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Biomedical subjects

L Colín

Publications and source records attributed to L Colín.

At least 19 recordsLinked to original sources
PubMed1993

[Influence of the permeability of the artery responsible for the infarction on the variability of heart rate and late potentials. Its importance in the risk stratification after myocardial infarction].

The use of the heart rate variability for the study of the Autonomic nervous system has been well established. We analyzed late potentials and heart rate variability in 29 control patients and in 102 consecutive patients with a first myocardial infarction. The data obtained were analyzed with both, the medical treatment (thrombolysis and beta-blockers) and the patency of the infarct related vessel. Patients with an infarct had diminished vagal tone as compared with the control group. Those patients with occluded related arteries showed higher incidence of late potentials; interestingly patients with late potentials also had diminished vagal tone. Without looking at the patency of the infarct related artery, thrombolitic and betablocker therapy did not have any effect on vagal tone. All the variables were correlated with the patency of the infarct related artery. Those patients with patent arteries had a preservation of the vagal tone; this was independent of the treatment received and the presence of late potentials. We concluded that the patency of the infarct related artery determines the absence of late potentials and preservation of the vagal tone. This might be one of the mechanisms of how thrombolitic therapy decreases the incidence of cardiac death.

Action Potentials↗
PubMedDate not supplied

[Complete congenital heart block. Its natural history and evolution].

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.

Adolescent↗
PubMedDate not supplied

[A complete atrioventricular block during exertion].

Exercise-induced atrioventricular (AV) block in patients with normal electrocardiogram at rest is uncommon. We report the clinical features of two patients with AV block during treadmill test. The first patient was a woman of 54 years of age with presyncope on exercise. She developed complete AV block during exercise testing without evidence of ischemic myocardial disease. Electrophysiologic study documented distal AV block. The second patient was a man 31 years old who developed angina and third-degree AV block with depression of ST segment during treadmill test. Myocardial perfusion study suggested ischemic heart disease. He received anti-ischemic drugs with improvement of symptoms. A control exercise testing demonstrated normal AV conduction and electrophysiologic study was normal. In the first case, exercise AV block was probably due to abnormal His Purkinje conduction system refractoriness to autonomic modulation, while in second case AV block was secondary to ischemic heart disease. Third-degree AV block at exercise can be present in patients without conduction system abnormalities at rest. Exercise-induced infra-Hisian AV block must be treated with pacing until ischemic heart disease has been ruled out.

Adult↗
PubMedDate not supplied

[Focal atrial fibrillation treated with radiofrequency].

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.

Adult↗
PubMedDate not supplied

[Sudden death in intermittent Wolff Parkinson White syndrome].

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.

Adult↗
PubMedDate not supplied

[Trans-surgical ablation of atrial flutter in patients treated with closure of atrial septal defect. Pilot project].

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.

Adolescent↗
PubMedDate not supplied

[Radiofrequency ablation and simultaneous insertion of an Amplatzer device in a patient with atrial septal defect and nodal reentry tachycardia].

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.

Catheter Ablation↗
PubMedDate not supplied

[The usefulness of electrophysiology in a patient undergoing cardiomyoplasty].

The cardiomyoplasty is a new surgical procedure that uses a skeletal muscle electrostimulated in order to reinforce or even substitute partially the cardiac muscle. We present the electrophysiology aspects in a patient with dilated cardiomyopathy that underwent cardiomyoplasty. First the latissimus dorsi muscle was prepared with a neurostimulant ITREL II. During the surgical procedure a dual-chamber pacemaker mode DDD brand CPI was placed. After three months, ablation radiofrequency of the AV node was performed in order to control the atrial fibrillation that caused heart failure. By means of the AV block we obtained synchrony between the ventricular stimulation and the latissimus dorsi muscle, and by this the patient improved. Using the modern pacemakers and radiofrequency we can control the bradyarrhythmias as well as the tachyarrhythmias frequent in patients with dilated cardiomyopathy, increasing the success rate of cardiomyoplasty.

Adult↗
PubMedDate not supplied

[Surgical resection of a focus of ventricular tachycardia guided by endocardial and epicardial mapping].

We describe a case of a 46 years old female with chagasic heart disease. In one year she presented six episodes of sustained ventricular tachycardia, heart rate 230 beats per minute, morphology of RBBB AQRS -60 degrees, with hemodynamic deterioration that needed electrical cardioversion. She was treated with several antiarrhythmic drugs but not good response was obtained. Programmed electrical stimulation was done and it show three different types of ventricular tachycardia, trough pace-mapping the site of the clinical tachycardia was located in the portion inferior and inferior-posterior of the left ventricle that was confirmed by entrainment. Epicardial mapping was performed in 38 ventricular sites following the modified Harken sketch and the location of the site of outlet was confirmed in the posterior base of the left ventricle, at this point the surgical resection was done with no complication. The results were satisfactory. Eight days later programmed electrical stimulation was done and the ventricular tachycardia could not be induced. Six months afterwards the patient is asymptomatic without medical treatment.

Cardiac Pacing, Artificial↗
PubMedDate not supplied

[The clinical and electrophysiological characteristics of patients with idiopathic ventricular tachycardia].

Clinical and electrophysiological characteristics in 20 patients with clinical ventricular tachycardia and normal hearts documented by physical examination, echocardiography, and angiocardiography were analysed. There were 11 males and 9 females. All patients had sustained ventricular tachycardia without hemodynamic instability during tachycardia. A right bundle branch block morphology of ventricular tachycardia was present in 14 patients and left bundle branch block morphology in six patients. During electrophysiologic studies, ventricular tachycardia was induced in 10/15 (66%) patients. Intravenous verapamil terminated the ventricular tachycardia in 9/10 (90%) of cases. However oral verapamil not prevented recurrences. Among 14 patients on whom exercise tests were performed, only two had exercise-induced ventricular/tachycardia. Late potentials were positive in 3/14 (21%) cases and one patient died suddenly during exercise without antiarrhythmic drugs.

Adolescent↗
PubMedDate not supplied

[Atrioventricular and ventriculoatrial conduction in patients operated on for the Wolff-Parkinson-White syndrome].

Over the last decade the surgical treatment of the Wolff-Parkinson-White syndrome has been well accepted. It is important to make an early diagnosis for surgical success. For this purpose we utilized programmed electrical stimulation to assess the functional characteristics of atrioventricular and ventriculoatrial conduction in our post-operative patients. In 55% of the cases we found accelerated nodal conduction. Programmed electrical stimulation correctly identified 90% of successfully treated patients. We did not found any false positive curve, therefore, this method has a high specificity. We concluded that in post-operative patients with the Wolff-Parkinson-White syndrome: 1- There is a high incidence of accelerated nodal conduction and 2- programmed electrical stimulation can correctly identify most of the patients who were successfully treated.

Adolescent↗
PubMedDate not supplied

[Electrophysiologic effect of intravenous propafenone in supraventricular tachycardia].

The electrophysiologic effects of intravenous propafenone were studied in twenty six patients with supraventricular tachycardias. Ten patients (38%) with intranodal reentrance tachycardia common type, and sixteen patients (62%) atrioventricular orthodromic reentrance tachycardia. Propafenone (2 mg/kg intravenously) given over ten minutes period caused termination of the intranodal reentrance tachycardia in 60% of the cases and 50% to the patients with atrioventricular reentrance tachycardia. The antiarrhythmic effects observed are related to the slowing of the conduction velocity and to the prolongation of the refractoriness in the AV node and accessory pathways preventing the reentrance mechanism. The reinduction of the tachycardia was possible in 46% of the patients. This effects was more significative in the group with accessory pathways (50%), and 40% of the patients with intranodal reentrance. The supraventricular tachycardia was inducible by programmed electrical stimulation in 46% of the patients. None of the patients developed side effects to the administration of the propafenone.

Adolescent↗
PubMedDate not supplied

[Positive exercise test in hypertensive patients correlated with coronary angiography].

With the purpose of evaluate the state of the coronary arteries in hypertensive patients with positive exercise test, 82 patients were selected, 50 male and 32 female with mean age of 56.9 +/- 13.2 years. Angiography was normal in 25 patients thirteen patients had a single coronary arteries narrow of less than 50% and 44 cases with significant coronary arteries lesions of more than 50%. The parameters obtained in the exercise test are not significant for statistic purposes. Systolic hypertension or flat response was more frequent in the group with advanced coronary lesions with a predicted positive value in coronary obstructions of 66 and 75%. We conclude that 70% of hypertensive patients have obstructive coronary lesions of some degree.

Arterial Occlusive Diseases↗
PubMedDate not supplied

[Surgical treatment of supraventricular tachycardias (Wolff Parkinson White and Occult Kent). Experience at the "Ignacio Chávez" National Institute of cardiology].

We report our initial experience in the surgical section of the accessory pathway in thirteen patients: eight patients with Wolff Parkinson White syndrome and five with accessory pathway functioning only in direction ventricle to atrium (Kent concealed), with recurrent episodes of paroxysmal supraventricular tachycardia with no response to medical treatment. Three of these patients had episodes of auricular fibrillation with interval RR lower than 250 msec and one patient presented syncope. A total of fifteen accessory pathways were sectioned: 7 left lateral, 5 left posterior, one left posterolateral, one right lateral, and another one right anteroseptal. In the same procedure two patients had correction of another heart malformation: one with patent ductus arteriosus and another with and another with atrial septal defect. All patients had successful outcome, one of them needed a second surgery for persistent accessory pathway. We had two post-operatory complications: one mediastinitis and one patient with ectopic auricular tachycardia.

Adolescent↗
PubMedDate not supplied

[Disorders of the rhythm and conduction in patients operated on for a total correction of tetralogy of Fallot].

The purpose of this paper is to analyze the incidence of arrhythmias and conduction disturbances in 81 patients after total surgical repair of tetralogy of Fallot. The study was done at the National Institute of Cardiology "Ignacio Chávez" from 1974 to 1989. Sixty five patients (78.9%) developed a pattern of right bundle block and ten patients (12.3%) had additional left anterior hemiblock following surgery. Two patients had complete heart block so pacemaker was implanted. The incidence of serious ventricular arrhythmias was found in 11 patients often polymorphic ventricular premature complexes. One case sustained monomorphic ventricular tachycardia. Electrophysiological study demonstrated that it source was the scar of the right ventricle outflow tract. This tachycardia is now under control with specific antiarrhythmic therapy.

Arrhythmias, Cardiac↗
PubMedDate not supplied

[Rational management of arrhythmias].

Despite the development of better diagnostic techniques and new modes of therapy, management of cardiac arrhythmias is still difficult. The lack of standardization in the indications of each technique has increased the risk of overtreatment and unnecessary cost. This paper describes the minimal requirements necessary for the different techniques and the appropriate information that should be collected from each. A well taken clinical history and a 12-lead EKG give very important information for the decision on when and how to treat.

Arrhythmias, Cardiac↗
PubMedDate not supplied

[Electrofulguration of refractory supraventricular paroxysmal tachycardias. (Experiences of the "Ignacio Cháves" National Institute of Cardiology].

The purpose of this paper is to report our experience with endocardial catheter ablation in the recurrent episodes of paroxysmal supraventricular tachycardia in ten patients. All cases were referred because previous drug trials had failed to control arrhythmia. In four patients with Wolff Parkinson White syndrome, the ablation was used in the accessory pathway, in five patients in the his bundle region, and one patient in the AV perinodal region. The follow-up ranges from 4 to 15 months. We had a complete success rate of 40% and a partial success in other 40%. We did not have any complications during the procedures.

Adolescent↗