Comparison of cardiac time intervals between echocardiography and impedance cardiography at various heart rates

Abstract The non-invasively measured initial systolic time interval (ISTI) reflects a time difference between the electrical and pumping activity of the heart and depends on cardiac preload, afterload, autonomic nervous control and training level. However, the duration of the ISTI has not yet been compared to other time markers of the heart cycle. The present study gauges the duration of the ISTI by comparing the end point of this interval, the C-point, with heart cycle markers obtained by echocardiography. The heart rate of 16 healthy subjects was varied by means of an exercise stimulus. It was found that the C-point, and therefore the end point of ISTI, occurred around the moment of the maximum diameter of the aortic arch in all subjects and at all heart rates. However, while the time difference between the opening of the aortic valves and the maximum diameter of the aortic arch decreased significantly with decreasing RR-interval, the time difference with respect to the moment of the C-point remained constant within the subjects. This means that the shortening of the ISTI with increasing heart rate in response to an exercise stimulus was caused by a shortening of the pre-ejection period (PEP). It is concluded that the ISTI can be used as a non-invasive parameter indicating the time difference between the electrical and mechanical pumping activity of the heart, both inside and outside the clinic.

Download Full-text

Heart rate as a marker of relapse during withdrawal of heart failure therapy in patients with recovered dilated cardiomyopathy: an analysis from TRED-HF

European Heart Journal ◽

10.1093/ehjci/ehaa946.1057 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

B Halliday ◽

A Vazir ◽

R Owen ◽

J Gregson ◽

R Wassall ◽

...

Keyword(s):

Heart Rate ◽

Cardiac Function ◽

Dilated Cardiomyopathy ◽

Funding Source ◽

End Point ◽

Therapy Withdrawal ◽

The Mean ◽

Withdrawal Of Therapy ◽

Continue Therapy

Abstract Introduction In TRED-HF, 40% of patients with recovered dilated cardiomyopathy (DCM) relapsed in the short-term during phased withdrawal of drug therapy. Non-invasive markers of relapse may be used to monitor patients who wish a trial of therapy withdrawal and provide insights into the pathophysiological drivers of relapse. Purpose To investigate the relationship between changes in heart rate (HR) and relapse amongst patients with recovered DCM undergoing therapy withdrawal in TRED-HF. Methods Patients with recovered DCM were randomised to phased withdrawal of therapy or to continue therapy for 6 months. After 6 months of continued therapy, those in the control arm underwent withdrawal of therapy in a single arm crossover phase. HR was measured at each study visit. Mean HR and 95% confidence intervals (CI) were calculated at baseline, 45 days after baseline, 45 days prior to the end of the study or relapse and at the end of the study or relapse. Patients were stratified by treatment arm and the occurrence of the primary relapse end-point. Heart rate at follow-up was compared amongst patients who had therapy withdrawn and relapsed versus those who had therapy withdrawn and did not. ANCOVA was used to adjust for differences in HR at baseline between the two groups. Results Of 51 patients randomised, 26 were assigned to continue therapy and 25 to withdraw therapy. In the randomised and cross-over phases, 20 patients met the primary relapse end-point; one patient withdrew from the study and one patient completed follow-up in the control arm but did not enter the cross-over phase. Mean HR (standard deviation) at baseline and follow-up for (i) patients in the control arm was 69.9 (9.8) & 65.9 (9.1) respectively; (ii) for those who had therapy withdrawn and did not relapse was 64.6 (10.7) & 74.7 (10.4) respectively; and (iii) for those who had therapy withdrawn and relapsed was 68.3 (11.3) & 86.1 (11.8) respectively [all beats per minute]. The mean change in HR between the penultimate visit and the final visit for those who had therapy withdrawn and did not relapse was −2.4 (9.7) compared to 3.1 (15.5) for those who relapsed. After adjusting for differences in HR at baseline, the mean difference in HR measured at follow-up between patients who underwent therapy withdrawal and did, and did not relapse was 10.4bpm (95% CI 4.0–16.8; p=0.002) (Figure 1 & Table 1). Conclusion(s) A larger increase in HR may be a simple and effective marker of relapse for patients with recovered DCM who have insisted on a trial of therapy withdrawal. Whether HR control is crucial to the maintenance of remission amongst patients with improved cardiac function, or is simply a marker of deteriorating cardiac function, warrants further investigation. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation

Download Full-text

Heart Rate–Induced Myocardial Ca 2+ Retention and Left Ventricular Volume Loss in Patients With Heart Failure With Preserved Ejection Fraction

Journal of the American Heart Association ◽

10.1161/jaha.120.017215 ◽

2020 ◽

Vol 9 (17) ◽

Author(s):

Daniel N. Silverman ◽

Mehdi Rambod ◽

Daniel L. Lustgarten ◽

Robert Lobel ◽

Martin M. LeWinter ◽

...

Keyword(s):

Heart Failure ◽

Heart Rate ◽

Ejection Fraction ◽

Sinus Rhythm ◽

Left Ventricular ◽

Atrial Pacing ◽

Preserved Ejection Fraction ◽

Volume Loss ◽

Heart Rates ◽

Patients With Heart Failure

Background Increases in heart rate are thought to result in incomplete left ventricular (LV) relaxation and elevated filling pressures in patients with heart failure with preserved ejection fraction (HFpEF). Experimental studies in isolated human myocardium have suggested that incomplete relaxation is a result of cellular Ca 2+ overload caused by increased myocardial Na + levels. We tested these heart rate paradigms in patients with HFpEF and referent controls without hypertension. Methods and Results In 22 fully sedated and instrumented patients (12 controls and 10 patients with HFpEF) in sinus rhythm with a preserved ejection fraction (≥50%) we assessed left‐sided filling pressures and volumes in sinus rhythm and with atrial pacing (95 beats per minute and 125 beats per minute) before atrial fibrillation ablation. Coronary sinus blood samples and flow measurements were also obtained. Seven women and 15 men were studied (aged 59±10 years, ejection fraction 61%±4%). Patients with HFpEF had a history of hypertension, dyspnea on exertion, concentric LV remodeling and a dilated left atrium, whereas controls did not. Pacing at 125 beats per minute lowered the mean LV end‐diastolic pressure in both groups (controls −4.3±4.1 mm Hg versus patients with HFpEF −8.5±6.0 mm Hg, P =0.08). Pacing also reduced LV end‐diastolic volumes. The volume loss was about twice as much in the HFpEF group (controls −15%±14% versus patients with HFpEF −32%±11%, P =0.009). Coronary venous [Ca 2+ ] increased after pacing at 125 beats per minute in patients with HFpEF but not in controls. [Na + ] did not change. Conclusions Higher resting heart rates are associated with lower filling pressures in patients with and without HFpEF. Incomplete relaxation and LV filling at high heart rates lead to a reduction in LV volumes that is more pronounced in patients with HFpEF and may be associated with myocardial Ca 2+ retention.

Download Full-text

Heart Rate and Performance in Manual Missile Guidance

Perceptual and Motor Skills ◽

10.2466/pms.1971.32.2.352 ◽

1971 ◽

Vol 32 (2) ◽

pp. 352-354

Author(s):

Bengt Bergstroem ◽

Peter Arnberg

Keyword(s):

Heart Rate ◽

Performance Data ◽

Tracking Performance ◽

Missile Guidance ◽

Heart Rates ◽

Laboratory Conditions ◽

Stress Studies ◽

And Performance

Earlier stress studies under laboratory conditions show that heart rates from 100 to 110 bpm are associated with significant decrements in missile-tracking performance. Data from real missile tracking by 8 operators with no stress deliberately induced indicate, however, that performance is unaffected up to 135 bpm, and only moderately affected in the 135- to 170-bpm region. The disagreement between the two sets of results highlights the difficulties in generalizing from stress experiments.

Download Full-text

Stress level in wild harbour porpoises (Phocoena phocoena) during satellite tagging measured by respiration, heart rate and cortisol

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315408003159 ◽

2009 ◽

Vol 89 (5) ◽

pp. 885-892 ◽

Cited By ~ 21

Author(s):

I.G. Eskesen ◽

J. Teilmann ◽

B.M. Geertsen ◽

G. Desportes ◽

F. Riget ◽

...

Keyword(s):

Heart Rate ◽

Respiration Rate ◽

Serum Cortisol ◽

Phocoena Phocoena ◽

Heart Rates ◽

Stress Effects ◽

Respiration Rates ◽

Stressed Animal ◽

Cortisol Levels ◽

Satellite Tagging

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were analysed from blood samples. Differences in heart rates, respiration rates and cortisol levels before and during the tagging events were investigated. An overall significant decrease of 31.5% in respiration rate was found during the tagging event period, while mature porpoises respired significantly more often than immature individuals. Though significant differences in heart rates were found for some individuals, no general significant change for all animals was detected. We found no correlation between cortisol concentration and either heart rate or respiration rate, nor did we find any relationships between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based on the factors investigated, on how to reduce stress during handling. However, pouring water over the animal and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises.

Download Full-text

Anticipatory, exercise, and recovery heart rates of girls as affected by four running events

Journal of Applied Physiology ◽

10.1152/jappl.1964.19.5.853 ◽

1964 ◽

Vol 19 (5) ◽

pp. 853-856 ◽

Cited By ~ 17

Author(s):

Vera Skubic ◽

Jane Hilgendorf

Keyword(s):

Heart Rate ◽

Cardiac Function ◽

Heart Rate Response ◽

Heart Rates

The heart rate response to running various distances was studied using five highly trained girls as subjects. A telemetering instrument was employed so that the testing could be done under actual sport conditions. The findings indicated that 1) the anticipatory heart rate just prior to exercise represented 59% of the total adjustment to exercise, 2) the heart rates during exercise were 2.5 times the resting values, and 3) heart rates observed at the end of the 220-, 440-, 880-yard, and mile events were simila cardiac function; exercise Submitted on October 22, 1963

Download Full-text

The influence of physical exertion on basic hematological parameters values and heart rate in trotters

Veterinarski glasnik ◽

10.2298/vetgl1406291s ◽

2014 ◽

Vol 68 (5-6) ◽

pp. 291-300

Author(s):

Dajana Slijepcevic ◽

R. Savic ◽

Dragisa Trailovic

Keyword(s):

Heart Rate ◽

Radio Telemetry ◽

Hematological Parameters ◽

Physical Exertion ◽

Good Health ◽

Blood Samples ◽

Optimal Values ◽

The Moment ◽

The Relationship ◽

Hematological Tests

One of very important prerequisites for achieving good results in races, in addition to genetic predisposition, quality training and good health, are optimal values for number of erythrocytes, concentration of haemoglobin and hematocrit, of which depends efficient oxygen supply of muscles during great efforts. The stated values, along with data on heart rate, are useful indicators of the degree of horse fitness and readiness for horse race. The influence of physical exertion on the values of basic hematological parameters as well as on heart rate, was investigated on 6 trotters, in training at the Belgrade racetrack (one head of Italian trotter, male, 3 years old; 3 heads of American trotter, male, 3,4 and 6 years old and two heads of Serbian trotter, female, 4 and 5 years old). The blood samples for hematological tests were taken by punction of jugular vein in resting phase - immediately before the commencement of work, after light trot warming for 3000 m and fast trot for 1000 m, with 30 minutes rest between the two runnings. The heart rate was monitored continuously by radio telemetry cardiometer, from the moment they were taken from their boxes and harnessing to the completion of work. The obtained results confirm the relationship between the rise of heart rate and hematocrit values: maximal hematocrit values were determined after the first running (0.49?0.05, in regard to 0.42?0.03 in resting phase), but 30 minutes after the second running there was a slight drop of hematocrit values (0.46?0.04). The blood samples in both cases were taken after fast trot during which there were recorded maximal pulse values, so in the moment of sampling the pulse lowered close to the values in resting - after the first running from 192.23?19.66, and after the second from 180.33?17.22 to 40.67?5.76.

Download Full-text

How well are heart rates measured by pulse oximeters and electronic sphygmomanometers? Practice-based evidence from an observational study of acutely ill medical patients during hospital admission

Acute Medicine Journal ◽

10.52964/amja.0767 ◽

2019 ◽

Vol 18 (3) ◽

pp. 144-147

Author(s):

Mary Rimbi ◽

◽

Immaculate Nakitende ◽

Teopista Namujwiga ◽

John Kellett ◽

...

Keyword(s):

Heart Rate ◽

Observational Study ◽

Hospital Admission ◽

Pulse Oximeter ◽

Medical Patients ◽

Limits Of Agreement ◽

Heart Rates ◽

Electrocardiogram Ecg ◽

Pulse Oximeters

Background: heart rates generated by pulse oximeters and electronic sphygmomanometers in acutely ill patients may not be the same as those recorded by ECG Methods: heart rates recorded by an oximeter and an electronic sphygmomanometer were compared with electrocardiogram (ECG) heart rates measured on acutely ill medical patients. Results: 1010 ECGs were performed on 217 patients while they were in the hospital. The bias between the oximeter and the ECG measured heart rate was -1.37 beats per minute (limits of agreement -22.6 to 19.9 beats per minute), and the bias between the sphygmomanometer and the ECG measured heart rate was -0.14 beats per minute (limits of agreement -22.2 to 21.9 beats per minute). Both devices failed to identify more than half the ECG recordings that awarded 3 NEWS points for heart rate. Conclusion: Heart rates of acutely ill patients are not reliably measured by pulse oximeter or electronic sphygmomanometers.

Download Full-text

Learned Control of Heart Rate and Blood Pressure

Perceptual and Motor Skills ◽

10.2466/pms.1971.33.1.219 ◽

1971 ◽

Vol 33 (1) ◽

pp. 219-226 ◽

Cited By ~ 5

Author(s):

Michael Hnatiow

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Systolic Blood Pressure ◽

Blood Pressure Variability ◽

Visual Display ◽

Waveform Analysis ◽

Target Range ◽

Heart Rates ◽

Systolic Blood Pressure Variability ◽

Continuous Measures

Cardiac rate-variability control and an initial demonstration of systolic blood-pressure variability control using visual feedback of physiological information were examined. Continuous measures of respiration, heart rate, EXG waveform analysis, and systolic blood pressure were obtained for both experimental groups and for yoked controls who saw the same visual display as the experimental Ss. Ss successful at reducing heart-rate variability showed clear changes in the P-R wave relationships of the EKG, indicating possible direct attempts to manipulate heart rate so as to reduce variability. Ss controlling blood-pressure variability who had high heart rates were more successful in reducing variability than those with low rates, possibly because of differential feedback to Ss with high and low heart rates. In addition, apparently as a reaction to E's adjustment of the visual target range, experimental Ss showed decreases in mean blood-pressure levels.

Download Full-text

Stability of Heart Rate at Physiological Thresholds Between Temperate and Heat Stress Environments in Endurance-Trained Males

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2020-0351 ◽

2020 ◽

pp. 1-4

Author(s):

Ed Maunder ◽

Daniel J. Plews ◽

Fabrice Merien ◽

Andrew E. Kilding

Keyword(s):

Heart Rate ◽

Heat Stress ◽

Relative Humidity ◽

Blood Lactate ◽

Endurance Athletes ◽

Heart Rates ◽

Stress Environments ◽

Positive Correlations ◽

Hot Environments ◽

Stress Training

Many endurance athletes perform specific blocks of training in hot environments in “heat stress training camps.” It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P > .05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P < .05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r = .92–.95, P < .05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress.

Download Full-text

Music-Assisted Training for Dart Throwing Novices: Post-Training Effects on Heart Rate and Performance Accuracy

Perceptual and Motor Skills ◽

10.1177/00315125211050629 ◽

2021 ◽

pp. 003151252110506

Author(s):

Ivor T. H. Tso ◽

James C. L. Law ◽

Thomson W. L. Wong

Keyword(s):

Heart Rate ◽

Control Group ◽

Heart Rates ◽

Performance Accuracy ◽

Throwing Accuracy ◽

Different Types ◽

Dart Throwing ◽

Post Test ◽

And Performance ◽

Athletes Heart

While previous research has suggested that lowering athletes’ heart rates can enhance sports performance, it is unknown whether slow-paced music might induce a lower heart rate and thereby improve some types of motor performance. In this study, we investigated the effects of different types of music during dart-throw training on both heart rate and dart-throwing performance in 45 ( M age = 19.7, SD = 0.31 years) novice dart throwers who were randomly assigned to either a Slow Music Group (SMG), a Fast Music Group (FMG), or a Control Group (CG). All participants completed three dart-throwing blocks - Pre-Test, Practice, and Post-Test. During the Practice block, participants practiced dart-throwing with either slow-paced, fast-paced or no music according to their assigned group. We recorded the participants’ heart rates and total dart-throwing accuracy scores during Pre-Test and Post-Test. Music-assisted dart-throw training with slow-paced music was effective in significantly inhibiting a performance-related increase in heart rate and was associated with the greatest dart throwing improvement after training.

Download Full-text