[Circadian variation of sudden cardiac death in young people with and without coronary disease]

Sudden cardiac death is not well known and provoking factors are yet mainly unknown. To clarify whether sudden cardiac death has a circadian rhythm in young people we have studied 40 patients < 45 years who died in Brescia between 1984 and 1993 of sudden cardiac death showing at autopsy features of coronary artery disease (CAD) and 12 patients aged < 30 years who died of sudden cardiac death without autoptic features of CAD. We observed a circadian rhythm in the hours of the morning in the two groups, more evident in patients without CAD. In patients with autoptic features of CAD, we also observed a higher rate of events during the winter months. We would like to stress the importance of the adrenergic system as a trigger able to produce the event. We believe that the role of the sympathetic nervous system is more important than other risk factors (for example platelet aggregability and blood viscosity) to precipitate sudden cardiac death, mainly because the circadian rhythm was more evident in patients without CAD. An increase of the data-base and a more detailed analysis of subgroups is necessary if we concretely want to prevent sudden cardiac death fitting antiarrhythmic therapy with circadian distribution of major events. We underline the practical impact of "chronorisk" together with the other cardiovascular risk factors.

[Ischemic cardiopathy in the young: coronarographic and autopsy picture in 100 subjects]

Many aspects of coronary artery disease in young people are not completely understood. Our study concerns a series of 100 patients < 45 years with acute coronary artery disease. Sixty patients survived and 40 died suddenly. All subjects have been divided into four groups: Group I includes 20 deceased patients with anatomic features of acute myocardial infarction. Group II includes 20 subjects dead without features of acute myocardial infarction. Group III includes 30 patients surviving the first acute myocardial infarction. Group IV includes 30 patients surviving unstable angina. The coronary arteries have been studied by anatomic dissection in Group I and II and with coronarography in Groups III and IV. The left main was only involved in Group I and II patients. Multivessel disease was more frequent in Group I and II, but the difference was not significant. These results underline that coronary artery disease with multivessel involvement is not rare in young patients. The rare occurrence of left main disease at coronary angiography could be the consequence of the natural preselection determined by sudden death.

Orbital ultrasound in the ocular ischaemic syndrome

The ocular ischaemic syndrome illustrates well the effects of hypoperfusion of the globe and is a useful model for studying disorders of the orbital circulation. Recent advances in orbital ultrasound techniques have provided a non-invasive method of examining flow velocities in the orbital vessels, particularly the ophthalmic artery. Orbital ultrasound studies were performed on 3 cases of the ocular ischaemic syndrome. Continuous or intermittent reversal of blood flow in the ophthalmic artery was seen in all cases. How this phenomenon relates to the symptoms and signs in affected patients, and the role of orbital ultrasound in the investigation of the ocular ischaemic syndrome, are discussed.

Ocular enlargement following infantile corneal opacification

Congenital hereditary endothelial dystrophy (CHED) is not generally thought to be associated with other ocular abnormalities. Ultrasonography in a series of twenty eyes (ten patients) with CHED shows ocular enlargement similar to that occurring in uncomplicated axial myopia. There was an inverse relationship between the degree of enlargement and the visual acuity or visual result following penetrating keratoplasty suggesting that infantile corneal oedema sufficient to cause stimulus deprivation may result in abnormal enlargement of the globe.

Doppler ultrasound velocity mapping of extra-ocular muscles: a preliminary report

Colour doppler imaging and conventional spectral doppler/B-mode techniques were used to detect and quantify rectus muscle movement during voluntary saccades. A velocity gradient was evident in all muscles studied--low velocities near the muscle origin at the back of the orbit increasing linearly to a maximum near the muscle insertion on the globe. A consistent reduction in velocity occurred along muscles injected with botulinum toxin. Doppler ultrasound complements current clinical eye movement recording techniques--electronystagmography, infrared light reflection methods and magnetic induction methods--insofar as it detects movement in parts of the muscle itself rather than movement of the globe secondary to muscle contraction. Future developments in colour doppler imaging will make the technique clinically more applicable.

Doppler ultrasound of orbital vessels

The techniques of doppler ultrasound have been applied to blood vessels within the orbit. The doppler frequency shifts of ultrasonic pulses scattered from blood cells moving within orbital vessels are a measure of velocities rather than the amount of blood flow. The doppler signal from the ophthalmic artery behind the globe is responsive to changes in ocular blood flow. Blood flow can also be detected at the optic nerve head, and from the coats of the eye adjacent to the nerve head. Flow rate in the ophthalmic artery is reduced following retrobulbar anaesthesia. The source of the pulsatile retrograde flow signal which can be detected in some cases of internal carotid stenosis is located in the region of the ophthalmic artery.

Doppler ultrasound studies of the ophthalmic artery

The doppler frequency shift of ultrasound pulses scattered off red blood cells in the ophthalmic artery can be detected and used as an index of velocity of flow in the artery. The doppler shift is shown to be responsive to changes in ocular blood flow induced by changes in mean arterial blood pressure at the level of the eye and changes in intraocular pressure. The technique may be useful in the study of eye disease in which blood flow is altered. Doppler frequency shifted signals have also been detected within the coats of the eye.

Ultrasonic Doppler studies of the vitreous

Simultaneous 'real-time' B-mode and doppler ultrasound techniques were used to study movements of the detached vitreous gel which occurred during duction movements of the eye. The velocity of sound scatterers within the vitreous gel were measured and it was possible to differentiate quantitatively gels which were 'stiff' from those which were 'sloppy'. Information obtained using this technique may throw light on the pathogenesis of rhegmatogenous retinal detachment and assist in the quantitative assessment of retinal mobility in eyes with vitreoretinopathies.

Ultrasonic examination in severe diabetic eye disease

B-scan ultrasound of the posterior segment is reported in 154 patients with severe diabetic eye disease. Epiretinal fibrosis, vitreous haemorrhage, vitreous detachment, and retinal detachment were frequently diagnosed. The ultrasonic findings are discussed in relation to the pathological changes in the vitreous in proliferative diabetic retinopathy.

Ultrasound in orbital diagnosis

Ultrasound is a safe and useful method of detecting, localizing, and differentially diagnosing orbital lesions. Diagnosis using B-scan and C-scan techniques depends on the qualitative recognition of patterns based on the location and shape of a lesion together with the distribution in number and amplitude of echoes arising from within a lesion. In addition, the sound-attenuating properties of a lesion, determined by changes in the appearance of deeper structures, may aid in identification.