Relationship Between High Blood Pressure, Atrial Cardiopathy, and Mortality in the General Population.

BACKGROUND: Atrial cardiopathy is associated with an increased risk of mortality. However, it is unclear whether this association is modified by hypertension, a risk factor for both atrial cardiopathy and mortality. METHODS: This analysis included 8,023 participants from the Third National Health and Nutrition Examination Survey. Electrocardiographic deep terminal negativity of P-wave in V1 ≥100 µV defined atrial cardiopathy. National Death Index was used to identify the date and cause of death. Cox proportional hazard analysis was used to examine the association of atrial cardiopathy with mortality among participants stratified by hypertension status. RESULTS: In total 2.7% of the participants had atrial cardiopathy. Over a median follow-up of 14 years, 2,922 all-cause deaths occurred, of which 1,058 were CVD. All-cause death rates were almost double among participants with concomitant atrial cardiopathy and elevated blood pressure (BP) (120-129/<80), stage 1 (130-139/80-89), or stage 2 hypertension (≥140/≥90) compared to their counterparts in the same hypertension stages without atrial cardiopathy (47.8, 61.3, and 80.2 vs. 23, 24.7, and 44.8 per 1,000 person-years (PY), respectively). In multivariable-adjusted models, a stronger association between atrial cardiopathy and all-cause mortality was observed in the presence compared to the absence of hypertension (HR (95% CI): 1.59 (1.25-2.01) vs. 0.67 (0.41-1.10), respectively, interaction P-value = 0.009). Similarly, an association between atrial cardiopathy and cardiovascular disease (CVD) mortality was observed in the presence compared to the absence of hypertension (HR (95% CI): 1.64 (1.08-2.47) vs. 0.63 (0.20-2.00), respectively, interaction P-value = 0.20). CONCLUSIONS: Concomitant presence of high BP and atrial cardiopathy carries a higher risk of mortality, and the risk increases with higher BP levels.

Association of Atrial Fibrillation Without Cardiovascular Comorbidities and Stroke Risk: From the REGARDS Study.

Background Atrial fibrillation (AF) is associated with a 5-fold increased stroke risk. While most patients with AF warrant anticoagulation, optimal treatment remains uncertain for patients with AF without cardiovascular comorbidities because the risk of stroke in this population has not been well-characterized. Methods and Results Participants (N=28 253; 55% women, mean age 64.6±9.4 years), from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study (2003-present) were classified into 1 of 4 groups based on the presence or absence of AF and the presence or absence of cardiovascular comorbidities. Cox proportional hazards analysis was used to compare the risk of stroke between groups. During 244 560 person-years of follow-up (median 8.7 years), 1206 strokes occurred. Compared with patients with neither AF nor cardiovascular comorbidities, we did not find an increased stroke risk (hazard ratio [HR], 1.23; 95% CI, 0.62-2.18 [P=0.511]) among participants with AF alone. Participants without AF but with cardiovascular comorbidities had both an elevated stroke risk (HR, 1.77; 95% CI, 1.48-2.18 [P<0.0001]) and an increased risk of cardioembolic stroke (HR, 2.34; 95% CI, 1.48-3.90 [P=0.0002]). Conclusions In this large cohort of participants with AF without cardiovascular comorbidities, we found that AF itself, without cardiovascular comorbidities, did not confer increased risk of stroke. Cardiovascular comorbidities, however, were associated with an increased risk of both stroke of any type and cardioembolic stroke, even in the absence of AF.

Smoking and risk of atrial fibrillation in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.

BACKGROUND: Whether smoking increases the risk of atrial fibrillation (AF) remains debatable due to inconsistent reports. METHODS: We examined the association between smoking and incident AF in 11,047 participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, one of the largest biracial, population-based cohort studies in the USA. Baseline (2003-2007) cigarette smoking status and amount (pack-years) were self-reported. Incident AF was determined by electrocardiography and history of a prior physician diagnosis at a follow-up examination conducted after a median of 10.6 years. RESULTS: During follow-up, 954 incident AF cases were identified; 9.5% in smokers vs. 7.8% in non-smokers; p<0.001. In a model adjusted for socio-demographics, smoking (ever vs. never) was associated with a 15% increased risk of AF [OR (95%CI): 1.15(1.00, 1.31)], but this association was no longer significant after further adjustment for cardiovascular risk factors [OR (95% CI): 1.12 (0.97, 1.29)]. However, heterogeneities in the association were observed among subgroups; the association was stronger in young vs. old participants [OR (95%CI): 1.31 (1.03, 1.67) vs. 0.99 (0.83-1.18) respectively; interaction p-value=0.005] and in those with vs. without prior cardiovascular disease [OR (95%CI): 1.18 (0.90, 1.56) vs. 1.06 (0.90, 1.25) respectively; interaction p-value 0.0307]. Also, the association was significant in blacks but not in whites [OR (95%CI): 1.51 (1.12, 2.05) vs. 0.99 (0.84, 1.16), respectively], but the interaction p-value did not reach statistical significance (interaction p-value=0.65). CONCLUSIONS: The association between smoking and AF is possibly mediated by a higher prevalence of cardiovascular risk factors in smokers, but there is marked heterogeneity in the strength of this association among subgroups which may explain the conflicting results in prior studies.