[Coronary angioplasty during acute myocardial infarction]. / L'angioplastica coronarica in corso di infarto miocardico acuto.

BACKGROUND: Percutaneous coronary angioplasty (PTCA) is an effective method to achieve myocardial reperfusion in acute myocardial infarction. In order to identify the predictors of primary success and major complications, we reviewed our experience in 107 patients (pts) who underwent PTCA of a totally occluded infarct-related coronary artery (IRA) within 24 hours (h) after the onset of symptoms. METHODS AND RESULTS: PTCA was successful in 92 pts (86%); PTCA failed without complications in 9 pts (8.4%), major complication (death and urgent coronary artery surgery) occurred in 6 pts (5.6%). Rescue PTCA was performed in 31% of cases and had similar success rate when compared to direct PTCA (85 vs 86%, p = NS). Pts with successful PTCA had repeat angiography 24 h after the procedure. According to primary and 24 h results, pts were divided into 3 groups: primary success with 24 h stable result (Group A: 76 pts, 71%); primary success with 24 h deterioration (Group B: 16 pts, 15%), among which 4 pts showed total reocclusion; primary failure (Group C: 15 pts, 14%). A longer time delay from symptoms onset (p < 0.05), cardiogenic shock (p < 0.001), previous bypass surgery (p < 0.05) were correlated with worse short-term outcome by univariate analysis. When compared to Group A, pts in Group C showed a lower EF (42 +/- 14 vs 51 +/- 16%, p < 0.05). IRA diameter was greater in Group A (3.1 +/- 0.4 mm) when compared to Group B (2.7 +/- 0.4 mm, p < 0.05) and Group C (2.7 +/- 0.5 mm, p < 0.05). Absence of cardiogenic shock (p < 0.001), decreasing time from symptoms onset (p < 0.01) and increasing ejection fraction (EF) (p < 0.05) were independent predictors of primary success by multivariate analysis. Cardiogenic shock (p < 0.001) and decreasing EF (p < 0.05) were independent predictors of major complications. CONCLUSIONS: PTCA of IRA is effective within 24 h from symptoms onset. Procedural failure is infrequent, usually occurring in patients with high-risk baseline characteristics.

[Idiopathic restrictive cardiomyopathy. Description of 4 cases]. / Cardiomiopatia restrittiva idiopatica. Descrizione di 4 casi.

The clinical and instrumental characteristics of four patients suffering from idiopathic restrictive cardiomyopathy are analysed. Patients were diagnosed following hemodynamic and histological tests. The major clinical symptom was cardiac decompensation and/or hyperkinetic or hypokinetic (3rd degree BAV) supraventricular arrhythmia (atrial fibrillation). Electrocardiographic and radiological alterations were not specific. The most typical echocardiographic symptom was the association of: biatrial dilation, dilation and hypertrophy of the right ventricle, normal left ventricular size, normal fractional shortening of the left ventricle. Septal hypertrophy was also observed in one case. Abundant pericardial effusion was present in all cases. When performed, echo-Doppler showed a relatively typical shortened deceleration time through the A-V valve. Catheterism revealed increased ventricular telediastolic pressures and a bi-plateau morphology of the ventricular pressure curve. Heart index was depressed in one patient and the ejection fraction was reduced in one case. Histological tests revealed interstitial fibrosis, cellular hypertrophy and, in one patient, myocardial amyloidosis. One patient underwent a heart transplant, two patients died while waiting for a transplant, one patient is still alive 13 years after the start of 3rd class symptoms.

[Comparison between one and two dimensional echocardiography in the study of segmentary kinetics of the left ventricle in post-infarct ischemic myocardiopathy]. / Confronto tra la metodica ecocardiografica mono e bidimensionale nello studio della cinetica segmentaria del ventricolo sinistro nella miocardiopatia ischemica postinfartuale.

Sixty two-dimensional M-mode echocardiograms of myocardial infarction patients, performed 3--6 months after acute attack, were compared with those of 30 normal subjects. In one-dimensional echocardiograms, the dimensions of the left ventricle and some segmentary signs of contractility such as diastolic thickness, excursion and systolic thickening of the septum and the posterior wall of the left ventricle were examined, in two-dimensional echocardiograms the contractility of single areas was compared to those adjacent. In heart attack patients parameters studied were changed in a statistically significant way (p less than 0,001); the degree of correlation between the site of hypo-akinesis and the ECG necrosis site was quite high; compensatory hyperkinesia was frequently found in the area diametrically opposite to dyskinetic areas. The two-dimensional examination was also very sensitive especially in the diagnosis of aneurysm, which is sometimes not noted in M-mode.

[Pathogenetic interpretation of left ventricle obstruction in hypertrophic obstructive myocardiopathy]. / Interpretazione patogenetica della ostruzione del ventricolo sinistro nella miocardiopatia ipertrofica ostruttiva (MCO).

Nine patients affected from IHSS have been studied by 2D-echocardiography examination. Following detected pictures the Authors try to explain the pathogenesis of the dynamic obstruction of the L.V. The Authors conclude ascribing it to the postero-medial papillary muscle that move abnormally towards the IVS. Instead the SAM could be ascribed to the chordee of the mitral value, but these are considered unable to obstruct L.V. The differences between SAM and L.V. obstruction are underlined and discussed.

[Occult pre-excitation. Differential diagnosis between latent Wolf-Parkinson-White syndrome and concealed atrial pre-excitation (endocavitary electrophysiological study)]. / La preeccitazione occulta. Diagnosi differenziale tra sindrome di W.P.W. latente e preeccitazione atriale nascosta (studio elettrofisiologico endocavitario).

Sixty patients (pts) with very disabling symptoms during supraventricular tachycardia (SVT) underwent electrophysiological study to determinate the mechanism of arrhythmia. 20 pts had, during normal sinus rythm (NSR), ECG pattern of ventricular pre-excitation (V-P); 40 pts, instead, had ECG pattern within normal limits (WNL). In V-P pts, circus movement tachycardia by overt accessory pathway (AP) was initiated. Among ECG-WNL pts group: 10 pts showed ectopic atrial rythm; 22 pts had SVT due to A-V nodal reciprocation; and 8 pts revealed the participation of concealed AP in the reentrant circuit of tachycardia. Among these latter, atrial stimulation at various sites and drugs-administration discovered extranodal by-pass liable for concealed V-P in 2 pts; in the remaining 4 pts it was possible to demonstrate concealed atrial preexcitation by ventricular stimulation, during NSR and SVT, and by atrial mapping during ventricular stimulation and SVT. Our report confirms the significative incidence of concealed AP at the basis of numerous cases of SVT (26%) and outlines the distinction between the latent W.P.W. syndrome and the atrial preexcitation, due to anomalous by-pass with anterograde block.

Hemodynamic changes induced by supraventricular tachycardia.

In nine patients (pts.) with recurrent SVT, we have performed a combined electrophysiological and hemodynamic study. Five pts. showed reciprocating nodal tachycardia and 4 pts. reentry tachycardia associated with WPW syndrome (2 with Kent bypass tract and 2 with James bypass tract). Hemodynamic parameters were recorded during sinus rhythm (SR), atrial (AP) and ventricular pacing (VP) and following the initiation of SVT. The arrhythmia was induced by rapid atrial pacing or with atrial or ventricular premature stimuli. Hemodynamic data were then compared. Our results point out a greater hemodynamic deterioration during SVT than during AP or sinus tachycardia at similar rates. We have often observed in SVT, and constantly in A-V nodal reentrant (AVN) cases, the appearance of giant waves in the right and left atrium. This finding confirms hypothesis of the primary role of the changes in atrioventricular contraction sequence during SVT, especially in AVN tachycardias, with subsequent reduction in stroke volume and cardiac output.

Relation between cholinergic and histaminergic components in reflex vasodilatation in the dog.

Previous studies have shown that phentolamine is able to reverse the reflex vasodilatation produced by transitory baroreceptor stimulation by blocking sympathetic, histaminergic, and cholinergic components. A direct anticholinergic action of phentolamine has never been described; however, since it is known that this drug is capable of inhibiting histamine release during the reflex vasodilatation, it is possible that its ability to block the cholinergic component of the reflex is related to the latter property. Therefore, this study was undertaken in an attempt to identify possible relationships between cholinergic and histaminergic components of the reflex vasodilatation. Accordingly, in mongrel dogs the gracilis muscle was isolated and perfused and then loaded with 14C-labeled histamine. A transitory systemic hypertension was induced by intravenous injection of norepinephrine; this produced a reflex vasodilatation, shown by the fall in perfusion pressure, which was accompanied by an increase of histamine release from the muscle. Vagal block induced by atropine pretreatment reduced the fall in perfusion pressure induced by the systemic hypertension and produced a reduction of histamine release during the vasodilatation. In another group of animals a vasodilatation in the perfused muscle was induced by injection of acetylcholine. This response was accompanied by an increase in histamine release from the gracilis muscle. Alpha-receptor blockade, which has been shown to inhibit histamine release, reduced this acetyl-choline-induced vasodilatation. These results, while confirming the participation of the cholinergic system in the reflex vasodilatation elicited by transitory stimulation of the arterial baroreceptors, seem to demonstrate that this component is mediated almost exclusively by histamine release.

Histamine mediation in muscular vasodilatation induced by beta adrenoceptor stimulation in dogs.

This study was designed to investigate the possibility of a histamine mediation in muscular vasodilation induced by beta adrenoceptor stimulation. Accordingly, in seven dogs the effects of isoproterenol administration on the release of 14C-histamine from the perfused gracilis muscle were studied. Beta adrenoceptors stimulation induced a vasodilatation, as shown by a decrease in perfusion pressure(-43 +/- 12 mm Hg); simultaneously, a significant increase of the radioactivity measured in the venous blood effluent from the gracilis muscle was observed. Both these events were blocked by propranolol. In the other five dogs, chlorpheniramine was able to reduce the vasodilatation induced by the injection in the gracilis muscle of isoproterenol. Under control conditions, isoproterenol induced a fall in perfusion pressure of 44 +/- 5 mm Hg while, after chlorpheniramine, perfusion pressure decreased by only 24 +/- 4 mm Hg. The results of this study seem to confirm the possibility of a histamine mediation in isoproterenol-induced vasodilatation. However, further investigation is needed in order to identify the exact role of histamine in the geneis of this phenomenon.

Effects of guanethidine on histamine release during reflex vasodilatation in the dog.

1 The effects of guanethidine pretreatment on the release of [14C]-histamine during the reflex vasodilatation induced in the atropinized gracilis muscle by rapid intravenous administration of noradrenaline, were studied in dogs. 2 After guanethidine treatment the haemodynamic reflex response was completely abolished and no appreciable modification of [14C]-histamine release from the gracilis muscle following intravenous noradrenaline was observed. 3 These results suggest the hypothesis that the withdrawal of the sympathetic discharge represents the mechanism of histamine release during the reflex vasodilatation. Therefore, guanethidine would suppress both the passive and the histaminergic component of the baroreceptor reflex through the abolition of the sympathetic tone.