Coronary angioplasty in patients 75 years and older; comparison with coronary bypass surgery.

From November 1988 to May 1992, 108 patients (79 men, 29 women) 75 years or older (mean 78 +/- 3, range 75-90 years) underwent coronary angioplasty (group I: n = 62) or coronary bypass surgery (group II: n = 46). Group II patients were younger (76 +/- 2 vs 79 +/- 4, P = 0.002) and had a higher proportion of multivessel disease. The two groups were comparable with regard to the presence of unstable angina, left ventricular ejection fraction and Q wave infarction. In-hospital mortality was similar in the two groups (6.4% vs 4.3%). Complete revascularization (72% vs 47%, P < 0.05) and left anterior descending artery revascularization (100% vs 45%, P < 0.01) were more frequent in group II. Two-year infarction-free survival was similar (group I: 76 +/- 6%; group II: 79 +/- 6%) but recurrent class III or IV angina (36% vs 9%, P < 0.05) and repeat procedures (26% vs 0%, P < 0.05) were more frequent in group I.

[Electrophysiological mechanisms of ventricular arrhythmia in myocardial infarction]. / Mécanismes électrophysiologiques des arythmies ventriculaires de l'infarctus du myocarde.

In experimental models of coronary occlusion, the physiopathology of ventricular arrhythmias varies with its timing, there being three main phases: early, late and chronic. The early phase covers the first 30 minutes and is dominated by tachycardias and fibrillations resulting from multiple micro-reentry circuits which are the consequence of major changes in conduction and excitability created by acute ischaemia. These arrhythmias may be triggered by extrasystoles which have a different mechanism related to the injury current generated in the border zone between ischaemic and healthy cells. The late phase lasts about 72 hours: it is characterised by polymorphic ventricular extrasystoles and bursts of relatively slow ventricular tachycardia. Much more rapid tachycardia can be induced by stimulation. The origin of these arrhythmias is usually in the surviving Purkinje fibres of the subendocardium. The mechanisms are variable: abnormal automaticity, reentry or activity triggered by delayed after depolarisations. During the chronic phase, reentrant tachycardia is possible but only when induced by stimulation. Delayed conduction is the consequence of non-uniform antisotropism related to the disorientation of the myocardial fibres caused by fibrosis. In the clinical situation, most research has been centered on sustained monomorphic ventricular tachycardias of the chronic phase. Their mechanism is almost exclusively reentry (the circuits usually being located in the subendocardium) as suggested by the triggering and interruption of clinical tachycardias by stimulation, the recording of fragmented activation or prepotentials at the site of emergence of the tachycardia and the phenomena of pacing.

Percutaneous coronary angioplasty in patients over 75 years old: immediate and mid-term results.

Ninety-five patients 75 years or older (range 75-90, mean 79) underwent PTCA from 1987 to 1991. Forty-two patients were 80 years or older. Forty-four had prior MI, 5% had prior coronary bypass surgery (CBS), 13% had a prior history of recent cardiac failure, and 81% (77/95) presented with unstable angina, refractory to intravenous treatment in 31 cases. The mean left ventricular ejection fraction was 62% (range 34%-80%). Thirty-nine percent had single vessel disease, 41% had two vessel disease, and 20% had three vessel disease. Coronary calcifications were present in 28%. A single vessel was dilated in 81 patients, two vessels in 14 patients; complete revascularization was achieved in 41%. The clinical angiographic primary success rate was 79% (75/95). There were five procedural deaths, five MI, five CBS and, ten hematomas. Follow-up data were obtained in 100% cases, with a mean follow-up duration of 12 months (ranging from 1-36). There were four deaths, one MI, and two CBS. Twenty percent (15/74) of patients had a second PTCA with a 73% success rate. Finally, 70% of the initial population was asymptomatic after first or second PTCA at mid-term follow-up. We conclude that PTCA is safe and effective in elderly patients, with 70% clinical success rate at mid-term follow-up in spite of frequent incomplete revascularization limited to the culprit lesion.

[How to evaluate the arrhythmogenic risk after myocardial infarction?]. / Comment évaluer le risque arythmique au décours d'un infarctus du myocarde.

The risk of sudden arrhythmic death after myocardial infarction is high, especially during the first months. The evaluation of this risk should be performed before hospital discharge in the same way as residual ischaemia and left ventricular function, which are independent risk factors for arrhythmia, are assessed. Holter monitoring provides information not only about ventricular hyperexcitability (especially the detection of unsustained ventricular tachycardia) but also about the activity of the autonomic nervous system by analysis of variations of the sinus rhythm, the decrease of which carries a poor prognosis. The search for an arrhythmogenic substrate requires signal averaged electrocardiography, but although the absence of late potentials carries a good prognosis, the positive predictive value of this investigation is very low. The association of non-invasive indices of poor prognosis greatly increases the probability of a major arrhythmic event; this may require consideration of programmed ventricular pacing, another method of substrate and risk assessment, which has the added advantage of sometimes indicating the most appropriate therapy.