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J C Macia

Publications and source records attributed to J C Macia.

14 recordsLinked to original sources

[Ventricular tachycardia due to branch to branch re-entry].

Ventricular tachycardia due to branch to branch re-entry constitutes a rare clinical entity. This circuit is remarkable by the fact that it is made up of the branches or hemi-branches of the bundle of His bifurcation. They occur under specific conditions, with a combination of left ventricular dilatation and atrioventricular or intraventricular conduction defects. They are also very often found in Steinert's disease. A positive diagnosis can sometimes be difficult and relies on a variety of factors. Recording of the His potential shows His activity preceding each ventriculogram, and variations in spontaneous cycles between 2 ventriculograms preceded by variations between the 2 His potentials. Atrial capture without modification of the QRS is possible, but fusion excludes the diagnosis. Drug therapy is only slightly effective, and the best treatment is ablation of the right branch of the bundle of His, which stops the tachycardia definitively.

Bundle of His↗

[Right atrial thrombus--a complication of central venous catheters].

We describe the development, in three days, of a pediculate mass hanging on the right atrial lateral wall in a 39-year-old woman with a subclavian venous catheterization. She was a current smoker and alcoholic but without drug addict. The hypothesis of a non valvular right atrial infective endocarditis was considered at first, but subsequent events directed the diagnosis towards a thrombus, which was resorbed by heparin. We discuss the incidence, the complications, the treatment and the differential diagnosis of thrombus caused by a central venous catheter. The prevention of right atrial thrombus caused by a central venous catheter depends on the position of the central venous catheter tip, either in the superior vena cava or at the superior vena cava-right atrium junction. A more distal position is a frequent source of thrombotic and embolic complications.

Adult↗

[The electrocardiogram of atrioventricular blocks].

Atrioventricular block (AVB) is defined as delay or absence of transmission of one or more atrial excitations to the ventricle. Physiological functional block protects the ventricle against very rapid atrial rhythms. Organic blocks may be transient, due to an acute regressive condition, or chronic, in which case they fall into two groups--permanent blocks or paroxysmal and generally rate-dependant blocks. The blocks are classified in three categories according to whether the atrial activation is delayed, conducted intermittently or not at all. The site of AVB may be determined by His bundle recordings but it may also be deduced from the surface ECG recording. Fundamental studies have questioned the reality of Rosenbaum's phase 3 and 4 blocks and suggest abnormalities of excitability in pathological zones.

Electrocardiography↗

[Diagnosis of narrow QRS complex tachycardias].

Tachycardias with normal QRS complexes (less than 0.12 seconds) may have multiple origins which may be classified in 4 groups: sinusal, atrioventricular nodal, atrioventricular junctional and finally, some ventricular tachycardias arising from near the conduction pathways. The electrocardiographic diagnosis requires analysis of the QRS complexes to detect an eventual irregularity which would suggest atrial fibrillation. When the tachycardia is regular, analysis of the P waves is fundamental (position in the ventricular cycle and morphology). The relationship of the P waves and the QRS complexes enables identification of those forms independent of the AV node and some rare types of tachycardia. Finally, the response to vagal stimulation is essential whether the tachycardia stops, slows down or persists unchanged.

Atrial Fibrillation↗

[Concealed phenomena in electrocardiography].

Concealed phenomena in electrocardiography are events which, having no direct effect on the electrocardiogramme, nevertheless change the following sequences giving rise to very unusual appearances. They are diagnosed by deduction. First of all, there is concealed anterograde or retrograde conduction in the AV node, the consequences of which are either a block or the suppression of an escape rhythm or even facilitation of the transmission of activation. Concealed conduction is also possible in the Bundle of His and its branches, explaining the frequency of dependent blocks and aberrant conduction. There is also concealed conduction in accessory pathways. The second form is concealed rhythms: hisian extrasystoles giving rise to pseudo A-V block, and concealed extrasystoles and parasystoles. With temporary pacing of tachycardia, it has finally been possible to describe "visible" concealed phenomena, not on the surface but on the endocavitary electrogramme.

Arrhythmias, Cardiac↗

[Parasystole].

Parasystole is usually an extrasystolic rhythm which can occur at every level, but particularly in the ventricle. It is admitted that the parasystolic focus is protected from the environing myocardium by an entry block but can manifest itself. Actually, a pure unidirectional block does not exist and the environing myocardium affects the parasystolic rhythm by an electrotonic current which modulates the output. A non-parasystolic complex which occurs prematurely in the parasystolic cycle delays it. Conversely it accelerates the cycle when it occurs late. By this fact, a parasystole pacing is possible and can lead to a fixed coupling. This arrhythmia is frequently unknown and can be experimentally, reproduced by a sucrose gap preparation.

Animals↗

Transcranial Doppler detection of cerebral microemboli during left heart catheterization.

The role of transcranial Doppler ultrasonography (TCD) in individual risk assessment of embolic complications and the development of prevention strategies during coronary angiography remains to be determined. The purpose of this study was to assess the prevalence, time of occurrence and potential significance of microembolic signals (MES) detected with TCD during femoral left heart catheterization. TCD monitoring of the right and left middle cerebral artery was performed in 51 consecutive patients (36 men, 15 women) who were referred for coronary angiography. Percutaneous coronary angioplasty was performed during the same procedure in 16 patients. MES were counted manually during and after (off-line analysis) the procedure. Two patients were excluded from analysis because of the absence of an adequate acoustic temporal window. No neurological event occurred within 24 h in the 49 included patients. MES were detected in all except 2 patients (mean number 17.1 +/- 12.8 per patient), mainly during left ventriculography (38%) and contrast media injection into the coronary arteries (55%), suggesting their gaseous origin. There was no statistically significant association between the number of MES and patient age, cardiovascular history and risk factors, or catheterization results. The presence of coronary artery disease was inversely related to the number of MES (15.8 +/- 0.3 compared to 21.8 +/- 0.2 per patient when a normal angiogram was present; p < 0.05). In conclusion, although asymptomatic microemboli commonly occur during left heart catheterization, the majority of them are probably of gaseous origin, since they occurred predominantly during contrast media injection in this study, and were not related to cardiovascular history or to atheroma risk factors. Because air embolism has been reported to be harmful, attempts to reduce its occurrence during catheter-based procedures could be pertinent.

Aged↗

[Bouveret's tachycardia].

In 1889, in an age preceding the invention of the electrocardiogram, a physician working in the hospitals of Lyon published a remarkable paper on essential paroxysmal tachycardia, of which Bristowe in England and Huppert in Germany had already spoken. The study described 12 cases (including 3 personal cases) of essential paroxysmal tachycardia and 6 secondary tachycardias. They were not all benign, there being 4 deaths out of the 12 cases. From this period on, the term "Bouveret's tachycardia" has been used in France and, with the advances in rhythmology, some have assimilated it to paroxysmal nodal tachycardia. In fact, many forms of paroxysmal essential tachycardia have been recognised at atrial (nodal tachycardia, accessory pathway tachycardia, idiopathic atrial flutter and fibrillation) and ventricular levels (benign or ventricular Bouveret's tachycardia). This is an occasion to review the variety of clinical medicine in the accuracy of a rhythmological diagnosis without forgetting that the electrocardiogram is essential when the recordings are analysable. The term of Bouveret's tachycardia should be retained but, before electrocardiographic analysis, it englobes all paroxysmal tachycardia occurring in healthy hearts, and not only paroxysmal nodal tachycardia.

Diagnosis, Differential↗

[Brugada's syndrome].

Sudden death by ventricular fibrillation is a possible complication of most cardiac diseases but there are some cases of ventricular fibrillation assumed to be idiopathic, in which the most complete aetiological investigations remain negative. Syncope and sudden death by torsades de pointe then ventricular fibrillation of long QT syndromes without cardiac disease are well known: they are purely electric abnormalities, the ionic and genetic bases of which are becoming progressively better known. In 1991, a new syndrome was described by Pedro and Joseph Brugada with particular electrocardiographic appearances (right bundle branch block with ST elevation in leads V1-V3) and episodes of ventricular fibrillation occurring in patients without apparent heart disease. This syndrome, clinically similar to the unexpected cases of sudden death during their sleep of young men from South East Asia or living there, has aroused much interest. Similarly to the congenital long QT syndrome, the concept of a purely arrhythmic abnormality seems apparent and our understanding of the sequence leading from the electrocardiographic changes to the underlying ionic abnormalities initiating them and the genetic disorders which program them, have made great strides.

Adult↗

Successful conservative surgery of acute ascending aortic dissection occurring during coronary angiography.

We reported the case of an acute aortic dissection complicating right guiding catheter manipulation during engagement in the right coronary ostium. Despite absence of hemodynamic deterioration, dissection progressed rapidly from the sinus of Valsalva to the ascending aorta along its entire length. At surgery, performed in emergency, the aorta was not dilated and the aortic wall did not appear pathologic. Therefore conservative surgery was performed, consisting of suture of the aortic tear and incollage of the false lumen, with good immediate and mid-term results.

Aged↗

Aspergillus flavus mitral valve endocarditis after lung abscess.

A 16-year-old male with bone marrow failure due to chemotherapy for recurrent acute lymphoblastic leukemia developed an abscess in the lower lobe of the left lung draining through a bronchogastric fistula, as well as mitral valve endocarditis with large vegetations. After a course of antifungal therapy, the left lobe was removed and the fistula closed. The mitral valve was then replaced, after a failed attempt at valve repair, by a mechanical, double-leaflet prosthesis. Microscopy of the lung and heart specimens disclosed hyphae. Cultures of both specimens on Sabouraud's medium recovered a fungus, which was identified by culturing on Czapek's medium as Aspergillus flavus. Despite further antifungal therapy, fatal embolism developed. The emboli contained the same A. flavus as the valve and lung specimens. This case confirms the grim prognosis of primary Aspergillus endocarditis in immunocompromised patients, and suggests that delayed surgical treatment and the presence of another focus of Aspergillus infection may increase the risk of death.

Adolescent↗

Left ventricular lead insertion using a modified transseptal catheterization technique: A totally endocardial approach for permanent biventricular pacing in end-stage heart failure.

This article describes a new technique of LV lead insertion, using transseptal catheterization performed through the right internal jugular vein, to obtain a totally endocardial biventricular chronic pacing in end-stage heart failure. Three patients with QRS widening (> 180 ms) linked to complete left bundle branch block (n = 2) or right ventricular pacing (n = 1) were included in this preliminary study. Catheterization was performed under fluoroscopy and transesophageal echocardiography guidance. Transseptal catheterization was achieved by puncture of the right internal jugular vein at the base of the neck and by using a Brockenbrough needle, the tip curve of which was more curved than the standard model. A flexible long sheath was advanced in the left atrium through the interatrial septum and then a unipolar electrode was placed easily in the LV. The proximal tip of the LV lead was tunneled from the neck to the subclavian area and connected to the ventricular channel of a dual (n = 1) or simple (n = 2) chamber pacemaker. Efficient acute sensing (V wave amplitude = 13 +/- 3 m V) and pacing (acute pacing threshold = 0. 7 +/- 0.4 V) were obtained in the three patients. Early loss of capture occurred in two patients requiring lead replacement. Functional status dramatically improved in all three patients. At 6-month follow-up, biventricular pacing was maintained in all patients (mean threshold 1.4 V) who were free of clinical embolic event with oral anticoagulation therapy. This modified technique of jugular transseptal catheterization appears promising for the development of left heart pacing.

Aged↗

[Patterns of left ventricular adaptation to arterial hypertension].

The level of arterial pressure is not the sole determinant of cardiac adaptation to hypertension. In order to identify other factors (such as preload as well as neuro-humoral factors) we categorized by M-mode echocardiography, 192 never treated patients with mild to moderate hypertension of short duration, according to values of end-diastolic relative wall thickness (RWT) and left ventricular mass index (LVMI). Mitral regurgitation was excluded in all patients by Doppler echocardiography. Among hypertensive patients, LVMI and RWT were normal in 43% (group 1), whereas 20% had increase RWT with normal LVMI "concentric remodeling" (group 2), 24% had concentric hypertrophy (increase both LVMI and RWT) (group 3) and 13% had increased LVMI with normal RWT (eccentric hypertrophy) (group 4). Results presented as means +/- SD. [table: see text] In addition the acute response after ACE-inhibition (captopril 50 mg) of mean arterial pressure was significantly attenuated in group 4 when compared with group 1. These results suggest that the effect of arterial pressure on the heart may be modulated by volume overload (low PRA and high CI) in hypertensive patients with eccentric LV hypertrophy with normal LV function.

Adaptation, Physiological↗