Atrial fibrillation hospitalization is associated with exposure to fine particulate air pollutants.

BACKGROUND: Although air pollutants have been associated with cardiopulmonary mortality, their effects on the occurrence of atrial fibrillation (Afib) remain unclear. This study examined the association between ambient air pollutants and Afib occurrence. METHODS: Using a representative sample from the National Health Insurance Database of Taiwan, we applied a case-crossover study design to explore the associations between air pollutants and patients hospitalized with Afib from 2006 to 2011. The event day was when a patient was hospitalized with Afib, and the control days were the same days of the following weeks of the same month. The association between Afib occurrence and levels of ambient air pollutants (including particulate matter [PM] 2.5 PM10, NO2, SO2, and O3) was examined after adjusting for temperature and relative humidity. A two-pollutant model was used to examine the effect of the second pollutant when the first pollutant was determined to be significantly related to Afib. RESULTS: During 2006-2011, 670 patients hospitalized with the first onset of Afib were identified. The occurrence of Afib was associated with PM2.5, in which a 22% (95% confidence interval = 3-44%) increase was related to an interquartile range increase (26.2 µg/m3) on the same day and a 19% (95% confidence interval = 0-40%) increase on the second day. A two-pollutant model was applied, and the results indicated that the effect of PM2.5 was significantly associated with the occurrence of Afib. Patients aged over 65 years with DM and with hyperlipidemia were more susceptible to the effect of PM2.5. CONCLUSIONS: In conclusion, the occurrence of Afib was associated with short-term exposure to fine particulate air pollutants in the general population.

Effects of night duty events on blood pressure and autonomic modulation in physicians.

BACKGROUND: The dynamic effects of duty events on the blood pressure (BP) and heart rate variability (HRV) of physicians on duty are unknown. METHODS: A study was conducted among 12 physicians on night duty. BP and HRV with and without the effect of a duty event were compared. The risk of higher BP and impaired HRV after a phone call were calculated. RESULTS: Physicians had higher mean BP (122.4 ± 11.1; 76.9 ± 7.1 mmHg) within 30 min after a phone calls than without a phone call (113.5 ± 5.3; 69.0 ± 3.8) and higher sympathetic tone (low frequency normalized units (LFnu) 68.5 ± 8.9; high frequency normalized units (HFnu) 27.7 ± 8.7) within 10 min of a phone call than without a phone call (62.9 ± 8.51; 33.5 ± 8.4). Elevated BP and sympathetic tone recovered to baseline levels 30 min after a phone call. CONCLUSIONS: Among physicians on night duty, sympathetic tone and BP might be elevated by clinical events, and these effects last for 30 min.

Insomnia and the Risk of Atrial Fibrillation: A Population-Based Cohort Study.

BACKGROUND: Although advancements in the treatment of atrial fibrillation have improved patient prognosis for this persistent condition, interest in atrial fibrillation development is growing. Of note is the fact that additional attention is being focused on the accompanying effect of insomnia. The aim of the study was to investigate the effects of insomnia on the risk of atrial fibrillation development. METHODS: This was a nationwide population-based retrospective cohort study using data from the Taiwan National health Insurance Research Database. We analyzed 64,421 insomnia cases and 128,842 matched controls without insomnia from January 1, 2000, to December 31, 2010. A Cox regression model was used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for atrial fibrillation development. RESULTS: During the follow-up period, the incidence of atrial fibrillation development was significantly higher in the insomnia cases than in the comparison cohort (2.6% vs. 2.3%, p < 0.001). Insomnia was associated with an increased risk of atrial fibrillation (HR = 1.08, 95% CI: 1.01-1.14). Males, those > 65 years of age, and patients with peripheral artery disease who have insomnia had a higher rate of atrial fibrillation development. CONCLUSIONS: The findings of this nationwide analysis support the hypothesis that insomnia is associated with a significant risk of atrial fibrillation development.

Increased night duty loading of physicians caused elevated blood pressure and sympathetic tones in a dose-dependent manner.

PURPOSE: Night duty has been recognized as a significantly harmful stressor for physicians. However, the relationship between various levels of duty loading and stress response is unknown. This study examined whether duty load increases cardiovascular stress indicators in a dose-dependent manner. METHODS: An unallocated prospective observational study was conducted among physicians performing various levels of duties in a secondary referral medical center between 2011 and 2012. Heart rate variability (HRV), blood pressure (BP), and other stress markers of 12 attending physicians were compared during different duty loads: non-duty day (NDD), duty day with one duty area and three wards (1DD), and duty day with two duty areas and six wards (2DD). RESULTS: During the regular sleep time (i.e., 11 p.m. to 5 a.m.), the relative sympathetic modulations measured using the HRV were 59.0 ± 9.3, 61.6 ± 10.4, and 64.4 ± 8.9 for NDD, 1DD, and 2DD, respectively (p = 0.0012); those for relative parasympathetic modulations were 37.4 ± 9.4, 34.8 ± 9.8, and 32.0 ± 8.8 for NDD, 1DD, and 2DD, respectively (p = 0.0015). The percentages of abnormal systolic BPs were 9.7 ± 13.2 %, 25.3 ± 21.8 %, and 31.5 ± 21.0 % for NDD, 1DD, and 2DD, respectively (p = 0.003), and the percentages of abnormal diastolic BP were 6.7 ± 11.0 %, 18.3 ± 11.1 %, and 27.1 ± 30.9 % for NDD, 1DD, and 2DD, respectively (p = 0.002). Total sleep time was negatively associated with sympathetic/parasympathetic balance and the percentage of abnormal diastolic BP. Admitting new patients was positively associated with the percentages of abnormal systolic BP. CONCLUSIONS: This observational analysis suggests that the dose-dependent stress responses of the cardiovascular system in physicians were caused by the duty load.

Administrative data on diagnosis and mineralocorticoid receptor antagonist prescription identified patients with primary aldosteronism in Taiwan.

OBJECTIVES: To develop algorithms of locating patients with primary aldosteronism (PA) using insurance reimbursement data and to validate the algorithms using medical charts. STUDY DESIGN AND SETTING: We extracted National Health Insurance (NHI) reimbursement data and medical charts in seven enrolled hospitals and analyzed diagnosis-related information for 1999-2010. The NHI codes PA as 255.1x, using the International Classification of Diseases, Ninth Revision, Clinical Modification. Confirmation of PA was based on suppression tests. RESULTS: We reviewed medical charts for 1,094 cases with at least one PA diagnosis. PA was confirmed for 563 cases. Compared with patients with essential hypertension, PA patients had higher systolic blood pressure, higher aldosterone, lower renin activity, and lower potassium level (all P-values <0.05). An algorithm based on PA diagnosis reported in at least one hospital stay or three outpatient visits had modest performance (sensitivity = 0.94 and specificity = 0.20). The best additional condition for the algorithm was use of mineralocorticoid receptor antagonist (MRA; sensitivity = 0.89 and specificity = 0.88). CONCLUSION: Using information on PA diagnosis and MRA prescription reported in insurance claims data can precisely locate PA patients in high-risk groups. This algorithm can construct a reliable PA sample for conducting research in various fields, including epidemiology and clinical practice.

Association between urine aldosterone and diastolic function in patients with primary aldosteronism and essential hypertension.

OBJECTIVE: To investigate the association between aldosterone and cardiac diastolic dysfunction. DESIGN AND METHODS: We prospectively enrolled 20 patients with primary aldosteronism (PA) and 22 patients with essential hypertension (EH). Plasma aldosterone concentration, plasma renin activity, and 24-h urine aldosterone level were measured. Echocardiography, including tissue Doppler image recordings, was performed. RESULTS: PA patients had a significantly higher left ventricular (LV) mass index and worse LV diastolic function than those in EH patients. Among various measures of aldosterone, log-transformed 24-h urine aldosterone level had the most consistent correlation with diastolic function. CONCLUSIONS: Aldosterone is strongly associated with LV diastolic dysfunction. Twenty-four hour urine aldosterone is a good indicator to evaluate the impact of aldosterone on LV diastolic function.

Angiotension receptor blockers reduce the risk of dementia.

OBJECTIVE: Recent studies implied that angiotension receptor blockers (ARBs) not only have an antihypertensive effect but also have beneficial effects on dementia. The purpose of this study was to investigate the effects of ARBs on dementia and the subtypes. METHODS: We conducted a population-based cohort study with data from the Taiwan National Health Insurance Research Database. A total of 24 531 matching pairs (1 : 1) of ARB-exposed and non-ARB-exposed patients were included. Each patient was individually tracked from 1997 to 2009 to identify incident cases of dementia (onset in 1999 or later). Cox proportional hazard regressions were employed to calculate the hazard ratios and 95% confidence intervals (CIs) for the association between ARBs and dementia, Alzheimer's disease and vascular dementia, conditional for matching pairs. RESULTS: There were 1322 cases (5.4%) of dementia in the ARB cohort and 2181 cases (8.9%) in the non-ARB cohort identified during the 11-year follow-up period. The multivariate-adjusted hazard ratios for dementia, Alzheimer's disease and vascular dementia were 0.54 (95% CI 0.51-0.59), 0.53 (95% CI 0.43-0.64) and 0.63 (95% CI 0.54-0.73) for patients with ARB treatments, respectively. In terms of cumulative dosage, patients with more than 1460 defined daily dose of ARBs had less risk than those patients with less than 1460 defined daily dose (hazard ratio 0.37 vs. 0.61; P < 0.05). CONCLUSION: These results suggest that ARB may be associated with a reduced risk of dementia in high vascular-risk individuals. Patients exposed to ARBs for higher cumulative doses experienced more protection from dementia and the subtypes.

WITHDRAWN: Association between the levels of carboxy-terminal propeptide of type I procollagen and aldosterone in patients with primary aldosteronism and essential hypertension.

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Myocardial ultrasound tissue characterization of patients with primary aldosteronism.

Primary aldosteronism (PA), an underdiagnosed cause of hypertension, is associated with more significant cardiac remodeling and myocardial fibrosis than is essential hypertension (EH). The aim of this study was to validate myocardial fibrosis and to evaluate factors associated with the degree of myocardial fibrosis in patients with PA. We prospectively analyzed 62 patients with PA (including 46 patients with aldosterone-producing adenoma and 16 with bilateral hyperplasia) between October 2006 and October 2010, and we enrolled 17 patients with EH as the control group. Echocardiography, including ultrasonic tissue characterization using cyclic variation of integrated backscatter (CVIBS), was performed in individuals in both groups. Among patients with PA, the diastolic blood pressures and plasma aldosterone concentrations were significantly higher than those of patients with EH. Moreover, the serum potassium levels and the plasma renin activities were significantly lower in patients with EH. As observed by echocardiography, patients with PA had greater interventricular septal thickness, greater left ventricular posterior wall thickness, and higher left ventricular mass indexes than did patients with EH. Patients with PA had significantly lower CVIBS values than patients with EH (7.1 ± 2.2 vs. 8.7 ± 1.5 dB; p = .005). In a correlation study that corrected for various clinical parameters, only log-transformed plasma renin activity values correlated significantly with CVIBS values. Ultrasonic tissue characterization with CVIBS is a useful tool for determining the extent of myocardial fibrosis. Patients with PA exhibit a more severe degree of myocardial fibrosis, as detected by CVIBS, than do patients with EH. Moreover, the severity of fibrosis, as detected by CVIBS, correlates with log-transformed plasma renin activity values.

Angiotensin-converting enzyme inhibitors enhance the effect of cyclooxygenase inhibitors on breast cancer: a nationwide case-control study.

OBJECTIVES: Angiotensin-converting enzyme (ACE) inhibitors are first-line antihypertensive and potential cancer preventive agents. Interest in breast cancer prevention is growing, and more clinical evidence is needed regarding the effects of preventive therapy, alone or in combination. METHODS: This was a nationwide case-control analysis from the Taiwan National health Insurance Research Database. We analyzed 16,847 female breast cancer patients (diagnosed between 1 January 2002 and 31 December 2008) and 50,541 matched individuals. Longitudinal exposure to ACE inhibitors and cyclooxygenase inhibitors was compared. RESULTS: The risk of developing breast cancer among patients taking both aspirin and an ACE inhibitor decreased as the ACE inhibitor dose increased. Among patients receiving between 28 and 364 cumulative defined daily doses (cDDDs) of aspirin, the adjusted odds ratios (ORs) were 0.97 (0.90-1.06), 0.91 (0.82-1.03), and 0.79 (0.68-0.92) for women taking ACE inhibitors for 0-27, 28-364, and more than 365 cDDD, respectively. Among women receiving more than 365 cDDD of aspirin, the adjusted ORs were 0.91 (0.80-1.03), 0.81 (0.70-0.94), and 0.81 (0.71-0.92) as the ACE inhibitor dose increased, respectively. Women taking nonaspirin NSAIDs along with an ACE inhibitor had the same finding. Among women taking 28-364 cDDD of NSAIDs, the adjusted ORs were 0.85 (0.81-0.89), 0.87 (0.81-0.94), and 0.80 (0.73-0.88); for women receiving more than 365 cDDD of NSAIDs, the adjusted ORs were 0.68 (0.62-0.74), 0.61 (0.53-0.70), and 0.60 (0.52-0.70) as the ACE inhibitor dose increased, respectively. CONCLUSION: The findings of this nationwide analysis support the hypothesis that ACE inhibitors enhance the antitumor effect of cyclooxygenase inhibitors on breast cancer.

Adrenalectomy reverses myocardial fibrosis in patients with primary aldosteronism.

OBJECTIVE: Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with more prominent left ventricular hypertrophy and increased myocardial fibrosis. However, the reversibility of cardiac fibrosis is still unclear. Our objective was to investigate myocardial fibrosis in primary aldosteronism patients and its change after surgery. METHOD: We prospectively analyzed 20 patients with aldosterone-producing adenoma (APA) who received adrenalectomy from December 2006 to October 2008 and 20 patients with essential hypertension were enrolled as the control group. Plasma carboxy-terminal propeptide of procollagen type I (PICP) determination and echocardiography including ultrasonic tissue characterization by cyclic variation of integrated backscatter (CVIBS) were performed in both groups and 1 year after operation in the APA group. RESULTS: APA patients had significantly higher SBP and DBP, higher plasma aldosterone concentration (PAC), higher aldosterone-renin ratio (ARR), lower serum potassium levels, and lower plasma renin activity (PRA) than patients with essential hypertension. In echocardiography, APA patients had a higher left ventricular mass index than essential hypertension patients. APA patients had significantly lower CVIBS (6.2 ± 1.5 vs. 8.7 ± 2.0 dB, P < 0.001) and higher plasma PICP levels (107 ± 27 vs. 85 ± 24 µg/l, P = 0.009) than essential hypertension patients. In the correlation study, CVIBS is correlated with log-transformed PRA and log-transformed ARR and PICP is correlated with log-transformed PRA, log-transformed PAC, and log-transformed ARR. One year after adrenalectomy, CVIBS increased significantly (6.2 ± 1.5 to 7.3 ± 1.7 dB, P = 0.033) and plasma PICP levels decreased (107 ± 27 vs. 84 ± 28 µg/l, P = 0.026). CONCLUSION: Increases in collagen content in the myocardium of APA patients may be reversed by adrenalectomy.

Reversal of myocardial fibrosis in patients with unilateral hyperaldosteronism receiving adrenalectomy.

BACKGROUND: Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with more prominent left ventricular hypertrophy and increased myocardial fibrosis. Unilateral hyperaldosteronism can be cured by adrenalectomy. However, the reversibility of cardiac fibrosis is still unclear. METHODS: We analyzed 11 patients prospectively with unilateral hyperaldosteronism (including 10 aldosterone-producing adenomas and 1 unilateral nodular hyperplasia) who received adrenalectomy from October 2006 to October 2007, and 17 patients with essential hypertension (EH) were enrolled as the control group. Echocardiography included ultrasonic tissue characterization by cyclic variation of integrated backscatter; it was performed in both groups and 1 year after operation in the unilateral hyperaldosteronism group. RESULTS: Patients with unilateral hyperaldosteronism had significantly higher diastolic blood pressure, higher plasma aldosterone concentration, lower serum potassium level, and lower plasma renin activity than patients with EH. In echocardiography, patients with unilateral hyperaldosteronism had thicker interventricular septal thickness, left ventricular posterior wall thickness, and higher left ventricular mass index than EH patients. Patients with unilateral hyperaldosteronism had significant lower cyclic variation of integrated backscatter than EH patients (7.1 ± 2.1 vs 8.7 ± 1.5 dB, P = .037). After analyzing the correlation of cyclic variation of integrated backscatter with clinical parameters for all participants, only log-transformed plasma renin activity was correlated significantly with cyclic variation of integrated backscatter. One year after adrenalectomy, interventricular septal thickness, left ventricular posterior wall thickness, and left ventricular mass index decreased significantly. In addition, cyclic variation of integrated backscatter increased significantly after adrenalectomy (7.1 ± 2.1 to 8.5 ± 1.5 dB, P = .02). CONCLUSION: Adrenalectomy not only reversed left ventricular geometry but also altered myocardial texture in patients with unilateral hyperaldosteronism. This finding implies that increases in collagen content in the myocardium of patients with unilateral hyperaldosteronism might be reversed by adrenalectomy.

Effects of metformin on rosiglitazone-induced cardiac hypertrophy in mice.

Thiazolidinediones (TZD) can cause adipose tissue accumulation and myocardial hypertrophy. This study aimed to determine if combined Metformin (Glucophage) and Rosiglitazone (Avandia) could reduce the risk of heart failure caused by Rosiglitazone in BALB/c mice. BALB/c mice were treated with oral Rosiglitazone/Metformin twice daily for four weeks. Metformin or Rosiglitazone alone and non-treated mice acted as double control. Myocardial hypertrophy and associated side effects of the combined therapy were determined through isolated heart and body weights. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were applied to evaluate expression of sulfonylurea receptor 2A (SUR2A) and Kir 6.2. The activities of peroxisome proliferator activated receptor alpha (PPARalpha) in the myocardium were also observed. Rosiglitazone/Metformin decreased body weight gain and food intake, and inhibited an increasing adipose ratio but did not reduce myocardial hypertrophy. Rosiglitazone increased Kir6.2/SUR2A, Kir6.2/SUR2B, and PPARalpha gene expression. The Rosiglitazone/Metformin combination further increased these gene expressions, especially PPARalpha. Metformin inhibits obesity but has no effect in reducing myocardial hypertrophy caused by Rosiglitazone. Whether Metformin can reduce side effects of TZDs in humans warrants further study.

Association of white blood cell count and peripheral arterial disease in patients with and without traditional risk factors.

Peripheral arterial disease (PAD) is an inflammatory process. The association between white blood cell (WBC) count and PAD in those with and without traditional risk factors is not clear. We examined data from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2004. A total of 5260 participants were included. The result showed that the prevalence of PAD rose from 2.8% +/- 0.5% in the lowest quartile of plasma WBC count to 8.0% +/- 1.2% in the highest quartile. In subgroup analysis, the graded association between WBC count and PAD was significant in patients without hypertension, diabetes, smoking, chronic kidney disease (CKD), and in patients with or without hypercholesterolemia but not significant in patients with hypertension, smoking, diabetes, or CKD. In those without hypertension, diabetes, smoking, or CKD, the cutoff value for WBC count was 6.75 x 10(9)/L. We concluded that the positive association between WBC count and PAD can be demonstrated in this national survey.

The immediate effects of pacemaker-related electric remodelling on left ventricular function in patients with sick sinus syndrome.

AIMS: The immediate effects of electric remodelling on the left ventricular (LV) function by dual-chamber pacemakers remain unknown. The purpose of our study was to assess the interaction between heart rates and right ventricular pacing (VP) on LV contractility and diastolic function. METHOD AND RESULTS: Twenty-five patients with dual-chamber pacemakers and sick sinus syndrome were evaluated. Echocardiographic examinations included standard and tissue-Doppler echocardiography at bilateral mitral annulus margins under either the intrinsic atrio-ventricular sequential conduction (ventricular sensing; VS) mode or right ventricular apical pacing (VP) mode. Under either mode, we accelerated the pacing rate at an increment of 15 b.p.m. step-by-step from 60 to 90/min. The tissue-Doppler echocardiography of mitral annulus showed that under the VS status, accelerating atrial pacing rate from 60 to 90 b.p.m. enhanced A'-wave velocity (P < or =0.002), whereas no significant change of LV ejection fraction (LVEF) and E'-wave velocity were noted. Under the VP status, acceleration of pacing rates exerted no effect on the LVEF, E'-, and A'-wave (P = NS). While shifting the pacemaker mode from VS to VP, the E'-wave velocity (P < or =0.002) and E'/A' ratio decreased significantly (P < or = 0.001). The A'-wave velocity also increased significantly during shifting to VP mode at 60 b.p.m. (P < or =0.004). CONCLUSION: At fixed pacing rates, shifting from VS to VP mode impaired LV diastolic function immediately with preserved LV contractility. The acceleration of heart rate impaired LV diastolic function under VS mode.