[Prognostic value of ventricular arrhythmia in hypertensive patients]

OBJECTIVE

Hypertensive left ventricular hypertrophy (LVH) is associated with increased risk of arrhythmias and mortality. However, no clinical study demonstrated a significant relation between ventricular arrhythmias and mortality in systemic hypertension.

DESIGN AND METHODS

To evaluate the prognostic value of arrhythmogenic markers in systemic hypertension, we included between 1987 and 1993. 214 hypertensive patients, 59.1 +/- 12.8 years old, without symptomatic coronary disease, myocardial infarction, systolic dysfunction, electrolyte disturbances or antiarrhythmic therapy. At inclusion, an ECG, a 24 h Holter ECG (204 patients) with Lown classification of ventricular arrhythmias, an echocardiography (reliable in 187 patients) with left ventricular mass index and ejection fraction calculation, a SAECG (125 patients, enrolled after 1988) with ventricular late potentials (LP) were recorded. QT interval dispersion (QTd) was calculated on 12 leads standard ECG and LVH was appreciated.

RESULTS

At baseline echocardiographic LVH was recorded in 63 patients (33.7%) with normal ejection fraction (75 +/- 7.4%). Non-sustained ventricular tachycardia (Lown IVb) was found in 33 pts (16.2%) and LP in 27 patients (21.6%). After a mean follow up of 42.4 +/- 26.8 months, all-cause mortality was 11.2% (24 patients); 17 patients died of cardiac causes (7.9%); of these 9 patients (4.2%) died suddenly. In univariate analysis, age, strain pattern of LVH, advanced Lown classes and abnormal QT dispersion (> 80 ms) were significantly related to global, cardiac and sudden death (p < or = 0.01). Left ventricular mass index was closely related to cardiac mortality (p = 0.002). LP failed to predict mortality. In multivariate analysis, only Lown class IVb was an independent predictor of global and cardiac mortality, increasing the risk of global death 2.6 fold [1.2-6.0] (CI 95%) and the risk of cardiac death 3.5 fold [1.2-9.7] (CI 95%).

CONCLUSIONS

In hypertensive patients the presence of non-sustained ventricular tachycardia on 24 h Holter has a prognostic value.

[Left ventricular repercussion of obesity-induced arterial hypertension in the dog]

Obesity and hypertension are frequently associated. The aim of our study was to assess the effects of high fat diet on weight, blood pressure and left ventricule in dogs. We studied 6 male Beagle dogs before and after 7 weeks of hypercaloric hyperlipidic diet. Echocardiography was used to measure left ventricular wall thickness, volumes, ejection fraction and mass. Results are expressed as % of variation of initial values. After 20 weeks, dogs presented abdominal obesity with increased body weight (11.9 +/- 2.3 to 15.2 +/- 2 kg; p < 0.03) associated with an increasing of systolic (196.5 +/- 14.6 to 260.1 +/- 17.5 mmHg; p < 0.03), diastolic (76.6 +/- 9 to 110.6 +/- 10.2; p < 0.004) and mean blood pressure (128.8 +/- 7 to 152.7 +/- 7.6 mmHg; p < 0.004). There were non significant changes concerning diastolic thickness of septum and posterior wall. Left ventricular volumes increased in diastole (41.1 +/- 4.5 to 48.9 +/- 10.3 cm3; p < 0.03) and systole (12.2 +/- 1.7 to 14.9 +/- 3.2 cm3; p < 0.03). So, despite any changes in wall thickness, we observed an increased of ventricular mass (67 +/- 15 to 80 +/- 24.3 g; p < 0.03). Ejection fraction remained unchanged.

CONCLUSION

it appears that hight fat diet induces obesity and hypertension in dogs; changes in left ventricule suggest a volodependent hypertension.

[Cardiac insufficiency with normal systolic function. Physiopathology and therapeutic implications]

Heart failure is a very common disease with ageing of the population and represents the leading cause of admission to hospital. The consequences of ageing, the frequency of ischaemic heart disease and hypertension predispose to the development of heart failure. Ageing promotes arterial, aortic and cardiac remodelling, resulting in an increase of cardiac work, myocardial hypertrophy and progressive alteration of ventricular function. The elderly heart has a reduced compliance, and loses its preload reserve and its chronotropic reserve. It adapts poorly to effort, arrhythmias and loss of atrial systole. Heart failure can be atypical with neurological and pulmonary or gastrointestinal signs. Radiological examination, and especially echocardiography, are essential. There is often a very predominant alteration of diastolic function (abnormalities of relaxation and compliance). Treatment is made difficult by the presence of multi-organ disease, which reduces the safety margin of digitalis alkaloids, diuretics and ACE inhibitors. Blood digoxin, creatinine and potassium levels must be regularly monitored. Revascularization techniques should not be abandoned and aortic valve surgery, in particular, gives good results when it is not performed too late. ACE inhibitors and vasodilators are generally well tolerated.

[Cardiac failure and nitrates]

Nitrates remain largely prescribed in heart failure. Their haemodynamic effects, a consequence of venous vasodilatation, have been clearly demonstrated in the acute situation, where they induce a fall in pulmonary pressure and left ventricular end-diastolic pressure, associated, at high doses, with an arterial vasodilator effect. Haemodynamic escape phenomena are observed during chronic administration and the peripheral vasodilator effect, in particular, tends to fade. Although, together with depletion of sulfhydryl radicals, activation of vasoconstrictor neuroendocrine systems, associated with haemodillution, plays an important role in this escape, coprescription of angiotensin converting enzyme inhibitors or diuretics has been shown to be unable to prevent these effects. The effects of nitrates on the exercise capacity remain controversial, although the combination of isosorbide dinitrate-hydralazine induced a significantly greater increase of maximal oxygen consumption than enalapril, together with a more marked increase in the ejection fraction. No trial has assessed the effects on mortality of nitrates, used as the only vasodilator agent, in heart failure, but in studies V-HeFT 1 and 2, the combination of isosorbide dinitrate-hydralazine significantly improved survival, with a 38% reduction of mortality at one year compared to placebo or prazosin groups. However, this reduction remained less than that obtained with enalapril. In the case of contraindication or impossibility of using angiotensin converting enzyme inhibitors, a combination of high doses of nitrates and hydralazine may be justified. On the other hand, when angiotensin converting enzyme inhibitors are already prescribed, nitrates can only be considered to improve symptoms in the case of persistence of dyspnoea. However, due to the hypotension which they can induce, their use should not interfere with the administration of the high doses of angiotensin converting enzyme inhibitor required. The dose of nitrates should then be determined as a function of their efficacy on symptoms and the blood pressure tolerance, while allowing an intervel of at least ten hours in order to attenuate the escape phenomenon.

Lack of haemodynamic effects of nitric oxide on post-capillary pulmonary hypertension induced by acute sino-aortic denervation

1. The aims of the present experiments were to define a new experimental model of pulmonary hypertension induced by a post-capillary mechanism and to assess the haemodynamic effects of nitric oxide on post-capillary pulmonary hypertension. 2. Cardiopulmonary variables of 28 male beagle dogs, anaesthetized with chloralose, 16 spontaneous breathing and 12 with assisted ventilation, were studied before and after sino-aortic denervation (SAD). The haemodynamic effects of inhaled nitric oxide (25 p.p.m., 10 min). N(omega)-nitro-L-arginine methyl ester (20 mg kg-1, i.v.), urapidil (0.5 mg kg-1-, i.v.) and propranolol (300 micrograms kg-1, i.v.) were studied after SAD. 3. SAD induced an acute and transient pulmonary hypertension, more marked in spontaneous breathing dogs. This pulmonary hypertension involved a post-capillary mechanism, secondary to the left ventricular haemodynamic effects of the acute increase of left ventricular after-load induced by systemic hypertension. In fact, the increase of mean pulmonary arterial pressure after SAD and the decrease of this parameter after urapidil or propranolol were strongly correlated with the variations of pulmonary capillary wedge pressure. Furthermore, no significant change in pulmonary vascular resistance was found after SAD or administration of alpha or beta-adrenoceptor antagonists. 4. Inhaled nitric oxide did not reverse pulmonary hypertension induced by SAD. N(omega)-nitro-L-arginine methyl ester had no significant haemodynamic effect of pulmonary circulation. 5. In conclusion, the lack of effect of inhaled nitric oxide and nitric synthase inhibitor on pulmonary circulation parameters SAD suggest that endothelium-derived oxide is not involved in the mechanisms leading to post-capillary pulmonary hypertension.

[Correlation between QT interval dispersion and ventricular arrhythmia in hypertension]

OBJECTIVE

To evaluate the correlation between QT interval dispersion (QTd) and ventricular arrhythmias in hypertensive patients (pts) with or without left ventricular hypertrophy (LVH). A secondary aim was to investigate correlations of QTd with other markers of arrythmogenic propensity: ventricular late potentials (LP) and heart rate variability (HRV).

METHODS

We retrospectively measured the QTd on the 12 standard surface ECG leads in 230 hypertensive pts (94F, 136M; 59.6 +/- 12.7 years old). A 24 hours ECG Holter recording was performed in 218 pts and ventricular arrhythmias were appreciated using the Lown classification. Left ventricular mass was determined by echocardiography (LVM-Devereux formula) and left ventricular mass index (LVMI) were determined in 202 subjects. LP (122 pts) and HRV (55 pts) were investigated.

RESULTS

The QTd varied between 20 and 160 msec (57.8 +/- 32.7 msec). The distribution of pts classified using Lown criteria was: 29 pts (13.3%) class O; 106 pts (48.6%) class I; 8 pts (3.6%) class II; 13 pts (6%) class III; 29 pts (13.3%) class IVa; 33 pts (15.1%) class IVb; 116 pts (69.5%) had LVH determined by echocardiography. The QTd was strongly correlated with the Lown classes (p < 0.0001). The QTd was significantly broader in Lown classes III, IVa and IVb compared to classes O, I and II cumulated (p < 0.002); there was no difference concerning QTd between Lown classes III, IVa and IVb. The QTd was also correlated with the absolute number of premature ventricular depolarizations/24 hours (p = 0.02; r = 0.16). The 75 pts with an increased LVMI had significantly elevated QTd compared to pts without it (p < 0.0001). Qtd was correlated with LVMI (r = 0.37; p < 0.0001). There was no correlation between QTd and the existence of LP (which were correlated with the Lown classes; p < 0.03) and HRV parameters.

CONCLUSION

Elevated QT interval dispersion is associated with more severe ventricular arrhythmias in hypertensive subjects with LVH. The mechanism of an increased inhomogeneity of repolarisation is probably related to the anatomic modifications induced by LVH. No significant correlation between QTd, LP and HRV was observed.

[Angiotensin converting enzyme inhibitors and ischemic heart diseases]

Experimental studies and molecular biological techniques have demonstrated the importance of angiotensin II in ventricular and vascular remodelling and in atherogenesis. Large scale clinical trials analysing the effects of converting enzyme inhibitors on the mortality and morbidity in post-infarction left ventricular dysfunction, have shown beneficial effects of these agents on major events of coronary artery disease. Experimental studies have shown reduction of intimal thickening and of the multiplication and migration of smooth muscle cells and of vascular fibrosis. Converting enzyme inhibitors seem to restore endothelial function by acting as donors of NO and could play a role in the stabilisation of atheromatous plaque, the prevention of platelet aggregation and on the activation of intravascular fibrinolytic systems. Large scale clinical trials (SOLVD and the prevention and treatment arms of SAVE) have also shown a 23% reduction in the risk of reinfarction and a 15% reduction in the risk of unstable angina. The results of ongoing trials in patients with coronary artery disease without cardiac failure are awaited with great impatience.

[Treatment of heart failure]

Heart failure is a disease which involves not only the heart but the entire circulatory system. Progression is directly related to interactions between myocardial disorders and neurohormonal and circulatory phenomena. Advances in treatment have resulted more from the development of vasodilator drugs with neurohormonal effects than from drugs with a direct effect on the myocardium. Diuretics are essential due to their rapid functional effect and the reduction in pressure on the ventricle wall. The effectiveness of digitalics is recognized not only in patients with atrial fibrillation, but also in those in sinus rhythm with ischemic heart disease. Conversion enzyme inhibitors are useful in all stages of heart failure, improving both quality of life and life expectancy as well as limiting myocardial and vascular remodeling and retarding progression of ventricular dysfunction. As current progress in the treatment of heart failure has not greatly reduced mortality, prevention is the major challenge facing all physicians. Treatment of asymptomatic ventricular function is one rational approach.

[Ventricular arrhythmias and arterial hypertension]

Hypertension has two major consequences on the heart: left ventricular hypertrophy and morphological and functional alterations of the coronary macro- and microvessels. These two cardiac modifications are responsible for three types of complications: myocardial ischaemia, left ventricular dysfunction and electrical instability which are involved in the pathogenesis of ventricular arrhythmias in hypertensive patients. The mechanisms of ventricular arrhythmias in hypertension, their incidence and severity, and their therapeutic and clinical implications will be discussed in this review article.

Prognostic value of late potentials in patients with congestive heart failure

To investigate whether detection of ventricular late potentials could provide prognostic information in patients with congestive heart failure with or without bundle branch block, we prospectively obtained a signal-averaged ECG from 151 patients with congestive heart failure, using specific criteria in 57 patients with bundle branch block. Late potentials were detected in 49 patients (32.5%); their incidence was not significantly different in patients without (31%; 29 patients) or with bundle branch block (35%; 20 patients). Late potentials were present in 25 of 73 patients (34%) with idiopathic dilated cardiomyopathy, in 20 of 57 patients (35%) with ischaemic cardiomyopathy and in four of 21 patients (19%) with hypertensive heart disease (ns). Age, NYHA class, ejection fraction and use of amiodarone were not statistically different among patients with or without late potentials. In contrast, patients with late potentials had more past episodes of sustained ventricular tachycardia (8.2%; four patients) than those without late potentials (1.9%; two patients). Twenty four hour ambulatory ECGs were obtained in 135 patients (89%). Non-sustained ventricular tachycardia was not correlated with the presence of late potentials found in 45 of 88 patients (51%) without late potentials and in 29 of 47 patients (62%) with late potentials (ns). The mean follow-up was 27 +/- 12 months; 51 patients died, 31 from progressive congestive heart failure and 13 suddenly; seven prospectively had sustained ventricular tachycardia. The total mortality rate, the cardiac mortality rate and sudden death risk were not significantly related to the presence of late potentials; their incidence were respectively 35% (36 patients), 32% (33 patients) and 10% (10 patients) in patients without late potentials and 31% (15 patients), 23% (11 patients) and 6% (three patients) in those without late potentials. The incidence of sustained ventricular tachycardia during follow-up was 2% (two patients) in patients without late potentials and 10% (five patients) in those with late potentials. The incidence of sustained ventricular tachycardia experienced by the patients before the study or seen during follow-up was significantly increased in the presence of late potentials: 18% (nine patients) vs 2% (two patients) in the absence of late potentials (P < 0.001). Removal from the study of data from patients with bundle branch block, patients with severe congestive heart failure (NYHA 3 or 4) or patients taking amiodarone did not alter these results. Thus, signal-averaged ECG results only improved risk stratification for sustained ventricular tachycardia in patients with congestive heart failure and failed to identify patients at high risk for sudden death.

[Coronary artery disease in octogenarians: contribution of coronary angiography and evaluation of therapeutic possibilities]

An increasing number of octogenarians is being referred for coronary angiography with a view to myocardial revascularisation. Based on a retrospective study of 168 octogenarians undergoing coronary angiography between January 1987 and December 1992, the authors reviewed the indications, the risks and therapeutic decisions taken in those patients with significant coronary artery disease. The population studied had acute myocardial ischaemia in 88.7% of cases, a low incidence of previous myocardial infarction and severe extracardiac pathology. Significant coronary lesions were observed in 90% of patients (151) with multiple vessel diseases in 57.8% of cases. The mortality attributed to coronary angioplasty was 0.59% (1 case) and the morbidity was 4.7%. The number of disease vessels did not influence the decision as 75.5% of single vessel, 75% of double vessel and 77.3% of triple vessel disease patients were referred for coronary surgery or angioplasty. Of the patients undergoing a revascularisation procedure (n = 108), those referred for surgery (n = 22) had more severe coronary disease than those referred for angioplasty (p < 0.05). The hospital mortality was high about 8%, irrespective of the therapeutic decision. The 3 year actuarial survival was 70% in the group undergoing myocardial revascularisation (whether by angioplasty or coronary surgery) and 53.6% in subjects treated medically. These results show that coronary angiography in a selected elderly population is possible although the mortality and morbidity should not be underestimated. A high proportion of these patients (72%) is referred for myocardial revascularisation.

[Atrial insertion of accessory pathways in permanent reciprocating junctional tachycardia]

Permanent reciprocating junctional tachycardia (PRJT) is an uncommon type of Tachycardia, usually associated with a retrogradely conducting accessory pathway situated near to the ostium of the coronary sinus. This study reports the localisation of the site of atrial insertion of the accessory pathway, confirmed by the efficacy of intracardiac catheter ablation. Five patients (4 men), aged 14 to 45, experienced PRTJT at rates of 120 to 150/mn over a period of 2 to 15 years. 4 patients were normal, expected in 2 patients in whom they were 16 and 20%. One of these suffered a thromboembolic complication after pharmacological interruption of the tachycardia. The presence of an accessory pathway with decremential retrograde conduction was confirmed in all cases. Catheter ablation was successful in the medio-septal (2 cases), posteroseptal (1 case), lateral (1 case) and anteroseptal (1 case) regions. Six to 30 applications of 20 to 30 watts of radiofrequency energy were used in the 5 cases. In one case (right lateral accessory pathway), a fulguration procedure was necessary with a cathodic shock of 160 Joules. The AV conduction was preserved and retrograde conduction was normalised in all cases. All patients remained asymptomatic for a period of 10 to 43 months without antiarrhythmic therapy. The ejection fractions of the two patients with left ventricular dysfunction returned to normal. The authors conclude that the accessory pathways of PRJT may be situated in different regions of the right atrium. The efficacy of catheter ablation was 100 % in this form of tachycardia.

[Absence of the effect of nitric oxide on pulmonary and systemic hypertension induced by sino-aortic denervation]

Inhaled nitric oxide, a selective pulmonary vasodilator, reverses hypoxic pulmonary vasoconstriction and is an effective treatment in some cases of human pulmonary hypertension. Localization of nitric oxide synthase had indicated a neural role for nitric oxide. Thus, we studied the interactions between inhaled nitric oxide and systemic and pulmonary vascular reactivity in acute neurogenic hypertension. In 6 male beagle dogs (mean weight: 15 +/- 1 kg), anesthetized by chloralose (8 cg/kg) and in spontaneous ventilation, the hemodynamic effects on systemic and pulmonary circulation of inhaled nitric oxide (12 ppm) were studied before and after acute sino-aortic denervation. The hemodynamic effects of intravenous propranolol (300 micrograms/kg) were studied after denervation. Mean arterial pressure (MAP), pulmonary capillary pressure (PCP), mean arterial pulmonary pressure (MAPP), cardiac input (CI) and oxygen venous saturation (SvO2) were measured. [table: see text] Sino-aortic denervation causes an acute and transitory pulmonary hypertension due to a double mechanism: a post-capillary hypertension (increase PCP) secondary to an increase left ventricular post-charge by systemic hypertension and a precapillary hypertension. In fact, vascular pulmonary resistances increase from 1.8 +/- 0.1 to 3.4 +/- 0.8 uW after denervation (p < 0.05). Change in pulmonary vascular reactivity induced by catecholamines is probably involved. Propranolol but not inhaled nitric oxide reverse pulmonary hypertension due to sino-aortic denervation.

[Myocardial infarction in non-menopausal women. Coronary lesions and prognosis]

Between 1977 and 1990, 64 premenopausal women, under 50 years of age (42 +/- 5.6 years), were admitted for typical acute myocardial infarction with pathological Q waves. Twenty one patients had attempted myocardial revascularisation either by intravenous thrombolysis or primary angioplasty (n = 3). All patients underwent coronary angiography with selective left ventriculography during their hospital admission. This group of 64 women was characterised by the association of coronary risk factors (2.8 per patient): smoking (89%), hyperlipidaemia (67%), diabetes (45%) and oral contraception (35%). Coronary angiography showed single vessel occlusion in 86% of patients receiving oral contraception, multiple vessel disease in 36.5% and single or double vessel disease in 31.7% of the other patients. There were 3 deaths during the hospital period (4.6%), 12 cases of left ventricular failure, 2 ventricular aneurysms, 2 operated ischaemic mitral regurgitations and 9 recurrences of pain treated by angioplasty. During follow-up (36.5 +/- 4 months), 22 patients were readmitted to hospital and there were 3 further deaths, 12 cases of persistent cardiac failure, 10 cases of latent ventricular dysfunction and 9 ischaemic reoccurrences treated by angioplasty or surgery. The results in this group of patients suffering from myocardial infarction at an unusually early age for women showed that although the mortality was similar to that observed in men of the same age (9%) there was a very high morbidity and a high risk of cardiac failure. The prognosis of myocardial infarction in women, though better than 10 years ago, should improve with immediate revascularisation, the correction of cardiovascular risk factors and the rapid application of all techniques of modern cardiology.

[Changes in myocardial beta adrenergic receptors in left ventricular hypertrophy caused by barometric and volumetric overloads]

While most prior studies examined late stages of heart failure, we determined initial changes of beta-adrenergic receptors (beta-AR) during left ventricular chronic volume and pressure overload. We investigated right auricular (RA) and left ventricular (LV) beta-AR density (Bmax, fmoles/mg protein) and beta 1-AR percentage in two groups of patients undergoing valve replacement without LV systolic dysfunction (LV ejection fraction > or = 60%), with normal plasma catecholamine levels and echocardiography LV hypertrophy. These results were compared with the values of a control group, composed by 8 patients with mitral stenosis and 5 cardiac transplant donors, and the values of 5 patients undergoing heart transplantation because of end-stage idiopathic dilated cardiomyopathy. These results show that, before alteration of LV systolic function occurs, left ventricular chronic overload induces a selective down-regulation of LV beta 1-AR compensated by an increase in beta 2-AR. These variations may be due to LV hypertrophy induced by volume or pressure overload.

Relationship between arterial blood pressure disturbances and alpha adrenoceptor density

To investigate the influence of blood pressure disturbances on human platelet alpha 2-adrenoceptor density, we studied 7 normotensive Parkinsonians with orthostatic hypotension and 23 mild essential hypertensive patients. Plasma catecholamine levels were measured by HPLC and alpha 2-adrenoceptor number and affinity determined by [3H]-yohimbine binding. Alpha-adrenergic reactivity was investigated by blood pressure response to noradrenaline infusion in Parkinsonians and by adrenaline-induced platelet aggregation in hypertensive patients. In Parkinsonians with orthostatic hypotension, in comparison with Parkinsonians without orthostatic hypotension and normotensive control subjects age and sex matched, noradrenaline plasma levels were significantly lower (62 +/- 11, 195 +/- 14 and 219 +/- 13 pg. ml-1 respectively, p < 0.05), platelet alpha 2-adrenoceptor number was significantly higher (313 +/- 52, 168 +/- 9 and 174 +/- 4 fmol.mg-1 protein respectively, p < 0.05) and the noradrenaline dose required for a 25 mm Hg increase of systolic blood pressure significantly lower (0.19 +/- 0.03, 0.86 +/- 0.11 and 0.68 +/- 0.10 microgram.Kg-1 respectively, p < 0.05). In hypertensive patients, in comparison with normotensive control subjects age and sex matched, plasma noradrenaline levels remained unchanged (306 +/- 68 vs 246 +/- 28 pg.ml-1) whereas both platelet alpha 2-adrenoceptor number (137 +/- 15 vs 177 +/- 15 fmol.mg-1 protein, p < 0.05) and velocity of adrenaline-induced platelet aggregation were significantly decreased. These results indicate that platelet alpha 2-adrenoceptor density is related to blood pressure values. In Parkinsonians with orthostatic hypotension, the up-regulation of alpha 2-adrenoceptors was induced by the decrease of endogenous catecholamines. In contrast, in essential hypertension a down-regulation of alpha 2-adrenoceptors was observed in spite of no significant increase of catecholamine levels. These results suggest that only sustained abnormal plasma noradrenaline levels could allow the development of alpha 2-adrenoceptor regulatory mechanisms.

[Inferior wall myocardial infarction and atrioventricular block; angiography and prognosis]

This study was based on 42 cases of 2nd or 3rd degree atrioventricular block out of 292 cases of inferior wall myocardial infarction. The criteria of selection were monitoring in the intensive care unit during the acute phase, selective coronary angiography in the first 48 hours to 5 days, and regular clinical follow-up during the first year after infarction. The conduction defect was either immediately recorded on the first ECG, delayed (between the 12th and 24th hour) or late (after the 3rd day). These 42 inferior wall infarcts with atrioventricular block (incomplete in 14 and complete in 28 cases) differed from inferior infarction without block by: - the severity of the clinical signs during the acute phase (35% with cardiac failure, 19% with cardiogenic shock); - the severity of the coronary lesions (71.4% with triple vessel disease in infarction with atrioventricular block compared with 32% in those without block, p < 0.02); - the prevalence of the association of > 70% stenosis of the right coronary and left anterior descending arteries; - the alteration of left ventricular function (53% patients with atrioventricular block had ejection fraction of under 30%); - the severity of these infarcts was not related to the atrioventricular block which regressed in 95% of cases but to the severity of the coronary disease, the left ventricular dysfunction and the advanced age of the patients (72.3 +/- 8 years).

Cardiac beta-adrenoceptors and adenylyl cyclase activity in human left ventricular hypertrophy due to pressure overload

The effect of left ventricular hypertrophy (LVH) due to chronic pressure overload on right atrial (RA) and left ventricular (LV) myocardial beta-adrenergic receptor (beta-AR) density and subtypes, adenylyl cyclase (AC) activity and ADP-pertussis toxin ribosylated proteins was investigated in humans with LVH due to aortic stenosis and in patients without LVH undergoing heart surgery for mitral stenosis or coronary artery disease taken as controls. Both groups presented normal systolic function or plasma catecholamine levels. In LVH and controls, beta-AR density was similar in RA (62 +/- 6 vs 77 +/- 12 fmol.mg-1 protein) and LV (39 +/- 7 vs 32 +/- 2 fmol.mg-1 protein). In LVH, beta 1-AR percentage was < than in controls in LV (35 +/- 11 vs 73 +/- 5%, P < 0.05) but not in RA (79 +/- 5 vs 73 +/- 8%). Basal AC activity in RA (19 +/- 4 vs 21 +/- 6 pmol.mg-1 protein) and LV (22 +/- 5 vs 27 +/- 3 pmol.mg-1 protein) was similar in LVH and in controls. Isoprenaline-induced stimulation of AC in RA was similar in LVH and in controls (51 +/- 18 vs 36 +/- 18%) but < in LV of LVH (7 +/- 6 vs 45 +/- 6%, P < 0.05). In the presence of ICI-118,551 (a beta 2-adrenoceptor antagonist), isoprenaline failed to induce any increase in cAMP in LVH. The quantification of ADP-pertussis toxin ribosylated proteins indicated a lower concentration of substrates in LV myocardial membranes from LVH. These data indicate that in LVH due to pressure overload, there is a down-regulation of beta 1-AR and an increase in beta 2-AR density. This is associated with alterations of the transmembrane signalling marked by a decreased capacity of isoprenaline to stimulate AC and an impaired expression of Gi proteins.

[Prognosis of silent myocardial ischemia]

Asymptomatic or silent myocardial ischemia (SI) is frequent in coronary heart disease and its prognostic value is controversial. The aim of our study is to compare coronary atherosclerosis, left ventricular function and clinical out come of 110 patients with S.I. (A group) and 210 patients with stable angina (B group). The 320 patients were submitted: to symptom limited exercise stress-test with permanent electrocardiographic control by a Case 12-15 digitalized system with ST segment depression interpretation. A test was considered positive for ischemia if there was ST depression of > 1 mv in magnitude from baseline, persisting for 0.08 sec or exercise angina and ischemia: to selective coronarography by Seldinger technic, with left ventricular cineangiography in 2 incidences. A significant coronary stenosis was defined as > 50% reduction of luminal diameter; to medical treatment with betablockers (87.5% of patients), calcium inhibitors (12.5%), aspirin (90%) and nitrates; to regular medical surveillance. During the follow-up (42.4 +/- 5 months in mean) the number of deaths, myocardial infarctions, heart failure, unstable angina and revascularizations were analyzed. Patients of A group with S.I. had a high percentage of risks factors (diabetes mellitus 55%, nicotinism 85%, dyslipidemia 22.5%) and history of previous myocardial infarction in 33% of cases. There are not significant differences between severity and extension of coronary disease, or ventricular dysfunction in patients of A group or B. The percentages of deaths (2.10 versus 3%), acute myocardial infarctions (9.5 versus 8.5%), heart failures (2.72 versus 3%), surgical indications (14.7 versus 15.7%) are not significantly different between the 2 groups. In A group, 34% of patients were treated by angioplasty versus 40% of patients in group B (p < 0.02). S.I. has a bad prognostic and the clinical out come of coronary heart disease is not dependent of presence of angina during exercise testing and daily activities.

Efficacy and acceptability of perindopril in mild to moderate chronic congestive heart failure

The aim of this 3-month double-blind, placebo-controlled, multicenter trial was to evaluate the clinical efficacy and safety of perindopril, a new long-acting angiotensin-converting enzyme inhibitor in the second-line treatment of mild to moderate chronic congestive heart failure. After a run-in period of at least 14 days, 125 patients with grade II or III New York Heart Association chronic congestive heart failure on baseline diuretic therapy were randomized to perindopril, 2 mg (n = 61), or placebo (n = 64), once daily. Assessment was at 2-week intervals for the first month and then monthly for the 2 following months. After 2 weeks, active treatment was increased to perindopril, 4 mg once daily, if systolic blood pressure was 100 mm Hg or greater. Apart from sex, the two groups were homogeneous before treatment. As shown by the end-point analysis, the increase in exercise time was greater with perindopril than with placebo for both the ergometric bicycle (+111 +/- 21 versus +16 +/- 20 seconds; p = 0.002) and the treadmill (+171 +/- 39 versus +36 +/- 42 seconds; p = 0.024). Compared with placebo, this increase in exercise tolerance with perindopril was accompanied by an improvement in New York Heart Association functional class (p = 0.009), overall heart failure severity score (p < 0.001), and cardiothoracic ratio (p = 0.05). Of the 12 withdrawals from the study, seven were attributed to adverse events, two in the perindopril group and five, including one death, in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Beta-adrenergic receptivity and left ventricular hypertrophy caused by pressure overload in man]

The effect of left ventricular chronic pressure overload on right atrial (RA) and left ventricular (LV) myocardial beta-adrenoceptor (beta-AR) density and subtypes ([I125] cyanopindolol binding), adenylate cyclase activity (AC) and ADP-pertussis toxin ribosylated proteins was investigated in 13 patients with aortic stenosis (AO) and compared with the results obtained in 10 patients with mitral stenosis (MI) taken as controls. None of the patients included had any impairement of systolic function or increased plasma catecholamine levels. The total number of beta-AR in RA (62 +/- 6 vs 77 +/- 12 fmoles/mg prot) and LV (39 +/- 7 vs 32 +/- 2 fmoles/mg prot) was similar in AO and in MI. The percentage of beta 1-AR was significantly lower in LV from AO (35 +/- 11 vs 73 +/- 5% in MI) but identical in RA (79 +/- 5 vs 73 +/- 8%). The basal activity of AC was similar in membranes from patients with AO (19 +/- 4 and 22 +/- 5 pmol.mg-1 prot in RA and LV) and in controls (21 +/- 6 and 27 +/- 3 pmol.mg-1 prot in RA and LV). Isoprenaline-induced stimulation of AC was significantly lower in LV membranes from patients with AO (7 +/- 6 vs 45 +/- 6% in MI) but remained identical in RA membranes (51 +/- 18 vs 36 +/- 18% in MI). The quantification of ADP-pertussis toxin ribosylated proteins indicated a lower substrate concentration in myocardial membranes from patients with AO when compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

[Action of converting enzyme inhibitors on myocardial ischemia and reperfusion injuries]

During myocardial ischaemia, either in chronic coronary insufficiency or the acute phase of myocardial infarction, the renin-angiotensin system is activated which, by its deleterious cardiac effects, aggravates the ischaemia. Angiotensin Converting Enzyme (ACE) inhibitors, by their indirect effects (improved conditions of left ventricular load, negative inotropism, attenuation of catecholaminergic stimulation), reduce myocardial oxygen consumption, and by their direct coronary vasodilator effect reduce myocardial ischaemia. In addition, by attenuating the formation of oxygen-free radicals, by participating in the inactivation of some of them and protecting the lysosomal membranes, they combat reperfusion injury. In the animal model of acute myocardial infarction, they reduce myocardial infarct size and the prevalence of reperfusion arrhythmias. In the clinical situation, their effects on the ischemic response to effort in anginal patients remain controversial, appear to be more marked in abnormalities of the coronary micro-circulation especially in syndrome X and in hypertensive heart disease. In ischemic heart disease, long-term treatment may be beneficial by their trophic coronary and myocardial effects and two large scale trials report a decrease in the recurrence of myocardial infarction with ACE inhibitors. In the acute phase of myocardial infarction if their possible actions on reducing the infarct size and reperfusion arrhythmias require further confirmation, they do limit expansion of the infarct and decrease early left ventricular dilatation. However, the appreciation of tolerance is variable and the timing of their introduction remains controversial.