Seguimiento en fase aguda de catpeteres electrodos de estimulación endocavitaria permanente: Comparación de tres modelos / Comparison of three brands of intracardiac pacemarker leads

Background: Electrode lead design and materials influence their performance, stability and manipulation characteristics. In our laboratory, we use straight intracardiac, active fixation, steroid eluting leads. These features are shared by three brands of pacemarker distributors. Aim: To compare the short term results of three brands of leads used in our laboratory in patients requiring the implant of a pacemarker of cardioverter. Material and methods: One hundred and four patients (mean age 70 years, 59 males) subjected to a pacemarker or cardioverter implant were studied and followed during the first three months post implant. In these patients, 49 Guidant Flextend® 4087 or 4088, 27 Saint Jude Tendril® 1488T and 10 Medtronic Capsurefix® 5076 leads were implanted in the right atrium and 60 Guidant Flextend® 4087 or 4088, 29 Saint Jude Tendril® 1488T and 19 Medtronic Capsurefix® 5076 leads were implanted in the right ventricle. Results: Implant parameters were adequate for all leads. A sub-acute rise in ventricular stimulation threshold was detected in one Flextrend® lead. Three atrial leads (two Flextend® and one Capsurefix®) and one Capsurefix® ventricular lead experienced an acute displacement. One patient with a Flextend® lead, had a cardiac tamponade caused by an atrial perforation. Conclusions: The three brands of leads tested can be successfully implanted with comparable parameters and without differences in the evolution of patients during the first three months.

Experiencia en el uso de un nuevo catéter electrodo de estimulación endocavitaria: Seguimiento a un año / Experience in the use of a new endocardial stimulation electrode

Background: Since February 2002, Flextend® electrode catheters are used at the Cardiovascular Unit of the Catholic University Clinical Hospital. These transvenous catheters have an IS-1 connector, silicone coating, active fixation and retractile helix with dexamethasone acetate. Aim: To report early and one year results using Flextend® catheters. Material and methods: Retrospective analysis of all patients that received an implant of a Flextend® catheter in the Unit. Results: Forty one Flextend® catheters were implanted in 24 patients, without acute displacement or clinical pericarditis. In 18 electrode catheters located in the right atrium the mean values for p wave, stimulation threshold and impedance at the moment of placement, were 2.9±1.4 mV, 0.8±0.4 V and 522±86 Ohms, respectively. The figures 24 hours after placement were 3.6±2.1 mV, 0.8±0.3 V and 612±69 Ohms, respectively. In 23 electrode catheters in the right ventricle, mean values at the moment of placement for R wave, stimulation threshold and impedance were 11.3±3.6 mV, 0.8±0.2 V and 756±108 Ohms, respectively. The figures 24 hours after placement were 3.6±2.1 mV, 0.8±0.3 V and 612±69 Ohms, respectively. In one patient, the stimulation threshold increased two months after placement and required a new intervention. Conclusions: Flextend® catheters ca be placed successfully with a low rate of complications and stable function parameters on follow up.

Experiencia de plan piloto para pacientes del FONASA portadores de arritmias atendidos en el Hospital Clínico de la Pontificia Universidad Católica de Chile / Treatment of beneficiaries of the Chilean public health system with arrhythmias in a University Clinical Hospital

Background: The costs of medical care increase along with technological advances. Therefore, highly complex and expensive procedures should be performed in a limited number of institutions. Aim: To report the initial experience on electrophysiological studies performed to beneficiaries of a public health insurance system in Chile (FONASA). Material and methods: An agreement was reached between the Electrophysiology Unit of the Clinical Hospital of the Catholic University and FONASA, to perform electrophysiological studies at a minimal cost, that only considered disposable materials and hospital stay. Thirty patients with supraventricular arrhythmias or ventricular arrhythmias without an associated cardiopathy, were attended using this agreement at the unit. Results: In all treated patients, arrhythmias disappeared. Costs remained within the assigned budget, excepting occasional complementary tests. Conclusions: This pioneering experience demonstrated that it is possible that public health insurance systems can buy complex and expensive procedures to private hospitals.

Fulguración con radiofrecuencia de taquicardia ventricular después de corrección quirúrgica de Tetralogía de Fallot: Caso Clínico / Radiofrequency ablation of ventricular tachycardia in a patient after surgery for Tetralogy of Fallot: Case report

Ventricular tachycardia is one of the most feared complications after surgical repair of Tetralogy of Fallot and it is associated with sudden death. We report a 26 years old female with a history of surgical repair of Tetralogy of Fallot at age of 4 year-old, who developed sustained ventricular tachycardia despite antiarrhythmic drugs. She was successfully treated with radiofrequency catheter ablation. Radiofrequency catheter ablation is a valid treatment for these patients.

Dolor torácico y alteración del segmento ST en pacientes con vías accesorias aurículo-ventriculares: Report of three cases / Chest pain and ST segment abnormalities in patients with accessory atrioventricular pathways

We report three patients with pre-excitation syndrome that resembled an acute coronary syndrome. A 65 years old woman, consulting in the emergency room for palpitations and retrosternal pain. EKG showed regular tachycardia and ST depression that reverted spontaneously after an episode of vomiting. A subsequent EKG demonstrated a pre-excitation syndrome and the accessory pathway was fulgurated. A 18 years old male presenting with tachycardia and chest pain elicited during exercise. An EKG showed a pre-excitation syndrome and ST segment elevation in V2 and V3. A coronary angiogram was normal. The accessory pathway successfully fulgurated. A 63 years old woman that presented tachycardia while exercising. She was subjected to an electrical cardioversion. An electrophysiological study showed an accessory pathway that was successfully fulgurated.

Flutter auricular: Resultados inmediatos y alejados de la fulguración con radiofrecuencia del istmo cavo-tricuspídeo / Results of radiofrequency ablation of the inferior vena cava-tricuspid valve isthmus for atrial flutter

Background: Radiofrequency ablation of the inferior vena cavatricuspid valve isthmus relieves atrial flutter in 95percent of cases. Aim: To evaluate the long term results of radiofrequency ablation of the inferior vena cavatricuspid valve isthmus in atrial flutter. Material and methods: Retrospective review of 86 patients with common atrial flutter, treated with radiofrequency ablation of the isthmus, while in sinus rhythm or flutter. Patients were contacted by telephone for a new clinical and electrocardiographic assessment, three to 40 months after the procedure. Results: Of all the patients treated, five died and five were lost from follow up, thus 76 patients (mean age 56 years, 58 males) were contacted for reassessment. At the moment of the procedure, 51percent had an underlying cardiac disease and 25percent had high blood pressure. All referred palpitations, 25percent had dyspnea, 84percent were receiving antiarrhythmic drugs and 33percent were on oral anticoagulants. Flutter was paroxystic in 83percent and chronic in 17percent. Fulguration was successful in all patients; one patient presented a high grade atrioventricular block as a complication of the procedure. At reassessment, 82percent of patients were in sinus rhythm, 16percent had atrial fibrillation and 2percent, an atypical flutter. Conclusions: Radiofrequency fulguration is a safe and effective treatment of atrial flutter.

Taquicardia recíproca de la unión auriculoventricular: características electrofisiológicas en un paciente con la variedad paroxística. Caso clínico / Paroxysmal tachycardia in a patient with a permanent form of junctional reciprocating tachycardia

Junctional reciprocating tachycardia is an atrioventricular reentrant tachycardia whose anterograde conduction occurs via the His Purkinje and the retrograde conduction via an accessory pathway with slow conduction. The most common form is incessant tachycardia but a paroxysmal form also exists. We report a 35 years old female with recurrent paroxysmal tachycardia, that underwent electrophysiological evaluation. A left posterolateral accessory pathway was documented. Reciprocating paroxysmal tachycardia was induced by electrical stimulation and a successful pathway ablation was performed (Rev MÚd Chile 2004; 132: 608-13).