Manejo de la insuficiencia cardíaca mediante resincronización biventricular con marcapasos / Management of heart failure by resynchronised biventricular pacing

El tratamiento farmacológico de la insuficiencia cardíaca no ha mejorado aún los síntomas y la calidad de vida de los pacientes con alguna cardiopatía terminal. La búsqueda de nuevas opciones de tratamiento para la insuficiencia cardíaca han permitido la introducción de la estimulación con marcapasos como un recurso más para estos enfermos. La falta de sincronía entre ambos ventrículos en casos de insuficiencia cardíaca grave tiene un papel importante en la falla cardíaca. Por ello se ha propuesto a la estimulación biventricular sincrónica con marcapasos como una medida terapéutica efectiva en el tratamiento de la falla cardíaca en pacientes con retraso de la conducción interventricular en el electrocardiograma de superficie (AU)

[Treatment of ventricular tachycardia]. / Tratamiento de la taquicardia ventricular.

Evaluation and management of postinfarct ventricular tachycardia has changed dramatically in the past two decades. The introduction of the implantable cardioverter defibrillator has played a major role in this change, alternating both, the purpose of the patients evaluation and treatment options. Episodes of sustained ventricular tachycardia can occur in a variety of clinical settings; the most common of which is the patient who has suffered a myocardial infarction. In this paper, I explore the causes and effects of some of these changes and review current strategies, specially the radiofrequency catheter ablation, for the management of the patient with postinfarct ventricular tachycardia.

[Electrocardiographic changes during stress test in a patient with "Brugada syndrome"]. / Alteraciones electrocardiográficas durante el esfuerzo en un paciente con "síndrome de Brugada".

We report a 28 year old man with the Brugada syndrome characterised by an electrocardiographic pattern of a right bundle branch block and an ST segment elevation in the right precordial leads as well as syncope. During an exercise test, we observed a normalization of the ST segment in V2+ while in the postexercise phase, the ST segment elevation in the right leads was established. This is the first case reported of the Brugada syndrome in Mexico, with spontaneous changes on the EKG masked during exercise and apparent during postexercise phase.

[Experience in 1,500 patients undergoing radiofrequency ablation in the treatment of tachycardias]. / Experiencia en 1,500 pacientes sometidos a ablación con radiofrecuencia en el tratamiento de las taquicardias.

Several reports have demonstrated that radiofrequency catheter ablation provides effective control of a variety of supraventricular and ventricular tachycardias. This report details the results of radiofrequency catheter ablation in 1500 consecutive patients with a wide variety of supraventricular and ventricular tachycardias treated in the Instituto Nacional de Cardiología "Ignacio Chavez", between April 22, 1992 until December of 1999. Tachycardias were associated with the presence of an accessory pathway in 987 patients (65.8%). Dual accessory pathways were present in 24 patients giving a total of 1,012 accessory pathways. The mechanism of the arrhythmia was atrioventricular nodal reentrant tachycardia in 321 patients (21.4%). Ablation of the reentrant circuit of atrial flutter within the right atrium was attempted in 109 (7.2%) patients and a primary atrial tachycardia in 13 patients (0.8%). Atrioventricular node ablation and permanent pacemaker implantation were performed in 26 patients (1.7%). Finally we performed radiofrequency catheter ablation in 37 (2.4%) patients with ventricular tachycardia. Radiofrequency catheter ablation was successful in 908 of 1012 (89.7%) patients with accessory pathways with a complication rate of 10 (0.98%) and a recurrence rate of 92 (9%). AV nodal reentry was successfully abolished in 319 of 321 patients by selective ablation of the slow pathway in 297/321 (92.5%) patients and the fast pathway in 22/24 (92%) patients. The complication rate of this group was 8/321 (2.4%) with a recurrence rate of 34 patients (10.5%). The reentrant circuit of atrial flutter was ablated successfully in 86 of 109 (76.8%) patients with a recurrence flutter in 14 (12.8%) patients. Five of 13 (38.4%) cases of primary atrial tachycardia were successfully ablated. Complete AV block was achieved in 26 of 26 (100%) patients with atrial fibrillation or flutter treated by AV nodal ablation. The procedure was successful in 28 of 37 (75.6%) patients with fascicular ventricular tachycardia. The results of this series of patients demonstrates the safety and efficacy of radiofrequency ablation for the treatment of a wide variety of taquicardias with high rate of success 1375 of 1500 patients (91.6%), with 142 recurrences (9.4%), 15 complications (1%), and no mortality.

[Malfunction of a permanent pacemaker]. / Disfunción de marcapaso definitivo.

Forty years have gone by since the first pacemaker implant; this fact had strong impact in the life of thousands of persons. The objective of this work is to report the case of definitive pacemaker malfunction with epicardiac lead and review the literature concerning the important aspects of the causes and diagnosis of pacemaker malfunction. We consider that physicians dealing with patients implanted these devices must be prepared to diagnose and treat them adequately.

[Radiofrequency ablation in the treatment of tachyarrhythmias. Experience concerning 1,000 consecutive patients]. / Ablación con radiofrecuencia en el tratamiento de las taquiarritmias. Experiencia en 1000 pacientes consecutivos.

Several reports have demonstrated that radiofrequency catheter ablation provides effective control of a variety of tachyarrhythmias. This report details the results of radiofrequency catheter ablation in 1,000 consecutive patients with a wide variety of tachyarrhythmias treated in the Instituto Nacional de Cardiología "Ignacio Chavez". Tachyarrhythmias were associated with the presence of an accessory pathway in 700 patients (70%). Dual accessory pathways were present in 21 patients, giving a total of 722 accessory pathways. The mechanism of the arrhythmia was AV nodal reentrant tachycardia in 204 patients (20.4%). Ablation of the reentrant circuit of atrial flutter within the right atrium was attempted in 56 (5.6%) patients and a primary atrial tachycardia in five patients (0.5%). AV node ablation and permanent pacemaker implantation were performed in 17 patients (1.7%). Finally we performed radiofrequency catheter ablation in 22 (2.2%) patients with ventricular tachycardia. Radiofrequency catheter ablation was successful in 630 of 700 (90%) patients with accessory pathways with a complication rate of 9/700 (1.2%) and a recurrence rate of 73 (12.4%). AV nodal reentry was successfully abolished in 190 of 204 (93%) patients by selective ablation of the slow pathway in 168/180 (93.3%) patients and the fast pathway in 22/24 (92%) patients. The complication rate of this group was 7/204 (3.4%) with a recurrence rate of 30 patients (14.2%). The reentrant circuit of atrial flutter was ablated successfully in 41 of 56 (73%). Four/five (80%) of patients with primary atrial tachycardia were successfully ablated. Complete AV block was achieved in 17/17 patients with atrial fibrillation or flutter treated by AV nodal ablation without complications or recurrence. The procedure was successful in 17/22 (77%) of patients with ventricular tachycardia. The results of this series of patients demonstrate the safety and efficacy of radiofrequency ablation for the treatment of a wide variety of tachyarrhythmias with high rate of success 899/1,000 (89.9%) and with an 1 1.8% of recurrence, low risk of complications (1.5%) and no mortality.

[The familial incidence of accessory atrioventricular pathways (the pre-excitation syndrome)]. / Frecuencia familiar de vías accesorias atrioventriculares (síndrome de preexcitación).

Cases of familial preexcitation syndrome represent a specific subgroup of patients that may result from diverse mechanisms: failure in development and genetic predisposition are the main mechanism involved. We determined the prevalence of this syndrome in first degree relatives of patients with proved accessory pathways by electrophysiologic study and compared such prevalence with the general population (0.15%). In five out of 469 patients (1.06%) we found an accessory pathway in one or more member of their family. Only 6 out of 3752 had preexcitation (0.15%); this prevalence was similar to the general population (P = NS). The identification of family members with this syndrome may be incomplete because we only chose for the study symptomatic patients. We did not observed multiple pathways and in one case we found atrial septal defect. Our data demonstrated familial preexcitation in five families suggesting hereditary predisposition.

Infectious endocarditis in pacemaker endocardial leads: report of three cases.

Three cases of endocarditis affecting endocardial leads of permanent pacemakers are presented with a review of the literature. Vegetations were identified using transesophageal echocardiography. Infection of pacemaker leads is far less common than infection at the site of the pulse generator with greater morbidity and mortality and generally requiring surgical removal of both electrodes and power source. The most frequent infective agents are stahylococcus varieties.

[Double tachyarrhythmia: left anterior fascicular ventricular tachycardia associated with atrial flutter and fibrillation. Report of a case]. / Doble taquiarritmia: taquicardia ventricular fascicular anterior izquierda asociada a fibrilación y flutter auriculares. Reporte de un caso.

A patient with episodes of palpitation in whom the electrocardiogram showed a right bundle branch (RBBB) configuration and right axis deviation underwent electrophysiologic study and radiofrequency ablation. Left ventricular endocardial mapping during ventricular tachycardia (VT) identified the earliest ventricular activation in the anterolateral wall of the left ventricle. The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 47 mseg, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. The stimulus to QRS time was equal to the Purkinje potential-QRS time. Several radiofrequency lesions were applied in this region, one of them resulted with termination of the tachycardia. Following delivery of this lesion the ventricular tachycardia couldn't be induced either at baseline or during isoproterenol infusion. During VT, atrial fibrillation and atrial flutter were observed, cardioversion was performed reverting to sinus rhythm.

Kearns-Sayre syndromes an absolute indication for prophylactic implantation of definitive pacemaker?

Kearns-Sayre syndrome is a mitochondrial cytopathy characterized by chronic progressive external ophthalmoplegia, retinitis pigmentosa and heart block, the last of which determines the survival of these patients. The case of a 23 year old man with Kearns-Sayre syndrome, conduction disturbances and mitral valve prolapse is presented. The characteristics of this syndrome are described and the criteria for prophylactic installation of a pacemaker discussed.

[Radiofrequency ablation in the treatment of supraventricular arrhythmias in pediatrics. Experience with 203 consecutive patients]. / Ablación con radiofrecuencia en tel tratamiento de las arritmias supraventriculares en pediatría. Experiencia en 203 Pacientes consecutivos.

We report the results of radiofrequency catheter ablation in 203 patients under 18 years of age with supraventricular tachyarrhythmias between April 1992 and June 1997. The presence of an accessory pathway caused the tachyarrhythmia in 181 patients (89.1%) with a total of 187 accessory pathways; atrioventricular nodal reentry caused the arrhythmia in 18 patients (8.8%) and atrial flutter in only 4 patients (1.9%). We eliminated the accessory pathway in 171 patients (91.4%), 23 patients showed recurrence of the tachycardia and we had complications in 4 patients (2.1%). The procedure was successful in the treatment of the atrioventricular nodal reentry in the 18 cases, with ablation of the slow pathway in 17 cases and in only one patient of the fast pathway, one patient showed total A-V block, and recurrence of the arrhythmia in 3 cases (16.6%). Finally the procedure was successful in the 4 cases of atrial flutter with one recurrence (25%). In the total of the series, the radiofrequency catheter ablation was successful in 193 patients (95%), with recurrence of the arrhythmia in 27 cases (13.3%) and with complications in only 5 patients (2.6%). Radiofrequency catheter ablation is a safe and effective procedure for the definitive treatment of supraventricular tachyarrhythmias in children.

[The effectiveness and safety of d,l-sotalol in the ambulatory treatment of atrial fibrillation and flutter]. / Eficacia y seguridad del d,l sotalol en el tratamiento ambulatorio de pacientes con fibrilación y flutter atriales.

Data on short and long term efficacy and safety of d,l sotalol in patients with atrial fibrillation or atrial flutter is limited. The aims of this study were to (1) assess the antiarrhythmic efficacy of d,l sotalol maintaining normal sinus rhythm in patients with refractory atrial fibrillation or flutter, (2) evaluate the efficacy of d,l sotalol in preventing recurrences of paroxysmal atrial fibrillation or flutter, (3) evaluate the control of ventricular rate in patients with paroxysmal or refractory atrial fibrillation or flutter unsuccessfully treated with other antiarrhythmic agents, (4) determine predictors of efficacy (5) assess the safety of d,l sotalol in this setting. Two hundred patients with chronic or paroxysmal atrial fibrillation or atrial flutter or both, who had failed one to six previous antiarrhythmic drug trials were treated with d,l sotalol 80 to 440 mg/day orally. Fifty four percent was female, age 47 +/- 16 years (range 7-79), follow up period 7 +/- 7 months (range 1 to 14 months), 79% of patients had the arrhythmia for more than one year. The atrial fibrillation in 37.5% of patients was chronic and paroxysmal in 23.5. The atrial flutter was chronic in 31% of patients and paroxysmal in 8%. Eighty two percent of patients was in functional class I (NYHA) and 82% had cardiac heart disease: left atrial (LA) size 44 +/- 10 mm, right atrial (RA) size 37 +/- 7 mm and left ventricular ejection fraction (LVEF) 58 +/- 8%. Total success was achieved in 58% of patients (atrial fibrillation 40% and 18% in atrial flutter), partial success in 38% (atrial fibrillation in 18% and 20% in atrial flutter) and 4% of patients failure. It was p < 0.07 when compared total success vs partial success among atrial fibrillation and atrial flutter groups. Patients with cardiac heart disease responded worst (p = 0.10) to the drug than those without it, specially if the heart was dilated. We concluded that d,l sotalol has moderate efficacy to convert and maintain normal sinus rhythm, as well as it acts controlling paroxysmal relapses and ventricular heart rate.

[Radiofrequency ablation of type I atrial flutter: combination of electrophysiological and anatomical techniques]. / Ablación con radiofrecuencia del flutter atrial tipo I: combinación de las técnicas electrofisiológica y anatómica.

Atrial flutter type I (FLA) is one of the most common arrhythmias found in clinical practice. Reentry into the right atrium (AD) is the mechanism of this arrhythmia. The reentry mechanism has critical sites where radiofrequency (RF) can act blocking the circuit. Both, electrophysiological and anatomical approaches using RF to FLA have demonstrated a success rate above 80%. Our group combined both techniques treating 35 patients with FLA type I (22 men and 13 women), with mean age of 40.8 +/- 15 years old (range 9-70). In 21 patients (60%) this arrhythmia was associated with cardiopathy. All patients had failed to respond to different antiarrhythmic therapy. The success rate was 82.8% (29/35). When compared failure vs success we observed that patients who failed were older (51.8 vs 38.5 years old, p < 0.05), had structural cardiopathy (83.3% vs 55.1%, p = NS), had FLA type I with P waves with shorter cycle length (195 vs 254 ms, p = 0.052), had the arrhythmia chronically (129.6 vs 68.1 month, p = NS), had great left atrium diameter (41.2 vs 36.7 mm, p = 0.052) and frequently had been associated with atrial fibrillation (33.3% vs 3.4%, p = 0.02). There were no complications. Six (20.6%) patients reverted to FLA. We followed our patients during mean time 8.37 +/- 8.8 months (1-36). Our results support the notion that FLA type I can be treated with high percentage of success and low risk of complications when both RF techniques are combined. Our predictors of failure were: gender and associated atrial fibrillation (p < 0.05). We conclude that RF is the treatment of choice in every patient with FLA type I who had failed to antiarrhythmic therapy. We recommend RF as soon as FLA has been diagnosed because the probability of success is higher in such instances.

[Persistent atrial paralysis: reported of 2 cases]. / Parálisis atrial persistente: reporte de 2 casos.

Persistent atrial standstill is an uncommon clinical finding, this condition has no atrial electrical activity and do not respond to electrical stimulation. Electrophysiologic mapping of the heart, demonstrates two types of standstill: total and partial. There are three types of patients with this condition: patients with chronic cardiopathy, patients with muscular dystrophy and the third idiopathic group. In this article, we present two clinical cases, the fist one with dilated cardiomiopathy, in which we demonstrated total atrial standstill. The second patient with rheumatic heart disease, in which we demonstrated partial standstill that included the apical portion of the rigth atrium. We discuss the clinical and electrophysiological finding of both cases and we review the literature.

[Usefulness of exercise test in programming dual chamber pacemakers]. / Utilidad de la prueba de esfuerzo en la programación de los marcapasos bicamerales.

Prospectively, we studied 42 patient to evaluate the usefulness of treadmill exercise to programme pacemaker DDD in relation to the functioning upper frequency (relation between block frequency of pacemaker and the upper rate frequency). We excluded patient who had no treadmill exercise test after implant pacemaker. During stress 7 (17%) patient presented AV conduction 1:1 (group I); 16 (38%) second degree AV block type Wenckebach (group II); 14 (33%) second degree AV block 2:1 (group III); and 5 (12%) showed inhibition of the pacemaker by intrinsic activity (group IV). Block frequency of the pacemaker in group I and II was superior in regard of the upper rate frequency, 156.85 +/- 22.16 vs 141.43 +/- 20.82 and 135.25 +/- 11.54 vs 121.25 +/- 5.9, respectively. In group III and IV, it was lower, 120.36 +/- 15.31 vs 138.57 +/- 13.29 and 121.0 +/- 7.38 vs 142.0 +/- 14.39. The comparative analysis of the block frequency of the pacemaker in relation with the upper rate frequency showed statistically significant differences (p < 0.05) between groups I and II, and between the group I and III. The appearance of second degree AV block 2:1 is nonphysiologic, is rather due to an abrupt falling in the cardiac output. This phenomenon is able to be predicted and corrected by programming with the use the telemetry with parameters as the AV delay, as well as upper rate frequency and post-ventricular refractory atrial period.

[Radiofrequency ablation in multiple accessory pathways]. / Ablación con radiofrecuencia en vías accesorias múltiples.

Radiofrequency ablation were performed in 465 consecutive patients with Wolff-Parkinson-White syndrome. We demonstrated evidence of multiple accessory pathways in 18 patients (3.9%); 17 had two, and one had three accessory pathways. In three of these there was additional right atrio-fascicular connection. There were 27 manifest and 10 concealed accessory pathways. Six patients had Ebstein's anomaly associated with accessory pathways. The location of the accessory pathways was in the right posterior portion of the ventricular septum in 16, the left posterior portion of the ventricular septum in 5, the right free wall in 5, the left wall in 7, the right anteroseptal in 3, the midseptum in 1, and one right anterolateral. Of the 37 pathways, 32 (86%) accessory pathways were ablated successfully without complications. Duration of the procedure was 100 +/- 58 minutes, and fluoroscopic time 40 +/- 17 minutes. The mean applications were 26 +/- 17 and the power level of the radiofrequency current 41 +/- 6 W. A follow-up of 80 +/- 40 days after ablation demonstrated incidence of recurrent conduction in 3 accessory pathways (8%). In conclusion, patients with multiple accessory pathways can be treated by radiofrequency ablation in a single session with a high success rate although slightly less than that in patients with a single accessory pathway.

[Ablation using radiofrequency in the treatment of ventricular tachycardia]. / Ablación con radiofrecuencia en el tratamiento de la taquicardia ventricular.

We performed radiofrequency catheter ablation in 14 consecutive patients with Ventricular Tachycardia (VT) 10 of which had healthy hearts, one patient with ischemic heart disease, one with arrhythmogenic dysplasia, one with dilated cardiomyopathy, and one with congenital heart disease. The localization of the VT was: 10 in the left posterior fascicular region, 3 in the right ventricular outflow tract (RVOT), and one patient with ischemic heart disease with the substrate in the left ventricular apex. All of them with VT refractory to pharmacological management, using an average of 2.7 drugs per patient. After all patients underwent Electrophysiological Study (EPS), an intracavitary mapping was performed, in order to locate the arrhythmogenic substrate. Later on, the RF ablation was performed, delivering an average of 15 pulses, using 40 Watts, and an average time of 25 sec. per pulse. The procedure was successful in 60% of the fascicular VT, with a 16% of recurrence; 100% of success with those originated in the RVOT with no recurrence; in the ischemic patient we achieved primary success, but with recurrence, a second session was successful with no recurrence up to date. No major complications occurred in this group. Those patients which showed no success required the use of antiarrhythmic drugs. The total success of the series is 71.4% with 10% recurrence, and no mortality.

[Radiofrequency ablation in the treatment of supraventricular tachyarrhythmia. Experience with 500 consecutive patients]. / Ablación con radiofrecuencia en el tratamiento de las taquiarritmias supraventriculares. Experiencia en 500 pacientes consecutivos.

Several reports have demonstrated that radiofrequency catheter ablation provides effective control of a variety of supraventricular tachyarrhythmias. This report details the results of radiofrequency catheter ablation in 500 consecutive patients with a wide variety of supraventricular tachycardia treated at the Instituto Nacional de Cardiología "Ignacio Chaávez". Tachyarrhythmias were associated with the presence of an accessory pathway in 355 patients (71%). The accessory pathways were capable of both anterograde and retrograde conduction in 220 of cases (60%), only retrograde conduction in 146 (40%), dual accessory pathways were present in 11 patients (2.2%) giving a total of 366 accessory pathways. The mechanism of the arrhythmia was AV nodal reentrant tachycardia in 115 patients (23%). Ablation of the reentrant circuit of atrial flutter within the right atrium was attempted in 15 (15%) patients and a primary atrial tachycardia in 3 patients (0.7%). AV node ablation and permanent pacemaker implantation were performed in 11 patients (2%). Radiofrequency catheter ablation was successful in 312 of 355 (87.9%) patients with accessory pathways 312 of 366 (85.2%) pathways with a complication rate of 6/355 (2%) and a recurrence rate of (12.4%). AV nodal reentry was successfully abolished in 110 of 115 patients by selective ablation of the slow pathway in 92/96 (95.8%) patients and the fast pathway in 18/19 (94.7%) patients. The complication rate of this group was 7/115 (6.0%) with a recurrence rate of 16 patients (12%). The reentrant circuit of atrial flutter was ablated successfully in 13 of 15 patients with recurrent atrial flutter in (27%) patients. 2/3 (66%) primary atrial tachycardia were successfully ablated. Complete AV block was achieved in 11 of 11 patients with atrial fibrillation or flutter treated by AV nodal ablation without complications or recurrence. The results of this series of patients demonstrates the safety and efficacy of radiofrequency ablation for the treatment of a wide variety of supraventricular arrhythmias with high rate of success and low risk of complications.

[Transtelephonic electrocardiography in Mexico. A report of the first 3434 cases]. / La electrocardiografía transtelefónica en México. Reporte de los primeros 3434 casos.

The transtelephonic electrocardiographic system started in the 70's and it was used mainly in the study of heart disease, cardiac arrhythmias, syncope and sudden death. This report, include 3434 electrocardiogram (ECG) of patients whom visit the emergency room at the General Hospital and private clinic, using three different forms of transtelephonic monitors. The total population were 1715 males and 1719 females with average age of 52.2 +/- 28.8 years. 26.9% had was present in history of systemic hypertension, non-insulin dependent diabetes 12.3% and myocardial ischemic disease in 5.3%. The main ECG indications were chest pain 38.7%, most of them atypical angina, palpitations in 6.9% and dyspnea in 6.5%. 50.1% of the ECG were abnormal. The most important diagnosis were: tachyarrhythmias (25.2%), intraventricular conduction abnormalities (17.7%), myocardial ischemic disease (16%), and premature ventricular and supraventricular beats (11.6%). We concluded that the transtelephonic electrocardiographic system is a very useful method, and available now in Mexico. We detected a high percentage of electrocardiographic abnormalities, it was possible to give the right diagnosis of arrhythmias, acute myocardial infarction, old infarction, and to evaluate the pacemaker functionality. Finally, it helped to get in brief time the diagnosis and treatment in cases of acute myocardial infarction or severe arrhythmias.