Sex differences on the electrocardiographic pattern of cardiac repolarization: possible role of testosterone.

BACKGROUND: Cardiac repolarization has been shown to be shorter and faster in men compared with women. In this study, we examined the electrocardiographic pattern of repolarization in patients with abnormal plasma levels of testosterone to gain insight into the role that this hormone plays in modulating repolarization. METHODS AND RESULTS: Repolarization was measured in 27 castrated men, 26 women with virilization, and 53 control subjects pair-matched for age and sex. Repolarization in castrated men was slower and longer than that of normal men. Women with virilization exhibited a shorter and faster repolarization than normal women and castrated men. These differences are the opposite of those found in the normal population. Finally, the changes observed in castrated men may be reverted by testosterone. CONCLUSIONS: We conclude that testosterone plays an important role in modulating cardiac repolarization.

Sex-dependent electrocardiographic pattern of cardiac repolarization.

BACKGROUND: Although sex-dependent differences in cardiac repolarization have been known for many years, few attempts have been carried out to define the individual contribution of each electrocardiographic (ECG) repolarization variable to the sex-dependent pattern. METHOD AND RESULTS: We analyzed several ECG repolarization variables that reflect both the duration and the rate of repolarization in 500 normal healthy subjects between the ages of 20 and 80 years (250 men and 250 women) and distributed into 5 groups according to age. Cardiac repolarization, measured in the precordial lead exhibiting the highest T-wave amplitude, was found to be shorter and faster in normal men compared with normal women (P <.001). The parameters with the highest individual weight in determining these sex differences were the J point and the ST angle, as indicated by nonlinear (logistic) multivariate regression analysis. CONCLUSION: We conclude that changes in the duration and rate of early repolarization are determinants for these sex-dependent ECG pattern differences.

Transseptal left heart catheterization: usefulness of the intracavitary electrocardiogram in the localization of the fossa ovalis.

One of the major difficulties in left heart catheterization through the interatrial septum is to ensure that the Brockenbrough needle tip is correctly laid on the fossa ovalis floor (FOF), which is the only area where the puncture must be done. The difficulties may be enhanced in patients with atrial enlargement and subsequent distortion of the anatomical structures. In order to reduce the hazards of the septal puncture, an electrocardiographic mapping of the right atrial endocardium was performed using the Brockenbrough needle as an exploratory electrode in a group of 20 patients. When the tip of the needle was laid against the FOF, the endoatrial electrocardiogram (EAE) registered a slight or no injury curve, even when the pressure was tight enough to perforate the septum. On the contrary, the pressure on any other area of the muscular septum or atrial walls elicited a bizarre monophasic injury curve. The peculiar electrocardiographic response of the FOF to the pressure exerted by the Brockenbrough needle tip was a valuable aid to identify the area where the transseptal puncture must be done. In addition, the sudden changes in the P wave morphology immediately after the septal perforation, provided the first clue that the left atrium has been reached.

Isosorbide-5-mononitrate and isosorbide dinitrate retard in the treatment of coronary heart disease: a multi-centre study.

A multi-centre study was carried out in 200 coronary patients to compare the efficacy and tolerance of isosorbide dinitrate retard (40 mg) and isosorbide-5-mononitrate (20 mg) with regard to the frequency of anginal attacks and consumption of sub-lingual (short acting) nitrates. After receiving treatment for 2 weeks with isosorbide dinitrate retard at a dosage of 2 or 3 tablets per day, only those patients continued the study who had a weekly average of 4 or more anginal attacks during this basal period. The selected patients were divided in 4 groups of 50 patients and received treatment for a further 4 weeks with either isosorbide dinitrate retard at a dosage of 2 tablets (Group D2) or 3 tablets (D3) per day or isosorbide-5-mononitrate at a dosage of 2 tablets (Group M2) or 3 tablets (Group M3) per day. A progressive improvement in symptoms was seen at the end of 2 and 4 weeks with both drugs. The greater therapeutic benefits were obtained in patients in Group M2; the greater difference was observed between Group M2 and D2 (p less than 0.01) and there were also significant differences (p less than 0.05) between Groups M2 and D3 and between Groups M3 and D3. Analysis of the results showed that the more frequently angina attacks had occurred during the basal period, the greater was therapeutic benefit obtained with isosorbide-5-mononitrate compared to isosorbide dinitrate retard at the end of the study. Heart rate at the end of the study showed a slight tendency to increase over initial levels in all groups. In contrast, systolic blood pressure decreased very significantly in all groups (p less than 0.001). Diastolic blood pressure also decreased in all groups but only to a highly significant degree in patients treated with isosorbide-5-mononitrate (p less than 0.001) and the two sub-groups M2 and M3 (p less than 0.005). In patients treated with isosorbide dinitrate retard, the reduction in diastolic pressure was only statistically significant when the 100 patients in the group were considered as a whole (p less than 0.05), while this was not the case for the two sub-groups D2 and D3. The most frequent side-effect was headache, which improved gradually. During treatment there was a progressive dissociation between reduction in the intensity and frequency of this adverse effect and the increasing anti-anginal action of the nitrates.