejection fraction heart failure and even less in patients with preserved ejection fraction. Therefore, the purpose of this prospective study was to describe and compare the occurrence and level of dyspnea in African American patients with preserved vs. reduced ejection fraction heart failure before and after the 6-minute walk test. A convenience sample of African Americans over 50 years of age (N = 45; preserved n = 19; reduced n = 26) was recruited from an outpatient clinic. Patients, randomly selected, participated in a substudy using brachial artery ultrasound to assess flow-mediated dilation (n = 13; preserved = 6; reduced = 7). Baseline dyspnea was measured using four dyspnea tools: Modified Research Council, Visual Analogue, 7-point Likert and Borg scales. During the 6-minute walk test dyspnea was measured using the Borg scale. Upon completion of the walk test dyspnea was measured using the Visual Analogue, 7-point Likert and Borg scales. The ultrasound substudy was performed before and after the walk test. Dyspnea scores were analyzed categorically using the Chi Square test and continuously using repeated measures analysis of variance to determine within and between group differences. There were no significant differences in age, gender, or co-morbidities between groups. At baseline the majority of the preserved group reported dyspnea across measures while the majority of the reduced group reported dyspnea with the Visual Analogue Scale. Both groups reported a significant increase in Borg scores from baseline to completion of the walk test (F1,43 = 40.8; p<.001) and from baseline to 3-minutes after the walk. Between group differences were insignificant. Using the Likert scale, 57% of preserved group reported less dyspnea, after walking while 46% of the reduced group reported their dyspnea level unchanged. Most patients selected walking as the most dyspnea-producing activity using the Medical Research Council scale. Both groups showed an abnormal response to ischemia during ultrasound.