José Barbosa Filho

Autonomic Modulation of the Heart in Systemic Arterial Hypertension

OBJECTIVE To analyze the heart rate variability in patients with mild to moderate systemic arterial hypertension. METHODS Thirty-two healthy (group I) and 70 systemic arterial hypertensive (group II) individuals, divided according to age (40 to 59 and 60 to 80 years old, respectively) and with a similar distribution by sex were studied. Thirty-one had left ventricular hypertrophy (LVH), 22 were overweight, and 16 had Type II diabetes mellitus. Smoking, alcohol ingestion, and sedentary habits were the same between groups. Variability in heart rate was analyzed in the time domain, using standard deviations of normal RR intervals (SDNN) and the differences between maximal brady- and tachycardia (D-BTmax) during sustained inspiration. Analysis of the frequency band of the power spectrum between 0.05 and 0.40 Hz at rest and during controlled respiration was chosen for analysis of the frequency domain. RESULTS In both time and frequency domains, variables were lower in group II than in group I. Within groups, statistically significant variables were only found for individuals in the 40 to 59 year old group. The presence of LVH, overweight, or diabetes mellitus did not influence the variability in heart rate to a significant extent. CONCLUSION Variability in heart rate was a valuable instrument for analyzing autonomic modulation of the heart in arterial hypertension. The autonomic system undergoes significant losses in cardio-modulatory capacity, more evident in subjects between 40 and 59 years old. In those over 60 years old, reduced variability in heart rate imposed by aging was not significantly influenced by the presence of systemic arterial hypertension.

Nonrespiratory Sinus Arrhythmia

We report here 2 cases of sinus arrhythmia considered to be a form of nonrespiratory sinus arrhythmia because they did not have variances in the RR interval sequence within the oscillations modulated by respiration. Because the patients had pulsus alternans similar that observed in bigeminy, and because they did not have signs or symptoms of heart failure, we believe the arrhythmias represent intrinsic alterations of the electric activity of the sinus node

Exercícios em curto prazo de resistência no quadríceps em indivíduos hipertensos refratários

INTRODUCTION: Resistant arterial hypertension may lead to muscle disuse and reduced functional capacity due to arterial and target-organs lesions. The main objective of this work is to evaluate the quadriceps strength and fatigue tolerance after a program of resistance exercise in subjects with resistant primary hypertension. METHODS: Six patients under pharmacological treatment were submitted to a four-week resistance exercise training program for the quadriceps (8-14 repetitions, 3 sets, 3 days per week). Strength was evaluated by isometric dynamometry, as the percentage change in maximum voluntary contraction over the four week program. Fatigue was analyzed by surface electromyography, as the change in both root mean square value and intercept of median frequency slope of vastus medialis and vastus lateralis. RESULTS: Significant increase in the maximum voluntary contraction was observed (p = 0.04). Fatigue tolerance was not improved as seen by root mean square as well as in the intercept of median frequency (p > 0.05). Additionally, no significant changes were observed in resting arterial blood pressure and heart rate throughout the training period. CONCLUSION: The prescribed protocol seemed to successfully increase localized muscle strength without negatively affecting the monitored cardiovascular variables in patients with resistant hypertension under pharmacological treatment.

Effect of oscillatory breathing on the variability of the RR Intervals and its prognostic importance in individuals with left ventricular global systolic dysfunction

OBJECTIVE To assess the effect of the oscillatory breathing on the variability of RR intervals (VRR) and on prognostic significance after one year follow-up in subjects with left ventricular global systolic dysfunction. METHODS We studied 76 subjects, whose age ranged from 40 to 80 years, paired for age and gender, divided into two groups: group I - 34 healthy subjects; group II - 42 subjects with left ventricular global systolic dysfunction (ejection fraction < or = 0.40). The ECG signals were acquired during 600s in supine position, and analyzed the variation of the thoracic amplitude and the VRR. Clinical and V-RR variables were applied into a logistic multivariate model to foretell survival after one year follow-up. RESULTS Oscillatory breathing was detected in 35.7% of subjects in vigil state of group II, with a concentration of the spectral power in the very low frequency band, and was independent of the presence of diabetes, functional class, ejection fraction, cause of ventricular dysfunction and survival after one year follow-up. In the logistic regression model, ejection fraction was the only independent variable to predict survival. CONCLUSION 1). Oscillatory breathing pattern is frequent during wakefulness in the left ventricular global systolic dysfunction and concentrates spectral power in the very low band of V-RR; 2). it does not relate to severity and cause of left ventricular dysfunction; 3). ejection fraction is the only independent predictive variable for survival in this group of subjects.

Symptom-guided Assessment of Atrial Fibrillation Recurrence After Radiofrequency Pulmonary Vein Ablation: is it a Reliable Strategy?

The impact of symptom-guided perception of atrial fi brillation (AF) recurrence after pulmonary vein radiofrequency ablation (PVRFA) has raised serious concern as a potential flaw in taking into account successful procedures. Although the defi nition of success may vary, bidirectional block through ablated regions is unnecessary in order to achieve a successful procedure¹, and in previously symptomatic patients short and long-term success of PVRFA is focused on detection of symptomatic episodes². Thus, asymptomatic AF episodes are not necessarily credited as recurrence. It is noteworthy that, as a potentially curative procedure, successful PVRFA implies long-term maintenance of sinus rhythm and further reduction of AF-related morbidities, e.g. cardio-embolism. Therefore, anticoagulant withdrawal is the aim.Using seven-day continuous ambulatory ECG monitoring, Hindricks et al³ demonstrated that asymptomatic recurrence of AF increased from 5% to roughly 36% during a 12-month follow-up. Same authors³ reported that when symptom-guided, a 70% rate of freedom of AF episodes after PVRFA in a six-month follow-up was observed. Rate of freedom decreased from 70% to 50% when assessed by seven-day continuous ambulatory ECG monitoring, and further to 45% when transtelephonic ECG transmission was employed. In this scenario, the actual rate of recurrence of AF episodes after PVRFA is proposed as being higher than previously reported using similar techniques