Biomedical subjects

Luís Providência

Publications and source records attributed to Luís Providência.

4 recordsLinked to original sources

PubMed2004

Pulmonary embolism.

Pulmonary embolism (PE) is an important health problem and often a major clinical challenge, not only because of the low specificity of its clinical manifestations but also because of the increasing number of medical circumstances that are risk factors for this illness and the importance of early identification, since prompt and appropriate treatment can decrease mortality from this disease by about 25%. In recent years research on PE has been extensive, directed mainly at trying to determine and characterize its risk factors, establish new clinical probability algorithms, develop new diagnostic methods and put existing ones into perspective, seek new therapeutic approaches (pharmacological and non-pharmacological), and above all establish protocols that can guide the clinician from the stage of clinical suspicion to measures to prevent recurrence. It was the authors' aim to review the most significant literature on this subject, in order to produce a text that reflects the state of the art concerning PE and that can be used as a guide in the clinical approach to this pathology.

Diagnosis, Differential↗

PubMed2004

Previous therapy with amiodarone increases the recurrence rate in successfully ablated patients with isthmus-dependent atrial flutter.

Ablation of isthmus-dependent atrial flutter in patients previously medicated with antiarrhythmic drugs may cause functional isthmus block during ablation, and subsequent discontinuation of therapy may lead to incomplete isthmus block (and recurrence). This may be particularly important if the drugs previously used have long plasma half-lives (and washout periods). The objective of this study was to evaluate whether the recurrence rate of isthmus-dependent atrial flutter was greater in patients previously medicated with antiarrhythmic drugs and whether there were differences in recurrence rate with different types of antiarrhythmic drugs. During a mean follow-up of 20 +/- 7 months, we observed 57 patients with previous successful ablation of isthmus-dependent atrial flutter. This population of patients was divided into three groups according to the type or absence of previous antiarrhythmic drugs: Group 1--n = 18, patients previously medicated with amiodarone; Group 2--n = 27, patients previously medicated with drugs with short plasma half-lives (propafenone; flecainide; beta-blockers); Group 3--patients without previous antiarrhythmic medication. In all 57 patients bidirectional isthmus block was achieved after the ablation procedure; 8 mm non-irrigated tip catheters were used. During follow-up a recurrence rate of 33% was observed in Group 1 (6 recurrences in 18 patients; p < 0.05 in comparison with Groups 2 and 3); 3.7% in Group 2 (1 in 27 patients) and 0% recurrence rate in Group 3. We conclude that in our study the patients previously medicated with amiodarone had a higher recurrence rate of the arrhythmia compared to patients not previously medicated with antiarrhythmic drugs or medicated with antiarrhythmics with short plasma half-lives.

Amiodarone↗

PubMed2002

Impact of diabetes on induction of the mitochondrial permeability transition.

Diabetes is one of the most common metabolic diseases of our times. Specific cardiovascular alterations are often associated with the progression of this disease. Considerable controversy exists in the literature concerning the greater or lesser susceptibility of the diabetic heart to ischemia and reperfusion. Cardiac mitochondria may be fundamental to the differential susceptibility of the cardiomyocyte to pathologic phenomena, particularly those due to the induction of the degenerative process known as the mitochondrial permeability transition (MPT), which is triggered by excessive mitochondrial calcium accumulation. The MPT has been associated with cellular dysfunction resulting from ischemia and reperfusion. The objective of this work was to examine the susceptibility of mitochondria isolated from diabetic rats to the MPT, in comparison to healthy control rats of the same age. Cardiac mitochondria from the diabetic rats had higher calcium loading capacity before the development of the MPT, with a decreased incidence of MPTP-associated features. This was associated with a greater capacity to sustain multiple pulses of externally added calcium, simultaneously with maintenance of the transmembrane electrical potential and reduced swelling amplitude. This could mean that cardiomyocytes from diabetic hearts may indeed be less prone to dysfunctions resulting from ischemia and reperfusion, at least in milder diabetic conditions, thus explaining many reports in the literature.

Animals↗

PubMedDate not supplied

The worse hospital outcome of diabetic patients is not explained by the severity of underlying coronary artery disease.

INTRODUCTION: Diabetes mellitus has a high prevalence in developed countries and is associated with high cardiovascular morbidity and mortality rates. In this study we evaluated in-hospital evolution of diabetic patients admitted to a cardiac care unit with acute coronary syndrome without ST segment elevation. METHODS: We analyzed a population of 176 consecutive patients, 36 (21%) with diabetes, admitted with chest pain at rest, elevated biological markers for myocardial necrosis and/or ST segment/T wave changes suggestive of myocardial ischemia. RESULTS: The groups were similar in terms of age, sex, presence of other risk factors for coronary artery disease (CAD), past history of CAD or myocardial revascularization. There were no differences between the groups with respect to extent of CAD, left ventricular function or blood levels of biological markers. The comparison between the two groups did not show any statistical difference concerning the following in-hospital events: non-Q wave MI, Q-wave MI, PTCA and death. On the other hand, the diabetic patients had a worse outcome in term of congestive heart failure (25% and 11%, p = 0.04), CABG (25% and 10%, p = 0.02) and combination of death, congestive heart failure and Q-wave MI (42% and 23%, p = 0.02). CONCLUSION: In spite of similar extent of CAD and similar left ventricular function, diabetes mellitus in patients with acute coronary syndrome without ST segment elevation identifies a higher-risk population with more complicated in-hospital outcome.

Acute Disease↗