Genesis and acoustic quality of the physiological fourth heart sound.

The genesis of the fourth heart sound (S4) is commonly related to the rapid set in vibration of the left ventricular walls, resulting from the rapid inflow of the blood due to the atrial contraction (Nishimura et al., 1989). S4 can be recorded in normal young subjects as an expression of physiologic atrial dynamics but it is more common in pathologic conditions characterized by decreased ventricular distensibility (Tavel, 1978). Employing the spectral analysis of heart sounds (Longhini et al., 1979; Longhini et al., 1981; Aubert et al., 1984) we searched for the relationship between different components of the frequency spectrum of S4 and various echocardiographic parameters, with the aim of identifying the cardiac structures involved in its genesis (Longhini et al., 1989; Baracca et al., 1991).

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.

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 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.

[Aortic aneurysms as complication of bacterial endocarditis. Report of two cases (author's transl)]. / Gli aneurismi iuxtaorifiziali aortici di origine batterica. A proposito di due osservazioni personali.

The authors report on two cases, one of supravalvular aortic aneurysm and one of subvalvular aortic aneurysm. Both patients suffered from bacterial endocarditis of the aortic valve, superimposed on previous rheumatic valvular disease. The authors believe that such aneurysms represent typical though rare complication of bacterial endocarditis of the aortic valve. Subvalvular aneurysms should be the consequence of the systolic stress acting on the myocardial wall involved by endocarditis, whereas supravalvular aneurysms could result from the jet-lesion through the affected valve.

Peripheral vascular circulation in trained athletes.

Modifications in the neurogenic control are important in cardiovascular adaptation to physical training. To examine the influence of such variations on arterial blood pressure, heart rate and limb blood flow the Authors have studied the reaction to cardiovascular stress tests of soccer players and sedentary controls. No difference was found in the blood flow response between athletes and sedentary subjects. However, the tests inducing sympathetic activation determined blood pressure response of different intensity, possibly related to the differences in the autonomic nervous system control.