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Background: Inspiratory muscle training (IMT) has been shown to generate significant benefits in different clinical conditions; however, there is scarce information regarding acute clinical and hemodynamic effects., Aim: The aim of this study was to evaluate clinical, hemodynamic and electrocardiographic responses during a single short IMT session in patients enrolled in cardiopulmonary rehabilitation program (CRP)., Design: Cross-sectional study., Setting: Patients referred and regularly attending a non-hospital based medically-supervised exercise program., Population: One hundred and sixty patients patients who regularly performed inspiratory muscle training, Methods: A convenience sample of 21 elderly patients (16 men; 60-87 years of age) had an ECG continuously recorded and heart rate (HR) and blood pressure (BP) measured before, during and one-minute after a single IMT session - two sets of 15 cycles with one-minute interval., Results: Comparing values obtained before, during second set and one-minute after IMT, no differences were found to HR (bpm) - 68±2 vs. 70±2 vs. 66±3 (P=0.05) and in systolic and diastolic BP (mm Hg) values, respectively, - 105±3 vs. 111±4 vs. 108±3 (P=0.06) and - 68±2 vs. 72±3 vs. 68±2 (P=0.14); (before, during second set and one-minute after TMI). During IMT, seven (33%) of patients presented minor cardiac arrhythmias, most of them isolated premature ventricular contractions. Additionally, no abnormal signs or symptoms were found., Conclusion: Apart of minor and clinically irrelevant ECG abnormalities seen in 1/3 of the patients, a short IMT session did not induce significant hemodynamic responses or relevant clinical abnormalities. Based on these results, for elderly patients involved in CPR, IMT seems to be clinically safe and continuous ECG monitoring did not seem to add significant or relevant information., Clinical Rehabilitation Impact: For elderly patients participating in CPR, short IMT sessions do not induce major hemodynamic responses and seem to be clinically safe. This is potentially useful information if IMT is to be prescribed in home-based programs.

Introduction: The meaning of electrocardiographic changes appearing during the clinical follow-up of Chagas disease (ChD) is unknown. In this study, a patient cohort with ChD was followed to describe the electrocardiographic changes that may make it possible to identify patients whose left ventricular function has deteriorated., Methods: The study sample consisted of a prospective cohort followed since 1998 to 1999, involving 220 patients aged 15 to 55 years, 30 controls, and 190 with ChD, without other comorbidities. The group was reexamined between 2004 and 2006, and new electrocardiograms were obtained for 153 patients, 25 (83%) of 30 in the control group and 128 (72%) of 177 in the ChD group. Electrocardiographic variables associated with a significant decrease in ejection fraction (5% or more) were identified., Results: A significant decrease in ejection fraction was observed in 21 patients in the ChD group (18.7%) but in none of the non-ChD group (P = .024). Only the presence of a new electrocardiographic abnormality and an increase in QRS duration correlated with a decrease in an ejection fraction of 5% or more. QRS duration was correlated with both an increase in left ventricle diastolic diameter and a deterioration in the ejection fraction (r(s) = 0.225, P = .017, and r(s) = -0.300, P < .001). A QRS increase of 5 milliseconds had 77.8% sensitivity and 62.2% specificity for identifying patients with significant decrease in ejection fraction., Conclusion: The increase in the duration of the QRS complex and the appearance of new electrocardiographic alterations may help in identifying patients with a significant decrease (of 5% or more) in left ventricle ejection fraction., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: To determine the viability of using a conventional electrocardiogram (ECG) tracing for assessment of CVA., Methods: We retrospectively analyzed 1395 individuals (995 males), aged 46 +/- 17.2 years (mean +/- standard deviation) with conventional ECG tracings to measure the delta RR (which represents the difference in milliseconds (ms) between the greatest and smallest RR interval) and results of a second autonomic parasympathetic evaluation, the 4-second exercise test (T4s), that quantifies CVA by the cardiac vagal index (CVI). ROC curves were obtained to determine the values of Delta RR for a closer correlation with sensitivity and specificity for 1.20 and 1.95 ms, the low and high CVA cutoff points, respectively., Results: The delta RR levels correlated significantly with those of the CVI (r=0.40; p<0.001). We identified < or = 60 and > or = 120 ms as the best cutoff points for low and high CVA. Sensitivity was 75% and 57%, specificity was 62% and 79%, and the areas of the ROC curves were 0.76 and 0.74, respectively., Conclusion: The visual measurement of delta RR on an ECG tracing seems to be a valid quick preliminary clinical evaluation of CVA and can be useful in medical offices, emergency units, or situations in which the use of more sophisticated methods may not be feasible, appropriate, or convenient.

Background: The importance of vagal tone on cardiac function and cardiovascular mortality is well established. Although the presence of an enhanced cardiac vagal tone (CVT) is frequently diagnosed using the 12-lead resting electrocardiogram (ECG) in daily practice, most of the proposed criteria have been determined on an empirical basis. Our objective was to evaluate the effects of pharmacological blockade of the parasympathetic component of the autonomic nervous system on resting ECG tracings., Methods: Nine healthy young adults (24+/-5 year-old) underwent parasympathetic blockade with atropine sulfate i.v. (0.04 mg kg(-1)) and resting ECGs were obtained before and 15 min thereafter. CVT was assessed by a dimensionless index, which measures the RR interval reduction caused by the vagal withdrawal induced by a 4-s exercise test performed on a cycle ergometer where the subjects pedal as fast as possible with no added resistance., Results: This index was 1.63+/-0.24 and 1.03+/-0.03, before and after atropine, respectively (P<0.0001). Atropine reduced the R-R intervals (P<0.0001), and the amplitude of T-waves in several leads (DII: P=0.03; V4: P=0.04; V5: P=0.03; V6: P=0.01), and abolished the appiculation of T-waves, J-point and ST-segment elevations (P<0.05), and U-waves (P<0.05), which were present in baseline ECG in all subjects in at least two leads. The R-wave amplitude in leads V4, V5, and V6 (all P>/=0.10) was not modified by atropine infusion., Conclusion: The duration of the R-R intervals and the amplitude of T-waves in leads DII, V4, V5, and V6, and the presence of T-wave appiculation, U-waves, and elevation of J-point and ST-segment should be used to detect enhanced cardiac vagal tone in healthy subjects.

Purpose: To identify the most important criteria for the ECG diagnosis of vagotonia in the opinion of cardiologists., Methods: A written questionnaire was applied to 40 cardiologists attending the 9th Brazilian Congress of Cardiac Arrhythmias (S. José do Rio Preto, SP, 1992). The sample represented approximately 15% of all participants and was intentionally biased to include 70% of the invited speakers and free communications presenters, and to exclude non-medical professionals, aiming to enhance the validity of the answers. It was divided in two parts: the first, with spontaneous response, answered without knowledge of the following; and the second, where a list of ECG criteria obtained in the literature was presented to the respondent in a random order. In both parts, the specialists were requested to attribute an order of importance for each criterion., Results: In the 1st part, 35 different criteria were cited, but only 3 were assigned by more than 25% of the sample: sinus bradycardia (95%), tall and peaked T waves (30%) and early repolarization (27.5%). In the 2nd part, the best classified criterion was sinus bradycardia, followed by J point elevation and ST segment elevation., Conclusion: Among cardiologists with a interest in electrocardiography and cardiac arrhythmias, apart of sinus bradycardia, there is no clear consensus concerning to the group of criteria to identify vagotonia in the standard 12-lead ECG. Further research is necessary to objectively validate the main criteria herein identified.

To evaluate the relative influence of the two branches of the autonomic nervous system on the 4-s exercise test which measures heart rate acceleration at the onset of exercise, 6 healthy male subjects performed the 4-s test under sympathetic blockade with propranolol, parasympathetic blockade with atropine and dual blockade. The magnitude of the 4-s test results (means +/- SD) was significantly different only between the conditions with and without atropine (1.04 +/- 0.03 vs 1.53 +/- 0.33, respectively), with no differences between the control (1.60 +/- 0.25) and the test under sympathetic blockade (1.51 +/- 0.33). These results support the conclusion that the 4-s exercise test is a specific method for the evaluation of parasympathetic activity.