Stratification of single-vessel coronary stenosis by ischemic threshold at the onset of wall motion abnormality during continuous monitoring of left ventricular function by semisupine exercise echocardiography

We studied the relation between the ischemic threshold at the onset of wall motion abnormality on exercise echocardiography (EE) and the severity of coronary stenosis in patients with 1-vessel coronary artery disease (CAD). We screened 216 consecutive patients who underwent coronary angiography and EE for suspected CAD. Ninety-five (74 men; age, 56 +/- 12 years) satisfied the study criteria, that is, the presence of 1-vessel disease or no evidence of CAD on angiography and a normal baseline echocardiogram. Eighty-seven patients had 1-vessel CAD on angiography, and exercise-induced wall motion abnormality occurred in 73 (77%). Optimal cutoff values of percent diameter stenosis and minimal lumen diameter for predicting a positive EE were 61% (sensitivity and specificity of 76%) and 1.12 mm (sensitivity and specificity of 74%). Among patients with positive EE, heart rate-blood pressure product at ischemic threshold was correlated with quantitative coronary stenosis (r = -0.72, P <.001). The ischemic threshold from continuous monitoring of left ventricular function during semisupine EE is correlated with the severity of coronary stenosis among patients with 1-vessel disease and a normal resting echocardiogram.

[Chronic ischemic left ventricular dysfunction: myocardial hibernation?]

Hibernating myocardium is a term which covers chronic ischaemic left ventricular dysfunction which is potentially reversible after revascularisation. Hibernating myocardium is classically associated with chronic hypoperfusion responsible for hypocontraction and cellular degeneration. This "classical" conception has been questioned as some workers emphasise that the reduction in coronary reserve responsible for repeated episodes of ischaemia and stunning could be the main causes of myocardial dysfunction. Position emission tomography (PET), and, most of all, myocardial scintigraphy and dobutamine echocardiography are the most commonly used techniques for detecting hibernating myocardium. Their sensitivity is good but the specificity and positive predictive value of dobutamine echocardiography seems to be better than the isotopic techniques. Structural abnormalities of hibernating myocardium and the delay, which is often long, between revascularisation and improvement, may explain some of the discordances between these techniques. Irrespective of the term used, hibernation or chronic ischaemic left ventricular dysfunction with myocardial viability, the reported data is in favour of coronary revascularisation with improved long-term quality of life and reduced mortality in patients with positive viability tests.

The new drugs (chlorpromazine & reserpine): administrative aspects. 1956

The article on the new drugs reprinted below appeared in the February 1956 issue of Mental Hospitals. It is based on a discussion held during the Seventh Mental Hospital Institute in October 1955 in Washington, D.C. Chlorpromazine and reserpine had been available in the United States less than two years when the institute participants met to discuss how their hospitals were coping with the demands of the new treatments. In a commentary and analysis beginning on page 333, Robert Cancro, M.D., considers the broader impact of the introduction of neuroleptics and examines the concerns of the 1956 institute participants in the context of today.

[The best of echocardiography in 1999]

As many techniques of medical investigation, echocardiography regularly benefits from technical innovations which, with application, prove to be extremely useful and, for some of them, even widen the field of investigation. The end of this decade has seen the introduction of major improvements. In daily practice, second harmonic imaging has been the most important technical advance with such improved quality of imaging that this mode has rapidly become the routine for transthoracic investigations in adults. All modern echocardiographs are, or can be, equipped at modest cost. Stress echocardiography, the diagnostic reliability of which is closely related to the quality of the imaging, has greatly benefited from this technique, to the point of obtaining equivalent results as nuclear medicine in the detection of myocardial ischaemia and cellular viability. The results are now sufficiently convincing for the technique to have a real prognostic value in myocardial ischaemia. Doppler tissue imaging is also a major advance but the clinical value is still under evaluation: the pulsed Doppler mode is quantifiable during the investigation, contrary to the calculation of transparietal velocity gradients which requires computerisation techniques not provided by all manufacturers. The regain in interest in contrast echocardiography is due to the development of agents which, injected intravenously, cross the pulmonary capillary barrier and opacify the left heart chambers. The reinforcement of the Doppler signal and improved detection of the endocardial echoes have justified the authorization of their commercialisation, but the essential point is their use in the investigation of myocardial perfusion which is under evaluation. Three-dimensional reconstruction has made great strides but its diffusion is still limited by the limited availability of the required powerful computers.

[Hypertrophic obstructive cardiomyopathy and double-chamber pacing. Long-term results in a consecutive series of 22 patients]

The authors report their experience with dual-chamber pacing in hypertrophy obstructive cardiomyopathy. 22 patients (14 women and 8 men) mean age 60 +/- 13 years were implanted between 1992 and 1998. The criteria for pace-maker implantation were the presence of severe symptoms related with hypertrophy obstructive cardiomyopathy (dyspnea, angina, syncope) and left ventricular outflow tract gradient at mean 30 mmHg. Before pacing, all patients received a medical therapy which included beta-blockers or calcium inhibitors. This treatment was considered as ineffective or responsible of side effects. Patients were followed-up at mean 35.1 +/- 20.3 months. During this period, symptoms improved (mean NYHA class 2.7 +/- 0.5 before pacing vs 1.4 +/- 0.5 after pacing) and left ventricular outflow tract lowered from 95.4 +/- 40.8 to 39.3 +/- 20.5 at 6 months. 34.3 +/- 23.4 at one year and 26.5 +/- 21 at the end of follow-up. Seven patients had RF ablation of atrio-ventricular junction for paroxysmal atrial fibrillation or for lack of hemodynamic improvement with pacing. This procedure permits a significative lowering of gradient and a better ventricular filling. In conclusion, dual-chamber pacing is effective for treatment of hypertrophy obstructive cardiomyopathy when medical therapy is ineffective or bad tolerated at condition of: perfect pacing with permanent ventricular capture and optimal AV delay; RF ablation of AV junction in one third of cases; medical therapy systematically associated in all patients.

Prognostic value of MIBG imaging in idiopathic dilated cardiomyopathy

Alterations of cardiac sympathetic innervation are likely to contribute to fatal outcomes in patients with heart failure. These alterations can be evaluated noninvasively by 123I-metaiodoben-zylguanidine (MIBG) imaging.

METHODS

The hypothesis that impaired cardiac sympathetic innervation, as assessed using MIBG imaging, is related to adverse outcomes was tested in 112 patients with heart failure resulting from idiopathic cardiomyopathy. Main inclusion criteria were New York Heart Association classes II-IV and radionuclide left ventricular ejection fraction (LVEF) < 40%. Patients were assessed for cardiac MIBG uptake, circulating norepinephrine concentration, LVEF, peak Vo2, x-ray cardiothoracic ratio, M-mode echographic end-diastolic diameter and right-sided heart catheterization parameters.

RESULTS

During a mean follow-up of 27 +/- 20 mo, 19 patients had transplants, 25 died of cardiac death (8 sudden deaths), 2 died of noncardiac death and 66 survived without transplantation. The only independent predictors for mortality were low MIBG uptake (P < 0.001) and LVEF (P = 0.02) when using multivariate discriminant analysis. Moreover, MIBG uptake (P < 0.001) and circulating norepinephrine concentration (P = 0.001) were the only independent predictors for life duration when using multivariate life table analysis.

CONCLUSION

Impaired cardiac adrenergic innervation as assessed by MIBG imaging is strongly related to mortality. MIBG imaging may help risk stratify patients with heart failure resulting from idiopathic dilated cardiomyopathy.

[Myocardial viability. Myocardial viability post-infarct: contribution of dobutamine-echography]

ROUTINE EXPLORATION: Echocardiography during dopamine perfusion has been widely proven as an effective tool for determining myocardial viability. Dobutamine has marketing authorization in France for stress-echocardiography and is widely used in clinical practice outside research protocols. The exploration must however be conducted within an appropriately equipped cardiac intensive care unit. Stress-echocardiography has certain advantages over isotropic techniques, in terms of equipment costs, examination time and exposure to isotopes. POST-INFARCTION: Dobutamine-echocardiography enables detection of viable myocardium within the infarct zone, evaluates the degree of residual ischemia in the infarct zone and provides information on prognosis. It would not however be reasonable to perform stress-echocardiography as a first line exploration after infarction. International guidelines recommend a sub-maximal ECG exercise test prior to coronarography. The contribution of stress-echocardiography after infarction is its ability to give precise information on myocardial viability and residual ischemia in one or more territories to compare with coronary lesions, thus allowing indication for revascularization. CHRONIC ISCHEMIC CARDIOPATHY: Dobutamine-echocardiography can be used to detect hibernating myocardium in patients with chronic ischemic cardiopathy. In this indication, the sensitivity of stress-echocardiography is slightly lower than thallium scintigraphy, but its specificity and positive predictive values are higher. The best predictive value is obtained with bimodal dobutamine-echocardiography: improve-med thickening at low doses and a degradation at high dose is predictive of functional improvement after revascularization in 72% of the cases. In more severe cases with ejection fraction < 35%, improvement in hibernating myocardium after revascularization leads to a significant improvement in left ventricular ejection fraction.

Is left atrial appendage flow a predictor for outcome of cardioversion of nonvalvular atrial fibrillation? A transthroacic and transesophageal echocardiographic study

Accurate echocardiographic parameters for predicting the success of cardioversion or maintenance of sinus rhythm are poorly defined. This prospective transthoracic and transesophageal echocardiographic study was conducted to test the hypothesis that the left atrial appendage flow pattern could be a predictive parameter of the success of cardioversion and maintenance of sinus rhythm in patients with nonvalvular atrial fibrillation. Eighty-two consecutive patients with nonvalvular atrial fibrillation of <6 months' duration underwent transesophageal examination after transthoracic echocardiography. After exclusion of left atrial thrombus, pharmacologic (n = 18) or electrical (n = 64) cardioversion was successful in 75 of 82 patients. In the group that underwent successful cardioversion, maintenance of sinus rhythm (n = 35) or recurrence of arrhythmia (n = 40) was assessed during a 1-year follow-up. During transesophageal examination, five left atrial appendage thrombi were found, spontaneous echo contrast was present in 26 (32%) patients, and mean peak left atrial appendage emptying velocity was 35 +/- 18 cm/sec. Peak left atrial appendage emptying velocity was found to be statistically related to parameters of left ventricular and left atrial function but not to long-term maintenance of sinus rhythm. No other echocardiographic parameter was identified as a predictor for either the success of cardioversion or the maintenance of sinus rhythm at follow-up. In patients with nonvalvular atrial fibrillation of recent onset, peak left atrial appendage emptying velocity appears to be a complex parameter depending on left atrial and left ventricular function but that does not predict either the success rate of cardioversion or long-term maintenance of sinus rhythm after successful cardioversion.

[Echocardiographic factors predicting the maintenance of sinus rhythm one year after cardioversion for non-valvular atrial arrhythmias]

Echocardiographic factors predictive of the maintenance of sinus rhythm after successful cardioversion were investigated in 94 patients with non-valvular atrial arrhythmias of recent onset. Seventy-five patients with atrial fibrillation and 19 with atrial flutter admitted for reduction of their arrhythmias underwent transthoracic and transoesophageal echocardiography. After excluding a thrombus in the left atrial appendage or checking that it had disappeared (5 patients), and electrical (n = 74) or pharmacological (n = 20) cardioversion was successfully performed. The maintenance of sinus rhythm (n = 44) or recurrence of arrhythmia (n = 50) were controlled every 3 months for one year. The mean value of the peak positive blood flow in the left atrial appendage was 38 +/- 20 cm/s for the whole group. It was not possible to identify an echocardiographic parameter predictive of maintenance of sinus rhythm at one year either in the whole group or in the subgroups with atrial flutter or atrial fibrillation. In the group in atrial flutter, the mean value of the peak positive blood flow in the left atrial appendage was significantly greater than in the group with atrial fibrillation: 49 +/- 22 cm/s vs 35 +/- 18 cm/s, respectively; p < 0.05. The peak of positive flow in the left atrial appendage was statistically related to indirect parameters of left atrial function and of left ventricular function in the group with atrial fibrillation but only with parameters of left ventricular function in the smaller group with atrial flutter.

Right ventricular late filling termination time and its relation to interstitial collagen content in early transplanted heart: a color M-mode Doppler digital analysis

BACKGROUND

Histologic changes in cardiac allografts resulting from fibrosis or acute rejection can modify ventricular diastolic function and ventricular inflow characteristics. These abnormalities may be detected by color M-mode Doppler echocardiography which has been shown to be sensitive in assessing ventricular diastolic function.

METHODS

Twelve cardiac allograft recipients were prospectively studied with serial color M-mode and single-gated Doppler echocardiography, as well as with endomyocardial biopsy, with a follow-up of approximately 10 weeks. The myocardial interstitial collagen content as evaluated by videodensitometry was compared with right and left ventricular late filling termination times measured in the absence of a severe episode of rejection.

RESULTS

A positive and significant correlation was found between the collagen content and the corresponding right ventricular late filling termination time (r = 0.89, p < 0.0001), but no correlation was found with the left ventricular late filling termination time. Moreover, variations in collagen content and variations in right ventricular late filling termination time were also highly correlated (r = 0.91, p < 0.0001). In allograft recipients who had episodes of rejection of grade 3A or greater, both right and left ventricular late filling termination times were significantly increased during rejection.

CONCLUSIONS

Measurements of right ventricular late filling termination time by color M-mode Doppler echocardiography performed in the absence of acute rejection can be use to monitor the evolution of interstitial collagen content in cardiac allografts. The early detection of abnormally prolonged late filling termination time could be followed by endomyocardial biopsy to confirm the histologic changes.

[Cerebral abscess disclosing tetralogy of Fallot with situs inversus in adulthood]

The authors report the case of tetralogy of Fallot (TOF) associated with situs inversus, the first description of this rare association in a previously asymptomatic adult. A 32 years old chauffeur was admitted to hospital with pyrexia and convulsions due to a left temporo-parietal cerebral abscess which had a favourable outcome. The chest X-ray and Doppler echocardiographic study showed a TOF with a high infundibular stenosis and dextrocardia. Abdominal ultrasonography confirmed a complete situs inversus. The good tolerance was attributed to the equilibrated character of the TOF. The orientation of the heart and the cono-truncal septation occur at different times during embryogenesis. However, there are genetic arguments in favour of the non-fortuitous nature of this association.

[Study of myocardial viability after recent infarction by echocardiography under dobutamine. Evidence of stunned myocardium]

After myocardial infarction treated by thrombolysis, secondary improvement of contractility may be observed due to the presence of viable but stunned myocardium in a zone of ischaemia. Echocardiography with lose dose Dobutamine has been proposed as a diagnostic test of myocardial viability. The inotropic effect of the pharmacological agent improves or induces myocardial thickening in zones of ischaemia. A positive response is observed in about one out of two cases. The sensitivity ranges from 79 to 86% and the specificity from 68 to 90% in the reported series. This mode of stress echocardiography for the study of post-infarction myocardial viability is under clinical evaluation: its advantages and limitations should be compared with those of other non-invasive methods, especially thallium myocardial scintigraphy.

[Doppler echocardiographic evaluation of mitral flow velocity and prognosis of cardiac insufficiency]

The aim of this study was to determine the role of Doppler echocardiography in establishing the prognosis of Stages to 4 cardiac failure. The echocardiographic indices of left ventricular filling were correlated with catheter data and the 2 year out come of patients. The study population included 54 patients examined prospectively in the context of an evaluation of their cardiac failure. Two years after the initial examination, 19 patients were dead or transplanted. Of the remaining 35 patients, 18 were reevaluated at 6 months. Of the echocardiographic parameters, "hyper normal" mitral flow with a high E/A ration indicated poor prognosis; when E/A > 2, the one year survival was 50% and the 2 year survival 42%. There was overlap between the groups of dead or transplanted and surviving patients only when the E/A ratio was between 2 and 3. The patients with E/A < 2 were all alive without any major events at 2 years. All patients with E/A > 3 had a poor prognosis. The E/A ratio was closely correlated with pulmonary capillary pressure levels (p < 0.001, r = 0.55) and lees closely with cardiac index (p < 0.05, r = 0.4) and radionuclide ejection fraction (p < 0.05, r = 0.28). After 6 months' vasodilator treatment with an angiotensin converting enzyme inhibitor (captopril) the E/A ratio decreased significantly from 1.85 +/- 0.78 to 1.0 0.55 (p < 0.02). A "hyper-normal" mitral flow is related to many factors, including high left ventricular filling pressures, mitral regurgitation and reduced left ventricular compliance. This appearance of mitral flow is a poor prognosis factor in severe cardiac failure.

Preservation of the aortic valve in acute aortic dissection: long-term echocardiographic assessment and clinical outcome

The aim of the present study was to determine the long-term status of the native aortic valve after surgical treatment of acute aortic dissection involving the ascending aorta. From 1972 to 1991, 93 patients underwent operation for type I or II aortic dissection. There were 76 men and 17 women. Mean age was 54 +/- 13 years. Eighty patients (86%) had a conservative procedure regarding the aortic root and aortic cusps: 74 had prosthetic replacement of the ascending aorta and 6, complete replacement of the aortic arch. Thirteen patients (14%) had simultaneous replacement of the aortic valve and the ascending aorta. The overall hospital mortality rate was 29% (27/93). The overall actuarial survival rate was 60.2% +/- 5.2%, 49.7% +/- 6.1%, and 35.9% +/- 8.1% at 5, 10, and 15 years, respectively. The survival rates for patients who had an ascending aortic procedure only were 63% +/- 5.5%, 54% +/- 6.5%, and 39% +/- 8.5% at 5, 10, and 15 years, respectively, and for patients who required aortic valve replacement, 45% +/- 14% and 22% +/- 17.5% at 5 and 10 years, respectively. Fifty long-term survivors (94% follow-up) with preservation of the aortic valve and aortic root were studied. Among them, 9 (18%) died within a mean interval of 97 +/- 46 months after operation. Causes of death were ischemic cardiac failure (2), aortic rupture or extension of dissection (4), renal disease (1), stroke (1), and sudden death (1). Forty-one patients had long-term clinical and echocardiographic evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Preservation of the aortic valve in acute dissection of the ascending aorta]

The aim of this study was to evaluate the status of the native aortic valve in patients operated for acute dissection of the ascending. aorta (ADAA). Between November 1972 and November 1991, 93 patients were operated for ADAA. There were 76 men and 17 women (average age 54 +/- 12 years). The aortic valve was reserved in 80 cases (86%). In 13 patients (14%) aortic valve replacement was associated with replacement of the ascending aorta. The early mortality was 29% (27/93). The global actuarial survival rates at 5, 10 and 15 years were 60.2 +/- 5.2%, 49.7 +/- 6.1% and 26.9 +/- 9.9% respectively. Fifty patients (94%) in whom the native aortic valve was preserved were followed up. Nine patients (18%) died and average of 97 +/- 46 months after surgery. The causes of death were aortic rupture or extension of the dissection (N = 4), ischemic cardiac failure (N = 2), renal failure (N = 1), cerebrovascular accident (N = 1) and sudden death (N = 1). Forty one patients underwent transthoracic echocardiography. Seven patients developed severe aortic regurgitation, 6 of whom had to be reoperated for aortic valve replacement. Echocardiography showed absence of of minimal aortic regurgitation in 22 cases and mild aortic regurgitation with normal left ventricular function in 12 cases (in 2 cases, aortic valve replacement was associated with surgical treatment of another valvular lesion or of coronary artery disease). Therefore, aortic valve replacement was performed in 8 patients 61.5 +/- 51.2 months after the initial operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-adrenergic contractile reserve as a predictor of clinical outcome in patients with idiopathic dilated cardiomyopathy

To examine the ability of beta-adrenergic contractile reserve assessment to predict the outcome of patients with heart failure, a prospective study was undertaken in 35 patients with idiopathic dilated cardiomyopathy and radionuclide ejection fraction below 40%. During right- and left-sided catheterization, right atrial and left ventricular (LV) pressures, peak positive LV dp/dt, cardiac index, and plasma norepinephrine and epinephrine concentrations were measured at baseline. After a left main intracoronary infusion of dobutamine (25 to 200 micrograms.min-1), beta-adrenergic contractile responsiveness was assessed as the net increase in peak positive LV dp/dt (delta LV dp/dt). After the initial examination, patients were treated with diuretics, digitalis, and angiotensin converting enzyme inhibitors and then followed-up. After a mean follow-up period of 13 +/- 7 months, two groups of patients were distinguished: those who responded to medical therapy (group A, n = 26) and those with clinical deterioration (group B, n = 9) leading to death (n = 4) or heart transplantation (n = 5). Initial peak positive LV dp/dt, LV end-diastolic pressure, cardiac index, and LV ejection fraction were better in group A than in group B (p less than 0.001). Initial plasma norepinephrine and epinephrine concentrations were significantly higher and delta LV dp/dt was lower in group B than in group A (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular flow propagation during early filling is related to wall relaxation: a color M-mode Doppler analysis

OBJECTIVES

This study was designed to evaluate the relation between the velocity of flow propagation and left ventricular relaxation by using color M-mode Doppler echocardiography to analyze flow propagation in the left ventricle.

BACKGROUND

Noninvasive attempts to identify alterations in left ventricular relaxation have been hampered because both the relaxation rate and left atrial filling pressure are the determinants of peak early velocity and filling rate.

METHODS

Color M-mode velocity data were transferred to a microcomputer and compared with conventional pulsed Doppler data to assess the ability of color M-mode echocardiography to analyze velocity field properties. The velocity of flow propagation was measured as the slope of the flow wave front during early filling in normal subjects (n = 29) and in patients with disease that alters relaxation (dilated cardiomyopathy [n = 31], ischemic cardiomyopathy [n = 8], hypertrophic cardiomyopathy [n = 5], systemic hypertension [n = 22] and aortic valve disease [n = 25]). In nine patients with end-stage dilated cardiomyopathy, echocardiographic and left heart catheterization data were obtained at baseline and during intracoronary dobutamine infusion.

RESULTS

Color M-mode and pulsed Doppler echocardiographic data were highly correlated (n = 217, r = 0.94, p less than 0.0001, velocity range 0.2 to 1.5 m/s). The velocity of flow propagation was lower in patients than in normal subjects (0.46 +/- 0.15 vs. 0.84 +/- 0.11 m/s, p less than 0.0001). The decrease was significant in all disease forms with or without left ventricular dilation. The velocity of flow propagation was related to peak early velocity in normal subjects (p less than 0.001) but not in patients. It varied inversely with the isovolumetric relaxation time constant during dobutamine infusion and the two variables were highly correlated (p less than 0.0001).

CONCLUSIONS

The velocity of flow propagation during early filling seems to be highly dependent on the left ventricular relaxation rate and could be an important tool in studying diastolic function.

Prognostic value of cardiac metaiodobenzylguanidine imaging in patients with heart failure

The prognostic value of 123I-metaiodobenzylguanidine (MIBG) imaging was compared with that of other noninvasive cardiac imaging indices in ninety patients (mean age = 52 +/- 7 yr) suffering from either ischemic (n = 24) or idiopathic (n = 66) cardiomyopathy. Patients had different measurements taken: cardiac MIBG uptake, radionuclide left ventricular ejection fraction, x-ray cardiothoracic ratio and echographic M-Mode data. Cardiac MIBG uptake was assessed as the heart-to-mediastinum activity ratio measured on the chest anterior view image obtained 4 hr after intravenous injection. The patients then had follow-up for 1-27 mo, at which time 10 patients had transplants, 22 had died and 58 were still alive. Data from patients with transplants were not used in the analysis, in which multivariate stepwise regression discriminant analysis showed that cardiac MIBG uptake was more potent to predict survival than other indices: H/M (p less than 0.0001), x-ray cardiothoracic ratio (p = 0.0017), echographic end-diastolic diameter (p = 0.0264) and radionuclide left ventricular ejection fraction (p = 0.0301). Moreover, multivariate life table analysis showed that cardiac MIBG uptake was also the best predictor for life duration: H/M (p = 0.0001), radionuclide left ventricular ejection fraction (p = 0.0098) and x-ray cardiothoracic ratio (p = 0.0139); echographic data were not useful. Thus, cardiac MIBG imaging may be helpful for heart transplantation decision making in patients with heart failure.

[Percutaneous transluminal angioplasty of the common trunk during the acute phase of myocardial infarction]

The prognosis of cardiogenic shock in the acute phase of myocardial infarction has been transformed since the introduction of techniques of myocardial revascularisation. We report the case of a patient in cardiogenic shock after a large anterior myocardial infarct in whom failure of early thrombolytic therapy led to referral for emergency percutaneous transluminal coronary angioplasty. The success of the procedure on the patient's haemodynamic condition was life-saving. The originality of this case resides in the fact that revascularisation concerned the left main coronary stem.

A modelized distribution of actomyosin interactions in the vertebrate cardiac muscle

Preliminary assumption of this model is that interactions between actin and myosin presupposes an exact three-dimensional geometrical correspondence between sites, due to the very short time constants present under physiological conditions. Only small and controlled torsions of the actin filaments are accepted. The model uses geometrical information concerning orientations and dimensions of myosin crossbridges and actin monomeres to modelize the distribution of their inter-actions. An orientation map of actin sites in the cross-section perpendicular to the filament axis is proposed, adapted to the specific filament array of vertebrate muscle. Orientation of myosin crossbridges follows Luther's rules. According to the model, any interaction between actin and myosin implies the superimposition of their respective cross-sectional planes. The axial length of actin monomere is 55 A; the distance between two crossbridges along the myosin filament axis is 143 A. The following properties are derived: 1) The shortening step of the sliding actin filament must be a multiple of 11 A (highest common factor). Taking into account the staggered disposition of the two actin strands and the presence of two heads for each cross-bridge, the most probable value for this shortening step is equal to 99 A. A specific scheme is proposed to describe the shortening process. The behavior of the modelized crossbridge does not need any elastic structure--2) Planes situated at 715 A (lowest common multiple) of actin and myosin coinciding planes are also in coincidence. In a hemi-sarcomere the maximal number of these planes, referred to as simultaneously activable planes, is 10 (20 if both myosin heads are considered). The proportion of interactions authorized by the site orientations is 1/12. In the model, the concept of randomly recruited crossbridges is replaced by a discretized recruitment, based on geometrical properties at an ultrastructural level. The proposed distribution is homogeneous: it can be extended radially in the sarcomere and authorizes the actin filament sliding in the whole physiological range under the control of a dual activation function, reproducing Ca++ temporal and spatial distribution.

[Neuroendocrine adaptations in chronic congestive heart failure]

Chronic congestive heart failure is typically accompanied by an abnormal production of vasoconstrictor antinatriuretic hormones and vasodilator natriuretic hormones. Decompensation occurs when the former prevail over the latter. These neuroendocrine abnormalities are increasingly taken into account to determine the prognosis and to decide on the best therapeutic approach in individual patients with chronic heart failure.

[Myocardial mass index in the diagnosis of acute rejection of allogeneic heart transplants]

Changes in an index of left ventricular mass were evaluated in the diagnosis of acute cardiac transplant rejection in a prospective study involving 28 transplant patients by comparison with the histology of endomyocardial biopsy. The surface of a ring of left ventricular myocardium obtained from a 2D echocardiographic examination was used as an index of mass. Eighty-three pairs of results--biopsy and index of mass--recorded within a 12 hour interval were obtained between the first day and 10th month of transplantation over a period of 12 consecutive months. Echocardiographic diagnosis of acute rejection was made when the index of myocardial mass increased by over 7 per cent compared with baseline values recorded during the first 3 days of transplantation or during a new period of equilibrium after an episode of rejection. Two groups of patients were identified from the results of biopsy, taken as the reference: in 16 patients with mild or moderate histological signs of rejection the variation of the index of mass was 18.3 +/- 9.1%; endomyocardial biopsy was negative in the 12 other patients and the change in index of mass was -1.5 +/- 5.2% (p less than 0.001). The overall concordance in the 83 successive results was good with a Kappa coefficient of 0.71. The other parameters which have been reported to be useful in diagnosing rejection (relaxation, antegrade diastolic mitral flow, acoustic density of myocardium) present a number of problems in routine practice related either to difficulties with the recording of the data or to its interpretation.(ABSTRACT TRUNCATED AT 250 WORDS)

Relations between posterior wall kinetics during diastole and left ventricular filling

M-mode echocardiography reveals an abrupt change between early and late left ventricular posterior wall kinetics during relaxation. No attempt has been previously made to relate this wall kinetic change and transmitral flow rate. In 25 normal subjects, 14 patients with dilated cardiomyopathy (Group 1) and 17 patients with hypertrophic cardiomyopathy (Group 2), M-mode echocardiographic studies were performed on the posterior wall and mitral valve. Transient values of mitral orifice area were calculated and transmitral flow velocities were recorded: area and velocity data yielded transmitral flow rates. Time intervals were determined from mitral opening to peak early area, velocity and flow rate and to posterior wall slope change. An additional group included five patients with a mitral prosthesis. The posterior wall slope change was present when part of the myocardial structures were almost akinetic or when mitral chordae tendineae were absent; slope change appeared as a regional phenomenon in the free wall. In the normal subjects, close values were found for the four time intervals. In the patients with dilated and hypertrophic cardiomyopathy, peak early velocity (95.7 +/- 16.7 and 146.2 +/- 31.4 ms, respectively), peak flow rate (84.7 +/- 18.2 and 137.4 +/- 29.5 ms) and time to slope change (91.4 +/- 18.6 and 133.6 +/- 32.7 ms) were significantly delayed (p less than 0.001) in comparison with peak area (56.6 +/- 9.5 and 84.3 +/- 22.5 ms). Slope change does not indicate the end of the early filling phase but, rather, its transition from acceleration to deceleration. Time to peak velocity or time to peak filling rate must be considered in a relaxation analysis.

[Dipyridamole echocardiography test during the acute phase of lower myocardial infarction]

Two-dimensional echocardiography with intravenous injection of dipyridamole (0.56 mg/kg) was performed in 33 consecutive patients with acute (2 +/- 2 days) postero-inferior myocardial infarction for semiquantitative segmental wall motion analysis. The results were compared with those of coronary angiography which was carried out during the hospital period. After a second evaluation of the recordings the following results were obtained: feasibility: 94 per cent with 85 per cent of segments analysed. Residual ischaemia in the first days of myocardial necrosis was common (70%). The ischaemia was often clinically silent including during the investigation (61%). When pain occurred, it always followed changes in regional wall motion. The dipyridamole test suggested multivessel disease with a sensitivity of 72 per cent and a specificity of 90 per cent, and residual arterial stenosis with a sensitivity of 75 per cent ans specificity of 80 per cent the secondary effects were minor. The main limitation of the test is related to the distinction between pharmacological and physiologic ischaemia. A positive test was associated with lesions justifying myocardial revascularisation (coronary bypass or angioplasty) in 19 out of 23 cases but with a very poor correlation with the topography of the coronary lesions. A negative test indicated arterial occlusion, residual stenosis with extensive myocardial damage or a normal coronary angiogram. Therefore, the dipyridamole echocardiography test may help identify a group of patients with little or no myocardial ischaemia in whom invasive investigations could be deferred; these patients contrast with the group with a positive test indicating residual ischaemia in which the coronary lesions should be documented by coronary angiography.

Abnormalities in myocardial segmental wall motion during lumbar epidural anesthesia

The effect of lumbar epidural anesthesia on myocardial wall motion was compared in two groups of patients using precordial two-dimensional echocardiography (2DE). All patients were scheduled to undergo lower abdominal or peripheral surgery. Group 1 included five healthy ASA PS 1 subjects and group 2 included 10 patients with coronary artery disease (CAD). In all patients 12.5 ml of 2% lidocaine HCl was injected into the lumbar epidural space, and systolic and diastolic blood pressures, and heart rate were continuously monitored. 2DE evaluation was performed before and at 10, 20, 30, and 60 min (T10-T60) after epidural lidocaine injection. The left ventricular wall was divided into 16 segments for parasternal long-axis, short-axis and apical four-chamber views. The wall motion of each segment was graded on a scale from 1 (dyskinesia) to 6 (hyperkinesia), with 5 representing normal motion. A decrease in segmental wall motion greater than or equal to 2 grades was considered indicative of ischemia. Plasma lidocaine and catecholamine levels were measured before and 10, 20, and 60 min after epidural lidocaine injection. Peak plasma lidocaine levels in groups 1 and 2 were 2.79 +/- 1.06 micrograms/ml (mean +/- SD) and 2.58 +/- 1.48 micrograms/ml at 10 min, respectively (NS). Plasma epinephrine and norepinephrine levels were unchanged from baseline. Systolic pressures decreased significantly in group 2 from T10 to T60. Diastolic pressure decreased significantly in the same group from T20 to T60, and in group 1 only at T10. Mean arterial pressure decreased significantly in both groups at T30, without change in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

[Early angioplasty in unstable angina. Results apropos of 60 consecutive patients]

Transluminal coronary angioplasty (TCA) is an attractive means of suppressing ischaemia in patients (pts) with unstable angina. Sixty consecutive pts underwent TCA 6 +/- 2.5 days on average after their admission. Only the ischaemic vessel was dilated (mean stenosis 79 p. 100). Primary success was obtained in 53 pts (88 p. 100) with 31 p. 100 of residual stenosis after TCA. Two pts underwent emergency surgery for extensive dissection; failure of traversing the stenotic segment occurred in 2 pts; 3 pts had myocardial infarction (MI) less than 1 h after TCA, 2 arteries have been recanalized by intracoronary streptokinase with persistence of a satisfactory result of TCA, the 3rd patient had occlusion of a secondary side branch. During their stay in hospital, 2 pts had coronary bypass for recurrent angina. After a follow-up period of 6 to 16 months (mean 10 months) early recurrence of angina was observed in a number of cases (before the sixth month in 7 pts). One pt developed MI during the fourth month. At six month, 10 or the initial 60 pts had undergone coronary bypass, 1 undilated pt was asymptomatic; out of 49 dilated pts (47 with one single TCA), 39 were symptom-free but 6 had a positive exercise test, 7 pts were in class II and one in class IV. At control coronary arteriography (46 pts) restenosis was present in 39 p. 100: 5 new TCA and 2 aorto-coronary bypasses were performed. At one year 28 pts had been followed up: 1 was in class IV and 1 in class II, the others being asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological bridge to cardiac transplantation

From September 1985 to August 1988, 32 patients were referred from various intensive care units throughout Paris for urgent cardiac transplantation or for a mechanical bridge to transplantation. At time of admission, under maximal sympathomimetic therapy, the cardiac index (CI) was 1.81 +/- 0.26 l/min per m2, the pulmonary capillary wedge pressure (PCWP 31 +/- 7 mmHg), systemic vascular resistances (SVR) 2053 +/- 469 dynes s cm-5. In 25, diuresis was less than 25 ml/h. Five were anuric. Prior to any final decision, a new inotropic agent, enoximone, was infused in addition to previous treatment as a 10 min bolus iv 1.5-2 mg/kg every 8 h. In 3, the situation further deteriorated, leading to a Jarvik 7-70 implantation within 12 h. In 29 however, within 3 h, the Cl increased to 2.69 +/- 0.56 as SVR dropped to 1410 +/- 453 and PCWP to 18 +/- 7. Diuresis increased to more than 100 ml/h in all. This permitted an indepth evaluation of the transplant candidates leading to contraindications to transplantation in 16. Nine patients could be weaned off iv enoximone. Four of these are still living (NYHA class III) with a follow up of 6-17 months. In 11, transplantation was performed within 2 days. Four died within a month, 2 with multiple organ failure. One patient died after 5 months. Six are back to normal life, NYHA class I (follow up 10 months-2.5 years). This protocol suggests that in patients with extreme heart failure, immediate survival may be increased by iv enoximone therapy, permitting a better selection of the recipients, more efficient pre-transplantation intensive care and consequently a decrease in the indications for a temporary mechanical bridge to a staged transplantation.

[Dose-response relation of intravenous enoximone in congestive cardiac insufficiency]

Enoximone (MDL 17043) is a new generation inotropic drug which acts by inhibiting phosphodiesterase and is endowed with both inotropic and vasodilator properties. The purpose of this study, which involved 23 patients aged from 18 to 75 years in NYHA class III or IV and with evidence of severe haemodynamic disturbances (cardiac index below 2.5 1/mn/m2, pulmonary wedge pressure above 15 mmHg), was to evaluate the acute haemodynamic responses to doses of enoximone that ranged from 0.25 to 2.50 mg/kg administered by bolus intravenous injection. Heart failure was either of ischaemic origin (6 cases) or idiopathic (10 cases) or due to various causes (7 cases). Group A patients (n = 11) received the drug in low doses (less than or equal to 1 mg/kg) as opposed to group B patients (n = 12) who were given high doses (greater than 1 mg/kg). Results were evaluated from the amplitude and duration of the haemodynamic response at maximum effect time (30 min). The following parameters were measured: cardiac index, pulmonary wedge pressure, systemic vascular resistance, mean arterial pressure and heart rate. Cardiac index and pulmonary wedge pressure were significantly improved in both groups (P less than 0.005): cardiac index +39 p. 100 in group A, +55 p. 100 in group B; pulmonary wedge pressure -36 p. 100 in group A, -48 p. 100 in group B; systemic vascular resistance -46 p. 100 in group B. Heart rate and arterial pressure were not significantly altered. The duration of response was 1 to 3 hours in group A patients and 4 to 8 hours in group B patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Home thrombolysis for myocardial infarction. A multicenter study of the feasibility and evaluation of short-term prognosis]

It has been proven since 1986 that in myocardial infarction the sooner thrombolysis is performed the better. Forty-four patients were selected to enter a double-blind randomized trial in which they received either an acylated plasminogen streptokinase activator complex or a placebo. The injections were given intravenously at home within the first 3 hours (within the first 2 hours in 26 of them), by doctors from Mobile care units. This home treatment in the acute phase made it possible to gain 75 minutes on average, and up to 90 minutes when it was performed by an anaesthetist trained in emergency management. No serious complication, such as haemorrhagic or allergic reaction, occurred, and arrhythmia was no more frequent in the treated group than in the placebo group. Home thrombolysis did not delay admission to a cardiology Intensive Care unit (66 min. versus 64 min). Mean coronary patency was 75 per cent, and up to 82 per cent, in patients treated within 2 hours of the first symptoms. There was no significant difference between areas of reperfused or not reperfused patients in relation to time (P less than 0.08). Diagnosis sensitivity was 100 per cent. Thus, home thrombolysis is feasible and safe when performed by trained emergency medical teams and when criteria for inclusion and exclusion are fulfilled.

Prehospital administration of anisoylated plasminogen streptokinase activator complex in acute myocardial infarction

25 patients have been included in a randomised trial aimed to compare prehospital and hospital administration of anisoylated plasminogen streptokinase activator complex (AP-SAC). Patients were first seen, at home, by a noncardiologist doctor working in a mobile-care unit and were then evaluated for entry into the study. If they had evidence of myocardial infarction lasting for less than 3 hours and if there was no contraindication to thrombolytic therapy they were randomly allocated to APSAC 30U or placebo. They were next referred to an intensive coronary unit (ICU). On arrival in the ICU patients were reevaluated and received APSAC if they had previously received placebo. For 24 patients, diagnosis of myocardial infarction was confirmed. One patient died at home after having received placebo. There was 1 hospital death. At-home injection was made within a median of 124 minutes after the beginning of pain, whereas hospital administration was made after a median of 180 minutes. On a clinical basis reperfusion occurred in 16 out of 21 evaluable patients. Four patients had coronary artery bypass graft surgery and 9 had angioplasty. We conclude that prehospital administration of APSAC is feasible, well-tolerated and is a good way to shorten the delay of thrombolytic treatment in myocardial infarction.

[Exudative enteropathy and residual tricuspid insufficiency following repair of tetralogy of Fallot. Regression following tricuspid valvuloplasty]

Chronic right ventricular failure was observed in a young female operated at 25 years of age for Fallot's tetralogy despite surgical refixation of the patch closing the ventricular septal defect which had previously worked loose. The signs of right ventricular failure were due to severe tricuspid incompetence, confirmed at catheterisation and selective right ventricular angiography. They were associated with major hypoproteinaemia which was not due to urinary loss nor hepatic dysfunction, but which was attributed to an exudative enteropathy. The correction of the valvular defect by valvuloplasty was followed by rapid correction of the biological abnormality. The authors review the relationship between serum proteins and cardiac disease, discuss those cardiac affections with known associations with exudative enteropathy, and also the possibilities of reversing the biological abnormality after surgical cure of the causal cardiac lesion.