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M J Carvalho

Publications and source records attributed to M J Carvalho.

31 records · Page 2Linked to original sources
PubMed1994

[The ambulatory recording of the long-term electrocardiogram].

In the past 5 years, a new approach was developed to evaluate the patient with sporadic symptoms as is the patient with syncope--the long-term ambulatory loop electrocardiogram monitoring. This method allow to assure the heart rate and rhythm at the moment of the symptoms hardly to be able with the other diagnostic tools disposable. The long-term ambulatory loop electrocardiogram monitoring was not to replace the actual tools, but complement them. Newer devices are smaller and too light, and have the ability of registry some minutes before and after the symptom. In the near future, the devices will be able to detected and store arrhythmias and to possess an easy and accessible management. With continued and profitable work that has been done in this area, a large proportion of patients with the diagnosis of "syncope of unknown etiology" can have a diagnostic and specify therapeutic and we will be able to assert with more strictness if the symptoms related by the patient are or not of cardiovascular origin.

Arrhythmias, Cardiac↗
PubMed1993

[Neurologic evaluation of 118 patients in the first postoperative period of cardiovascular surgery].

118 patients (79 mean and 39 women, mean age of 50.7 years) who underwent cardiovascular surgery and extracorporeal oxygenation were prospectively evaluated for neurologic complication and its correlation with risk factors. 71 were submitted to coronary artery graft by-pass (RM), 18 to valve replacement (TV), 6 to prosthetic valve replacement (RV), 11 to commissurotomy(Co), 5 to thoracic aortic aneurysm correction (An Ao T) and 7 to other surgeries (OT). All of them received extracorporeal oxygenation. No deaths were registered; 14 (11.9%) patients had neurologic abnormalities: delirium in 7 cases, ischemic stroke in 6, epileptic seizure in 3. Patients with systemic arterial hypertension and older patients exhibited a statistically significant (p < 0.05) higher risk of complication. Compared to data of the literature, we had a lower index of morbidity and mortality.

Adolescent↗
PubMed1993

[Malignant vasovagal syncope: a case of prolonged asystole induced by the "tilt" test and aggravated by therapy with a beta blocker (a clinical case and diagnostic, physiopathologic and therapeutic review)].

The authors describe a case of a middle-age male with recurrent syncope, in whom the tilt test was useful in the diagnosis and therapeutic evaluation. Malignant criteria of vasovagal syncope were established and the beta blocking worsening effect was documented, in spite of the general agreement of the first choice drug.

Adult↗
PubMed1993

Spectral analysis of heart rate variability in athletes.

The objectives of the study were to characterize power spectrum pattern of the heart rate variability and assessment of the relative contributions of sympathetic and parasympathetic cardiac nervous system control in athletes. Thirty-three male athletes, swimming (1), canoeing (10), cycling (6), athletics (4), football (3), roller-skating (2) and volleyball (7) aged 23.4 +/- 5.5 years, with a mean athletic level of 18 hours/week (8-45) and 33 sedentary healthy control subjects were included. Ecg signals were recorded after a period of 15 minutes in supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive heart beats, we calculated mean average, standard deviation, maximum and minimum R-R intervals and, after computing the fast Fourier transform, total spectrum power, low frequency (LF), high frequency (HF) components and its ratio (LF/HF). The average R-R interval was 987.7 +/- 168.8 ms and 762.7 +/- 125.3 ms, the variance was 5.44 and 2.51 ms2 and ratio of R-R interval maximum/minimum (E/I ratio) 1.53 +/- 0.16 and 1.41 +/- 0.16, respectively for athletes and control group. Differences between groups were significant (p < 0.01) for all parameters, with higher variability in the athletes. Both spectral bands (LF and HF) had higher power in athletes (LF = 925 +/- 920 and HF = 2258 +/- 2349 ms2) than in the control group (LF = 442 +/- 446 and HF = 1179 +/- 1542 ms2) (p < 0.01). There were no significant differences for LF/HF ratio, or normalized LF (LF%) or normalized HF (HF%) between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Respiratory system mechanics in patients treated with isotonic or hypertonic NaCl solutions.

Twenty-one patients who underwent elective surgery for coronary artery bypass were studied right after chest wall closure. They were anesthetized, paralyzed, and artificially ventilated with a constant-flow ventilator. Airflow, changes in lung volume, and tracheal pressure were measured. Respiratory system resistance (Rrs,max) was partitioned into its homogeneous (Rrs,min) and uneven (Rrs,u) components. Respiratory system elastance (Ers) was also measured. The subjects were randomly divided into two groups injected with test solutions just after chest wall closure: eleven patients received isotonic saline (0.9% NaCl solution), whereas the remaining ten were injected with hypertonic saline (7.5% NaCl solution). In all patients, mechanical parameters were measured at six different times: just before infusion, at 5 and 10 min (end of infusion); and at 15, 20, and 25 min after beginning of injection. No statistically significant differences were observed in respiratory system mechanical parameters between groups or between different times within each group. Our data suggest that hypertonic saline infusion does not result in significant changes in respiratory system mechanics in patients submitted to coronary artery bypass.

Adult↗
PubMed1991

[Study of the autonomous nervous system with heart rate spectral analysis in acute myocardial infarction].

OBJECTIVES: Characterize power spectrum pattern of heart rate variability (HRV) and assessment of relative cardiac nervous system in patients with acute myocardial interaction of sympathetic and parasympathetic infarction. We also compared the spectral power with some known prognostic risk variables. STUDY DESIGN: Study of patients with acute myocardial infarction (AMI) and sedentary healthy subjects sex matched. SUBJECT AND METHODS: 19 postinfarction patients aged 55.7 +/- 10.5 years and 19 healthy subjects controls aged 53.9 +/- 11.0. ECG signals were recorded after 15 minutes of supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive sinus beats, we calculated the average, standard deviation, maximum and minimum values and rate between the longest and shortest R-R interval (E/I). We also calculated, after computing the fast Fourier transform, the total spectrum power, low frequency component (LF, from 0.01 to 0.15 Hz), high frequency component (HF, from 0.15 to 0.50 Hz) and its ratio (LF/HF). Thereafter, we correlated these results with radionuclide ejection fraction, duration of treadmill test, Holter ventricular premature complex and localization of infarction. RESULTS: The average R-R interval was 757.9 +/- 116.3 and 850.9 +/- 133.9 msec (p less than 0.05), the R-R corrected standard deviation was 15.3 +/- 6.0 and 38.2 +/- 8.5 msec (p less than 0.001) and ratio E/I was 1.13 +/- 0.06 and 1.32 +/- 0.09 (p less than 0.001) in AMI and control group, respectively. In AMI group, low frequency spectral band was very decreased (LF = 0.03 +/- 0.02 sec2) and high frequency was virtually absent (HF = 0.01 +/- 0.01 sec2) compared with control group (LF = 0.13 +/- 0.06 and HF = 0.14 +/- 0.15 sec2), p less than 0.001; ratio LF/HF was increased in AMI group. There were no significant differences between groups for normalized LF (LF%) and HF (HF%). CONCLUSIONS: These results showed that spectral pattern in AMI patients had very low LF and HF power density. Decreased HRV in that group was mainly due to diminished parasympathetic influence in cardiac regulation; nevertheless ratio LF/HF was increased which represents an imbalance of sympatho-vagal activity with predominance of sympathetic tone. We found poor correlation between frequency domain indices and other risk variable; best correlation was between total spectral power and radionuclide ejection fraction (r = 0.642, p less than 0.01), which could express independent prognostic value in AMI patients risk stratification.

Autonomic Nervous System↗
PubMed1991

[Spectrum analysis of the variability of heart rate in athletes].

OBJECTIVES: Characterize power spectrum pattern of the heart rate variability and assessment of the relative contributions of sympathetic and parasympathetic cardiac nervous system control in athletes. STUDY DESIGN: Prospective study of athletes and sedentary healthy control group sex and age matched. SUBJECT AND METHODS: 8 athletes, 3 female and 5 male, swimming (4), canoeing (2) and cycling (2), aged 17.4 +/- 3.6 years, and 8 sedentary healthy controls. ECG signals were recorded after a period of 15 minutes in supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive heart beats, we calculated the average, the standard deviation, the maximum and the minimum values and the rate between the longest and the shortest R-R interval (E/I). We also calculated, after computing the fast Fourier transform, the total spectrum power, the low frequency component (LF, from 0.01 to 0.15 Hz) and the high frequency component (HF, greater than 0.15 Hz) and its ratio (LF/HF). RESULTS: The average R-R interval was 921 +/- 154.2 msecs and 673.2 +/- 98 msecs, the standard deviation was 72.5 and 29.4 msecs and the ratio E/I 1.63 +/- 0.14 and 1.28 +/- 0.08, respectively for athletes and control group. Differences between groups were significant (p less than 0.01) for all parameters, with higher variability in the athletes. Both spectral bands (LF and HF) and higher power in athletes (LF = 0.54 +/- 0.23 and HF = 0.76 +/- 0.14) than in the control group (LF = 0.14 +/- 0.10 and HF = 0.18 +/- 0.15) (p less than 0.001). There were no significant differences for LF/HF ratio, or normalized LF (LF%) or normalized HF (HF%) between groups. CONCLUSIONS: The present results indicates higher power of both spectral bands (LF and HF) and higher amplitude of the respective peaks in athletes when compared with healthy sedentary, with a clear predominance of the HF band in the total spectral power density, which suggest that the higher heart rate variability observed in athletes reveals the predominance of parasympathetic activity, without reduction of the sympathetic tone.

Adolescent↗
PubMed1991

[High resolution electrocardiogram and late potential monitoring].

The signal-averaged ECG became an important noninvasive method for identifying life-threatening ventricular arrhythmias. It is most accurate in patients with coronary artery disease and can be helpful in predicting whether a patient with an unexplained syncope or nonsustained VT is at risk of developing sustained ventricular tachycardia or not. A patient with an entirely normal signal-averaged ECG is at very low risk of sustained VT. In contrast, an abnormal signal-averaged ECG should raise suspicion about VT, and prompt further studies, including electrophysiological testing. Signal-averaged ECG can also be used repeatedly with acceptable reproducibility. Technological advances and improvements in the frequency analysis of the averaged signal may increase the predictive accuracy of the technique and consequently enhance its clinical applications.

Electrocardiography↗
PubMed1985

Sporadic acute viral hepatitis A, B and non-A non-B. A prospective study of 150 consecutive cases in São Paulo, Brazil.

In a consecutive series of 150 patients with acute viral hepatitis in São Paulo, Brazil, without previous selection as to age group, 57.3% of patients were 1 to 10 years old, and only 20.7% were 21 or over. Serological analysis of hepatitis A and hepatitis B markers revealed that 82% of patients had hepatitis A, 12.0% hepatitis B and only 6% non-A non-B. Considering only the adult patients (21 years or over), hepatitis B represented 54.8% of cases and hepatitis A and non-A non-B hepatitis, 22.5% each.

Acute Disease↗
PubMedDate not supplied

Nocardial keratitis following myopic keratomileusis.

PURPOSE/METHODS: Interface opacities were detected in a patient who underwent uncomplicated myopic keratomileusis. RESULTS AND DISCUSSION: Nocardia asteroides keratitis was confirmed by microbiologic work-up and guided the correct treatment. The eye recovered 20/60 spectacle-corrected visual acuity and had a residual stromal scar.

Adult↗