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Biomedical subjects

C Morais

Publications and source records attributed to C Morais.

26 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↗
PubMed1990

[Atrial pacing in the evaluation of coronary disease].

In order to assess the value of atrial pacing in the diagnosis of myocardial ischemia, 23 patients (mean age 53 +/- 8 years), submitted to coronary angiography, were studied. Atrial Pacing at incremental frequencies was performed until the appearance of electrocardiographic changes (ST segment depression) and/or typical anginal pain. The highest frequency of stimulation was 160/min. The test was negative in four of five patients (80%) without significant obstructive coronary artery disease. Atrial pacing test was positive in 17 of 18 patients (94%) with abnormal angiography. The authors concluded that clinical and ECG abnormalities induced by atrial pacing seems to be correct indicators for the diagnosis of myocardial ischemia. This test can be an useful alternative in patients unable to perform a conclusive stress test.

Cardiac Pacing, Artificial↗
PubMed1990

[Atrial pacing and the exercise test in the evaluation of coronary disease. A comparative study].

OBJECTIVE: to compare the relative value of Atrial Pacing and Exercise Electrocardiography in the diagnosis of Myocardial Ischaemia. DESIGN: prospective study in patients referred for coronary cineangiography. SETTING: Cineangiography and Ergonometry Departments of Cardiology Service. Santa Maria Hospital. PATIENTS: 16 patients (mean age 52.4 +/- 6.3), 13 males and 3 females. All were submitted to Atrial Pacing, Exercise Test and Coronariography. RESULTS: both tests were concordant in all cases but one, with negative Atrial Pacing, positive Exercise Test and negative Coronariography. CONCLUSIONS: Atrial Pacing compares favourably with Exercise Test in the diagnosis of Coronary Ischaemic Disease. It may constitute a valid alternative in patients unable to perform a conclusive Exercise Test.

Cardiac Pacing, Artificial↗
PubMed1989

[Holter ECG in evaluating myocardial ischemia. Validation using the exercise test].

OBJECTIVES: Validation of ST-T ischemic changes in the Holter system by those recorded in the 12-lead ECG during the exercise test. DESIGN: The changes induced by the exercise test in the ST segment of the two Holter leads--aVF e V5 like--were compared with the changes simultaneously registered in the 12-lead ECG. SETTING: Exercise Test Laboratory and Holter Laboratory of the UTIC-Arsénio Cordeiro. Hospital de Santa Maria de Lisboa. PATIENTS: 31 patients, 23 male and 8 female, with a mean age of 55 +/- 7 years, 84% with ischemic heart disease. METHODS: The patients underwent a treadmill exercise test. 28 with the Bruce protocol and 3 with the Naugton protocol, during which the electrocardiogram was registered simultaneously with a 2-channel Holter recorder and by a conventional 12-lead system. The changes induced in the ST segment in the two systems were compared. RESULTS: The results of the two tests were concordant in 94% of the patients. In 4 patients (13%) there was not a good correlation between the inferior and anterior leads of the two methods, which diverged mainly between the Holter lead aVF and the inferior leads of the conventional ECG. The morphology of the ST depression was similar in both methods, and the severity of ST depression as judged by its amplitude showed an excellent positive linear correlation (r = 0.8542, p less than 0.001). CONCLUSIONS: The sensitivity and the specificity of the Holter system is similar to the conventional 12-lead ECG in detecting ischemic changes during exercise whenever they have electrocardiographic evidence.

Adult↗
PubMedDate not supplied

High-resolution heteronuclear correlation spectra between 31P and 27Al in microporous aluminophosphates.

A solid-state nuclear magnetic resonance (NMR) experiment, which provides high-resolution two-dimensional heteronuclear correlation (HETCOR) spectra between 27Al and 31P, is described. The first part of the experiment uses triple-quantum or quintuple-quantum magic-angle spinning (MQMAS) NMR of spin-5/2 nuclei (27Al) to produce an isotropic echo that is unaffected by the second-order quadrupolar broadening. The magnetization is then transferred to the spin-1/2 (31P) nuclei via cross-polarization (CP), resulting in isotropic resolution in both spectral dimensions. To illustrate its usefulness, this method (referred to as MQHETCOR) is applied to two important microporous framework aluminophosphates, hydrated VPI-5 and AIPO4-40.

Aluminum↗