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Biomedical subjects

J A González-Hermosillo

Publications and source records attributed to J A González-Hermosillo.

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

[Congenital atrioventricular junction tachycardia. Favorable response to anti-arrhythmia agents].

The congenital junctional ectopic tachycardia, is an unusual tachyarrhythmia, with early clinic manifestation and poor antiarrhythmic drugs response with a great infant mortality reaching rates of 35%. It deserves a special attention in its timely detection as well as in its appropriate handling with different modalities of pharmacological and nonpharmacological therapy. We reported two cases in which age of presentation of tachyarrhythmia was at three months and whose particularity was the good response to antiarrhythmic drugs; verapamil and later propafenone, used for the acute stages and a combination of propafenone plus propranolol initially for the chronic stage. Due to intolerance it was necessary to change the treatment after a year for sotalol and digital with good response. We review the literature about this topic.

Anti-Arrhythmia Agents↗
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

[Radiofrequency ablation in the treatment of tachyarrhythmias. Experience concerning 1,000 consecutive patients].

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.

Adolescent↗
PubMedDate not supplied

[Electrocardiographic changes during stress test in a patient with "Brugada syndrome"].

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.

Adult↗
PubMedDate not supplied

[Usefulness of adenosine to detect advanced paroxysmal atrioventricular block as a cause of syncope].

We present the case of a 66 years old man with recurrent episodes of syncope, up to three times during the last two months without previous symptoms. An ECG after the syncope showed a bilateral block (left anterior fascicle block and right bundle branch block) and first grade atrioventricular block. The exercise test did not demonstrate either AV conduction disorders or tachyarrhythmia episodes. Holter monitoring showed premature ventricular complexes; tilt testing and carotid sinus massage were normal. The electrophysiologic study revealed no alteration in the conduction system. Throughout atrial and ventricular stimulation documented no tachyarrhythmias. However, intravenous administration of 12 mg of adenosine induced complete AV infra-His block with ventricular asystolia of 7.2 sec duration. Adenosine testing can identify patients with syncope due to paroxysmal AV block even when the electrophysiological findings and other conventional tests are not conclusive.

Adenosine↗
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

[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

[The electrocardiographic changes in patients stung by scorpions].

Scorpion sting is a hazardous and potentially lethal condition. Venom of some variety of scorpion can cause dramatic cardiovascular and electrocardiographic changes, that have been related to heart stimulation by autonomous nervous system. We prospectively studied 722 patients following scorpion sting. Mean age for the group was 25.5 +/- 18.3 years. 67% were less than 30 years of age. In 294 patients (40.7%) we found electrocardiographic changes. These cases were followed until those changes disappeared. First degree atrioventricular block was found in 10.2%. Intraventricular conduction disturbances in 12.8% with predominance of right bundle branch block. In 11% we found arrhythmias. In 15% reversible ventricular repolarization changes. Of this no one died. This lack of mortality could be attributed to a prompt therapeutic intervention.

Age Factors↗
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[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

[The diagnosis of perioperative myocardial infarction in heart surgery].

Fifty three consecutive patients undergoing open heart surgery were prospectively studied to assess current techniques for diagnosing perioperative myocardial infarction (PMI). All patients had preoperative and postoperative electrocardiograms, serial determinations of serum creatine phosphokinase (CK), myocardial fraction of CK (CK-MB) and scintigraphy with technetium-99m labeled pyrophosphate. Seven patients (13.2%) sustained perioperative myocardial infarction. Four of these patients exhibited abnormal Q waves, and one poor R wave progression. Three of them had a positive scintigram. Two patients with a non-Q-wave infarction had a abnormal radioisotopic imaging. The CK and CK-MB were higher in patients with infarction (818.1 U) than in those without this complication (349 U) p less than 0.05. The relative sensitivity and relative specificity of given variables in the diagnosis of PMI were as follows: electrocardiogram 71.4% and 97.5% respectively; scintigraphy 71.4% and 94.1%; and serum enzymes 100% and 71.8%. Age, incidence of prior myocardial infarction, unstable angina, elevated left ventricular filling pressure, number of diseased coronary arteries, and number of grafts per patient did not correlate with PMI. Duration of extracorporeal circulation and number of electric shocks during surgery were slightly higher in the infarction group, but the difference was not significant. These results indicate that the combination of these three diagnostic procedures is the best way to evaluate myocardial damage after open heart surgery.

Adult↗
PubMedDate not supplied

[Value of the exercise test in asymptomatic myocardial ischemia].

To evaluate the predictive value of ischemic ST segment depression without associated chest pain during exercise testing, data were analyzed from 7305 studies. Two hundred thirty six patients were included in this study and were separated in 2 groups. Group A consisted of 169 patients without chest pain who, during exercise testing, showed a positive ST segment response (at least 1.5 mm of horizontal or downward ST segment depression for at least 0.08 second, compared with the resting baseline value), and Group B consisted of 67 patients who had both chest pain and a positive ST segment response. Selective coronary angiogram was performed on all patients. Each Group was separated into 3 sub-group according to the Cohn criteria: sub-group I (asymptomatic persons 8.3 vs 19.4%); sub-group II (patients with history of Myocardial Infarction 36.7% vs 19.4%); sub-group III (patients with chronic angina 55% vs 61.2%). The clinical characteristics, coronary risk factors, distribution of coronary artery disease, and exercise test response were similar in both groups. During treadmill exercise, the mean heart rate was 140.6 +/- 22 in group A versus 127.1 +/- 23 in the group B. The pressure-rate product was 2.4 +/- 0.8 versus 1.9 +/- 0.5, respectively (P less than or equal to 0.05). The predictive value for severe coronary artery disease of an exercise test in patients with asymptomatic ischemia was 77.5% as compared with 89.6% in the group with angina. This study confirms the high frequency of asymptomatic myocardial ischemia during exercise testing, compared with patients who had angina during exercise testing, with high percentage of prediction (77.5%) for coronary artery disease.

Aged↗
PubMedDate not supplied

[Myocardial infarct immediately after a normal exercise test].

Two cases of myocardial infarction immediately following a normal stress testing, are described. The incidence and possible pathophysiological mechanisms are discussed. In one of the patients it was difficult to establish the pathophysiological mechanism which was the cause of the ischemic event. In the other, the coronary arteriography revealed only minimal obstructive disease. Therefore, coronary vasospasm with thrombus formation as a cause of the infarction ia an interesting speculative possibility in view of the angiographic findings. Acute myocardial infarction after a normal electrocardiographic response to maximal exercise testing is extremely rare, and the precise pathophysiologic mechanism that leads to his complication is not clear.

Adult↗
PubMedDate not supplied

[Arrhythmia in acute myocardial infarction with involvement of the right ventricle].

Arrhythmias and conduction disorders were studied in 110 patients with posteroinferior myocardial infarction with right ventricular involvement. All the patients were hospitalized in the coronary care unit, and were compared with another 110 patients with posteroinferior myocardial infarction without extension to the right ventricle. 99% of the patients with right ventricular infarction and 96.3% of the patients with isolated inferior infarction had some type of arrhythmia. The disorders of automatism were similar in both groups (90% vs 91%, respectively). The conduction disturbances were observed in 68% of the infarctions extended to the right ventricle and in 20% of the isolated left ventricular infarctions (p greater than 0.01). A-V block occurred in 52% of the infarctions with right ventricular involvement and only in 10.9% of the control group. Intraventricular conduction disorders also were more frequent in right ventricular infarction (24.5% vs 10.9%) (p less than 0.02), especially the RBBB (18.2% vs 6.4%). Ventricular fibrillation was observed in 5.5% and 0.9%, and polymorphic ventricular tachycardia (torsades de pointes) in 12.7% and 1.9% respectively. In 62 patients with right ventricular infarction it was necessary to implant a pacemaker as compared to 12 patients in the control group. Mortality was higher in the patients with inferior infarction extended to the right ventricle (23 patients vs 2 patients). None of the deaths were due to arrhythmias. It can be concluded that conduction disorders and the number of pacemaker implants are more common in the infarctions with right ventricular involvement due to more severe damage to the conduction system.

Arrhythmias, Cardiac↗
PubMedDate not supplied

[Diltiazem in chronic stable angina].

The safety and efficiency of the administration of diltiazem was evaluated in 10 patients with class II-III chronic stable angina. All the patients had ischemic heart disease documented by coronary angiography and/or an abnormal exercise test. A dose related improvement in both frequency of angina and exercise capacity were obtained by diltiazem administered in increased doses using a single blind protocol. The weekly frequency of angina was reduced from 7.5 +/- 9.8 with placebo to 3.8 +/- 5.5, 1.1 +/- (p less than 0.05) and 0.7 +/- 0.9 (p less than 0.01) with doses of 120, 240 and 360 mg/day respectively. The exercise duration on treadmill was significantly increased from 8.5 +/- 3.6 to 10.6 +/- 3.7 min (p less than 0.05) with the 360 mg/day dose. The mean exercise time required to develop 1 mm ST depression was 6.1 +/- 3 min on placebo and was significantly delayed to 9.0 +/- 3.8 min (p less than 0.05) with the 240 mg/day dose and to 10.7 +/- 4.0 min with 360 mg (p less than 0.01). In a double blind randomized crossover phase, the time to the onset of ischemia during exercise was increased from 8.5 +/- 3.8 min with placebo to 11.05 +/- 2.8 min with 360 mg/day of diltiazem (p less than 0.01). Diltiazem in doses ranging from 120 to 360 mg/day is an effective antianginal agent with no significant adverse effects.

Adult↗