Early Heart Rate Increase Research Articles

Comparative analysis of health-related fitness in patients with acute versus chronic Chagas disease.

Although Chagas disease causes high levels of morbidity, the muscle function and tolerance to physical activity in Chagas disease patients are still not completely understood. To compare health-related fitness of patient groups with acute Chagas disease versus chronic Chagas disease. We conducted a cross-sectional study involving 18 patients. The data were obtained from patient´s records, and functional capacity was measured with the sixminute walk test, the peripheral muscle strength with handgrip strength, and respiratory muscle strength using the maximum inspiratory pressure and the maximum expiratory pressure. The 18 patients were divided in two groups: acute Chagas disease (n=9) and chronic Chagas disease (n=9). The distance walked in the six-minute walk test was lower than the predicted distance walked in both groups (p < 0.0001). The maximum expiratory pressure was lower than the predicted one (p = 0.005), and statistically significant for chronic Chagas disease patients (p = 0.02). Heart rate increased faster in the chronic Chagas disease group within the first two minutes of the six-minute walk test (p = 0.04). The sixminute walk test in the acute Chagas disease group presented a strong correlation with peripheral muscle strength (p = 0.012) and maximum inspiratory pressure (p = 0.0142), while in the chronic Chagas disease group, only peripheral muscle strength and maximum inspiratory pressure were correlated (p = 0.0259). The results suggest lowered functional capacity and reduced respiratory and peripheral muscle strength in patients with Chagas disease, although no differences were observed between groups. The early increase in heart rate during exercise in the chronic Chagas disease group implies a greater myocardial overload.

THE FUNCTIONAL STATE OF THE CARDIOVASCULAR SYSTEM IN THE CONDITIONS OF A STRESS TEST IN JUNIOR FEMALE STUDENTS WITH MANIFESTATIONS OF PSYCHO-EMOTIONAL IMBALANCE

Introduction. The purpose of the study is to assess the state of the functional reserves of the cardiovascular system in junior female students with manifestations of maladaptation and excessive anxiety in conditions of stress. Research materials and methods. At the initial stage, 70 female students were examined using standardized questionnaires by Cohen and Spielberger. Based on the results of the survey, the main group of girls (n = 26) with signs of maladjustment and excessive anxiety, and the control group with negative survey results (n = 12) were formed. Female students in both groups were of the same age and had the same body mass index. At the second stage of the study, indicators of the cardiovascular system were studied among girls of both groups at the height of the cardiac stress test (CST) test according to the Cornell protocol. At the same time, the heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), the stroke volume (CV), minute blood volume, and the index of the chronotropic and inotropic reserves of the heart were determined. Research results. It was established that the girls of the main group had a decrease in the tolerance of the CST to (103.85 ± 4.43) W, against the average indicator of (147.92 ± 6.86) W in the control group. The result obtained in the main group was accompanied by an early increase in HR, minute blood volume, SBP, and a decrease in indicators of inotropic and chronotropic reserves, a double product, which indicated the presence of hidden disorders of the regulatory mechanisms of the stress-limiting system. Changes in hemodynamics detected in female students of the main group correlated with low stress resistance, excessive anxiety. At the same time, in the control group of female students, hemodynamic indicators underwent changes at the late stage of the SCT, which indicated a better state of neurohumoral reserves. Conclusion. Timely detection of homeostasis disorders in adolescence and their consequences through the use of diagnostic tests and functional tests will make it possible to detect adaptation disorders and possible psychosomatic conditions in adolescent girls and to develop ways to prevent them or reduce clinical manifestations and improve the quality of life, including the learning process and further professional activity.

Heart rate response to orthostatic challenge in patients with dementia with Lewy bodies and Alzheimer's disease.

To elucidate the differences in autonomic dysfunction between dementia with Lewy bodies (DLB) and Alzheimer's disease using a simple and convenient method, we investigated the heart rate response to orthostatic challenge. Ninety-seven people participated in this cross-sectional study, and data from 26 DLB patients, 29 Alzheimer's disease patients, and 25 healthy elderly individuals were analysed. Participants underwent postural changes, including 5 min in a supine position, 1 min in a sitting position, and 3 min in an orthostatic position. Their heart rates were continuously recorded. Two heart rate variables were analysed as main outcomes: (i) the difference between heart rate in the sitting position and the peak heart rate within 15 s of orthostasis, defined as the 'early heart rate increase'; and (ii) the difference between the peak heart rate and the negative peak heart rate after this, defined as 'early heart rate recovery.' An early heart rate increase has been considered to reflect parasympathetic and sympathetic functions. Early heart rate recovery is considered to reflect parasympathetic function. We also investigated the frequency domains of resting heart rate variability. A significant difference was observed across the three groups in early heart rate increase, and that of the DLB group was lower than that of the healthy control group. Early heart rate recovery also differed significantly across the three groups, and that of the DLB group was less than that of the healthy control group. In addition, the power of the low-frequency component, which represents both sympathetic and parasympathetic activity, was significantly decreased in the DLB group compared to the Alzheimer's disease group. Impaired heart rate response to standing was detected in patients with DLB. Electrocardiogram is a convenient, non-invasive method that might be useful as a subsidiary marker for DLB diagnosis and differentiation from Alzheimer's disease.

Modeling human orthostatic responses on the Moon and on Mars.

Since manned missions to the Moon and Mars are planned, we conducted active standing tests with lunar, Martian, terrestrial, and 1.8 loads of inertial resistance (+Gz) modeled through defined parabolic flight maneuvers. We hypothesized that the cardiovascular response to active standing is proportional to the +Gz load. During partial-+Gz parabolic flights, 14 healthy test subjects performed active stand-up maneuvers under 1 +Gz, lunar (0.16 +Gz), Martian (0.38 +Gz), and hyper inertial resistance (1.8 +Gz) while heart rate and finger blood pressure were continuously monitored. We quantified amplitudes and timing of orthostatic response immediately following standing up. The maximum early heart rate increase was 21 (SD ± 10)bpm with lunar, 23 (± 11)bpm with Martian, 34 (± 17)bpm with terrestrial +Gz, and 40 (± 11)bpm hyper +Gz. The time to maximum heart rate increased gradually with increasing loads of inertial resistance. The transient blood pressure reduction was most pronounced with hyper +Gz but did not differ significantly between lunar and Martian +Gz. The mean arterial pressure nadir was reached significantly later with Martian and lunar compared to 1 +Gz. Paradoxically, the time for blood pressure to recover was shortest with terrestrial +Gz. While load of inertial resistance directly affects the magnitude of the transient blood pressure reduction and heart rate response to active standing, blood pressure stabilization is most rapidly attained during terrestrial +Gz. The observation might suggest that the human cardiovascular system is tuned to cope with orthostatic stress on earth.

Exercise-onset heart rate increase is slowed in multiple sclerosis patients: Does a disturbed cardiac autonomic control affect exercise tolerance?

To explore the etiology of exercise intolerance in patients with MS, it is analyzed whether a disturbed cardiac autonomic control could be observed during exercise testing in patients with MS, and is related to exercise tolerance. From 26 MS patients and 15 healthy subjects, exercise-onset (first 20 and 60 seconds) and -offset (1-minute recovery) HR change was determined during a 6-minute constant-load exercise bout on bike. Blood lactate, HR, oxygen uptake, expiratory volume and perceived exertion were assessed during exercise, and compared between groups. In 15 MS patients, a 6-min walking test was executed. Twenty-second exercise-onset HR increase was significantly smaller in MS patients (14 ± 7 bts/min) vs. healthy subjects (20 ± 8 bts/min, p < 0.05), and independently related to MS and age in total group (p < 0.05). Sixty-second exercise-onset and -offset HR changes were not different between groups, nor independently related to MS presence (p > 0.05). A significant correlation was found between 20-second exercise-onset HR increase and walking capacity in MS patients (r = 0.64, p < 0.01). In MS patients, the early increase in heart rate during endurance exercise is significantly slowed, indicating a disturbed cardiac autonomic control, and is related to exercise tolerance.

Prediction of Head-Up Tilt Test Result: Is it Possible?

The determination of early, accurate, predictive criteria for a positive result would permit a reduction in the duration of the head-up tilt testing (HUTT). Previous studies propounded that existence of early sympathetic overreactivity (rapid and sustained increase in heart rate) during HUTT predicts positive result. However, the exact value of this variable is unknown. We analyzed the early heart rate (HR) responses to HUTT and evaluated their ability to predict HUTT result. Consecutive patients referred to the syncope unit of our center for recurrent unexplained syncope were studied. We studied 189 consecutive patients and 67 (35%) patients had a negative HUTT; 122 (65%) patients had a positive HUTT. The early HR increase was defined as the maximum HR during the first 10 minutes of tilting minus the resting HR before tilting. The receiver-operator curves (ROCs) show the overall performance of the HR changes for predicting the HUTT result. For all variables, area under the ROC curve (AUC) was nearly equivalent to 0.50 and early HR increase was not a predictor of the negative result of HUTT (AUC = 0.546). Also there was no any significant correlation between the magnitude of early HR increase and patient age (r =-0.03, P = 0.76). The results suggest that the early increase in HR during the first 10 minutes of the HUTT may not be a useful parameter for predicting the test result. Many factors, such as late exaggeration in sympathetic activity during HUTT and age-dependent reduction in baroreflex sensitivity, may attenuate the predictive value of early HR increase.

Predictor of a Negative Tilt-Table Test Result Based on Early Heart Rate Variation in Patients With a History of Syncope

Lack of early sympathetic overreactivity measured by early increase in heart rate has been shown to predict a negative tilt-table (TT) test result. The goal of this study was to evaluate this observation in patients with a history of syncope. The author retrospectively identified 27 patients with a history of syncope undergoing TT testing. The difference between maximal heart rate during the first 10 minutes of the tilting and baseline heart rate was used for early heart rate change. There was a significant association between the probability of a negative TT test result and failure to increase early heart rate over 19 beats per minute. The sensitivity of a negative TT test result was 93.3%, with a specificity of 66.7% (odds ratio, 0.1; confidence interval, 0.14-0.69; P=.001). This study confirms previous findings that failure to increase the heart rate early during a TT test can predict low probability of syncope.

Early Heart Rate Increase Does Not Predict the Result of the Head-Up Tilt Test Potentiated With Nitroglycerin

The magnitude of the change in heart rate during the first few minutes of the head-up tilt test has been used to predict the test's result. The aim of this study was to investigate whether the heart rate increase during the head-up tilt test potentiated with nitroglycerin is related to the development of syncope. The study included 158 consecutive patients with syncope, with stable sinus rhythm, and without structural cardiac disease who were undergoing a head-up tilt test with nitroglycerin. The heart rate increment induced by the tilt maneuver and by nitroglycerin administration was calculated, and its relationship to clinical variables and to the test's results was analyzed. The head-up tilt test gave positive results in 117 patients (74%). The heart rate was 68.7 (11.3) bpm in the decubitus position and 85.1 (15.4) bpm during the first 6 min of tilting. There was strong inverse correlation between the heart rate increase induced by tilting and age (r=--0.63; P<.001), but the increase (16.8 [9.3] bpm in patients with syncope versus 14.9 [11.3] bpm in those without; P=.3) did not predict the result of the test. The heart rate increase induced by nitroglycerin was also similar for patients with and without syncope during the pharmacologic phase of the test (27.3 [12.6] bpm and 26.7 (13.4) bpm, respectively; P=.8). The magnitude of the heart rate increase during the first few minutes of tilt-testing and after nitroglycerin administration is inversely related to age but does not predict the result of the head-up tilt test with nitroglycerin.

Does an early increase in heart rate during tilting predict the results of passive tilt testing?

Head-up tilt testing is a useful but time-consuming procedure. If we could accurately predict the tilt testing results; we would be able to substantially shorten the duration of tilt protocol. To clarify the hypothesis that an early increase in heart rate (HR) during tilting can predict the passive tilt results in our protocol (80-degree angle for 30 minutes), we studied 115 consecutive patients (72 men, 43 women, mean age 46 +/- 19 years) who were clinically diagnosed with neurally mediated syncope. Twenty-nine (25%) patients had a positive tilt test (P group), whereas 86 (75%) patients had a negative test (N group). The early HR increase was defined as the maximum HR during the first 5 minutes of tilting minus the resting HR before tilting. The early HR increase was significantly higher in the P group (23.8 +/- 9.5 beats/min) than in the N group (17.5 +/- 8.2 beats/min, P = 0.0008), but it was negatively correlated with the tilt duration to positive response (r = -0.52, P = 0.0032) and the patient age in the entire study population (r = 0.62, P < 0.0001). Results of multiple regression analysis indicated that age, tilt result, and tilt duration were independently associated with the early HR increase. As a result, an early HR increase > or = 18 beats/min, the best apparent cut-off point obtained in our study, was a sensitive (100%) marker for prediction of a positive response at < or = 15 minutes of tilting, but it showed a low specificity (61%). In conclusion, an early HR increase during 80-degree tilting may be only predictive for a positive result < or = 15 minutes because it depends on the tilt duration to a positive response and patient age.

Systemic effects of formoterol and salmeterol: a dose-response comparison in healthy subjects

BACKGROUNDThe main adverse effects of inhaled long acting β2 agonists relate to their systemic activity. The systemic effects seen over eight hours after inhalation of three doses of salmeterol and...

Haemodynamic response to an isometric exercise test in obese patients: influence of autonomic dysfunction.

To investigate blood pressure (BP) and heart rate (HR) responses to an isometric exercise test in obese non diabetic patients and to correlate the results with vagal function and plasma insulin concentration. 63 obese patients, 36 of whom had abnormal cardiac parasympathetic control (PS+), and 35 healthy control subjects. Analysis of HR variations during three standardized tests: deep-breathing, lying-to-standing and Valsalva. Isometric contraction (handgrip) for 5 min. In the PS+ obese patients, resting HR and body mass index (BMI) were significantly higher than in the PS- subjects and there was a trend to higher plasma insulin concentrations. Age-matched comparison showed that during the handgrip test, the increase in HR at the first minute was significantly higher in the PS- obese patients than in the controls. The increase in BP was significantly lower in the PS+ obese patients than in age-and-BMI-matched PS- obese patients. These data suggest that 1) there is an increase in cardiac vagal tone in PS- obese patients, since the early increase in HR at 1 min of the handgrip test, results from the withdrawal of vagal tone; 2) BP response to an isometric contraction is impaired in PS+ obese patients due to a lower sympathetic activation; 3) high plasma insulin concentrations may also contribute to limiting the BP response; and 4) autonomic disorders may account for alterations in the haemodynamic changes during exercise.

Different effects of bisoprolol on heart rate in patients with ischemic or idiopathic dilated cardiomyopathy (a 24-hour holter substudy of the cardiac insufficiency bisoprolol study [CIBIS

The effect of beta blockade on heart rate in patients with either idiopathic or ischemic cardiomyopathy was studied. It was found that beta blockade reduced the early morning increase in heart rate to a greater extent in patients with idiopathic dilated cardiomyopathy than in those with ischemic dilated cardiomyopathy.

Prediction of head-up tilt test result by analysis of early heart rate variations.

Head-up tilt testing is a useful test for investigating vasovagal syncope. The determination of early, accurate, predictive criteria for a negative result would permit a reduction in the duration of the tilt test. Patients with no drug use and no illnesses other than recurrent unexplained syncope were recruited. In an initial study (110 consecutive patients), we aimed to determine a predictive criterion based on heart rate variations during the first minutes of upright tilting that could distinguish between patients with positive and negative tilt tests (patients with an early continual decrease in heart rate or blood pressure were excluded). Then we tested the predictive value of the established criterion in a second independent sample of patients with unexplained syncope (109 consecutive patients). An early sustained increase in heart rate < or = 18 bpm during the first 6 minutes of upright tilting at a 60 degree angle allowed us to predict negative tilt tests with 100% specificity, 100% positive predictive value, and 88.6% sensitivity. This criterion was validated in the second, prospective arm of the study (96.4% specificity, 98.4% positive predictive value, and 87.3% sensitivity), even with subsequent use of isoproterenol in low doses. In patients with no drug use and no illnesses other than recurrent unexplained syncope, a simple clinical criterion identifies patients who will not develop syncope during a prolonged upright tilt.

Partial epileptic seizures of different origin variably affect cardiac rhythm.

The present study was aimed at evaluating electrocardiographic (ECG) changes associated with partial epileptic seizures without seizure activity secondarily generalized. We assessed heart rate (HR) changes occurring during 100 partial epileptic seizures, as recorded by ambulatory EEG-ECG in 50 outpatients. Consecutive R-R intervals were measured for the 30 s immediately preceding the onset and for the first 10-s period of discharge. In addition, HR was sampled at 10-s intervals during EEG paroxysmal discharge and for 1 min after the end of discharge. The highest and lowest respective HR peaks achieved during these seizures were 186 and 44 beats/ min. Analysis of the R-R intervals during the first 10-s period of EEG discharge showed a significant early HR increase in 49% of the seizures; the corresponding figure for an early HR reduction was 25.5%. Eighty percent of the seizures showing an early HR decrease were of temporal lobe origin. No severe cardiac arrhythmias were noted during the seizures. Our data suggest that an early HR decrease is more probable in temporal lobe seizures than in seizures of other origin. An accurate HR measurement, focused on discharge onset, may provide both a reliable way of evaluating the possible effect of partial seizures on HR and valuable information about the cerebral sites involved in the control of cardiac rhythm.