Gender differences and quality of life in atrial fibrillation: The mediating role of depression

Objective This study investigated gender differences, depression, and health-related quality of life (QoL) in a cross-sectional sample of patients with atrial fibrillation (AF). Methods This cross-sectional study involved a convenience sample of AF patients from two tertiary-care clinics in Toronto, Canada. Ninety-three AF patients completed psychometrically validated measures of generic QoL and depression. Mediation analyses evaluated the relationship between gender and QoL using depression as mediating variable. Results Relative to male patients, female patients reported lower physical, but not mental, QoL. Gender was associated with both depression and physical QoL, while depression was correlated with poorer physical QoL. Path analyses demonstrated that depression significantly mediated the relationship between gender and physical QoL. Conclusion Among AF patients, female patients report lower physical QoL relative to male patients, and this relationship may be mediated by self-reported symptoms of depression. Albeit correlational, the findings underscore the need to develop a better understanding of the role of depression in physical QoL, especially when considering the burden of AF in women.Social Sciences and Humanities Research Counci

Psychological correlates of quality of life in atrial fibrillation

Objective: Atrial fibrillation (AF) is associated with significant health-related quality of life (QoL) impairments. Markers of heart disease severity have explained little variance in QoL and it is unclear what other factors will better account for the observed differences in adjustment. We examined whether specific personality traits and illness management styles would help explain the severity of QoL impairments reported in this population. Methods: Patients with AF (N = 93) completed validated questionnaires measuring disease burden (dependent variables: physical and mental QoL, symptom severity, psychological distress), personality (independent variables: anxiety sensitivity, optimism), and illness management style (mediating variable: symptom preoccupation). Hypothesized relationships were evaluated using mediation models. Results: Anxiety sensitivity was associated with poorer physical and mental QoL, greater symptom severity, and higher distress. Optimism was correlated with better mental QoL and lower distress, but unrelated to physical QoL and symptom severity. Symptom preoccupation significantly mediated the relationships between anxiety sensitivity and each of the QoL measures, as well as the relationships between optimism and mental well-being. Conclusions: Personality traits and illness management styles are important to consider when assessing the impact of AF on QoL. The data support a cognitive-behavioral model that explains the direct and indirect relationships between psychological predictors and multiple indices of QoL.Social Sciences and Humanities Research Counci

305 N-3 Polyunsaturated fatty acids alter expression of fibrotic and hypertrophic genes in a dog model of atrial cardiomyopathy

Omega-3 polyunsaturated fatty acids (PUFAs) may reduce vulnerability to atrial fibrillation (AF). The mechanism underlying this effect is unknown. A genome wide approach was used to identify gene expression profiles involved in a new model of vulnerability to AF, and determine whether they were altered by PUFA therapy. Thirty-six dogs were randomized into 3 groups of 12. Two groups were paced using simultaneous atrial and ventricular pacing (SAVP) at 220 bpm for 14 days to induce atrial enlargement, fibrosis and susceptibility to AF. One group was supplemented with oral PUFAs (850 mg/day) for 21 days, commencing 7 days before the start of pacing (SAVP-PUFAs); the other received no PUFAs (SAVP-No PUFAs). The final group was unpaced, unsupplemented and served as controls (CTRL). Atrial tissue from left appendages was sampled at the end of the protocol. PUFA supplementation caused a 24% increase in tissue phospholipid PUFA concentration. Gene expression was analyzed via microarray. Results were confirmed with QT-RT-PCR and histology. SAVP-No PUFAs dogs had significantly increased mRNA levels of MHCα, elevated levels of other proremodeling genes Akt, EGF, TIMP1, JAM3 and CD99, and significantly decreased levels of fibrosis inhibiting Smad6. PUFA supplementation was associated with significant down-regulation of Akt, EGF, TIMP1, MHCα, CD99 and lower JAM3 levels. PUFAs reversed the 34% increase in myocyte cross sectional area caused by pacing. PUFAs appear to attenuate, at the genetic level, adverse remodeling in response to mechanical stress

Controlled Exposure Study of Air Pollution and T-Wave Alternans in Volunteers without Cardiovascular Disease

Background: Epidemiological studies have assessed T-wave alternans (TWA) as a possible mechanism of cardiac arrhythmias related to air pollution in high-risk subjects and have reported associations with increased TWA magnitude. Objective: In this controlled human exposure study, we assessed the impact of exposure to concentrated ambient particulate matter (CAP) and ozone (O:3) on T-wave alternans in resting volunteers without preexisting cardiovascular disease. Methods: Seventeen participants without preexisting cardiovascular disease were randomized to filtered air (FA), CAP (150 μg/m3), O3 (120 ppb), or combined CAP + O3 exposures for 2 hr. Continuous electrocardiograms (ECGs) were recorded at rest and T-wave alternans (TWA) was computed by modified moving average analysis with QRS alignment for the artifact-free intervals of 20 beats along the V2 and V5 leads. Exposure-induced changes in the highest TWA magnitude (TWAMax) were estimated for the first and last 5 min of each exposure (TWAMax_Early and TWAMax_Late respectively). ΔTWAMax (Late–Early) were compared among exposure groups using analysis of variance. Results: Mean ± SD values for ΔTWA:Max were –2.1 ± 0.4, –2.7 ± 1.1, –1.9 ± 1.5, and –1.2 ± 1.5 in FA, CAP, O3, and CAP + O3 exposure groups, respectively. No significant differences were observed between pollutant exposures and FA. Conclusion: In our study of 17 volunteers who had no preexisting cardiovascular disease, we did not observe significant changes in T-wave alternans after 2-hr exposures to CAP, O:3, or combined CAP + O3. This finding, however, does not preclude the possibility of pollution-related effects on TWA at elevated heart rates, such as during exercise, or the possibility of delayed responses