Echocardiographic Risk Assessment to Guide Screening for Atrial Fibrillation.

BACKGROUND: Although atrial fibrillation (AF) is a significant population health burden, and an avoidable cause of stroke, AF screening remains controversial. The aim of this study was to investigate whether coincidental echocardiography could provide information about patients at risk for AF. METHODS: Asymptomatic participants ≥65 years of age with more than one AF risk factor (N = 445) undergoing echocardiography for risk evaluation were followed over a median of 15 months for incident AF. Left atrial volume index (LAVi), left ventricular (LV) global longitudinal strain (GLS; absolute value), left atrial (LA) strain, and LV mass were measured. During the follow-up period, AF was diagnosed clinically by primary care physicians or by using a single-lead portable electrocardiographic monitoring device (five 60-sec recordings performed by participants over 1 week). RESULTS: AF was diagnosed in 45 patients (10%; mean age, 70.5 ± 4.2 years; 55% women). AF detection was higher in those with LV hypertrophy, GLS < 16%, LAVi > 34 mL/m2, and LA reservoir strain < 34%. GLS, LAVi, and LA reservoir strain were independently associated with AF (P < .05). Those with AF had reduced GLS, higher LAVi, and higher LV mass (P < .05), but LA strain was similar in both groups (P > .05). GLS and LAVi were the strongest predictors, and cut points of 14.3% for GLS and 39 mL/m2 were associated with increased risk for developing AF. Those with all four risk parameters (LV hypertrophy, GLS < 16%, LA reservoir strain < 34%, and LAVi > 34 mL/m2) had a 60% AF detection rate, compared with 7% without these features (P = .004). CONCLUSION: Echocardiography is widely used in patients at risk for AF, and simple LV and LA measurements may be used to enrich the process of AF screening.

Association between socioeconomic status and incident atrial fibrillation.

BACKGROUND: Low socioeconomic status is associated with cardiovascular diseases, and an association with atrial fibrillation (AF) could guide screening. AIM: To investigate if indices of advantage/disadvantage (IAD), index of education/occupation (IEO) and index of economic resources were associated with incident AF, independent of risk factors and cardiac function. METHODS: We studied community-based participants aged ≥65 years with AF risk factors (n = 379, age 70 ± 4 years, 45% men). The CHARGE-AF score (a well validated AF risk score) was used to assess 5-year risk of developing AF. Participants also had baseline echocardiograms. IAD, IEO and index of economic resources were obtained from the 2011 Socio-Economic Indexes for Areas score, in which higher decile ranks indicate more advantaged areas. Patients were followed up for incident AF (median 21 (range 5-31) months), with AF diagnosed by clinical review, including 12-lead electrocardiogram (ECG), as well as single-lead portable ECG monitoring used to record 60 s ECG tracings five times/day for 1 week. Cox proportional hazards models were used to assess the association between socioeconomic status and incident AF. RESULTS: Subjects with AF (n = 50, 13%) were more likely to be male (64 vs 42%, P = 0.003) and had higher CHARGE-AF score (median 7.1% (5.2-12.8%) vs 5.3% (3.3-8.6%), P < 0.001). Areas with lower socioeconomic status (IAD and IEO) had a higher risk of incident AF independent of LV function and CHARGE-AF score (hazard ratio for IAD 1.16, 95% confidence interval 1.05-1.29, P = 0.005 and hazard ratio for IEO 1.18, 95% confidence interval 1.07-1.30, P = 0.001). CONCLUSION: Regional socioeconomic status is associated with risk of incident AF, independent of LV function and clinical risk. This association might permit better regional targeting of prevention.

Serial assessment of left ventricular morphology and function in a rodent model of ischemic cardiomyopathy.

Left ventricular remodelling (LVr) occurs post myocardial infarction (MI), predisposing people to heart failure (HF). LV mechanics and morphology are important in this process. We hence sort to characterize LV mechanics and geometry in a post-MI rodent model. Thirty-two male Sprague-Dawley rats (150-200 g) sustained MI (n = 24) or sham (Sham; n = 8) surgery. In another six sham rats invasive blood pressure measurements were performed. Ultrasound imaging was done at baseline, and 1, 3, 7, 14, 30 and 60 days following surgery, and LV mechanics and morphology assessed. LV volumes increased with time (p < 0.01), at a greater rate in the MI group than the Sham group (p < 0.01). Strain was impaired in MI rats at day 1 (13.50 ± 6.64 vs. 25.71 ± 4.94%, p < 0.01) and remained impaired at day 60 (14.07 ± 5.37 vs. 22.98 ± 5.87%, p < 0.01). Strain rate was lower at day 1 (4.11 ± 1.29 vs. 8.10 ± 2.18%/s, p < 0.01), remained lower throughout follow-up (p < 0.01), and decreased at a greater rate in MI rats (p < 0.01). Mean systolic (204 ± 43 vs. 322 ± 75 1/m, p < 0.01) and diastolic (167 ± 21 vs. 192 ± 11 1/m, p < 0.01) curvature was lower in the MI rats at day 1 post surgery and throughout follow-up (p < 0.01). Maximum principal curvature decreased throughout time (p < 0.01), while minimum principal curvature did not (p = 0.86). Wall stress increased significantly after infarction in MI rats (p < 0.01). ST-elevation myocardial infarction (STEMI) changed LV shape and contractile function. The assessment of these indices may prove useful in understanding LVr and the development of HF.