Relationships between single-vessel coronary artery obstructions and wall motion dysfunction analyzed by four computer-based methods

We analyzed regional wall motion in 238 patients by using cineangiograms recorded in the 30 degrees right anterior oblique projection. The sample was divided into three groups: a normal group (n = 71), a group with isolated obstruction of the left anterior descending coronary artery and previous anterior myocardial infarction (n = 85), and a group with isolated obstruction of the right coronary artery and previous inferior myocardial infarction (n = 82). Both anterior and inferior groups also had motion abnormality within the corresponding anterior or inferior wall as judged by the qualitative analysis of cineangiograms. Four quantitative methods were compared: a long axis method and a center of mass method using internal reference systems, a method derived from the Stanford model and an area-based method using external reference systems. Normal regional values were determined from the normal group to evaluate the specificity and sensitivity of the methods. The area-based method was the most sensitive in the anterior infarction group, whereas the center of mass method was the most sensitive in the inferior infarction group. We conclude that there is no evidence that any method, among those tested, is superior to others for every expected location of wall motion abnormality.

Logic and empiricism in the selection of antiarrhythmic agents. The role of drug combinations

Advances in investigative techniques of cardiac arrhythmias through invasive procedures (clinical electrophysiology) or through ambulatory electrocardiographic monitoring provide a better understanding of the mechanism responsible for these disturbances and a better assessment of therapeutic efficacy. Yet, it cannot be inferred that the selection of antiarrhythmic agents is orientated in all cases by logical reasoning. Too many factors are unknown, especially those regarding the spontaneous mechanism of initiation of clinical arrhythmias. Patient management very often remains mainly empirical. The problem becomes even more complex when dealing with arrhythmias resistant to single-agent therapy. Drug combinations are then used, often successfully, particularly those combining membrane-stabilising agents with amiodarone or beta-adrenergic blocking agents or combining amiodarone with verapamil. Explanations of the efficacy of these combinations at reduced doses become less certain, but it is more important to achieve efficacy than to understand its mechanism, which does not always amount to a simple increase in plasma drug levels. When attempting to determine the reasons behind the theoretically logical selection of an antiarrhythmic agent, it appears that, in spite of advances in electrophysiology and pharmacology, the logic of this selection owes more to chance than to reason. The problem becomes further complicated when drug combinations are to be used which, in clinical practice, are often the therapeutic solution in difficult cases. Advances made in recent years bring up the question of knowing whether or not logic is near to replacing empiricism.

Comparison of geometrical models for evaluating left ventricular wall motion from cineangiograms

Regional wall motion of the left ventricle (LV) has been analyzed from contrast ventriculograms by using 4 methods based on different geometrical frameworks. Two of them utilize moving internal reference systems, the center of mass (CMM) and the long axis (LAM) methods; the two other ones use fixed external reference systems, the area-based (ABM) and the Palo Alto (PAM) methods. The techniques were applied on a set of 81 patients: 42 were normal and composed the group I; 22 had a single vessel obstruction greater than 75% of the left anterior descending coronary artery (group II) with old necrosis or active ischemia of the LV anterior wall; 17 had a single vessel obstruction greater than 75% of the right coronary artery (group III) with old necrosis or active ischemia of the LV inferior wall. ABM and PAM showed the highest specificities and sensitivities on the studied sample. Therefore, we believe these two methods, of the techniques tested, are the best to quantitate wall motion from cineangiograms.

The potential role of the implantable defibrillator in malignant ventricular arrhythmias

A malignant arrhythmia is one which threatens life and is difficult to predict, prevent or treat. Any arrhythmia which falls into this category is an indication for the implantable defibrillator. The simplicity of this statement is of course deceiving. Transthoracic defibrillation, which for 20 years has been the therapeutic standard, has provided us with the greatest insight and understanding of cardiac arrhythmias. In the long run, the same information will be acquired with the implanted defibrillator. However, technical, medical and economic factors are more complex and will not be resolved in the near future.

[Surgical atrioventricular disconnection in Wolff-Parkinson-White syndrome]

Surgical atrioventricular disconnection is a possible means of treating patients with severe paroxysmal arrhythmias resistant to medical treatment due to the Wolff-Parkinson-White syndrome. Between 1971 and April 1982 we operated 50 patients (38 men and 12 women) with the WPW syndrome. Thirty seven patients were operated for arrhythmias (paroxysmal tachycardia) resistant to medical therapy or with a high risk of sudden death. Thirteen patients had associated cardiac disease with less severe arrhythmias (aortic valve disease: 6 cases; mitral and aortic valve disease: 3 cases; mitral valve disease: 3 cases, and atrial septal defect: 1 case). The causes of paroxysmal tachycardia were atrial fibrillation (13 cases), atrial flutter (2 cases), orthodromic reciprocating tachycardia (30 cases), with associated atrial fibrillation in 9 cases, and with associated atrial flutter in 4 cases. Antidromic reciprocating tachycardia was present in 2 cases. In 3 cases, the preexcitation was a chance finding. Electrophysiological studies performed before and after antiarrhythmic drug administration showed type A WPW (LV preexcitation) in 23 cases, and type B WPW (RV preexcitation) in 20 cases. The ECG was normal in the horizontal plane in 7 cases. The atrioventricular accessory pathway was permeable in both directions in 39 cases; in 9 cases the pathway was permeable only in the retrograde direction and in 2 cases it was permeable only in the anterograde direction. In 7 patients an atrio-hisian short circuit was demonstrated. The site of the accessory conduction pathway was located by epicardial mapping, the first surgical stage, in the left lateral region of the atrioventricular junction (28 cases), in the right lateral region (6 cases), in the posterior septal region (15 cases) (right sided in 4 cases, left sided in 11 cases), and in the anterior septal region (1 case). The accessory pathway (so-called Bundle of Kent) was interrupted by atrioventricular disconnection. Six patients died during surgery, mainly at the beginning of the series; the operative risk is now low (1 death in the last 34 cases: 2,95%). Complete interruption of the accessory pathway was obtained in 38 cases, 1 of which had to be reoperated. Three patients had an incomplete result due to partial interruption or the presence of a second accessory pathway. However, these patients no longer have severe arrhythmias. Surgical section failed in 3 cases, but the patients are now controlled by medical therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

[Mobitz type II suprahisian atrioventricular block : block in the subnodal-suprahisian (NH) zone?]

The electrophysiological properties of the atrioventricular node differ from those of the His bundle. Nodal conduction is always decremential; this is its principal physiological characteristic, and accounts for the fact that almost the only form of block found at this level is Wenckebach block. The His bundle is characterised by an all-or-nothing response and usually blocks in the Mobitz II mode. Wenckebach phenomena have been described in the His Purkinje system, but Mobitz II block has not been reported in the atrioventricular node. Similarly, phase IV paradoxical block is found in the His Purkinje system but has not been described in the atrioventricular node in the absence of vagal phenomena. In addition, the atrioventricular node is very sensitive to the influence of the autonomic nervous system, the His bundle much less so. The first patient had a normal resting electrocardiogram showing sinus rhythm; second degree atrioventricular block was observed when the atrial rhythm was increased by exercise, atropine or atrial pacing. His bundle recordings showed the block to be suprahisian; the blocked atrial potentials were not followed by a His potential, whilst the conducted atrial activity was followed by a normal His potential and a normal HV interval. However, this atrioventricular block was of the Mobitz II and not the expected Mobitz I type, conduction to the ventricles suddenly blocking (with a 3/2 or 2/1 response) when the atrial rate was increased, without obvious lengthening of the PR or AH intervals before the blocked atria.(ABSTRACT TRUNCATED AT 250 WORDS)

[Atrial septal defect type ostium secundum at the age of 40 or more. Apropos of 86 cases with hemodynamic exploration]

The authors propose a haemodynamic classification for ASD, taking into account the very frequent drop in systemic blood pressure which is observed in this disease in elderly people. The authors examine the clinical signs and the clinical course in terms of this haemodynamic classification and they stress the mitral abnormalities and the arrhythmias. 56% of patients were followed up for a mean of 6 years for non-operated patients and almost 10 years for operated patients. The pathophysiology of ASD is discussed. It appears to be very dependent on left ventricular function. The operation needs to be discussed in terms of the haemodynamic findings, even in elderly subjects and in almost asymptomatic subjects.

[Adiastole caused by a secondary cardiac hemochromatosis. Successful treatment with an iron chelating agent]

Severe congestive cardiac failure developed in a few weeks in a 44 year old man who had undergone porto-caval anastamosis for post-hepatitis cirrhosis one year previously and then treated for anaemia by repeated blood transfusion and chronic daily oral iron therapy. Infiltrative, congestive and restrictive cardiomyopathy was diagnosed in the presence of global cardiomegaly, electrocardiographic changes (microvoltage, diffuse ST-T wave changes), echocardiographic appearances (dilatation of the left ventricle, with hypertrophic and hypokinetic walls), and hemodynamic signs of adiastole with equalisation of filling pressures at 15 mmHg and a cardiac index of 1,88 l/min/m2. Cardiac haemochromatosis was confirmed by the laboratory (serum iron: 35 mumol/l; siderophilin saturation: 100 p. 100; serum ferritin: 1854 ng/ml; induced siderouria: 51 mg/24 hours) and histological findings (endomyocardial biopsy showing pigment overload). The absence of a family history, of homozygote A3 antigen, of diabetes, of iron overload on hepatic biopsy one year previously, excluded the diagnosis of familial idiopathic haemochromatosis. A secondary form of the disease was diagnosed on a possible genetic predisposition (heterozygote A3 antigen) and on environmental factors (blood transfusions, iron therapy, cirrhosis, alcoholism and perhaps the porto-caval anastamosis. Cardiac haemochromatosis was cured in this case by iron chelating therapy comprising daily subcutaneous infusions of 2 g of desferrioxamine for 2 months. The cure was confirmed by regression of the signs of clinical cardiac failure and of cardiomegaly, the increase in QRS voltages and the near normalisation of the hemodynamic and laboratory findings.

Subcostal M-mode computerised echocardiography. An alternative or complementary approach to parasternal echocardiography?

Subcostal M-mode echocardiography has been suggested as a method for assessment of left ventricular size and function. Parasternal and subcostal measurements (direct and derived) of left ventricular function were compared in 30 healthy young subjects. We calculated instantaneous left ventricular diameter and wall thickness every 10 ms for both the subcostal and parasternal approaches using a computer program for echocardiographic digitisation and compensation. All variables were filtered to calculate instantaneous first derivative (velocity) and logarithmic derivative (normalised velocity). The program provided normal values for computerised variables of left ventricular function from the subcostal approach. It was found that there was no identity and no correlation or a poor one between subcostal and parasternal left ventricular internal diameters and volumes. The parietal wall thickness was significantly greater using the subcostal approach, and the comparative velocities study showed striking variations between the two approaches, especially in diastole, where the peak lateral wall thinning rate was 20% lower than the posterior thinning rate. We conclude that for a normal and young population, the subcostal and standard parasternal data cannot be used interchangeably for precise studies of left ventricular function. The subcostal approach, however, provides useful complementary information about lateral wall motion.

[The implantable automatic defibrillator. Preventive treatment of sudden death caused by ventricular arrhythmia]

The material and implantation technique of the implantable defibrillator developed by M. Mirowski and used by the authors in 3 patients are described. Through lateral thoracotomy, 4 electrodes are installed, including one patch on the apex of the heart. In case of sustained ventricular arrhythmia the instrument delivers, after less than 30 seconds, a 25 joules shock increased to 30-35 joules if this fails. The results were very encouraging since conversion of severe ventricular arrhythmia was obtained in all 3 patients after the first shock. There was no false detection or inappropriate start. The limitations and indications of the technique are discussed and compared with other treatments of ventricular arrhythmia.

Systemic arterial compliance in patients with non obstructive cardiomyopathy (NOCM), and coronary artery disease (CAD)

Arterial compliance had been estimated in three groups of patients: control, NOCM, and CAD, from analysis of the arterial pressure curve. In the three groups, a simple first order Winkessel model had been validated during normal and post extrasystolic beats. The measured arterial compliance depends mainly on i the diastolic pressure, ii, the mechanical properties of the aorta and major arteries. For the same range of age and diastolic pressure, the arterial compliance was not significantly different in the three groups of patients. Because of the significant variations of the arterial compliance during slight modifications of the diastolic pressure, the lack of difference in the compliance of control, NOCM, and CAD patients may be attributed to similar arterial mechanical properties.

[Reciprocating tachycardia and anterograde conduction by a nodoventricular pathway]

Two patients were investigated for paroxysmal regular tachycardia with left bundle branch block centrifugation. A right-sided nodo-ventricular accessory pathway was demonstrated in both cases at electrophysiological investigation with His bundle recording and atrial and ventricular programd pacing techniques. However, the function of this pathway was different in the two cases. In the first case, there were no signs of an accessory pathway on the surface ECG in sinus rhythm but it could be unmasked by simple right atrial pacing at the same rhythm (widening of the QRS and shortening of HV from 40 to 25 ms). The tachycardias could be only initiated by ventricular extrastimulus. They showed major pre-excitation with left sided delay and a 1/1 atrio-ventricular response. There was no His potential before the ventriculogramme which retained the same configuration throughout the attack. The investigations also suggested the presence of a dual nodal pathway with the accessory pathway connected to the slow pathway. In the second case, the presence of an accessory pathway could be suspected from the appearance of the QRS complex in sinus rhythms. Tachycardia was initiated by an atrial extrastimulus with initially a first complex showing slightly more marked pre-excitation and a distinct His potential before the QRS but with a shorter HV interval than in sinus rhythm. Then the reciprocating tachycardia had appearances of major pre-excitation, left-sided delay and a 1/1 atrio-ventricular response. However, in contrast to the first case, all ventricular complexes were preceded by a His potential and the degree of pre-excitation was variable with a HV interval ranging from 0 to 15 ms. These two cases merit attention because of: --their points in common: nodal duality and an accessory pathway which was not atrio-ventricular (decremental conduction) but nodo-right ventricular, conducting well in the anterograde direction but more or less masked in sinus rhythm; the presence of the accessory pathway was clearly visible during reciprocating tachycardia; --the differences: in the first case the nodo-ventricular pathway formed part of the circuit of the reciprocating tachycardia which was antidromic: descending limb, the slow nodal pathway and then the accessory nodo-ventricular pathway; ascending limb, the His bundle and then the rapid nodal pathway. In the second case, the reciprocating tachycardia was entirely intranodal, the accessory pathway not being involved in the circuit but connected to it in parallel with the normal Hisian pathway.

[Antidromic reciprocating rhythm in Wolff-Parkinson-White syndrome precipitated by a ventricular extrasystole arising at the emergence of the preexcitation pathway]

A 9 year old child was investigated for attacks of wide QRS complex tachycardia occurring exclusively during the daytime and favoured by exercise or stress, with ventricular extrasystoles of the same form occurring between attacks. Endocavitary investigation showed a concealed atrioventricular accessory pathway during sinus rhythm with anterograde 1/1 conduction up to 270/min; retrograde conduction was not so good with block occurring at 175/min. The spontaneous tachycardia was reproduced by catecholamine infusion: it was an antidromic reciprocating rhythm triggered by a ventricular extrasystole of identical form to that of a pure preexcitation complex and to that of the tachycardia complexes. Spontaneous termination of attacks always occurred when conduction from the ventricle to the atria stopped. The attacks could be induced by ventricular extrastimuli when they caused an increment in retrograde conduction time resulting from retrograde conduction up the nodohisian pathway and not the Kent bundle. The tachycardia could also be initiated by atrial extrastimuli providing pure pre-excitation could be obtained. In both cases, retrograde conduction of the nodohisian pathway had to be improved by catecholamines. When the patient was given betablocker therapy the attacks of tachycardia completely disappeared. The association of ventricular extrasystoles and antidromic reciprocating rhythm and their morphological identity suggest that these extrasystoles were in fact automatic activity of the Kent bundle. Escape phenomena as signs of passive automatism have been described in this conditions but, to our knowledge, extrasystoles suggesting an active automatic process have not been previously reported.

Effects of acebutolol on myocardial infarct extension: a randomized electrocardiographic, enzymatic and angiographic study

The effect of acebutolol (1 mg/kg i.v. during the first 2 days followed by a daily oral dose of 600 mg for 3 weeks) was studied in a randomized trial involving 26 patients seen within 24 hours after the onset of uncomplicated anterior transmural myocardial infarction (TMI). Myocardial ischemia and necrosis were evaluated by precordial maps recorded daily for 9 days. Left ventricular pump function and dyssynergy were quantitatively measured on 30 degrees right anterior oblique cineangiograms. Angiography was performed, using the postextrasystolic potentiation technique, within the first 24 hours after TMI and was repeated 1 month later. The basal and postextrasystolic beats from the initial angiography were computerized and compared with those from the final angiogram. MB-CK serum level was measured from blood samples drawn every 3 hours for the first 72 hours. Fourteen patients selected at random received acebutolol within the first 24 hours; 12 subjects were untreated and served as controls. During the 1-month study, no other drugs were administered. Treated patients showed a significant reduction in capillary wedge pressure, extent of hypokinesis and ST-segment elevation; no significant differences were observed in the control group. However, the predictability based on the angiographic data was the same in both groups, and beta blockade did not alter this predictability significantly. Furthermore, no significant difference was found during the final evaluation for treated compared with control patients for any single variable or set of variables. The incidence of infarct extension was not decreased, but only significantly delayed in treated patients. The high variability of the measurements, probably related to the high variability of the pathophysiologic factors, may account for the failure to demonstrate the efficacy of acebutolol.

[Effect of nitroglycerin and N-ethoxycarbonyl-3-morpholinosydnonomine on the walls of large arteries]

Systemic arterial compliance was measured in 20 patients with left ventricular failure due to congestive cardiomyopathy. The method consisted in evaluating arterial compliance by analysing the exponential fall of the arterial pressure curve on a simple visco-elastic model. In the patient group, significant correlations were found between arterial compliance and age (r = 0,64 ; p less than 0,01) and arterial compliance and systolic blood pressure (r = -0,58 ; p less than 0,001). These relationships suggest that arterial compliance depends on the height of the systolic blood pressure and/or the elasticity of the arterial walls. Two groups of patients were defined : Group I (10 patients) given a single oral dose of 7,5 mg of nitroglycerine (Lenitral), and Group II (10 patients) giben a single oral dose of 4 mg N ethoxycarbonyl-3-morpholinosydnonomine (Molsidomine). There was no significant difference in the hemodynamic parameters or arterial compliance between the two groups before administration of these drugs. However, systolic blood pressure was significantly lower (p less than 0,01) and compliance significantly higher (p less than 0,05) after treatment in Group II. In Group I, nitroglycerine caused a significant increase in compliance (p less than 0,01), a significant decrease in systolic (p less than 0,02) and mean blood pressure (p less than 0,05) whilst heart rate, cardiac output and total systemic resistance remained unchanged. In Group II, Molsidomine caused a significant increase in arterial compliance (p less than 0,01), a decrease in systolic (p less than 0,001), diastolic (p less than 0,01) and mean blood pressure (p less than 0,01) and in cardiac output (p less than 0,01), whilst heart rate and total systemic resistance remained unchanged. This study shows that both drugs studied had significant effects on the walls of the large arteries.