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Biomedical subjects

M C Vagueiro

Publications and source records attributed to M C Vagueiro.

36 records · Page 2Linked to original sources
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↗
PubMed1975

Electrophysiologic effects of the antiarrhythmic agent disopyramide phosphate.

The electrophysiologic effects of the antiarrhythmic agent disopyramide phosphate given intravenously were studied in 10 patients with cardiac disease. Studies included determinations of sinus recovery time and refractoriness of the atria, the atrioventricular (A-V) node and the His-Purkinje system. Measurements were performed at rest and 15 and 30 minutes after administration of disopyramide. Serum drug levels were measured at these times. Sinus recovery time was shortened at both 15 and 30 minutes, with an average decrease of 39.5 and 146.2 msec, respectively (P less than 0.01). Atrial refractoriness was not altered significantly, but tended to be reduced; the mean effective refractory period was 289.5 msec before administration of disopyramide and 259 and 270 msec 15 and 30 minutes, respectively, after administration. The functional refractory period of the atrioventricular (A-V) node was definitely prolonged in seven patients 15 minutes after administration of disopyramide. The relative refractory period of the His-Purkinje System was not altered. Although this study does not elucidate the mechanism by which disopyramide acheives its antiarrhythmic effects, animal work has shown that it is similar to that of quinidine. In the doses used the drug does not seem to cause first, second or third degree A-V block or fascicular or bundle branch block; it did not increase the severity of first degree A-V block in the three patients with this disturbance. The drug may be particularly useful when arrhythmias are associated with slow sinus rates.

Adult↗
PubMed1975

Syndrome of short P-R, narrow QRS and repetitive supraventricular tachyarrhythmias: the possible occurrence of the R-on-T phenomenon and the limits of this syndrome.

The R-on-T phenomenon was observed in two patients with narrow QRS complexes and repetitive supraventricular tachyarrhythmias. Case 1 had a typical Lown-Ganong-Levine syndrome in which the shortening of the P-R interval was due to a reduction of the A-H interval. In Case 2 the P-R interval (140 msec) was not short but the A-H interval was at the lower limits of normal (50 msec) and the P-A interval at the upper limits of normal (40 msec). Both patients showed the R-on-T phenomenon during periods of 1:1 A-V conduction occurring during atrial stimulation at a rate of 200/min (Case 1) and atrial flutter with a rate of 300/min (Case 2). Although total A-V conduction time was prolonged, the magnitude of this prolongation appeared to have been less than that occurring in normal subjects. This was attributed to the presence of an accessory pathway bypassing the area where the most significant delay occurred at the A-V node. The findings in Case 2 suggest, but do not prove, that a similar bypass might be operative in patients with atrial flutter with periods of 1:1 conduction, regardless as to whether the R-on-T phenomenon is, or is not, present.

Arrhythmias, Cardiac↗
PubMed1968

Endocardial electrograms from pacemaker catheters.

Proper placement of pacemaker catheters can be facilitated by recording endocardial electrograms from the catheters. These electrograms are also helpful in the investigation of pacemaker failure. Endocardial contact is indicated by S-T segment elevation. When bipolar catheters are used, these "contact currents" may be visible in electrograms from the tip or ring electrodes, or both. Right ventricular cavity electrograms are characterized by their high voltage and are influenced by intraventricular conduction defects and acute myocardial infarction. Serial changes have been described indicating myocardial injury, infarction, and healing in the area underlying the catheter tip.

Cardiac Catheterization↗
PubMedDate not supplied

Pacemakers for refractory heart failure: the road not taken?

Dual chamber pacemaker implantation has been investigated as a possible treatment modality for patients with advanced congestive heart failure (CHF) who do not respond to current pharmacologic approaches. By optimizing atrioventricular contraction with pacing, hemodynamics have been shown to improve in short-term studies. The long-term benefits of therapy have not been demonstrated conclusively, and clinical trials are now in progress to study pacemaker implantation with and without implantable cardioverter defibrillators as a possible therapeutic option.

Heart Failure↗
PubMedDate not supplied

[Magnetic resonance in cardiology. The current clinical outlook].

Magnetic resonance imaging (MRI) is a diagnostic technique used clinically in cardiology over the last ten years. It offers great advantages over other methods as it is noninvasive, does not use radiation, is tomographic and multiplanar. MRI is a very flexible technique based on the interaction between atomic nuclei, usually hydrogen, and external magnetic fields. This leads to image formation and to other important functional diagnostic information. MRI has undergone great technical developments and has proven to be most useful in several areas: cardiovascular structure; global and regional cardiac function; cardiovascular flow; coronary anatomy; myocardial perfusion and metabolism. The initial clinical diagnostic goals of MRI were mainly the anatomic characterization of aortic pathology, congenital heart disease, pericardium diseases and cardiac masses. With the development of cine MRI and, more recently, with rapid imaging and flow evaluation techniques, it has been increasingly used in the functional assessment of cardiovascular diseases. The functional study of the above mentioned clinical pathologies is now possible and information can also be obtained in other important areas; cardiac volumes and function; cardiovascular shunts, valvular heart disease; ischemic heart disease (ischemia detection, infarction quantification, coronary anatomy and flow). It also has an important role in myocardial characterization and is promising for myocardial metabolism, evaluated by spectroscopy. The goal of this review is the presentation of the main MRI techniques and the present clinical applications of this imaging method in cardiovascular diagnosis.

Cardiovascular Diseases↗