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Biomedical subjects

M C Vagueiro

Publications and source records attributed to M C Vagueiro.

At least 19 recordsLinked to original sources
PubMed1999

[The implantation of VDD pacemakers with a single electrode--a comparative study. The experience of the last 5 years].

OBJECTIVE: To compare the epidemiological characteristics and immediate results of all first single lead VDD pacemaker (PM) implantations with those of an equal number of dual chamber DDD PM, implanted during a 5-year period in a tertiary-care hospital. POPULATION AND METHODS: A total of 41 patients (pts) (25 males, mean age of 69.0 +/- 11.8 years) underwent a VDD PM implantation, from 30-11-92 to 15-9-97. This group was compared with an equal number of patients (28 males, mean age of 69.9 +/- 7.31 years) with a DDD PM implanted in the same period, selected by a criterion of immediate temporal proximity of procedure. For each patient we collected the clinical and electrocardiographic (ECG) indications for PM implantation, parameters of atrial (AS) and ventricular (VS) sensing and ventricular pacing (VP), X-ray exposure time (XRT) and complications. RESULTS: In the VDD group, 46.3% of the patients had syncope, 51.2% had complete AV block on the ECG, and 14.6% were PM-dependent. Analyzed procedure-related parameters were as follows: P-wave amplitude: 2.1 +/- 0.6 V; AS threshold: 1.2 +/- 0.7 V; R-wave amplitude: 9.1 +/- 3.3 V; VS threshold: 7.0 +/- 2.0 V; VP thresholds: 0.68 +/- 0.24 mA, 0.43 +/- 0.12 V (for a spike duration of 0.5 ms); ventricular impedance: 644.9 +/- 132.0 ohm; XRT; 7' 43" +/- 8' 23". There were two minor complications, for an incidence of 4.9% (one local hematoma and a vagal reaction). In the DDD group the clinical and ECG characteristics were similar, but there was a 22.0% prevalence of sinus-node dysfunction, VS 0% in the VDD group). The P-wave amplitude and AS threshold were significantly (p < 0.005) better (2.8 +/- 0.9 V and 2.8 +/- 0.9 V respectively). The other parameters were similar to those of the VDD group. CONCLUSIONS: The immediate results of VDD PM implantation are good and comparable with those of DDD PM, although with worse acute AS parameters.

Aged↗
PubMed1998

[Treatment of malignant ventricular arrhythmia guided by electrophysiologic study].

The purpose of this study was to assess the results of the treatment of malignant ventricular tachyarrhythmias guided by electrophysiologic studies. Thirty patients with ventricular arrhythmias, aged 56.6 +/- 14.1 years, were submitted to EP testing. The clinical presentation of arrhythmia was sustained monomorphic ventricular tachycardia in 24 (80%), non-sustained ventricular tachycardia in three and another three were survivors of sudden cardiac death. Twenty five patients (83%) had evidence of structural heart disease and left ventricular ejection fraction was less than 40% in 16 (53%). Antiarrhythmic drugs were considered effective when sustained monomorphic ventricular tachycardia was noninducible or significantly slowed in serial EP testing. Sustained monomorphic VT was induced in 19 patients (63%) and an effective drug therapy was found in 13 (68%). In the other 11 patients sustained arrhythmias were not induced, although in six of them the study was done already under antiarrhythmic drugs, that were continued in the follow-up. In the six patients in which an effective drug regimen could not be found and in two sudden death survivors with primary ventricular fibrillation and negative EP testing, an Implantable Cardioverter-Defibrillator was implanted. After 17.8 +/- 10.5 months, there was recurrence of the arrhythmia in 4 (18%) of the 22 patients on antiarrhythmic drugs and half of the patients with ICDs received appropriate therapy from the device. Three patients (10%) died in the follow-up, of which only one due to sudden death. We conclude that selection of optimal antiarrhythmic treatment based on the results of EP testing, is associated with decreased episode recurrence and sudden death.

Adult↗
PubMed1998

[Coronary angioplasty in the acute phase of myocardial infarct].

Primary coronary angioplasty is a reperfusion method increasingly used for the treatment of acute myocardial infarction. Several studies are reviewed, demonstrating a reduction in mortality and morbidity, namely due to recurrent ischaemia and haemorrhagic stroke, in comparison to thrombolysis. This benefit seems larger in high risk patients, such as those with cardiogenic shock, anterior wall infarction, elderly patients and those with contraindications thrombolysis or with a non diagnostic electrocardiogram.

Angioplasty, Balloon, Coronary↗
PubMed1997

[A comparison of unipolar versus bipolar mapping in the ablation of left-sided accessory atrioventricular conduction pathways].

PURPOSE: To compare the utility of unipolar versus bipolar mapping to guide radiofrequency catheter ablation of manifest left-sided accessory pathways. SETTING: University Hospital PATIENTS AND INTERVENTIONS: We studied twelve patients with a mean age of 42 +/- 13 years, submitted to a successful left-sided accessory pathway ablation. Detailed mapping was performed with the ablation catheter, recording simultaneous unipolar (distal electrode) and bipolar electrograms, in sinus rhythm. Twenty-three recordings were analyzed, including twelve successful, and eleven unsuccessful sites. The following measurements were analyzed: atrial and ventricular amplitude; interval between atrial and ventricular electrogram onset; interval between onset of ventricular electrogram and delta wave; interval between ventricular electrogram activation and delta wave and; unipolar morphology, classified as P-rS, P-QS or PQS. MAIN RESULTS: Accessory pathway ablation required a mean of 6.3 +/- 7.9 (median of 2) energy applications. Analysis of the electrogram revealed that ventricular activation was significantly earlier in successful versus unsuccessful sites. Unipolar morphology was also different according to the ablation result: among unsuccessful applications the P-rS configuration occurred in one, and the P-QS in ten cases, while in successful sites, seven had P-QS, and five had PQS morphology. CONCLUSIONS: Unipolar recordings are useful to guide radiofrequency catheter ablation of manifest left-sided accessory pathways and should be used in association with bipolar electrograms.

Adult↗
PubMed1995

[The catheter ablation of atrioventricular nodal reentry tachycardia: the results of a mixed electrophysiological/anatomical technic].

OBJECTIVE: To describe the results of radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) by using a mixed electrophysiologic/anatomic mapping technique. DESIGN: Consecutive patients with AVNRT, submitted to AV node modification between November 1992 and March 1995. SETTING: Cardiology Department at an University Hospital. INTERVENTIONS: Twenty consecutive patients with AVNRT were submitted to AV node modification. The ablation technique included two sequential steps. Initially, a detailed electrophysiologic mapping was performed with the ablation catheter, positioned near the coronary sinus ostium, looking for a specific recording: fractionated atrial electrogram, suggestive "slow pathway" potential and a ratio of atrial: ventricular electrogram amplitude > 1. In case of failure, after 5 applications of radiofrequency energy, an anatomic technique was used. The fluoroscopic image, in left anterior oblique projection, was used to guide catheter progression, and the radiofrequency energy applied sequentially in the posterior (P), followed by medium (M) and anterior (A) septal areas if needed. Radiofrequency energy was applied a power of 16-36 watts for 30-60 sec. If a His bundle deflection > 0.0025 mV was recorded, energy was not applied. MEASUREMENTS AND RESULTS: Suppression of a AVNRT was initially obtained in 19 patients (95%). A mean of 8.3 +/- 6.1 energy application were required. Mean during of the entire procedure was 142 +/- 45 min and the fluoroscopy duration was 22 +/- 12 min. There were no complications. The location of successful ablation areas was: P in 15 patients, M in three and A in one. After a mean follow up of 10 +/- 6 months, two patients had recurrence of AVNRT. A second procedure was successful in the initially failed patient and in these two recurrences. CONCLUSIONS: A mixed electrophysiologic/anatomic mapping technique to perform radiofrequency catheter ablation of AVNRT was associated with high efficacy and no complications.

Adult↗
PubMed1994

[Atrioventricular junction ablation: therapy of refractory atrial tachyarrhythmia].

OBJECTIVES: To assess the safety and efficacy of radiofrequency atrio-ventricular junctional ablation. DESIGN: Consecutive group of patients with refractory atrial tachyarrhythmias in whom catheter ablation of the atrio-ventricular junction was performed. SETTING: Cardiology Department at University Hospital. INTERVENTIONS: Atrio-ventricular junctional ablation was performed in 13 patients with a mean age of 53 +/- 13 years. Among six patients there was no evidence of organic heart disease, two had operated congenital heart disease, two had hypertensive heart disease, one had rheumatic heart disease with a prosthetic valve and the other had ischemic heart disease. The indication for ablation was drug-refractory atrial tachyarrhythmia in all patients: atrial fibrillation with uncontrolled rate in eight patients, atrial flutter in three, atrial tachycardia in one and inappropriate sinus tachycardia in one. An average of 3.7 +/- 0.9 anti-arrhythmia drugs was previously ineffective or associated with significant side-effects. Radiofrequency energy was applied between the distal pole of the ablation catheter and an indifferent cutaneous electrode with intensity of 40-65 volts for 30-60 secs. The ablation was initially performed utilizing the classical technique with the ablation catheter across the tricuspid valve. In the case of failure, an alternative method was used, with the ablation catheter positioned in the left ventricular septum. After the procedure a VVI-R permanent pacemaker was inserted in all patients. MEASUREMENTS AND RESULTS: Atrio-ventricular junctional ablation was successful in all patients after an average of 4.4 +/- 3.7 radiofrequency applications. The classical technique was successful in 11 patients (85%). The average amplitude of the His bundle electrogram recorded in the successful sites was not significantly different from the average maximum amplitude at unsuccessful sites (0.1 +/- 0.05 mV vs. 0.17 +/- 0.12 mV). There were no complications related to the procedures. During a mean follow-up of 7 +/- 4 months there was functional and symptomatic improvement in all patients. The only significant complication was an episode of sustained ventricular tachycardia that occurred three months after the ablation in a patient with Tetralogy of Fallot. CONCLUSIONS: In patients with refractory atrial tachyarrhythmias, atrio-ventricular junctional ablation is a safe and effective therapeutic option. The alternative technique should be reserved for cases of unsuccessful ablation with the classic method. Due to its potential significant side-effects, this therapy should be a last alternative option.

Adult↗
PubMed1994

[Coronary disease and noncardiac surgery. An evaluation of the surgical risk].

Coronary artery disease is one of the leading causes of death in developed countries and one of the factors contributing to high mortality associated with noncardiac surgical procedures. This is the reason why is so important to correctly assess surgical risk in patients with ischemic heart disease. These patients can be evaluated by a simple clinic examination, electrocardiogram and chest X-ray. In asymptomatic patients or in patients with angina (Class I-II), normal electrocardiogram and chest X-ray, the operative risk is low. On the other hand, patients with severe heart failure (Class IV NYHA), unstable angina or acute myocardial infarction have a high surgical risk. The exercise stress testing must be performed in some cases in order to identify preoperative factors (electrocardiographic ischemic changes, low functional capacity) that might affect the development of cardiac events after noncardiac surgery. When not possible a thallium-dipyridamole scintigraphy should be considered. We discuss preoperative indications for coronary angiography and coronary revascularization. Coronary artery bypass surgery must be thought based on clinic severity, therapeutic results, left ventricular function and patient age, among other factors.

Coronary Disease↗
PubMed1994

[Efficacy and safety of adenosine triphosphate in the control of supraventricular paroxysmal tachycardia].

Our purpose was to assess the efficacy and safety of intravenous ATP for the acute termination of paroxysmal supraventricular tachycardia. There were 14 women and 10 men, aged 38 +/- 15 years. Three patients had evidence of structural heart disease (Ebstein's anomaly associated to atrial septal defect, operated mitral stenosis with insertion of a mechanical heart valve and CAD respectively). Twelve patients had Wolff-Parkinson-White syndrome and another had undergone surgical ablation of an accessory pathway. At the time of electrophysiologic testing, ATP was administered during episodes of paroxysmal supraventricular tachycardia, via a central vein, in incremental doses of 5, 10 and 20 mg followed by a flush of 10 c.c. of isotonic saline. The mechanism of the arrhythmia was orthodromic AV reentrant tachycardia in 19 (79%), AV nodal reentrant tachycardia in 4 (16.6%) and atrial tachycardia in one patient. The mean frequency of the tachycardia was 174 +/- 33 b.p.m. A dose of 5 mg was effective in 16 patients (66%), 5 required 10 mg and two required 20 mg for termination of the tachycardia. In the patient with atrial tachycardia ATP was not effective. The average time after injection to termination of the arrhythmia was 16 +/- 8 seconds. Orthodromic AV reentrant tachycardia was interrupted in the AV node limb in all but one patient and AV nodal reentry was terminated in the "slow-pathway" in three of the four patients. Nine patients had premature ventricular complexes, isolated or in couplets, after the termination of the SVT. Three patients had immediate recurrence of the SVT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1994

[Permanent pacing in childhood: a review of 11 years of experience].

STUDY OBJECTIVE: To review our eleven year experience in the implantation and follow-up of permanent Pacemakers in the paediatric age group. DESIGN: Retrospective study. SETTING: Children submitted to permanent cardiac Pacing implantation and accompanied in the Pacing Center of the Hospital de Santa Maria. PATIENTS: Children from both sexes, aged from neonate to 14 years old, with brady-dysrhythmia and indication for permanent cardiac Pacing implantation. MATERIAL AND METHODS: From November 1980 to September 1991, 16 children had permanent Pacemaker implantation. We describe the clinical and electrocardiographic characteristics of the population, mode of Pacing used, technical data from the implantation and evolution. RESULTS: One children died due to associated cardiac defect not related to the Pacemaker. The other 15 children remain in follow-up with normofunctioning Pacemakers and free of symptoms. We had to perform 11 reinterventions in 8 children due to generator or electrode problems (28,2 months reintervention interval). CONCLUSIONS: Improvements in Pacemaker technology and a careful technique of implantation can significantly reduce the morbidity associated to permanent pacemaker implantation in this age group.

Adolescent↗
PubMed1993

[The diagnosis and ablation of accessory atrioventricular pathways in the initial electrophysiological exam: a new therapeutic modality in pre-excitation syndromes].

OBJECTIVE: To describe the experience and results in the diagnosis and catheter ablation of atrioventricular accessory (AP) pathways during the initial electrophysiologic study. DESIGN: We performed catheter ablation at the time of an initial electrophysiologic study in 22 consecutive patients (12 W and 10 M, mean age 42 +/- 15) with Wolff-Parkinson-White syndrome or supraventricular tachycardia. SETTING: Cardiology Department at University Hospital. INTERVENTIONS: The precise AP mapping was performed with the ablation catheter (4 mm distal electrode and deflectable tip) according to the earlier ventricular activation during sinus rhythm or the earlier atrial activation during ventricular pacing or orthodromic reentrant tachycardia. For left-sided pathways the ablation catheter was positioned on the mitral annulus retrogradely across the aortic valve, while for right-sided pathways it was positioned on the tricuspid annulus or near the coronary sinus os. Radiofrequency energy was applied for 20-60 segs with 55-65 Volts. MEASUREMENTS AND RESULTS: Seventeen AP were manifest and five were concealed. AP were left lateral in 11 patients (50%), left posterior in 5, and right postero-septal, right posterior or antero-septal in 2 patients each. The ablation was initially successful in 18/22 (82%), with 9 +/- 8 radiofrequency applications. Mean duration of the entire procedure was 145 +/- 59 min and the fluoroscopy duration was 39 +/- min. There were no major complications. During 2-9 months of follow-up AP conduction returned in two patients. CONCLUSIONS: Radiofrequency catheter ablation of AP is effective and safe and can be performed at the time of an initial electrophysiologic test, avoiding the need for long-term antiarrhythmic drug therapy or surgical ablation.

Adolescent↗
PubMed1990

[The use of Holter electrocardiography in permanent pacemaker users].

The authors selected 37 permanent pacemaker patients followed for eleven successive months, with symptomatology eventually related to the pacing system. An Holter ambulatory monitorization was performed to all of them during 24 hours. Twenty one had single chamber systems and the others double chamber. Twelve malfunctions were found in ten patients. Six due to "undersensing", 4 related to "oversensing", and 2 from loss of capture. Two patients had tachycardia pacemaker mediated. An inadequate mode of pacing was found in other two cases. Fifteen rhythm disturbances not related to the pacemaker systems were registered in thirteen patients: supra-ventricular in 9; ventricular greater than or equal to 3 degree of lown in 5; and 2nd degree A.V.B. Mobitz type I in one case. Four patients were submitted to surgical intervention in order to modify the mode of pacing. It was also necessary to reprogram ten patients. The Holter Ambulatory Electrocardiography revealed to be an important diagnostic method for the detection of intermittent malfunction of pacing systems. The occasional changes of cardiac rhythm not linked with pacing were also revealed.

Adult↗
PubMed1982

Arrival of excitation at the left ventricular apical endocardium in Wolff-Parkinson-White syndrome type B.

Electrograms were recorded from the His bundle area, right ventricular apex, right ventricular inflow tract, and left ventricular apical endocardium in four patients (aged, 1, 1, 1.5, and 16 years) with Wolff-Parkinson-White syndrome type B. In beats without preexcitation: (a) delayed activation of the right ventricular inflow tract reflected the occurrence of a conduction disturbance through the "distal" or "peripheral" ramifications of the right bundle branch; and (b) the slightly earlier activation of the left ventricular apical endocardium (in reference to the right ventricular apex) may have been due to an earlier emergence from the divisions of the left bundle branch, presumably due to the greater length of the right bundle branch. In beats with preexcitation: (a) the "incomplete" right bundle branch block pattern was concealed because the right ventricular inflow tract was activated before the right ventricular apex; (b) the delta-right ventricular apical intervals were shorter than those of adults with Wolff-Parkinson-White type B; and (c) arrival of excitation at the left ventricular endocardium was a function, either of the impulse emerging from the left bundle branch, or of that propagating from the preexcited site. Therefore, the delta-left ventricular apical endocardial intervals were considered to have represented conduction time from preexcited region to endocardium of left ventricle only when it could be proven that the conduction time (from atrial site of origin to left ventricular apical endocardium) was shorter through the right sided accessory pathway than through the normal pathway. This study suggests that some beats, which may be interpreted as representing "pure" Wolff-Parkinson-White type B complexes from epicardial maps, may in reality be "fusion" complexes.

Adolescent↗
PubMed1978

Persistent atrial standstill with atrial inexcitability.

Electrophysiologic studies including His bundle recording, atrial, and ventricular stimulation, were performed in three symptomatic patients with persistent atrial standstill of unknown etiology. The rhythm was junctional in two cases and ventricular in one. In two cases, evidence suggestive of associated impairment of the His bundle conduction system was found. The atria were inexcitable at multiple sites and no retrograde conduction to the right atrium could be elicited by ventricular pacing. Follow-up in the three cases, respectively for 48, 42 and 12 months after pacemaker implantation, revealed no return of spontaneous atrial electrical activity.

Adult↗
PubMed1976

[Angina pectoris].

The present treatment of angina pectoris is briefly examined. It would appear from the literature published over the last three years that no cure has yet been found. Improvement in prognosis may be expected, particularly in stable forms. Existing clinical, ECG and angiocardiographic methods of diagnosis are described. Better awareness of the factors responsible for angina, coupled with more accurate diagnosis, enable clinical improvement to be achieved in a large number of cases by means of rationally planned medical or surgical management.

Angina Pectoris↗
PubMed1976

[Angina pectoris. Results of investigations to date (author's transl)].

Among the most important coronary risk factors are a diet rich in saturated fatty acids, cholesterol and calories, hypercholesterolemia, high blood pressure and excessive smoking. The typical pain can be elicited by putting a strain on the patient, e.g. climbing stairs. The disappearance of the pain after treatment with nitroglycerine is one of the most important pointers. Treatment is with nitroglycerine which, moreover, remains the drug of choice, also with nitrates such as pentaerythritol tetranitrate and with betablockers like propranolol. Favorable results have also been reported with a combination of isosorbide dinitrate and propranolol.

Adrenergic beta-Antagonists↗