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The Japanese second deep ice coring project was carried out at Dome Fuji, Antarctica. Following the drilling of the pilot hole in 2001, deep ice core drilling led by the Japanese Antarctic Research Expedition (JARE) was conducted over four austral summer seasons, beginning with the 2003/04 season and reached a depth of 3035.22 m near the bedrock in January 2007. The new drill was designed and developed with the goals of (1) solving the problems encountered during the first JARE deep coring drill and (2) achieving more efficient drilling. In particular, the maximum core length that can be drilled at one time was increased from 2.30 m to 3.84 m and the chip storage efficiency was enhanced by a special pipe with many small holes. This paper gives an outline of the improved drilling system, the progress of drilling and various drilling data.

Previous Background: Hemodynamic factors, like blood pressure, have been established to be major determinants of cardiac left ventricular structure. However, several factors other than blood pressure to influence cardiac mass have been implicated. When we did medical survey, cardiac left ventricular mass index (LVMI) of one ethnic group that had higher blood pressure was found to be smaller than that of the other ethnic groups with a lower blood pressure. Such contradicted data from the present study were analyzed combining blood pressure, LVMI and chemical parameters obtained from blood and urine. Methods: In a medical survey conducted in Xinjiang, China, 279 people (65 - 70 years old) from three ethnic groups (Kazakh, Uygur and Han) from two separated regions provided blood and urine samples and underwent echocardiography and 24-h ambulatory blood pressure monitoring (ABPM). Results: Systolic and diastolic blood pressure obtained from ABPM and urinary sodium excretion values were significantly higher in Kazakh than that in Uygur and Han. However, LVMI in Kazakh was lower than that in other 2 groups. Plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were significantly lowest in Kazakh. The values of LVMI in all ethnic groups were positively related to both blood pressure and PAC. An inverse correlation was identified between PAC and urinary sodium excretion value. Conclusion: Although higher blood pressure in Kazakh subjects, their LVMI was lower than those of Uygur and Han, whose blood pressure was lower than that in Kazakh. These results suggest that blood pressure is not always a determinant for LVMI value. There is a possibility that relatively lower PAC resulted from higher sodium intake suppressed the rise in LVMI caused by higher blood pressure in Kazakh.

Many of the elderly Kazakhs have been found to exhibit non-dipping blood pressure variations (BPV). Such variations are seen in both normotensive and hypertensive Kazakhs. The purpose of this study was (1) to determine whether middle-aged Kazakhs also include large numbers of non-dippers, (2) to compare the characteristics of non-dipping and dipping, and (3) to clarify the mechanisms responsible for non-dipping type BPV by examining the autonomic nervous activity and physical activity. We performed ambulatory blood pressure (BP) monitoring. The subjects were divided into two groups (dipping and non-dipping type). We monitored the subjects' physical activity with accelerometry and assessed their autonomic nerve activity by performing a frequency domain analysis of their heart rate variability (HRV). The power spectral density (PSD) of the HRV was calculated using fast Fourier transformation. We analyzed the systolic blood pressure (SBP) variations with the maximum entropy method (MEM). The dippers and non-dippers accounted for 48% and 52% of the subjects, respectively. MEM analysis revealed that the SBP variations of the non-dippers exhibited a 24 hour periodicity with a very weak PSD as well as an ultradian periodicity. The non-dippers exhibited higher low-frequency/high-frequency (LF/HF) ratio and lower HF/(LF + HF) ratios than the dippers, particularly during the nighttime. In addition, the non-dippers performed less physical activity than the dippers. These differences in cardiac autonomic function and physical activity might contribute to the generation of a weak circadian rhythm in SBP, and thus, ultimately lead to the non-dipping SBP variations observed in non-dipper Kazakhs.

Smoothelin is a specific type of cytoskeletal protein found in smooth muscle cells (SMCs). Several previous research studies have examined the relationship between smoothelin and atherosclerotic plaque. The aim of the present study was to further assess the association between the human SMTN gene and cerebral infarction (CI) using a haplotype-based case–control study. A total of 168 CI patients and 259 supercontrols were genotyped for the five single-nucleotide polymorphisms (SNPs) used as genetic markers for the human SMTN gene (rs2074738, rs5997872, rs56095120, rs9621187 and rs10304). Data were analyzed for three separate groups that included total subjects, men and women. The genotypic distribution of rs10304 for men showed a significant difference between the control and CI groups. In addition, the frequency of the C-T-T-A haplotype (established by rs5997872, rs56095120, rs9621187 and rs10304) was significantly higher in the CI versus the control group ( p = 0.013), while the frequency of the C-A-T-G haplotype (established by rs5997872, rs56095120, rs9621187 and rs10304) in the CI group was significantly lower than that seen in the controls ( p = 0.021). In conclusion, we confirmed that the haplotype constructed using rs5997872, rs56095120, rs9621187 and rs10304 was a useful genetic marker of CI in Japanese men.

Smoothelin is a specific cytoskeletal protein that is associated with smooth muscle cells. The human SMTN gene encodes smoothelin-A and smoothelin-B, and studies using SMTN gene knockout mice have demonstrated that these animals develop hypertension. The aim of the present study was to investigate the association between the human SMTN gene and essential hypertension (EH) using a haplotype-based case-control study. This is the first study to assess the association between essential hypertension and this gene. A total of 255 EH patients and 225 controls were genotyped for the five single-nucleotide polymorphisms (rs2074738, rs5997872, rs56095120, rs9621187 and rs10304) used as genetic markers for the human SMTN gene. Data were analyzed for three separate groups: total subjects, men and women. Although there were no differences for genotype distributions, or the dominant and recessive model distributions noted for total subjects, men and women for all of the SNPs selected for the present study, for the total subjects group, the frequency of the G-C-A-C haplotype constructed with rs2074738-rs5997872-rs56095120-rs9621187 was significantly lower in the essential hypertension patients than in the controls (P = 0.002). The G-C-A-C haplotype appears to be a useful protective marker of essential hypertension in Japanese, and the SMTN gene might also be a genetic marker for essential hypertension.

Objectives: Smoothelin is a specific kind of cytoskeletal protein present in smooth muscle cells. Some researchers have shown the relationship between smoothelin and atherosclerotic plaque. The human SMTN gene encodes smoothelin-A and smoothelin-B. The aim of the present study was to assess the association between the human SMTN gene and myocardial infarction (MI) using a haplotype-based case–control study. Methods: A total of 227 MI patients and 257 supercontrols were genotyped for five single-nucleotide polymorphisms used as genetic markers of the human smoothelin gene. Data were analyzed for three separate groups: total subjects, men, and women. Results: For the women, the frequency of the C-T-T-G haplotype (established by rs5997872, rs56095120, rs9621187, and rs10304) was significantly higher in the MI group than in the control group (p=0.012). Conclusions: We confirmed that the haplotype constructed using rs5997872, rs56095120, rs9621187, and rs10304 is a useful genetic marker of MI in Japanese females.

CYP4A11, which is a member of the cytochrome P450 family, acts mainly as an enzyme that converts arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite involved in the maintenance of cardiovascular health. Recently, it was reported that many subfamilies of CYP genes have an association with myocardial infarction (MI). The aim of the present study was to assess the association between the human CYP4A11 gene and MI, using a haplotype-based case-control study with a separate analysis of the gender groups. A total of 239 MI patients and 285 controls were genotyped for 3 single-nucleotide polymorphisms (SNPs) of the human CYP4A11 gene (rs2269231, rs1126742, rs9333025). The data obtained via haplotype-based case-control studies were assessed for 3 separate groups: total subjects, men, and women. For the total, men and women groups, the distribution of the genotypes and alleles of the 3 SNPs did not show any significant difference between the MI patients and the control subjects. For the total and the men groups, the overall distribution of the haplotypes constructed with the 3 SNPs significantly differed between the MI patients and control subjects (P < 0.001). Also, for the total and for the men, the frequency of the T-T-A haplotype constructed with the 3 SNPs was significantly lower for the MI patients than for the control subjects (both P

Background: The International Conference on Harmonization E14 Guideline specifies detailed assessment of QT interval or corrected QT interval prolongation when developing new drugs. We recently devised new software to precisely measure the QT interval. Methods and Results: The QT intervals of all leads for a selected single heart beat were compared between automated measurement with the new software from Fukuda Denshi and manual measurement. With both automated and manual measurement, QT intervals obtained by the tangent method were shorter than those obtained by the differential threshold method, but the extent of correction was smaller. QT interval data obtained by the differential threshold method were more similar to values obtained by visual measurement than were data obtained by the tangent method, but the extent of correction was larger. Variability was related to the T-wave amplitude and to setting the baseline and tangent in the tangent method, while skeletal muscle potential noise affected the differential threshold method. Drift, low-amplitude recordings, and T-wave morphology were problems for both methods. Among the 12 leads, corrections were less frequent for leads II and V3–V6. Conclusion: We conclude that, for a thorough assessment of the QT/QTc interval, the tangent method or the differential threshold method appears to be suitable because of smaller interreader differences and better reproducibility. Correction of data should be done by readers who are experienced in measuring the QT interval. It is also important for electrocardiograms to have little noise and for a suitable heart rate and appropriate leads to be selected. Ann Noninvasive Electrocardiol 2011;16(2):156–164

G-protein-coupled purinergic receptor P2Y2 (P2RY2) has an important role in the process of atherosclerosis related to cerebral infarction (CI). The aim of this study was to investigate the relationship between the P2RY2 gene and CI through a haplotype-based case-control study, including the separate analysis of two gender groups. A total of 237 CI patients and two control groups (control 1, 254; control 2, 255) were genotyped for five single nucleotide polymorphisms (SNPs) in the human P2RY2 gene (rs4944831, rs1783596, rs4944832, rs4382936, rs10898909). Among women, the distribution of the dominant rs4944832 phenotype (GG vs. GA+AA) differed significantly between the CI patients and the control 1 group (P=0.043) and between the CI patients and the control 2 group (P=0.029). Logistic regression analysis showed that the GG genotype of rs4944832 was significantly more prevalent in the female CI patients than in the control 1 (P=0.021) and control 2 groups (P=0.005). For all subjects, the overall distribution of the haplotype established by rs1783596-rs4382936-rs10898909 was significantly different between the CI patients and the control 1 group (P=0.027). For all subjects, the frequency of the T-A-G haplotype (rs1783596-rs4382936-rs10898909) was also significantly higher (P=0.031), whereas the frequency of the T-C-G haplotype (rs1783596-rs4382936-rs10898909) was significantly lower (P=0.029) in the CI patients than in the control 1 group. The present results indicate that the T-A-G haplotype of the human P2RY2 gene is a susceptibility haplotype for CI in Japanese subjects, and that the GG genotype is a genetic marker for CI, particularly in Japanese women.

Background: Atherosclerosis leads to myocardial infarction (MI) and P2RY2 plays an important role in this process. The aim of the present study was to investigate the association between human P2RY2 and MI via a haplotype-based case-control study that additionally analyzed the group by sex. Methods and Results: The 310 MI patients and 254 controls were genotyped for 5 single-nucleotide polymorphisms (SNPs) of the human P2RY2 gene (rs4944831, rs1783596, rs4944832, rs4382936, rs10898909). Data were separately analyzed for the total, male, and female subjects. For men, the GA+AA genotype of rs10898909 was significantly higher in MI patients as compared with controls (P=0.040). Logistic regression analysis found a significant difference for the genotype (P=0.016). As compared with controls, the frequencies of the C-A and T-C-A haplotypes were significantly higher (P=0.016, and P=0.045, respectively) in men, whereas the frequencies of the C-G and T-A-A haplotypes were significantly lower (P=0.023, and P=0.025, respectively) in MI patients. Conclusions: The GA+AA genotype, as well as the C-A and T-C-A haplotypes, of human P2RY2 could be genetic markers for MI in Japanese men. (Circ J 2009; 73: 2322-2329)

BACKGROUND CYP4F2, a member of the cytochrome P450 family, acts mainly as an enzyme and is involved not only in the metabolism of leukotriene B4, but also in that of arachidonic acid. It converts arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite involved in the regulation of the vascular tone in the brain. The aim of this study was to assess the association between the human CYP4F2 gene and cerebral infarction (CI), using a haplotype-based case-control study with separate analyses of data from the gender groups. METHODS A total of 175 CI patients and 246 control subjects were genotyped for five single-nucleotide polymorphisms (SNPs) of the human CYP4F2 gene (rs3093105, rs3093135, rs1558139, rs2108622, rs3093200). For data analysis, three separate groups were assessed: all subjects, men, and women. RESULTS In the male subjects, the G allele frequency for rs2108622 was significantly higher in CI patients as compared to control subjects (P = 0.025). The overall distribution of the haplotypes in the men was significantly different between the CI patients and the control subjects (P = 0.027). Additionally, the frequency of the T-C-G haplotype for men was significantly higher in the CI patients than in the control subjects (P = 0.008). Multiple logistic regression analysis also revealed the significance of the T-C-G haplotype in men, even after adjustment for confounding factors. CONCLUSIONS The results of this study indicate that, in Japanese men, CI is associated with the G allele of rs2108622 and, in addition, that the T-C-G haplotype appears to be a useful genetic marker for CI.

Objective CYP4A11 is an enzyme that converts arachidonic acid to 20-hydroxyeicosatetraenoic acid, which is involved in regulation of vascular tone in the brain. Recent evidence indicates that the polymorphism of the CYP genes is associated with cerebral infarction (CI). The aim of the present study was to assess the association between the human CYP4A11 gene and CI using a haplotype-based case-control study divided by gender. Methods Three SNPs of the human CYP4A11 gene (rs2269231, rs1126742, and rs9333025) were selected and genotyped for 174 CI patients and 293 controls. The data were assessed for three separate groups: total subjects, men and women. Results In men, the genotype distribution of rs9333025 significantly differed between the CI patients and control subjects (P = 0.047). The distribution of the dominant model of rs9333025 (GG vs. GA + AA) significantly differed between both the total and the men groups (P = 0.033, P = 0.028, respectively). Logistic regression analysis adjusted for the history of hypertension and diabetes mellitus also showed that the GG genotype was significantly more frequent in the CI patients than in the controls, both for the total and men groups (P < 0.001, P = 0.008, respectively). The overall distribution of the haplotypes constructed with the 3 SNPs showed significant differences between the CI and the control in total group (P = 0.049). The T-C-G haplotype was significantly more frequent in control subjects than in the CI patients in the total group (P = 0.020). Conclusions The GG genotype of rs9333025 could be a genetic marker for CI in Japanese men. In addition, the T-C-G haplotype might also be a protective marker for CI in Japanese.

Background A major mechanism of hypertension in many postmenopausal women is deficiency of female gonadal steroids. A long postmenopausal period may thus represent one factor that influences the prevalence of hypertension because of long periods of estrogen loss. Methods When we conducted a medical survey in northwestern China, we also asked 150 postmenopausal female subjects to provide age at menopause in a questionnaire. Age at menopause ranged from 37 to 57 years for all subjects. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) in all subjects were obtained from 24-h ambulatory blood-pressure monitoring. Results An inverse correlation was identified between age at menopause and SBP and DBP, and a positive correlation was found between postmenopausal period and either SBP or DBP. Blood pressure, age at menopause, and postmenopausal period were not significantly related to body mass index, plasma renin activity, glomerular filtration rate, or urinary excretion values of sodium and potassium. Conclusions Our results clearly demonstrated that higher blood-pressure levels in postmenopausal women depend on age at menopause and postmenopausal period, but not subjects’ age, suggesting that a longer absence of female gonadal steroids represents a major factor contributing to increased blood pressure in elderly women.

Atrial premature depolarizations (APDs) triggering atrial fibrillation (AF) originate from mainly the pulmonary veins (PVs), but, in some cases, atrial ectopic beats (AEBs) triggering AF originate from the right atrium (RA) or the superior vena cava. Accurate identification of the origin of APDs in the PVs by means of RA and coronary sinus mapping is difficult. Purpose: The aim of this study was to identify the origin of AEBs triggering AF before transseptal catheterization. Electrode catheters were placed in the posteroseptal RA (PSRA), right pulmonary artery (RPA), left pulmonary artery (LPA), and esophagus in 10 patients with paroxysmal AF. We analyzed endocardial electrograms from the PSRA, RPA and LPA, and epicardial electrograms from the esophagus. The origin of the AEBs in the PVs was determined before PV ablation by mapping 4 PVs simultaneously. Four AEBs originated from the left superior PV (LSPV), 2 from the left inferior PV (LIPV), 4 from the right superior PV (RSPV), 2 from the RA or superior vena cava. In AEBs originating from the RA, the PSRA activation was the earliest and it proceeded in a cranial to caudal direction. In AEBs originating from the RUPV, RPA was the earliest. The esophageal activation sequence was in a cranial to caudal direction. In AEBs from the LSPV, LPA was the earliest and the esophageal activation sequence proceeded in a cranial to caudal direction. In AEDs from LIPV, LPA was the earliest, and the esophageal activation sequence was nearly simultaneous. Atrial activation sequences from the PSRA, RPA, LPA, and esophageal catheters can accurately identify the location of the initiating foci of AF before a transseptal procedure.

Background The purpose of this study was to determine whether the extent of atrial electrical remodeling affects the recurrence of atrial fibrillation (AF) after cardioversion of persistent AF (PAF). Methods and Results Internal atrial cardioversion was performed in 47 patients with PAF. The right atrial monophasic action potential duration (RA-MAPD) at pacing cycle lengths (PCLs) of 800-300 ms and P wave signal-averaged electrocardiogram were recorded after cardioversion. Bepridil (150-200 mg/day) and carvedilol (10 mg/day) were administered to all patients after cardioversion. Of the 47 patients, 20 had recurrent AF within 3 months. No relation was observed between age, left atrial dimension, left ventricular ejection fraction, and AF recurrence. The AF duration was significantly longer (p

Crista Terminalis and Double Potentials in Atrial Flutter. Introduction: The activation sequence in typical atrial flutter (AFL) around the tricuspid annulus is well described. However, activation of the remainder of the right atrium (RA) is not well defined. Previous studies have shown a linear block at the crista terminalis (CT) during AFL. The aim of this study was to evaluate the relationship between the location of the CT and the line of block by intracardiac echocardiography (ICE). Methods and Results: Twenty-one patients with typical AFL were included in the study. The ICE imaging catheter (9-French with 9-MHz ultrasound transducer) was advanced to the RA. Under ICE guidance, a 20-pole roving catheter was used to map double potentials (DPs) during AFL, and three-dimensional images of the RA were reconstructed. During counterclockwise (CCW), clockwise (CW) AFL, or both, a line of conduction block manifested by DPs was identified at a septal site adjacent to the CT in 12 patients and in the posteroseptal RA in 9 patients. Conclusion: The functional line of block in CCW and CW AFL is localized not at the CT but at the septal edge of the CT or in the posteroseptal RA.

Brugada syndrome is characterized by right bundle branch block morphology and ST-segment elevation in the right precordial leads and a propensity to develop ventricular arrhythmias. Mutations in a cardiac sodium channel gene have been linked to this syndrome, and the ionic mechanisms responsible for the electrocardiographic phenotype are temperature-dependent. This case report describes a patient in whom a typical Brugada ECG pattern developed during fever and could be reproduced at normal body temperature by administration of pilsicainide.

Objective: Many cases of non-dipping-type blood pressure variations and hypertension have been documented amongst elderly and middle-aged Kazakhs. The purpose of this study was to discover whether there are also large numbers of non-dippers among young Kazakhs and to compare the blood pressure variations seen in these individuals with those observed in age-matched dipping-type Kazakhs. Design and Method: We performed ambulatory blood pressure monitoring and defined non-dippers as individuals that exhibited a nighttime systolic blood pressure (SBP) reduction of Results: Dippers and non-dippers accounted for 73% and 27% of the subjects, respectively. The physiological characteristics of the dippers and non-dippers did not differ, nor did their 24-hr SBP values. However, daytime SBP was lower and nighttime SBP was higher in the non-dippers than the dippers (non-dippers vs. dippers: daytime SBP: 117 ± 5 vs. 123 ± 10 mmHg, P = 0.022; nighttime SBP: 109 ± 7 vs. 97 ± 7 mmHg, P = 0.005). MEM analysis of the non-dippers detected SBP variations with a 24-hr frequency periodicity, a very weak power spectral density (PSD), and an ultradian periodicity. The HRV analysis revealed that the low frequency/high frequency ratio was lower in the non-dippers than in the dippers during the morning. Conclusions: Young non-dipping Kazakhs exhibited SBP variations with a 24-hr frequency periodicity, a very weak PSD, and an ultradian periodicity. Furthermore, the non-dippers displayed less sympathetic nerve activity during the morning than the dippers.

The aims of the present study were to find new genetic markers of essential hypertension (EH) and to investigate relationships between EH and polymorphisms of the renin gene. Using single strand conformation polymorphism, we discovered a new variable number of tandem repeat (VNTR) polymorphism in intron 7 that is 18 bp upstream from the boundary with exon 8. Nucleotide sequencing revealed that this VNTR polymorphism is a tandem repeat of the 4-nucleotide sequence TCTG. There were 6 alleles of this VNTR polymorphism, ranging from 7 repeats to 12 repeats. We analyzed the association between EH and this VNTR polymorphism. There was no significant difference in the overall distribution of this VNTR polymorphism between the EH and normotensive subjects. In summary, we discovered a novel VNTR polymorphism in the renin gene, and this polymorphism was not associated with EH. (Hypertens Res 2003; 26: 473-477)

Right atrial monophasic action potentials were recorded before and after 60 minutes of rapid atrial pacing (pacing cycle length (CL); 127 +/- 10 ms) in 12 closed-chest dogs. The right atrial (RA) monophasic action potential (MAP) duration at 90% repolarization (RAMAPD) was measured at CLs of 400 ms and 250 ms. CL-dependent changes in RAMAPD (CL 400 ms - 250 ms) before and after rapid atrial pacing were 24 +/- 1 ms and 16 +/- 5 ms, respectively (p 5 minutes) was induced in 1 of 12 dogs at a pacing CL of 130 ms before rapid atrial pacing and in 4 of 12 dogs at a pacing CL of 135 +/- 17 ms after rapid atrial pacing. Onset of AF was always preceded by the RAMAPD alternans. Sixty minutes of rapid atrial pacing leads to diminution of rate adaptation of atrial action potential duration (APD) and appearance of APD alternans of greater magnitude at longer CL, both of which may contribute to the initiation and perpetuation of AF during its early phase.

Atrioventricular nodal reentrant tachycardia (AVNRT) is a relatively common paroxysmal supraventricular tachycardia. This study investigated whether adenosine-5'-triphosphate (ATP) injection during sinus rhythm might be useful in the noninvasive diagnosis of dual AV nodal pathways. The study group consisted of 9 patients with slow/fast AVNRT and 11 control patients without antegrade dual AV nodal physiology (DAVNP). ATP (2.5 to 30 mg, in 2.5-mg increments was injected during sinus rhythm until signs of DAVNP (> or = 50 msec increase or decrease in AH or PR interval in two consecutive beats) or > or = second-degree AV block was observed. DAVNP was diagnosed by ATP test in all 9 patients with slow/fast AVNRT. DAVNP was observed by ATP test in 3 of the 11 control patients. Thus, the test had a sensitivity of 100% and specificity of 73%. ATP test given during sinus rhythm is useful for identifying patients with dual AV nodal pathways who are prone to AVNRT.

Right bundle branch block and ST segment elevation (RBBB-STE) in the right precordial leads have been reported as a distinct clinical and electrocardiographic syndrome in patients prone to ventricular fibrillation (VF) in the absence of structural heart disease (Brugada syndrome). The purpose of the study was to investigate the role of signal averaged electrocardiogram (SAECG) in identifying patients at high risk among asymptomatic RBBB-STE patients. Thirteen patients with the RBBB-STE ECG were identified. Symptoms were: syncope (n=3, cases 1, 3, and 11), atypical chest pain (n=3, cases 4, 10, and 12) and palpitations (n=2, cases 6, and 7). The other 5 patients were asymptomatic. SAECG and programmed electrical stimulation (PES) were conducted in all patients. Body surface late potentials (LPs) were present in 7 of 13 patients before PES. Vf was induced in 6 of 7 LP positive patients. Vf was induced in 3 of 6 LP negative patients, but LP became positive in 2 of 3 patients in whom Vf was induced. One patient with syncope due to VF (case 1), 1 patient without symptoms who died suddenly during follow up (case 2), and 1 asymptomatic patient (case 9) showed reproducibly positive LP. In a patient (case 9) with positive LP at baseline, LP transiently became negative during follow up. In RBBB-STE patients, reproducibly positive LP is at risk for malignant ventricular arrhythmias and sudden death. Repeated SAECG recording may be useful for screening high-risk patients who should receive electrophysiological study among asymptomatic RBBB-STE patients.

Background: The relation between ECG and activation patterns within atria in typical atrial flutter (AFL) patients (pts) has not been defined due to the lack of simultaneous multisite right and left atrial mapping.

Natriuretic peptides (NPs) regulate cardiovascular homeostasis, including natriuresis, diuresis, vasodilation, regulation of endocrine secretion, and inhibition of cellular growth. Atrial natriuretic peptide receptor C (NPRC) has a short cytoplasmic domain that lacks guanylyl cyclase activity. We used information available for the cDNA of human NPRC to amplify products covering all genomic regions of the gene by long polymerase chain reaction (PCR) and thermal asymmetric interlaced (TAIL)-PCR. PCR products were sequenced directly after extraction and purification. The human NPRC gene spans >65 kb and contains eight exons and seven introns. All of the exon-intron junction sequences contain the GT/AG consensus junction sequence. We then used the PCR-single-strand conformation polymorphism (PCR-SSCP) to identify polymorphisms of the human NPRC gene. All eight exons and neighboring introns were analyzed by PCR-SSCP for 96 subjects, and migration variants were observed for intron 1, exon 2, and exon 5. Direct sequencing of these variants revealed the following sequence differences: a C to T transition in intron 1, an A to C transition in exon 2, and a C to T transition in exon 5. PCR-restriction fragment length polymorphism analysis (PCR-RFLP) was used to evaluate all three variations. We have determined the structural organization and identified polymorphic sites in the human NPRC gene. The results of this study will facilitate further genetic analyses of the human NPRC gene function.

Since myocardial lesion size during radio-frequency (RF) ablation is limited at high power by impedance rise when electrode tip temperature exceed 100 °C, controlling tip temperature by continuous intraelectrode saline infusion could permit generation of larger lesion. (1) Two dogs randomly received either standard or cooled tip RF ablation at 4 to 6 separate LV sites. Power output of 30 W was delivered via modified 7 Fr deflectable catheter with 4 mm tip for up to 120 sec or until impedance rise occurred. (2) Six dogs randomly received cooled tip RF ablation at power output of 20, 30, 40 W for 120 sec. (3) Three dogs randomly received cooled tip RF ablation using room temperature saline (21–25 °C) or chilled saline (1–4 °C) infusion.

Contrast echocardiography employing intracoronary injection of Albunex was performed in a patient with right atrial myxoma. An echolucent area within the tumor mass was observed on 2-dimensional echocardiography and Albunex injection caused an appreciable opacification of this echolucent area suggesting the presence of a vascular-like structure. This finding was subsequently confirmed by coronary arteriography and from a pathologic specimen.

Background. Deficiency of potassium (K) intake is associated with hypertension, and high dietary K intake may have a preventive effect. The prevalence of hypertension and incidence of stroke are higher in Kazakhs than in other ethnic groups in the People's Republic of China (PRC). The Barkol area in the Xinjiang region in PRC is an area with a high population of Kazakhs. We carried out a study in this region that involved blood pressure monitoring and the examination of serum and urinary electrolytes in the Kazakh and Han populations of the area. Methods. Twenty-four-hour ambulatory blood pressure monitoring and urine collections were performed for each study subject. In each subject, urine was collected simultaneously for 24 h during the blood pressure monitoring. Serum and urinary electrolytes were measured. Results. The prevalence of hypertension was higher in the Kazakh population than in the Han (men, 53%; women, 43% in the Kazakhs; men, 40%; women, 30% in the Han; P < 0.001). Urinary excretion of potassium was lower in Kazakhs than in Han (Kazakh, 18.9 ± 8.7 mmol/day; Han, 36.5 ± 11.3 mmol/day; P < 0.001). Urinary excretion of sodium was lower in Kazakhs than in Han (Kazakhs, 181.4 ± 77.6 mmol/day; Han, 194.1 ± 75.9 mmol/day; P < 0.001). Mean 24-h blood pressure was higher in Kazaks than in Han, and this value correlated positively with the urinary sodium/potassium ratio (r = 0.39; P < 0.001). Conclusions. The prevalence of hypertension was higher in Kazakhs than in Han in the Barkol area in the Xinjiang region. Kazakhs had a low intake of potassium. The sodium/potassium ratio was higher in Kazakhs than in Han. A high Na/K ratio, together with low intake of potassium, may be a factor in Kazakh hypertension.

C-type natriuretic peptide (CNP) dilates arteries, lowers blood pressure and inhibits proliferation of vascular smooth muscle cells via the type B natriuretic peptide receptor (NPRB). The CNP-NPRB system may play a crucial role in the development of cardiovascular disease. We recently determined the structure of the human NPRB gene. In the present study, our objectives are to identify the polymorphisms of the NPRB gene and investigate the association of this gene with essential hypertension (EH). We used the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique to study the NPRB gene polymorphism, and conducted an association study using a novel polymorphic marker. PCR-SSCP analysis of all 22 exons was done in 90 subjects, and abnormally-migrating bands were observed in the analyses of exon 11 and intron 18. Direct sequencing of these DNA fragments revealed the following sequence alterations: a C to T transition at nucleotide (nt) 2077 in exon 11 and a 9-bp insertion/deletion (I/D) in intron 18. PCR-restriction fragment length polymorphism analysis (PCR-RFLP) was developed to detect the C2077T transition. PCR-RFLP analyses of healthy subjects revealed that the C2077T polymorphism had complete linkage to GT repeats in intron 2 reported previously. The I/D polymorphism was identified by polyacrylamide gel electrophoresis, and it was not linked to any known polymorphic alleles of this gene. Therefore, the possible association between the I/D polymorphism and EH was investigated. A total of 123 individuals with EH and 123 age-matched normotensive control subjects were studied. Overall distributions of allele frequencies in the two groups were not significantly different. Although the I/D polymorphism in intron 18 of the NPRB gene was not associated with EH, the results of this study, which identified two novel polymorphisms in the human NPRB gene, will facilitate further genetic analysis of this gene and cardiovascular disease.

To compare the effects of class Ic and III antiarrhythmic agents on the termination and prevention of atrial fibrillation, the present study investigated the use-dependent electrophysiological effects of flecainide, nifekalant and d,l-sotalol on the human atrium. Flecainide significantly prolonged effective refractory period (ERP), intra-atrial conduction time (IACT) and monophasic action potential duration (MAPD), and its effects on ERP and IACT were use-dependent. Nifekalalant significantly prolonged ERP and MAPD, and these effects were reverse use-dependent; however, there was no significant change in IACT. d,l-Sotalol significantly prolonged MAPD and the effect was reverse use-dependent. It significantly prolonged ERP, but the effect was not reverse use-dependent. d,l-Sotalol increased IACT in a use-dependent manner. Thus, for atrial fibrillation, class Ic antiarrhythmic agents might be more effective in termination and class III antiarrhythmic agents might be more effective in prevention. (Jpn Circ J 2001; 65: 1 - 6)

Missense mutations in the calcium-sensing receptor (CaSR) gene have previously been identified in patients with familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism. We identified a newborn with hypercalcemia in our hospital by mass screening. The family members were studied, and we found a novel CaSR missense mutation with polymerase chain reaction single-strand conformational polymorphism analysis. The mother, grandmother, and aunt of the baby all had FHH. A heterozygous missense mutation in exon 6 that substitutes a glutamic acid for the glycine at codon 557 (Gly557 Glu), which corresponds to the extracellular domain of CaSR, was identified and shown to cosegregate with the disease. Identification of the mutation responsible for the FHH phenotype in this family may facilitate rapid testing of individuals at risk for FHH.

Most of the class III antiarrhythmic agents developed in recent years blocks the rapid component of delayed rectifier potassium current (IKr). IKr blocker shows reverse use-dependency and also may cause torsades de pointes at slower heart rate. Ibutilide fumarate, a novel class III antiarrhythmic agent, increases window Na+ current at the action potential plateau phase. We studied the rate-dependent effect of ibutilide on the electrophysiological parameters of human atrium and ventricle. Franz catheter and a pacing catheter were placed closely in the high right atrium and right ventricular apex to record monophasic action potentials (MAP) during pacing at cycle length (PCL) of 600[emsp4 ]ms and 350[emsp4 ]ms in eight patients who underwent electrophysiological study. MAP duration of right atrium (RA-MAPD) and right ventricle (RV-MAPD), effective refractory period of RA and RV (RA-ERP and RV-ERP), intra-atrial conduction time (IACT) and intra-ventricular conduction time (IVCT) were measured before and after intravenous administration of ibutilide (0.01[emsp4 ]mg/kg up to 1[emsp4 ]mg). A conduction time from RA pacing spike to distal coronary sinus potential was used to measure IACT, while QRS duration of surface ECG during RV pacing was used to measure IVCT. Ibutilide prolonged RA-MAPD by 60[emsp4 ]ms at PCL 600[emsp4 ]ms and by 53[emsp4 ]ms at PCL 350[emsp4 ]ms; RV-MAPD by 48[emsp4 ]ms at PCL 600[emsp4 ]ms and by 55[emsp4 ]ms at PCL 350[emsp4 ]ms. Ibutilide did not affected RA and RV-ERP/MAPD ratio, IACT, and IVCT. Ibutilide prolongs MAPD and ERP of human atrium and ventricle without reverse use-dependency.

The natriuretic peptide (NP) system may play a crucial role in the development of cardiovascular and renal diseases. C-type NP dilates arteries and lowers blood pressure, and it inhibits the proliferation of vascular smooth muscle cells via the type B NP receptor (NPRB). We determined and analyzed the structure of the NPRB gene and found an insertion/deletion (I/D) polymorphism in intron 18. In this experiment, we studied this I/D polymorphism in the NPRB gene in 241 subjects, including 118 patients with cerebral infarction (the CI group) and 123 control subjects (the non-CI group). Our goal was evaluate the association of this polymorphism with cerebral infarction. Our findings showed that genotype frequencies of the I/D polymorphism were in Hardy-Weinberg equilibrium. The frequencies for the II, ID, and DD alleles were 0.569, 0.374, and 0.057, respectively, in the non-CI group and 0.576, 0.356, and 0.068, respectively, in the CI group. No association was found between this polymorphism and cerebral infarction. These results suggest that this polymorphism in the NPRB gene is not linked to a pathogenic CI gene.

The changes in carotid artery structure during the natural longevity of the Uighurs people were compared with other ethnic groups. The 419 subjects were divided into (1) longevity and (2) older groups as follows: Uighurs longevity group in Hotan (ULH); and Uighurs, Hans and Kazaks older groups in Hotan or Balikun (UOH, HOH, HOB and KOB). The wall thickness of the common carotid artery (CCA) was measured by ultrasonography. Risk factors were evaluated by measuring total cholesterol (T-C), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG) and fasting glucose, and by 24-h ambulatory blood pressure monitoring. Wall thickness and blood pressure were greater in the Balikun groups than in the Hotan groups. The CCA wall was thicker in Uighurs and Kazaks than in Hans, in the ULH than in the UOH. There was no significant difference in blood pressure among the Hotan groups. LDL-C and glucose were higher and HDL-C was lower in the Hotan groups than in the Balikun groups. T-C, LDL-C, TG and glucose were higher in the HOH than in the ULH and UOH. Systolic blood pressure and LDL-C were higher and TG was lower in the KOB than in the HOB. These results suggest that an increased CCA wall thickness can be attributed to age in Hotan, and to a higher blood pressure level in Balikun, and that the higher blood pressure affected the Balikun groups more than the Hotan groups.

The Uygur in Hotan (Xinjiang, China) are reported to have a long life expectancy. The purpose of this study was to clarify the relationship between variations in blood pressure (BP) and longevity. Cross-sectional surveillance was carried out in both Hotan and Barkol. The subjects were divided into five groups: 1. Uygur longevity subjects in Hotan (103 subjects, age >90 yr); 2. Uygur elderly subjects in Hotan (107 subjects, age 65-70 yr); 3. Han elderly subjects in Hotan (41 subjects, age 65-70 yr); 4. Kazakh elderly subjects in Barkol (117 subjects, age 65-70 yr); 5. Han elderly subjects in Barkol (50 subjects, age 65-70 yr). BP was monitored and analyzed using the fourteen devices of ambulatory BP monitoring. The prevalence of hypertension was lowest in the Uygur (16.2% in Uygur elderly subjects in Hotan; 23.7% in Uygur longevity subjects in Hotan; 27.0% in Han elderly subjects in Hotan; 42.0% in Han elderly subjects in Barkol; 50.0% in Kazakh elderly subjects in Barkol). The ratio of dips in BP was largest in the Han (57% in Han elderly subjects in Barkol; 50% in Han elderly subjects in Hotan; 50% in Uygur longevity subjects in Hotan, 49% in Uygur elderly subjects in Hotan; 17% in Kazakh elderly subjects in Barkol). The 24-h mean systolic BP in Uygur longevity subjects in Hotan was not different from those in Uygur elderly subjects and Han elderly subjects in Hotan, nor did the 24-h mean diastolic BP differ from those in Uygur elderly subjects and Han elderly subjects in Hotan respectively. In conclusion, Uygur subjects seem to be less hypertensive, compared to Kazakh subjects. Uygur longevity subjects had more dipping in their BP variation than did the Kazakh subjects in Xinjiang, China.