The structural arteriolar changes in diabetes mellitus and essential hypertension. The relative contribution of ageing and high blood pressure.

AIM: To evaluate the relative contribution of blood pressure, non-insulin dependent diabetes mellitus and ageing on arteriolar structural changes in essential hypertension and diabetes mellitus. POPULATION AND METHODS: One hundred subjects, 25 with hypertension (A), 25 with hypertension and diabetes (B), 25 with diabetes (C) and 25 healthy subjects (D). Blood pressure average values, obtained with non-invasive monitoring, and minimal vascular resistance, calculated with strain-gauge plethysmography, were statistically correlated. Multiple regression analysis was performed to assess the contribution of blood pressure and age. RESULTS: Minimal vascular resistance was higher in A, B and C than in D, and higher in B than in A and C. The coefficient of blood pressure in the multiple regression analysis was significant for all the parameters in A and B but not in C and D; that of age was significant only in A and only for the average values of mean and diastolic blood pressure. CONCLUSION: Hypertension and diabetes show arteriolar structural changes of similar gravity. Age does play a role in hypertension but a smaller one than that played by blood pressure. In hypertension and diabetes the lack of significance of the contribution of age to the correlation between minimal vascular resistance and pressure could be ascribed to other neurohumoral factors. These factors play a much more important role in diabetes; where neither blood pressure nor age show any correlation with high vascular resistance.

The mechanism of the physiologic disappearance of the third heart sound with aging.

The third heart sound (S3) is often present in children and adolescents but is not present in most adults. Applying at the left ventricle a mathematical model, the mechanism of the disappearance of S3 was studied employing the frequency analysis of the sound and echocardiographic data. The existence of a significant correlation between the spectrum energy of S3 and the diameter and thickness of the left ventricle at the moment of S3 in 25 healthy subjects (aged 21 +/- 7 years) allowed us to interpret the origin of S3 based on a viscoelastic oscillating system. Once the left ventricle starts vibrating it behaves as a simple physical model composed of a mass (m), a spring (k) and a viscous element. The abrupt deceleration of the blood mass (m) against the left ventricular walls (k) triggers the vibration of the system according to the equation Fd = 1/2 pi.square root of k/m.square root of 1 - zeta 2, where Fd is the natural damped frequency and zeta is the damping factor. The equation shows that the vibrating system can oscillate only if zeta is < 1. During the growth of the individual the increased myocardial mass may lead to augmented viscous forces causing a gradual increase in zeta until the system becomes overdamped and consequently unable to vibrate causing the disappearance of S3.

The response of the ageing heart to regular physical exercise. An echo and Doppler study.

In upper middle age healthy subjects the functional cardiac reserve is known to be decreased (Port et al., 1980; Aubert et al., 1994). On the other hand regular physical exercise improves the cardiovascular function (Nishimura et al., 1980). The aim of this study was to establish whether regular physical exercise is associated with a significant change in the ageing process of the cardiovascular system.

Peripheral hemodynamic effects of ibopamine in patients with congestive heart failure. A placebo-controlled, double-blind study.

Under double-blind conditions, 150 mg of ibopamine (di-isobutyric ester of N-methyldopamine) or placebo were given orally to 11 patients with congestive heart failure; after 3 hours, 50 mg of sulpiride were administered intramuscularly. Peripheral hemodynamics were evaluated at the level of the forearm using strain-gauge plethysmography. Ibopamine increased arterial blood flow and venous capacity and decreased arterial peripheral resistance; these effects were counteracted by sulpiride. No significant changes were observed after placebo and sulpiride. These findings confirm the vasodilating effects of ibopamine on peripheral hemodynamics and its utility in patients for the treatment of congestive heart failure.

[Evaluation of the cardiac and peripheral vascular effects of the administration of single-dose enalapril and captopril in essential arterial hypertension]. / Valutazione degli effetti cardiaci e vascolari periferici della somministrazione in dose singola di enalapril e captopril nell'ipertensione arteriosa essenziale.

The effects of single orally-administered dose of enalapril and captopril on central and district-peripheral circulations have been studied in 20 patients with essential arterial hypertension. Either drug caused a decrease in arterial pressure, telesystolic and telediastolic parietal stress, and a reduction in the peripheral vascular resistance of upper limb district. Furthermore, at the upper limb district level, increases in arterial flow and venous-system capacity have been observed. The entity of these modifications induced by enalapril and captopril appeared comparable, according to the respective peak-time and used dosages. Under this study conditions, the difference between the drugs resulted to be essentially of chronological nature.

Effects of ibopamine on peripheral hemodynamics: a strain gauge plethysmographic study in patients with congestive heart failure.

Peripheral hemodynamics were studied using strain gauge plethysmography in patients with congestive heart failure after administration of ibopamine (SB-7505), the orally active 3,4-diisobutyryl ester of N-methyldopamine, a dopaminergic agonist, and of sulpiride, a specific dopaminergic antagonist. 50 mg of sulpiride were administered parenterally in 12 patients 3 h after a single oral dose of 150 mg of ibopamine. Ibopamine increased significantly resting arterial blood flow and venous capacity and decreased peripheral resistance. Sulpiride was found to significantly counteract the activity of ibopamine.

Idiopathic apical left ventricular aneurysm in hypertrophic cardiomyopathy. Report of 3 cases, and review of the literature.

In a review of 160 cases of hypertrophic cardiomyopathy which underwent hemodynamic studies, 3 cases of apical aneurysm of the left ventricle of unidentifiable etiology were found. Bearing in mind the rarity of apical idiopathic left ventricular aneurysms, the authors believe this association with hypertrophic cardiomyopathy is of some interest and point out the possible pathogenetic mechanisms.

Phonometric study of the second heart sound in normal man.

The fast Fourier transform (FFT) was employed to analyze the frequency spectra of the second heart sound in 19 healthy subjects. The data obtained show that the second heart sound is mainly composed of low-frequency vibrations, and that the frequency vs. amplitude spectra for the various filters do not exceed 150 Hz. The different spectra obtained can represent a useful reference to compare with pathological acoustical findings.

Effect of ibopamine on peripheral haemodynamics.

Peripheral haemodynamics was studied in healthy volunteers by strain gauge plethysmography after administration of ibopamine (IB), diisobutyric ester of N-methyl-dopamine, an orally active dopaminergic agonist. Seven subjects received a single oral dose of ibopamine of 150 mg and 6 received a daily dose of 150 mg (50 mg t.i.d.) for 5 consecutive days. Arterial resting blood flow and venous capacity increased and peripheral resistance decreased significantly. Six further subjects were then studied; 3 h after an oral dose of ibopamine 150 mg, the parenteral administration of Sulpiride 50 mg, a specific vascular dopaminergic antagonist, was found significantly to counteract its peripheral activity. Heart rate and arterial blood pressure were never affected and tolerability was good.

Two-dimensional echocardiography in post traumatic tricuspid incompetence.

Four patients with post traumatic tricuspid incompetence underwent complete two-dimensional echocardiographic study. Systolic intra-atrial protrusion of the anterior tricuspid leaflet beyond the valvular ring, with total loss of coaptation with the other leaflets, was documented in all patients. These abnormalities were not evident in all transducer locations suggesting the possibility of false negative echocardiograms. An echocardiogram showing a marked systolic excursion of a tricuspid leaflet into the right atrium beyond the level of the tricuspid ring together with the total loss of coaptation does not necessarily mean the rupture of the subvalvular apparatus.

Mechanographic evaluation of left atrial activity in mitral valve prolapse.

Twenty-five patients suffering from mitral valve prolapse were studied to demonstrate any diagnostic modifications of the indirect (esophageal) left atrial pulse (ESO). Valvular prolapse is demostrated on the ESO by a sudden change in slope of the curve after the "x" point, in coincidence with a midsystolic click. Late systolic mitral insufficiency, when associated with prolapse is illustrated on the ESO tracing in two ways: a) an abnormally tall "v" wave; b) a late systolic plateau which begins immediately after the click and continues beyond the second heart sound. After the infusion of methoxamine or isometric exercise the ESO is usually of the a) conformation, while after the inhalation of amyl nitrite the tracing tends to be of the b) type. The "c" wave is at times altered but not always. This alteration is characterized by a greater amplitude and sharper peak. Based on the physiopathogenesis of the alterations of the ESO, it can be stated that they are specific, and sensitive enough to be both qualitative and quantitative.