A 73-yr-old Korean man with permanent atrial fibrillation visited outpatient clinic with severely increased International Normalized Ratio (INR) values after taking a usual starting dosage of warfarin to prevent thromboembolism. We found out later from his blood tests that he had hyperthyroidism at the time of treatment initiation. His genetic analysis showed CYP2C9*1/*3 and VKORC1+1173TT genotypes. We suspect that both hyperthyroidism and genetic variant would have contributed to his extremely increased INR at the beginning of warfarin therapy. From this case, we learned that pharmacogenetic and thyroid function test might be useful when deciding the starting dosage of warfarin in patients with atrial fibrillation.
Aged ; Anticoagulants/blood/metabolism/therapeutic use ; Aspirin/therapeutic use ; Atrial Fibrillation/*diagnosis ; Chromatography, High Pressure Liquid ; Cytochrome P-450 CYP2C9/*genetics ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; Tandem Mass Spectrometry ; Thromboembolism/prevention & control ; Thyrotoxicosis/*diagnosis ; Vitamin K Epoxide Reductases/genetics ; Warfarin/*blood/metabolism/therapeutic use

OBJECTIVETo analyze the association between T393C single nucleotide polymorphism (SNP) of GNAS1 gene and non-valvular atrial fibrillation (AF) in Chinese Han patients.

METHODSNinety patients with non-valvular AF and 90 healthy subjects were examined for T393C SNP of GNAS1 gene using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The allele genotypes and the distribution of allele frequencies were analyzed and compared between the two groups. The relationship between allele frequency distribution characteristics and the heart rate variability (HRV) were also studied for analysis of the association between T393C SNP of GNAS1 gene and the autonomic nervous activation in non-valvular AF.

RESULTSThe two groups showed a significant difference in the frequencies of genotypes of T393C SNP of GNAS1 gene and allele frequencies (P<0.01). CC genotype and T393C allele frequency were significantly increased in the case group. pNN50, LF, or LF/HF showed no significant difference between different genotypes (P<0.05).

CONCLUTIONSThe T393C SNP of GNAS1 gene is closely associated with non-valvular AF in Chinese Han patients.

Adult ; Aged ; Aged, 80 and over ; Alleles ; Asian Continental Ancestry Group ; genetics ; Atrial Fibrillation ; genetics ; metabolism ; physiopathology ; Chromogranins ; Female ; GTP-Binding Protein alpha Subunits, Gs ; genetics ; Gene Frequency ; Genotype ; Heart Rate ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Polymorphism, Single Nucleotide ; Risk Factors

BACKGROUNDTumor necrosis factor-alpha (TNF-α) is a pleiotropic proinflammatory cytokine and contributes to many kinds of cardiovascular diseases via its receptors (TNFR1/TNFR2). We hypothesize that TNF-α plays a role in the pathogenesis of chronic atrial fibrillation (AF).

METHODSSixty-seven consecutive patients who were scheduled to have cardiac surgery were enrolled into the study. Thirty-one patients with rheumatic heart disease (RHD) and AF were enrolled as study group (AF group). The sinus rhythm (SR) control groups consisted of 20 patients with RHD and 16 patients with coronary artery disease (CAD). Peripheral blood sample was collected before the operation. About 5 mm(3) left atrial tissue was disserted during the operation and was separated into three parts for Western blotting, real time polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) analysis.

RESULTSCompared with the controls (RHD SR and CAD SR), the levels of TNF-α ((14.40 ± 5.45) pg/ml vs. (4.20 ± 3.19) pg/ml vs. (2.68 ± 2.20) pg/ml, P = 0.000) and its soluble receptor 1 (sTNFR1) ((1623.9 ± 558.6) pg/ml vs. (1222.3 ± 175.6) pg/ml vs. (1387.5 ± 362.2) pg/ml, P = 0.001) in plasma were higher in patients with AF. TNF-α level had positive correlation with the left atrial diameter (LAD) (r = 0.642, P = 0.000). Western blotting analysis showed that the protein levels of TNF-α (0.618 ± 0.236 vs. 0.234 ± 0.178 vs. 0.180 ± 0.103, P = 0.000) were higher in patients with AF. The RT-PCR analysis results demonstrated that the mRNA expression of TNF-α (0.103 ± 0.047 vs. 0.031 ± 0.027 vs. 0.023 ± 0.018, P = 0.000) increased in patients with AF. IHC analysis displayed that, comparing to the SR, the expression of TNF-α (0.125 ± 0.025 vs. 0.080 ± 0.027 vs. 0.070 ± 0.023, P = 0.000) increased in the AF group. The protein level and mRNA expression of TNF-α also had positive correlation with left atrium diameter (LAD) (r = 0.415, P = 0.000 and r = 0.499, P = 0.000).

CONCLUSIONSThe results revealed that TNF-α elevated in the plasma and left atrial tissue and had positive correlation with LAD in patients of chronic AF. TNF-α might involve in the pathogenesis of chronic AF.

Aged ; Atrial Fibrillation ; blood ; metabolism ; Blotting, Western ; Female ; Heart Atria ; metabolism ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Real-Time Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha ; blood ; genetics ; metabolism

OBJECTIVETo study the relationship between atrial structural remodeling and the expressions of matrix metalloproteinase (MMPs) and their tissue inhibitors (TIMPs) in atrial fibrillation (AF).

METHODSBiopsy samples of the right atrial appendages were collected from 20 patients with sinus rhythm and 30 with AF undergoing heart valve replacement surgery for rheumatic heart diseases. All the patients received echocardiographic examination preoperatively. MMP-1, -3, -7, -9 and TIMP-1, -2, -3, -4 protein expressions were detected by immunohistochemistry and RT-PCR.

RESULTSCompared with those in patients with sinus rhythm, the AF patients had significantly increased left and right atrial diameters and mRNA levels of MMP-3, -7, -9 and TIMP-1, -2, -3, -4 (P<0.01). MMP-1 expression also showed an increase in AF patients, but the difference was no statistically significant from that in patients with sinus rhythm.

CONCLUSIONThe expressions of MMP-1, -3, -7, -9 and TIMP-1, -2, -3, -4 increase in fibrillating atrial tissue, which may contribute to atrial structural remodeling and atrial dilatation in AF patients.

Adult ; Aged ; Atrial Fibrillation ; enzymology ; pathology ; physiopathology ; Female ; Humans ; Male ; Matrix Metalloproteinases ; genetics ; metabolism ; Middle Aged ; Tissue Inhibitor of Metalloproteinases ; genetics ; metabolism

BACKGROUND/AIMS: Underlying cardiac pathology and atrial fibrillation (AF) affect the molecular remodeling of ion channels in the atria. Changes in the expression of these molecules have not been demonstrated in Korean patients with mitral valvular heart disease. Thus, the purpose of this study was to analyze ion channel expression in patients with chronic AF and mitral valvular heart disease. METHODS: A total of 17 patients (eight males and nine females; mean age, 57 +/- 14 years [range, 19 to 77]) undergoing open-heart surgery were included in the study. Twelve patients (seven with coronary artery disease and five with aortic valvular disease) had sinus rhythm, and five patients (all with mitral valvular disease) had chronic, permanent AF. A piece of right atrial appendage tissue (0.5 g) was obtained during surgery. RT-PCR was used to evaluate the expression of L-type Ca2+ channels, ryanodine receptor (RyR2), sarcoplasmic reticular Ca2+-ATPase (SERCA2), gene encoding the rapid component of the delayed rectifier Ikr (HERG), gene encoding calcium-independent transient outward current I(to1) (Kv4.3), gene encoding the ultrarapid component of the delayed rectifier Iku (Kv1.5), K+ channel-interacting protein 2 (KChIP2), hyperpolarization-activated cation channel 2 associated with the pacemaker current If (HCN2), and gene encoding Na+ channel (SCN5A). RESULTS: Reduced L-type Ca2+ channel, RyR2, SERCA2, Kv1.5, and KChIP2 expression and borderline increased HCN2 expression were observed in the patients with AF and mitral valvular heart disease. Left atrial diameter was negatively correlated with RyR2 and KChIP2 expression. Fractional area shortening of the left atrium was positively correlated with RyR2 and KChIP2 expression. CONCLUSIONS: Alterations in ion channel expression and the anatomical substrate may favor the initiation and maintenance of AF in patients with mitral valvular heart disease.
Adult ; Aged ; Aortic Valve Stenosis/metabolism ; Atrial Fibrillation/*metabolism ; Calcium/metabolism ; Chronic Disease ; Coronary Artery Disease/metabolism ; Female ; Heart Valve Diseases/*metabolism ; Humans ; Ion Channels/*genetics ; Male ; Middle Aged ; *Mitral Valve ; Potassium Channels/genetics ; Ryanodine Receptor Calcium Release Channel/genetics ; Sodium Channels/genetics

OBJECTIVETo investigate the association of ATP binding cassette transporter A1 (ABCA1) gene R219K polymorphisms with atrial fibrillation (AF) in Chinese population.

METHODSA total of 250 patients with AF and 250 control subjects were selected. Polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP) was used to determine the ABCA1 genotype, and the serum concentration of C-reactive protein (CRP) and high-density lipoprotein cholesterol (HDL-C) were measured in all the subjects.

RESULTSThe frequency of the RR , RK , KK , allele R , allele K genotype of ABCA1 in AF group and control group was 42.0%, 42.8%, 15.2%, 34.0%, 43.2% and 22.8%, 63.4%, 36.6%, 55.6%, 44.4%, respectively. The frequency of the KK genotype was significantly higher in the control group than in the case group (P=0.03), and the frequency of the allele K genotype was significantly different between the two groups (P=0.012). The serum CRP concentrations was significantly higher in AF group than in the control group (P=0.004), but serum HDL-C level showed no difference between the two groups. The serum CRP concentrations were significantly higher in patients with RR genotype than in those with KK genotype (P=0.013), and patients with RR genotype had significantly lower HDL-C level than those with RK and KK genotypes (P=0.009 and 0.027, respectively).

CONCLUSIONPatients with AF have elevated serum CRP level in comparison with healthy individuals, and the K allele of R219K polymorphism is an independent protective factor against AF.

ATP Binding Cassette Transporter 1 ; ATP-Binding Cassette Transporters ; genetics ; Aged ; Alleles ; Asian Continental Ancestry Group ; genetics ; Atrial Fibrillation ; blood ; genetics ; C-Reactive Protein ; metabolism ; Female ; Genetic Predisposition to Disease ; genetics ; Genotype ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; methods ; Polymorphism, Restriction Fragment Length

BACKGROUNDWe hypothesize that increased atrial oxidative stress and inflammation may play an important role in atrial nerve sprouting and heterogeneous sympathetic hyperinnervation during atrial fibrillation (AF). To test the hypothesis, we examined whether the antioxidant and anti-inflammatory treatment with probucol attenuates atrial autonomic remodeling in a canine model of AF produced by prolonged rapid right atrial pacing.

METHODSTwenty-one dogs were divided into a sham-operated group, a control group and a probucol group. Dogs in the control group and probucol group underwent right atrial pacing at 400 beats per minute for 6 weeks, and those in the probucol group received probucol 1 week before rapid atrial pacing until pacing stopped. After 6-week rapid atrial pacing, general properties including left atrial structure and function, atrial hemodynamics and the inducibility and duration of AF were measured in all the groups. Atrial oxidative stress markers and serum C-reactive protein (CRP) concentration were estimated. The degree of nerve sprouting and sympathetic innervation at the right atrial anterior wall (RAAW) and the left atrial anterior wall (LAAW) were quantified by immunohistochemistry, atrial norepinephrine contents were also detected. Atrial beta-nerve growth factor (beta-NGF) mRNA and protein expression at the RAAW and LAAW were assessed by real-time quantitative RT-PCR and Western blotting respectively.

RESULTSAtrial tachypacing induced significant nerve sprouting and heterogeneous sympathetic hyperinnervation, and the magnitude of nerve sprouting and hyperinnervation was higher in the RAAW than in the LAAW. Atrial beta-NGF mRNA and protein levels were significantly increased at the RAAW and LAAW, and the upregulation of beta-NGF expression was greater at the RAAW than at the LAAW in the control group. The beta-NGF protein level was positively correlated with the density of sympathetic nerves in all groups. Probucol decreased the increase of CRP concentration and attenuated atrial oxidative stress caused by atrial tachypacing. In addition, probucol could effectively inhibit atrial beta-NGF upregulation, significantly attenuate atrial nerve sprouting and heterogeneous sympathetic hyperinnervation, and dramatically reduce the inducibility and duration of AF.

CONCLUSIONSThe atrial over-expression of beta-NGF possibly caused by increased oxidative stress and inflammation may be the main mechanism underlying atrial autonomic remodeling during AF. Probucol attenuates atrial autonomic remodeling possibly by its antioxidant and anti-inflammatory actions.

Animals ; Antioxidants ; therapeutic use ; Atrial Fibrillation ; drug therapy ; Blotting, Western ; C-Reactive Protein ; metabolism ; Cardiac Pacing, Artificial ; adverse effects ; Disease Models, Animal ; Dogs ; Electrocardiography ; Female ; Heart Atria ; Immunohistochemistry ; Male ; Nerve Growth Factor ; genetics ; metabolism ; Norepinephrine ; metabolism ; Probucol ; therapeutic use ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the mRNA and protein expression of mineralocorticoid receptor (MR) in patients with atrial fibrillation.

METHODSTwenty-five patients with rheumatic heart valve disease, 12 in sinus rhythm and 13 in chronic atrial fibrillation (>or= 6 months), underwent transthoracic echocardiography and right and left atrial lateral wall tissue samples were obtained from these patients during mitral/aortic valve replacement operation. Realtime quantitative PCR and Western blot were used to determine the mRNA and protein expression of MR in atria specimens. The distribution of MR in human atria was analyzed by specific immunohistochemical staining.

RESULTSThe left atrial diameters increased markedly in atrial fibrillation group compared with that in sinus rhythm group (P<0.01). And the results showed that the level of mRNA and protein of MR were increased significantly in atrial fibrillation group compared with those in sinus rhythm group (P<0.01 or 0.05), whereas the expression of mRNA and protein of MR were found to be no difference between left atria and right atria both in fibrillation and sinus groups (all P>0.05). The special immunohistochemical staining demonstrated that MR was abundant in the human atrial myocardium and MRs were located mainly in the cytoplasm of atrial cells, which were more evident in atrial fibrillation group than those in sinus rhythm group.

CONCLUSIONThese findings suggested that MRs were upregulated in atrial fibrillation and aldosterone antagonists may be effective in treating atrial fibrillation.

Adult ; Atrial Fibrillation ; metabolism ; Humans ; Male ; Middle Aged ; Myocardium ; metabolism ; RNA, Messenger ; genetics ; Receptors, Mineralocorticoid ; metabolism

OBJECTIVETo discuss the role of calcium-overloading in initiation and maintenance of atrial fibrillation (AF).

METHODSThe right atrial appendages were obtained from 14 patients with AF and 12 patients with sinus rhythm. The mRNA expression of proteins influencing the calcium homeostasis was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA level of glyceraldehyde-3- phosphate dehydrogenase. The left atrial diameter (LAD), mitral valvular area (MVOA), and systolic pulmonary arterial pressure were obtained by echocardiography before surgery.

RESULTSCompared to sinus rhythm group, the mRNA levels of L-type calcium channel alc, sarcoplasmic reticulum (SR), calcium adenosine triphosphatase (Ca2+ -ATPase), and ryanodine receptor type-2 (R(Y) R2) were significantly decreased (P < 0.01); the mRNA level of inositol triphosphate receptor type-1 (IP3R1) was significantly increased (P < 0.05). No changes in the mRNA expression of phospholamban and calsequestrin were observed between two groups (P > 0.05). Correlations were found between MVOA and mRNA levels of LVDC-Calc, SR Ca2+ -ATPase (r = 0.719, P = 0.004; r = 0.625, P = 0.017). The mRNA level of SR Ca2+ -ATPase was negatively correlated with LAD (r = -0.573, P = 0.032).

CONCLUSIONSCalcium loading may be responsible for the occurrence and maintenance of AF, and abnormal regulation in the mRNA expression may be the molecular mechanism of intracellular Ca2+ overload. The progressive nature of AF involves structural change.

Arrhythmia, Sinus ; metabolism ; Atrial Fibrillation ; metabolism ; pathology ; Calcium ; metabolism ; Calcium Channels ; biosynthesis ; genetics ; Calcium-Binding Proteins ; biosynthesis ; genetics ; Calcium-Transporting ATPases ; biosynthesis ; genetics ; Chronic Disease ; Heart Atria ; metabolism ; pathology ; Humans ; Mitral Valve ; pathology ; Myocardium ; metabolism ; RNA, Messenger ; biosynthesis

OBJECTIVETo compare the changes of both inward rectifying K(+) (Kir) current(I(k1)) density and mRNA expression level of Kir2.1, a major subfamily of Kir in chronic human atrial fibrillation (CAF) with those in normal sinus rhythm (NSR).

METHODSI(k1) density was measured with whole-cell patch clamp technique in single myocyte isolated by an enzymatic dissociation method from right atrial appendages in patients with CAF (n = 8) and those with NSR (n = 12). The mRNA expression levels of Kir2.1 was determined in right atrial appendages from CAF (n = 19) and NSR (n = 18) by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR).

RESULTThe average resting membrane potentials were similar between CAF and NSR (-78.95 mV +/- 4.67 mV and -70.22 mV +/- 11.08 mV, P>0.05). I(k1) density in single myocyte significantly increased at hyperpolarized potential level (-100 mV) in CAF compared to that in NSR (-9.59 pA/pF +/- 2.47 pA/pF vs. -5.58 pA/pF +/- 2.52 pA/pF, P<0.01). The mRNA level of Kir2.1 was also significantly higher in CAF than that of NSR (0.50+/-0.16 vs. 0.34+/-0.09, P<0.05).

CONCLUSIONThe data suggest that Kir2.1 up-regulation and I(k1) current increase might contribute to the electrical remodeling in CAF patients.

Atrial Fibrillation ; genetics ; metabolism ; physiopathology ; Gene Expression ; Humans ; Myocytes, Cardiac ; metabolism ; physiology ; Patch-Clamp Techniques ; Potassium Channels, Inwardly Rectifying ; genetics ; metabolism ; RNA, Messenger ; genetics