Manifestaciones eléctricas de alteraciones miocárdicas asociadas a preexcitación ventricular / On the electrical manifestations of some heart diseases associated with ventricular preexcitation

Electro-Vectorcardiographic curves, corresponding some heart diseases, must be analyzed in the light of the ventricular depolarization sequence, as well as on the heart's position and rotation. A more than 30-msec interval between the end of the initial slurring (delta) and the vertex of the R wave in the left unipolar leads or the main axis of the vectorcardiographic ventricular curves, allows us to infer the coexistence of left ventricular hypertrophy. On the other hand, segmental irregularities or distorsions of the electric curves suggest the presence of a limited myocardial zone unable to be activated. Extensive or multiple deformations of these curves are more suggestive of a diffuse myocardial damage. Sometimes signs of preexcitation, due to a pharmacological action, can also appear.

[On the electrical manifestations of some heart diseases associated with ventricular preexcitation]. / Manifestaciones eléctricas de alteraciones miocárdicas asociadas a preexcitación ventricular.

Electro-Vectorcardiographic curves, corresponding some heart diseases, must be analyzed in the light of the ventricular depolarization sequence, as well as on the heart's position and rotation. A more than 30-msec interval between the end of the initial slurring (delta) and the vertex of the R wave in the left unipolar leads or the main axis of the vectorcardiographic ventricular curves, allows us to infer the coexistence of left ventricular hypertrophy. On the other hand, segmental irregularities or distorsions of the electric curves suggest the presence of a limited myocardial zone unable to be activated. Extensive or multiple deformations of these curves are more suggestive of a diffuse myocardial damage. Sometimes signs of preexcitation, due to a pharmacological action, can also appear.

[The Einthoven's electrocardiograph after 100 years]. / A los 100 años del electrocardiógrafo de Einthoven.

The initial studies about the "irritability" of animal tissues by iatrophysic and iatromechanic scientists are reviewed. These studies led to discover the so called animal electricity envisaged by Luigi Galvani in the XVIII century and demonstrated by Carlo Matteucci and his followers in the XIX. Beginning with the Galvani's "reoscopic" frog, which allowed to assess the electrical current in a qualitative sense, it was possible to arrive, at the beginnings of the XX century, to the string electrocardiograph presented by Willem Einthoven in 1901. This opened the way that led to fabrication of ever more sophisticated instruments until the present systems of endocardial mapping by magnetic technology or by multipolar catheters, which permit to quickly identify the site of origin or the spreading ways of a tachycardia for their ablation with radio-frequency. Intracardiac echocardiography is also employed to define the anatomy of right atrium, during intracardiac cartography, in order to establish the most adequate sites for ablation. On the other hand, a logic i.e. rational, method for the interpretation of results from the electrical exploration of the heart has been developed. This one was introduced by Frank N. Wilson in Ann Arbor and has been fittingly applied by Demetrio Sodi Pallares in Mexico. Important diagnostic advances and notable therapeutic inferences have been derived from these latter developments.

[Trans-surgical ablation of atrial flutter in patients treated with closure of atrial septal defect. Pilot project]. / Ablación transquirúrgica del flutter atrial en pacientes sometidos a cierre de comunicación interauricular. Estudio piloto.

Atrial flutter is one of the most common arrhythmias in patients with atrial septal defect, after surgery 14% of patients can develop it and may be associated with high morbidity. In this study we performed prophylactic and therapeutic ablation of atrial flutter during atrial septal closure surgery drawing 4 lines; line 1, isthmus cavo-tricuspid, the area between the inferior vena cava and the tricuspid ring; line 2, the area between coronary sinus ostium and inferior vena cava; line 3, the area between tricuspid valve annulus and coronary sinus ostium; and line 4, the area between lateral atriotomy and atrial septal defect. Twenty-one patients were included, 6 (28.5%) patients had atrial flutter before surgery and 15 (71.4%) were in sinus rhythm. There were no new cases of atrial flutter, but at six months follow up 2 (33.3%) patients recidivated with atrial flutter. One patient developed high degree atrio-ventricular block and a pacemaker had to be implanted. Older age at the time of surgery and high systolic pulmonary pressure were significantly higher in those patients with atrial flutter before surgery and in patients with arrhythmias recurrence. Ablation of atrial flutter during atrial septal closure surgery can be a good option for the treatment and prevention of atrial arrhythmias, but more studies are still needed.

The rational approach to the electrical exploration of the heart.

A rational approach is inevitable in any scientific activity. Such an approach is opposed not only to irrationality, at all inadmissible in scientific thinking, but also to empiric reasoning. Many years ago, Sodi Pallares introduced the rational method in the electrical exploration of the heart based on experimental findings obtained in his laboratory. This method has progressively been accepted and used with good results for diagnoses and has led to logical therapeutic inferences. To confirm the results from the logical interpretation of electrical tracings, we present some examples of its application in three fields: arrhythmias, myocardial infarction, and left ventricular hypertrophy. In the studied cases--two with tachycardia, one with a posterior infarct, and two with left ventricular hypertrophy--a very satisfactory correlation has been observed between the electrical exploration findings and those obtained through direct examination of the heart. It is desirable, and even profitable, to analyze in this way the electrical tracings to get as close as possible to reality, rejecting the stereotyped aspects of a simple routine exploration, which often induce errors and lead to some fallacious asseverations.

[Sudden death in intermittent Wolff Parkinson White syndrome]. / Muerte súbita en el síndrome de Wolff Parkinson White intermitente.

Sudden death is a rare condition in asymptomatic patients with asymptomatic intermittent Wolff Parkinson syndrome (WPW); for this reason it is believed that these patients should not undergo to radiofrequency ablation. We report an asymptomatic 44 year old man who developed ventricular fibrillation with a pre-excited RR interval less than 200 msec during atrial fibrillation, as a first manifestation of WPW syndrome. The Holter monitoring showed intermittent pre-excitation at low heart rate (70 bpm). During the electrophysiological study a successfully radiofrequency catheter ablation of a right posteroseptal accessory pathway was performed. We concluded that intermittent pre-excitation may not be used to identify patients who are at risk of sudden death. Radiofrequency catheter ablation should be recommended in those patients with a very high success rate, and a low incidence of serious complications.

[Usefulness of superficial electrocardiogram in the diagnosis of narrow QRS tachycardias: correlation with intracavitary electrocardiograms]. / Utilidad del electrocardiograma de superficie para el diagnóstico de las taquicardias con QRS estrecho: correlación con los registros intracavitarios.

INTRODUCTION AND OBJECTIVES: The electrocardiogram is an important tool to diagnose tachycardias. The sequence of analysis of the superficial electrocardiogram was evaluated for the diagnosis of supraventricular tachycardias with narrow QRS complexes (<= 110 ms) establishing correlation with intracavitary electrograms. PATIENTS AND METHODS: Between November 1996-October 1998, 674 electrophysiological studies were revised. 173 cases were selected, during which supraventricular tachycardias were inducted. In each study, the superficial electrocardiographic leads were correlated with the intracavitary electrograms during tachyarrhythmias. The P waves were located with respect to the R waves, the R-T or T-R' intervals, and the T waves, and relations between atrioventricular and ventriculoatrial intervals were established with the P-R' and R-P intervals, respectively, in the electrocardiogram. RESULTS: 107 patients were female. Upon locating the P waves in the electrocardiogram, in each supraventricular tachycardia we observed: a) P waves coincided with the R waves: 30 typical nodal reentries; b) P waves between R and T waves: 95 orthodromic atrioventricular reentries, 27 nodal reentries, 1 atrial tachycardia; c) P waves between T and R' waves: 4 nodal reentries, 5 orthodromic atrioventricular reentries, 7 atrial tachycardias, and

Endoscopic ligature of the sphenopalatine artery for severe posterior epistaxis.

OBJECTIVE: To present our experience with endoscopic ligature of the sphenopalatine artery in the treatment of severe posterior epistaxis of patients who had previously undergone conservative procedures. METHODS: Eleven patients with severe posterior epistaxis were treated during a 25-month period with an endoscopic ligature of the sphenopalatine artery. The basic principle of the surgical technique is to identify the branches of the sphenopalatine artery through an endoscopic endonasal approach and to apply a titanium clip under direct vision. RESULTS: The endoscopic ligature of the sphenopalatine artery was performed unilaterally in 10 patients and bilaterally in 1 patient, with a total of 12 ligatures. It was possible to identify the sphenopalatine artery in all cases with a successful outcome using this surgical technique alone. CONCLUSION: Endonasal endoscopic ligature of the sphenopalatine artery has been an effective surgical technique for treating severe posterior epistaxis.

[Radiofrequency ablation and simultaneous insertion of an Amplatzer device in a patient with atrial septal defect and nodal reentry tachycardia]. / Ablación con radiofrecuencia y colocación simultánea de un dispositivo Amplatzer en un paciente con comunicación interatrial y taquicardia por reentrada intranodal.

The association of AV nodal reentry tachycardia and interatrial septal defect has not been described previously. This article reports a 47-year-old woman with an atrial septal defect (ostium secundum) and history of palpitations without documental tachycardia through resting and ambulatory electrocardiography. Rapid atrial pacing under the influence of isoproterenol, during an electrophysiology study, elicited and AV nodal reentry tachycardia of the common type. Successful radiofrequency catheter ablation was performed targeting the slow pathway. Immediately an Amplatzer device was used for closure of the septal defect. Both procedures were successful and without complications. What makes this case unusual is that both interventional procedures were performed during the same session.

[Ventricular tachycardia associated with isolated right ventricular dysfunction as indicator of arrhythmogenic dysplasia of the right ventricle]. / Taquicardia ventricular asociada a disfunción del ventrículo derecho aislada como indicador de displasia arritmogénica del ventrículo derecho.

We report the case of a 21 year-old patient with arrhythmogenic right ventricular dysplasia manifested by episodes of QRS tachycardia greater than 0.12 sec and isolated dysfunction of the right ventricle. The patient treated with amiodarone however, the tachycardia episodes persisted. The surface electrocardiogram showed left branch block with the axis down, which suggested a right ventricle origin, and was therefore considered an arrhythmogenic dysplasia. Echocardiography and cardioangiography showed alterations in the anatomy of the outflow tract of the right ventricle. A myocardial gammagraphy revealed no perfusion alterations. The endomyocardial biopsy showed perivascular fibrosis. An electrophysiology study was performed, stimulating the outflow tract of the right ventricle, which induced two types of ventricular tachycardias, one of them identical to that recorded clinical. The patient was treated with sotalol, and has been being free of ventricular tachycardia episodes for 18 months of follow-up. We consider that this entity should be studied in a systematic way in those patients with ventricular tachycardia originated in the outflow of the right ventricle and with primary cardiac illness.

On the electrocardiographic diagnosis of biventricular infarctions.

To diagnose posterior and anterior biventricular infarctions it is necessary to record from right and left thoracic and high abdominal unipolar leads. These supplementary leads are dependable, can be repeated as many times as needed and show the evolution from signs of myocardial injury to those of dead tissue (Q waves of 0.04 sec or more). This electrocardiographic evolution increases the diagnostic value of the electrical exploration, since the injury current can be observed also in other conditions. The diagnosis of right ventricular infarction can be established even in the presence of RBBB. Signs of a dead zone in the free right ventricular wall are more frequently observed in posterior biventricular infarctions than in anterior ones. In these cases, the signs of subepicardial injury are more accentuated in the right thoracic unipolar leads than in V3, indicating anterior right ventricular involvement. These signs are also observed in experimental studies made in animals. This electrocardiographic exploration opens a wide field for the diagnosis of myocardial infarction, particularly in biventricular involvement, including old myocardial scars, and in discarding signs of pericarditis manifested only by the upward displacement of the ST segment. A review of the medical literature concerning diagnosis of biventricular infarctions is presented.

Radiofrequency catheter ablation for the treatment of supraventricular tachycardias in children and adolescents.

We report our experience in radiofrequency catheter ablation between April, 1992 and December, 1998, in which we treated 287 patients less than 18 years of age (mean 14.3 +/- 3.1 years) with supraventricular tachycardia. Accessory, pathways were the arrhythmic substrate in 252 of the patients (87.8%), the patients having a total of 265 accessory pathways. Atrioventricular nodal re-entry was the cause of tachycardia in 26 patients (9.0%), while atrial flutter was detected in the remaining 9 patients (3.1%). We were able successfully to eliminate the accessory pathway in 236 patients (89%), but 25 patients had recurrent arrhythmias. Ablation proved successful in all cases of atrioventricular node re-entry tachycardia, the slow pathway being ablated in 25 patients, and the fast pathway in only one case. Recurrence of the arrhythmia occurred in three patients (11.5%). We performed a second ablation in these children, all then proving successful. The ablation was successful in all cases of atrial flutter, with one recurrence (11.1%). Overall, therefore, ablation was immediately successful in 271 patients (94.4%), with a recurrence of the arrhythmia in 29 cases (10.7%). The incidence of serious complications was 2.09%. There was one late death due to infective endocarditis, 3 patients suffered complete heart block, 1 had mild mitral regurgitation, and 1 patient developed an haematoma in the groin. We conclude that radiofrequency catheter ablation can now be considered a standard option for the management of paroxysmal supraventricular tachycardias in children and young adults.

[Focal atrial fibrillation treated with radiofrequency]. / Fibrilación auricular focal tratada mediante radiofrecuencia.

Atrial fibrillation is usually thought to be due to multiple circulating reentrant wavelets. From previous studies, a focal mechanism is considered to be very unlikely. This focal source could be successfully treated by radiofrequency catheter ablation. We report a patient without structural heart disease, but with multiple episodes of syncope and palpitations related to atrial tachycardia and atrial fibrillation. Electrophysiological study demonstrated that all atrial arrhythmias were due to one focus located in the left atrium at the ostium of the left superior pulmonary vein that was successfully treated with the use of a mean of three radiofrequency pulses, without complications. The pulmonary veins are an important source of ectopic beats, initiating frequent paroxysm of atrial fibrillation. These foci respond to treatment with radiofrequency ablation.

[Is the concept of "jumping wave" still valid?]. / Es aún válido el concepto de "salto de onda"?

UNLABELLED: The concept of the "jumping wave" phenomenon, i.e. of the slow and difficult passage of activation fronts from one septal mass to the other through an "intraseptal barrier", is derived from experimental studies of the Mexican School of Electrovectorcardiography. OBJECTIVE: To confirm the existence of histologically bipartite interventricular septum and of the electric independence of both septal masses. METHODOLOGY: We examined the histological characteristics of both septal masses in rat, canine, and human hearts. We also analyzed the morphological and chronological data of intracavitary records in the presence of different degree proximal blocks, comparing these findings with those obtained when peripheral blocks existed. RESULTS: We found a medial, longitudinal band between the two septal masses in animal as well as in human hearts. The analysis of intracavitary electric records confirmed a slow and difficult transmission of the activation fronts from one septal mass to the other, in the presence of proximal blocks and ventricular arrhythmias. Morphological and chronological changes of intraventricular complexes could not be explained if the septal activation process were of syncytial type. CONCLUSIONS: Results of this study firmly support the validity of our approach to the septal activation process in the presence of ventricular conduction disorders and arrhythmias. This approach helps to detect the possible coexistence of dead septal tissue.

[Permanent rhythm and conduction disorders in patients surgically treated for atrial septal defect]. / Trastornos del ritmo y de la conducción permanentes en pacientes operados de comunicación interatrial.

Atrial septal defect (ASD) represents a congenital heart disease with good prognosis, however, atrial arrhythmias are well-documented complications. A retrospective study was performed to assess the prevalence, types and risk factors of arrhythmias in patients with ASD after surgical correction. 920 patients were analyzed retrospectively; cases with complex congenital heart disease or another systemic alteration conditioning atrial rhythm disturbances were excluded. 460 patients with ASD corrected by surgery were followed at least for six months after the procedure. 29.3% of patients were male and 70.7% female. Direct closure was performed in 63%, pericardial patch was installed in 27%. 29 patients (6.3%) had conduction and rhythm disturbances before surgery, the most common arrhythmias were atrial flutter (34.5%), first degree A-V block (31%) and low right atrial rhythm (27.6%). Six months after atrial defect closure, 65 patients (14.13%) had arrhythmias, 44.6% atrial flutter, 20% ectopic atrial rhythm, 10.8% sick sinus syndrome. The risk of atrial arrhythmias was related to age at surgical repair, pulmonary hypertension and atrial arrhythmias before surgery.

[Complete congenital heart block. Its natural history and evolution]. / Bloqueo auriculoventricular completo congénito. Historia natural y evolución.

This study describes the natural history and evolution of 67 patients with congenital auriculoventricular heart block admitted in the Instituto Nacional de Cardiología "Ignacio Chávez", Mexico, D.F. from 1944 to 1998. There were 35 (52%) females and 32 (47%) males, with mean follow up period of 93.7 +/- 104 months. Most of the patients were without structural cardiovascular disease (90%). The most frequent symptoms were dyspnea and syncope. Electrocardiograms showed a ventricular heart rate of 42.2 +/- 9 beats/minute. 85.7% of patients had a supra-Hisian complete heart block. In 31% of patients a pacemaker was implanted because syncope. Overall mortality was 4.4% and malignant ventricular arrhythmias were the principal contributors. Risk factors for mortality identified in this study were junctional escape rhythm lower than 50 beats/minute, inappropriate chronotropic response during exercise, R-R interval prolongation at night, enlargement of cardiac chambers, depressed left ventricular ejection fraction and prolonged QT interval. In all of these conditions we recommend permanent pacemaker implantation.