We sought to determine whether a family history of hypertension is quantitatively associated with the prevalence of hypertension and blood pressure in a screened cohort. Clinical data and family (parents and siblings) histories regarding hypertension were collected from 9,914 individuals (probands) who were interviewed and examined during a one-day clinic by the Okinawa General Health Maintenance Association in 1997. We used logistic analysis to calculate odds ratios with adjustments for age, sex, body mass index, total cholesterol, presence of diabetes mellitus, alcohol use, cigarette smoking, and status of physical exercise. The age- and sex-adjusted hypertension prevalences in probands were 29.0% for those with 1 family member with a history of hypertension (n=2,112), 37.6% for those with 2 hypertensive family members (n=374), and 47.3% for those with 3 or more hypertensive family members (n=68). In contrast, only 16.4% of probands who reported no family history of hypertension (n=7,360) were hypertensive themselves. The trend of the prevalence according to the number of family members with a history of hypertension was significantly positive (p=0.003). The adjusted odds ratios (95% confidence interval) of hypertension were 2.74 (2.43-3.10) for 1 member, 4.62 (3.62-5.90) for 2 members, and 6.04 (3.51-10.4) for 3 or more members with a history of hypertension. In patients without antihypertensive medication (n=9,009), systolic/diastolic blood pressure (mean +/- SD) was 121 +/- 17/75 +/- 11 for 1 member, 124 +/- 18/77 +/- 12 for 2 members, and 127 +/- 17/78 +/- 11 for 3 or more members with a history of hypertension. In contrast, the mean systolic/diastolic blood pressure of probands who reported no family history of hypertension (n=7,360) was 119 +/- 15/74 +/- 10 mmHg, which was significantly (p<0.05) lower than that of any of the groups with hypertensive family members. In conclusion, an increase in the number of family members with hypertension was associated with an increasing prevalence of hypertension and blood pressure in the probands, independent of conventional risk factors for hypertension. Family members of hypertensive subjects may need to be treated in primary prevention efforts related to hypertension.

Bradycardia is a trigger of ventricular arrhythmias in patients with arrhythmia including Brugada syndrome and long QT syndrome. The HCN4 channel controls the heart rate, and its mutations predispose to inherited sick sinus syndrome and long QT syndrome associated with bradycardia. We found a 4 base-insertion at the splice donor site of the HCN4 gene in a patient with idiopathic ventricular tachycardia, which was supposed to generate a truncated channel. To investigate the role of the HCN4 channel in ventricular arrhythmia, we introduced a ventricular action potential of I f channel produced by HCN4 in a computer simulation model and found that the I f channel generated a leaky outward current during the plateau phase of ventricular action potential. Currents through the I f channel were suggested to contribute to the shortening of the action potential duration and the prevention of early after-depolarization in bradycardia. These observations suggested that the HCN4 channel played a preventive role in triggering bradycardia-induced ventricular arrhythmias.

Multiple drug use was observed in haemodialysis patients. The number of prescribed drugs was a significant predictor of short-term mortality. Male sex, diabetes mellitus, and duplication of drugs were correlated with increases in the number of medications.

At any MAP level, hemodialysis patients had a higher SBP, lower DBP, and higher PP values than those control subjects with a normal renal function who were matched for age, sex, diabetes mellitus, and body mass index. Further study is needed to determine whether preventing or reducing an elevated PP improves the prognosis for hemodialysis patients.

Clustering of risk factors was significantly associated with hypertension. The number of risk factors positively correlated with the blood pressure levels in nonhypertensive subjects. The accumulation of risk factors may play an important role in the pathogenesis of hypertension, and thus the aggregation of risk factors may need to be addressed in primary prevention efforts related to hypertension.