[Placement of a biventricular resynchronization device in a patient with a persistent left superior vena cava: report of one case]. / Terapia de resincronización cardiaca en paciente con vena cava superior izquierda persistente: caso clínico.

Persistent left superior vena cava is the most common venous congenital malformation and is usually asymptomatic. Its presence could increase the difficulty for transvenous lead implantation. We report a 71-year-old woman with an idiopathic dilated cardiomyopathy, atrial fibrillation and heart failure that required biventricular resynchronization therapy. During the placement of the device a persistent left superior vena cava was detected. The device was placed without problems and the patient had a satisfactory postoperative evolution.

Terapia de resincronización cardiaca en paciente con vena cava superior izquierda persistente: Caso clínico / Placement of a biventricular resynchronization device in a patient with a persistent left superior vena cava: Report of one case

Persistent left superior vena cava is the most common venous congenital malformation and is usually asymptomatic. Its presence could increase the difficulty for transvenous lead implantation. We report a 71-year-old woman with an idiopathic dilated cardiomyopathy, atrial fibrillation and heart failure that required biventri-cular resynchronization therapy. During the placement of the device a persistent left superior vena cava was detected. The device was placed without problems and the patient had a satisfactory postoperative evolution.

[Requirement of fast ventricular stimulation to induce atrio ventricular nodal tachycardia: report of one case]. / Necesidad de estimulación ventricular rápida en la inducción de taquicardia por reentrada del nodo aurículo-ventricular: Caso clínico.

We report a 59 year-old woman who had recurrent episodes of paroxystic supraventricular tachycardia despite pharmacologic therapy. A previous electrophysiological study (EPS) was done two years earlier without induction of any sustained arrhythmia. A new EPS was performed, during which atrial and ventricular programmed stimulation failed to induce tachycardia, and only by fast ventricular stimulation during intravenous isoproterenol infusion, a typical atrio ventricular nodal reentrant tachycardia (AVNRT) was induced. We successfully ablated the slow nodal pathway. After ablation the tachycardia was not inducible. We comment the occasional difficulties to induce AVNRT and the importance of a complete induction protocol to avoid false negative studies during the EPS.

[Cryoablation of pulmonary veins as complementary treatment of atria I fibrillation in valvular surgery]. / Criocoagulación de venas pulmonares como tratamiento complementario de la fibrilación auricular en cirugía valvular.

BACKGROUND: The Cox MAZE III operation for the treatment of atrial fibrillation (AF) is complex and consumes significant operative time. Cryoablation of the pulmonary veins (CPV) is a simpler alternative for patients that require concomitant valvular surgery. AIM: To evaluate CPV in patients with AF submitted to valvular surgery. PATIENTS AND METHODS: Twenty one patients had simultaneous valvular surgery and CPV, 81 % of them had permanent AF for an average of 5 years. Twenty patients had mitral valve disease. The etiology was rheumatic in 14. Average left atrial diameter was 60 mm. In 7 patients the mitral valve was replaced, in 5 it was repaired, in 7 both mitral and aortic valve were replaced, in 1 the mitral valve was repaired and the aortic valve was replaced and in 1 only the aortic valve was replaced. A combined transeptal and superior approach was used for all patients. The CPV was performed after the valvular procedure with cryothermy at -60 degrees C for 2 minutes with two 15 mm cryoprobes applied simultaneously. RESULTS: CPV increased surgical time by 10 to 20 minutes. Operative mortality was 4.8% (1 patient). One patient developed a pericardial effusion and another a complete heart block that required a permanent pacemaker. All patients improved their functional class. At the end of an average 10.5 months of follow-up, 50% of patients were in normal sinus rhythm and 25% persisted in AF. The remaining patients were in some type of regular rhythm. CONCLUSIONS: CPV as a complementary procedure in patients with AF undergoing valvular surgery had good results to abate AF. It restored normal sinus rhythm in 50% of the cases, with low morbidity and mortality and little increment in surgical time.

[Multisite right ventricular stimulation for cardiac failure refractory to biventricular resynchronization therapy. Case report]. / Estimulación ventricular derecha multisitio en insuficiencia cardíaca refractaria a tratamiento con resincronización biventricular.

The prevalence of congestive heart failure has increased in the world. Despite advances in pharmacological treatment, some patients have progression of the disease and deterioration of their functional class. In this group of patients cardiac resynchronization therapy has been accepted as a treatment option. However, some patients are non-responders to cardiac resynchronization, and others who respond favorably, will experience reappearance of their symptoms. For these patients, multisite stimulation with the implant of a second electrode in the right ventricle has been published as a new option. We report a 76 year-old woman with a dilated cardiomyopathy, who was treated with resynchronization therapy with good clinical response during two years, but symptoms of congestive heart failure reappeared and her functional class deteriorated to NYHA class IV. She was successfully treated with right ventricular multisite stimulation, with a reduction of symptoms that has lasted during the two months of follow up after the procedure.

[Loss of biventricular resynchronization due to an uncommon cause: Report of one case]. / Pérdida de resincronización biventricular: Causa inhabitual. Caso clínico.

Cardiac resynchronization therapy is a non-pharmacological treatment for patients with dilated cardiomyophaty and congestive heart failure. The success of this therapy depends of permanent biventricular stimulation. We report an 84 year-old man, with intermittent loss of biventricular pacemaker stimulation despite having adequate sensing and stimulation thresholds in the right atrium and both ventricles. The problem was solved after correcting some programming parameters.

[Comparison of three brands of intracardiac pacemaker leads]. / Seguimiento en fase aguda de catpeteres electrodos de estimulación endocavitaria permanente: comparación de tres modelos.

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 pacemaker distributors. AIM: To compare the short term results of three brands of leads used in our laboratory in patients requiring the implant of a pacemaker or cardioverter. MATERIAL AND METHODS: One hundred and four patients (mean age 70 years, 59 males) subjected to a pacemaker 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.

Síndrome de Twiddler: una causa infrecuente de disfunción de marcapaso definitivo. Caso clínico / Twiddler syndrome: Report of one case

We report a 26year old patient who had a single chamber pacemaker implantation one year before. During a routine pre-operative evaluation, pacemaker dysfunction was demonstrated due to sensing and pacing failure, associated to left pectoral muscle rhythmic contraction. Chest X-ray confirmed Twiddler syndrome, in which twisting or rotation of the device inside the pocket results in lead dislodgement and device malfunction.

Necesidad de estimulación ventricular rápida en la inducción de taquicardia por reentrada del nodo aurículo-ventricular: Caso clínico / Requirement of fast ventricular stimulation to induce atrio ventricular nodal tachycardia: Report of one case

We report a 59 year-old woman who had recurrent episodes of paroxystic supraventricular tachycardia despite pharmacologic therapy. A previous electrophysiological study (EPS) was done two years earlier without induction of any sustained arrhythmia. A new EPS was performed, during which atrial and ventricular programmed stimulation failed to induce tachycardia, and only by fast ventricular stimulation during intravenous isoproterenol infusion, a typical atrio ventricular nodal reentrant tachycardia (AVNRT) was induced. We successfully ablated the slow nodal pathway. After ablation the tachycardia was not inducible. We comment the occasional difficulties to induce AVNRT and the importance of a complete induction protocol to avoid false negative studies during the EPS.

Criocoagulación de venas pulmonares como tratamiento complementario de la fibrilación auricular en cirugía valvular / Cryoablation of pulmonary veins as complementary treatment of atria I fibrillation in valvular surgery

Background: The Cox MAZE III operation for the treatment of atrial fibrillation (AF) is complex and consumes significant operative time. Cryoablation of the pulmonary veins (CPV) is a simpler alternative for patients that require concomitant valvular surgery. Aim: To evaluate CPV in patients with AF submitted to valvular surgery. Patients and Methods: Twenty one patients had simultaneous valvular surgery and CPV, 81 percent of them had permanent AFfor an average of 5 years. Twenty patients had mitral valve disease. The etiology was rheumatic in 14. Average left atrial diameter was 60 mm. In 7patients the mitral valve was replaced, in 5 it was repaired, in 7 both mitral and aortic valve were replaced, in 1 the mitral valve was repaired and the aortic valve was replaced and in 1 only the aortic valve was replaced. A combined transeptal and superior approach was used for all patients. The CPV was performed after the valvular procedure with cryothermy at -60°C for 2 minutes with two 15 mm cryoprobes applied simultaneously. Results: CPV increased surgical time by 10 to 20 minutes. Operative mortality was 4.8 percent (1 patient). One patient developed a pericardial effusion and another a complete heart block that required a permanent pacemaker. All patients improved their functional class. At the end of an average 10.5 months of follow-up, 50 percent of patients were in normal sinus rhythm and 25 percent persisted in AF. The remaining patients were in some type of regular rhythm. Conclusions: CPV as a complementary procedure in patients with AF undergoing valvular surgery had good results to abate AF. It restored normal sinus rhythm in 50 percent of the cases, with low morbidity and mortality and little increment in surgical time.

Estimulación ventricular derecha multisitio en insuficiencia cardíaca refractaria a tratamiento con resincronización biventricular / Multisite right ventricular stimulation for cardiac failure refractory to biventricular resynchronization therapy. Case report

The prevalence of congestive heart failure has increased in the world. Despite advances in pharmacological treatment, some patients have progression of the disease and deterioration of their functional class. In this group of patients cardiac resynchronization therapy has been accepted as a treatment option. However, some patients are non-responders to cardiac resynchronization, and others who respond favorably, will experience reappearance of their symptoms. For these patients, multisite stimulation with the implant of a second electrode in the right ventricle has been published as a new option. We report a 76 year-old woman with a dilated cardiomyopathy, who was treated with resynchronization therapy with good clinical response during two years, but symptoms of congestive heart failure reappeared and her functional class deteriorated to NYHA class IV. She was successfully treated with right ventricular multisite stimulation, with a reduction of symptoms that has lasted during the two months of follow up after the procedure.

Pérdida de resincronización biventricular: Causa inhabitual. Caso clínico / Loss of biventricular resynchronization due to an uncommon cause: Report of one case

Cardiac resynchronization therapy is a non-pharmacological treatment for patients with dilated cardiomyophaty and congestive heart failure. The success of this therapy depends of permanent biventricular stimulation. We report an 84 year-old man, with intermittent loss of biventricular pacemaker stimulation despite having adequate sensing and stimulation thresholds in the right atrium and both ventricles. The problem was solved after correcting some programming parameters.

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.

Implante de marcapaso definitivo en pacientes con vena cava superior izquierda persistente y ausencia de vena cava superior derecha: Caso clínico / Permanent pacemaker implantation in patients with persistent left superior vena cava and absent right superior vena cava: Report of three cases

Persistent left superior vena cava and absent right superior vena cava is an uncommon anatomical association. This is a challenging situation for permanent pacemaker implantation. We report three patients with this anomaly and a permanent pacemaker successfully implanted through the left superior vena cava and coronary sinus, without acute or chronic complications.

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.

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.

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.

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.