scholarly journals Study of behavior of cardiac pacemaker batteries capacity in different situations of electro-electronic variations

2021 ◽  
pp. 45-55
Author(s):  
ALO Oliveira ◽  
FPL Leite ◽  
CSS Santineli ◽  
Adriana Del Monaco ◽  
Evandro Drigo
Keyword(s):  
Heart Rate ◽  
Cardiac Pacemaker ◽  
Research Process ◽  
Cause Of Failure ◽  
Electrical Stimuli

The research analyzes issues related to events that originate the behavior of a pacemaker battery in certain electro-electronic variations. Based on idea that pacemaker has the purpose of supporting the heart rate with electrical stimuli, the existence of errors in equipment's battery can lead to reduced autonomy and restricted failures that cause it to malfunction. The research process is based on bibliographic reviews and objective is to investigate cause of failure and explain in a technical way how this error can be minimized in order to reduce likelihood of these undesirable events in the equipment's operation.

Effectiveness of enteral ivabradine for heart rate control in septic shock: A randomised controlled trial

2021 ◽  
pp. 0310057X2110099
Author(s):  
Priyankar K Datta ◽  
Vimi Rewari ◽  
Rashmi Ramachandran ◽  
Preet M Singh ◽  
Bikash R Ray ◽  
...  
Keyword(s):  
Heart Rate ◽  
Septic Shock ◽  
Adverse Events ◽  
Standard Therapy ◽  
Controlled Trial ◽  
Cardiac Pacemaker ◽  
Stroke Volume Index ◽  
Volume Index ◽  
Serious Adverse Events ◽  
Group I

Persistent tachycardia in patients with septic shock predicts poor outcome. This study sought to investigate the effect of the cardiac pacemaker current inhibitor ivabradine on heart rate and cardio-circulatory function in patients with septic shock. After informed consent, 60 patients with septic shock and persistent tachycardia (heart rate >95 /minute) were prospectively randomly assigned to receive either standard therapy for septic shock (group S) or standard therapy along with enteral ivabradine (group I) for the initial 96 hours after enrolment. Primary outcome was the difference in heart rate between the two groups during the first 96 hours. Secondary outcomes included the effect of ivabradine on haemodynamic, oxygenation, myocardial function and organ function parameters, incidence of adverse events and 30-day overall survival. Heart rate was lower in group I compared to group S (median difference in area under the curve –25.6 (95% confidence intervals –31.4 to –15.9) /minute; P <0.001). Vasopressor requirements, blood lactate levels, Sequential Organ Failure Assessment scores and E/e′ ratio were lower in group I compared to group S. Stroke volume index and ejection fraction were higher in group I while cardiac index and oxygen delivery parameters were maintained similar to group S. There was no difference in 30-day mortality or in the incidence of serious adverse events. Enteral ivabradine is effective in reducing heart rate, and improving haemodynamic parameters and cardiac function in patients with septic shock and persistent tachycardia, without increasing the incidence of adverse events.

Cardiac changes during arousals from non-REM sleep in healthy volunteers

2007 ◽  
Vol 292 (3) ◽  
pp. R1320-R1327 ◽  
Author(s):  
Eugene Nalivaiko ◽  
Peter G. Catcheside ◽  
Amanda Adams ◽  
Amy S. Jordan ◽  
Danny J. Eckert ◽  
...  
Keyword(s):  
Heart Rate ◽  
Neural Control ◽  
Cardiac Pacemaker ◽  
Ventricular Myocardium ◽  
Rapid Eye Movement Sleep ◽  
Sleep Studies ◽  
Cardiac Responses ◽  
Pr Interval ◽  
Consistent Change ◽  
Ventricular Filling

Our aim was to evaluate cardiac changes evoked by spontaneous and sound-induced arousals from sleep. Cardiac responses to spontaneous and auditory-induced arousals were recorded during overnight sleep studies in 28 young healthy subjects (14 males, 14 females) during non-rapid eye movement sleep. Computerized analysis was applied to assess beat-to-beat changes in heart rate, atrio-ventricular conductance, and ventricular repolarization from 30 s before to 60 s after the auditory tone. During both types of arousals, the most consistent change was the increase in the heart rate (in 62% of spontaneous and in 89% of sound-induced arousals). This was accompanied by an increase or no change in PR interval and by a decrease or no change in QT interval. The magnitude of all cardiac changes was significantly higher for tone-induced vs. spontaneous arousals (mean ± SD for heart rate: +9 ± 8 vs. +13 ± 9 beats per min; for PR prolongation: 14 ± 16 vs. 24 ± 22 ms; for QT shortening: −12 ± 6 vs. −20 ± 9 ms). The prevalence of transient tachycardia and PR prolongation was also significantly higher for tone-induced vs. spontaneous arousals (tachycardia: 85% vs. 57% of arousals, P < 0.001; PR prolongation: 51% vs. 25% of arousals, P < 0.001). All cardiac responses were short-lasting (10–15 s). We conclude that cardiac pacemaker region, conducting system, and ventricular myocardium may be under independent neural control. Prolongation of atrio-ventricular delay may serve to increase ventricular filling during arousal from sleep. Whether prolonged atrio-ventricular conductance associated with increased sympathetic outflow to the ventricular myocardium contributes to arrhythmogenesis during sudden arousal from sleep remains to be evaluated.

Independence of heart rate and circadian period in the golden hamster

1993 ◽  
Vol 264 (2) ◽  
pp. R235-R238
Author(s):  
R. Refinetti ◽  
M. Menaker
Keyword(s):  
Heart Rate ◽  
Cardiac Pacemaker ◽  
Myocardial Cell ◽  
Circadian Oscillation ◽  
Circadian Period ◽  
Isolated Hearts ◽  
Rate Oscillations ◽  
The Mean ◽  
Freely Moving

Cardiac contractions are under the influence of at least two processes of biological timing, one responsible for the mean level of heart rate (oscillations with a frequency of up to several hundred per minute) and another responsible for the circadian rhythm of heart rate (oscillations with a frequency of one per 24 h). To investigate whether the mean level of heart rate is proportional to the frequency of circadian oscillation, we compared the heart rates of normal golden hamsters (circadian period approximately 24 h) and tau-mutant hamsters (circadian period approximately 20 h). Neither in anesthetized preparations nor in freely moving animals was there a difference in heart rate between the two groups despite the 20% difference in circadian period. Thus the mean level of heart rate seems to be independent of the circadian period. It is likely that the tau gene, which affects the frequency of the circadian pacemaker, has no effect on the intrinsic frequency of the cardiac pacemaker. In vitro studies of isolated hearts or myocardial cell cultures are necessary to confirm this inference.

Evoked bradycardia as response criterion for the detection of electrical stimuli in catfish

2008 ◽  
Vol 58 (3) ◽  
pp. 287-299
Author(s):  
Robert Veeneklaas ◽  
Albert Schoenhage ◽  
Lonneke Eeuwes ◽  
Robert Peters
Keyword(s):  
Heart Rate ◽  
Response Criterion ◽  
Ultradian Rhythm ◽  
Mechanical Stimuli ◽  
Heart Rate Deceleration ◽  
Orienting Reflex ◽  
Sensory Stimuli ◽  
Ictalurus Nebulosus ◽  
Rate Deceleration ◽  
Electrical Stimuli

AbstractHeart rate deceleration (HRD) after exposure to novel stimuli is part of the orienting reflex, and can be used as a tool to investigate the susceptibility of various organisms to sensory stimuli. HRD as response criterion was used in unrestrained catfish, Ameiurus (Ictalurus) nebulosus (Lesueur, 1819) to investigate its susceptibility to electrical stimuli. HRD in catfish occurs after stimulation with light, mechanical stimuli, and electrical stimuli. HRD shows habituation and correlates with stimulus strength. The response to sinusoidal electrical stimuli from 70 to 700 μV/cm p-p was determined in the range from 0.1 to 1000 Hz. Using HRD as response criterion we found that at 85 μV/cm catfish react to stimuli from 0.1 to 3 Hz. In the absence of stimuli, the heart rate develops an ultradian rhythm with periods of 7 to 15 min. About twice a day cardiac arrest of 1 min occurs. During anaesthesia oscillations with a period of about 1 min are recorded. Comparison of this study with others supports the notion that there exist at least two neural channels for processing electrical stimuli. One channel is involved in predation, namely processing the fast potential changes accompanying the passage of a bioelectric dipole; another is involved in processing uniform DC fields used for navigation.

Temporary pacing

Curationis ◽  
1983 ◽  
Vol 6 (2) ◽  
Author(s):  
L.J. Workman
Keyword(s):  
Quality Of Life ◽  
Heart Rate ◽  
Heart Block ◽  
Cardiac Pacing ◽  
Pacemaker Therapy ◽  
Temporary Pacing ◽  
Different Types ◽  
The Many ◽  
Electrical Stimuli

Artificial cardiac pacing, the use of electrical stimuli to cause contraction of heart muscle, is a sophisticated therapeutic and diagnostic tool. Its rapid technologic improvement since first developed in the late 1930’s by Hyman, has made it possible not only to avoid certain cases of death due to heart block, but also to extend and improve the quality of life. Pacemaker therapy is generally used to treat heart rate or rhythm disturbances, being either tachy- or bradyarrhythmias that produce a detrimental drop in cardiac output. Of the many different types of pacemakers and electrodes currently available, ventricular demand pacing is the most commonly used.

scholarly journals Induction of oscillatory ventilation pattern using dynamic modulation of heart rate through a pacemaker

2008 ◽  
Vol 295 (1) ◽  
pp. R219-R227 ◽  
Author(s):  
Charlotte H. Manisty ◽  
Keith Willson ◽  
Justin E. R. Davies ◽  
Zachary I. Whinnett ◽  
Resham Baruah ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Cardiac Pacemaker ◽  
Breathing Patterns ◽  
Cardiac Pacemakers ◽  
Oscillatory Ventilation ◽  
Disease States ◽  
Ventilation Pattern ◽  
End Tidal ◽  
Respiratory Gases

For disease states characterized by oscillatory ventilation, an ideal dynamic therapy would apply a counteracting oscillation in ventilation. Modulating respiratory gas transport through the circulation might allow this. We explore the ability of repetitive alternations in heart rate, using a cardiac pacemaker, to elicit oscillations in respiratory variables and discuss the potential for therapeutic exploitation. By incorporating acute cardiac output manipulations into an integrated mathematical model, we observed that a rise in cardiac output should yield a gradual rise in end-tidal CO2 and, subsequently, ventilation. An alternating pattern of cardiac output might, therefore, create oscillations in CO2 and ventilation. We studied the effect of repeated alternations in heart rate of 30 beats/min with periodicity of 60 s, on cardiac output, respiratory gases, and ventilation in 22 subjects with implanted cardiac pacemakers and stable breathing patterns. End-tidal CO2 and ventilation developed consistent oscillations with a period of 60 s during the heart rate alternations, with mean peak-to-trough relative excursions of 8.4 ± 5.0% ( P < 0.0001) and 24.4 ± 18.8% ( P < 0.0001), respectively. Furthermore, we verified the mathematical prediction that the amplitude of these oscillations would depend on those in cardiac output ( r = 0.59, P = 0.001). Repetitive alternations in heart rate can elicit reproducible oscillations in end-tidal CO2 and ventilation. The size of this effect depends on the magnitude of the cardiac output response. Harnessed and timed appropriately, this cardiorespiratory mechanism might be exploited to create an active dynamic responsive pacing algorithm to counteract spontaneous respiratory oscillations, such as those causing apneic breathing disorders.

scholarly journals PHYSICAL EXERTION MONITORING: ELITE ATHLETES MODIFY THEIR COACH’S TASK

2015 ◽  
Vol 2 (97) ◽  
pp. 34-40
Author(s):  
Artūras Sujeta ◽  
Kristina Poderienė ◽  
Jonas Poderys
Keyword(s):  
Heart Rate ◽  
Elite Athletes ◽  
Training Session ◽  
Physical Exertion ◽  
Research Process ◽  
Physical Load ◽  
Long Distance ◽  
Physical Test ◽  
Research Findings ◽  
The Stability

Background. The objective of this study was to establish how accurately elite athletes carried out the task of a coach to perform an exercise at a given intensity. Methods. Cardiovascular indices were registered and analysed during a two-step research process. Two groups including six well-trained long-distance runners and 21 healthy non-athletes performed graded stress exercise up to the inability to continue the task. Runners took part in the second study in which heart rate and running pace were recorded during an aerobic training session. Results. Research findings showed that athletes demonstrated higher physical performance, but the maximum heart rate values achieved in the last fatigue phase did not differ significantly between the groups. No ischemic events were observed in elite athlete group during the entire physical test. Relatively stable heart rate indices in the maximal physical load step were observed in both groups, but heart rate indices were significantly lower during all physical load steps in the group of elite runners. Conclusions. Elite athletes carried out the coach’s task only in the first phase of running and further modified the task by maintaining the stability of the cardiovascular system

scholarly journals Particularities in Cardiovascular Recovery by Physical Training in a Patient with Prosthetic Valve, Permanent Electrical Cardiac Stimulation and Aortocoronary Bypass

2019 ◽  
Vol 16 (5) ◽  
pp. 85-95
Author(s):  
Cristina Adam ◽  
Magda Mitu ◽  
Dana Mîndru ◽  
Ana-Karina Gîlcă ◽  
Radu Sebastian Gavril ◽  
...  
Keyword(s):  
Heart Rate ◽  
Stress Test ◽  
Maximal Oxygen Consumption ◽  
Cardiac Pacemaker ◽  
Mechanical Valve ◽  
Rehabilitation Program ◽  
Exercise Heart Rate ◽  
Second Phase ◽  
Aortocoronary Bypass ◽  
Adaptation To Exercise

AbstractIntroduction: Going through a complete cardiac rehabilitation is essential for all cardiac patients undergoing complex surgery, including those who wear intracardiac devices. Determining the effort capacity after the surgical intervention might provide satisfactory results with the improvement of the quality of life.Case presentation: We present the case of a male patient, 44 years old, known with aortic bicuspid valve, aortic mechanical valve evolved with prosthesis mismatch and aortocoronary bypass (right coronary artery), followed by total atrioventricular block which required cardiac pacemaker VVI, who is admitted in the Cardiovascular Rehabilitation Clinic to continue the second phase of the rehabilitation program. The ergospirometry test (which was performed in order to evaluate the impairment of the effort capacity) showed a moderate-severe decrease of effort capacity (42% of maximal oxygen consumption, class C Weber), effort hypotension and chronotropic incompetence which led to pausing cardiopulmonary test before anaerobic threshold. Stepper exercise or climbing stairs did not cause the lowering of blood pressure and heart rate, which led to the idea of controlling and adjusting the stimulation parameters. Within cardiopulmonary testing in patients with pacemaker special regards should be paid towards: parameters assessment during effort (heart rate during the test in pacemakers without adaptation to exercise, heart rate during the test in pacemakers with adaptation to exercise, evaluation of the effort response in patients undergoing resynchronization therapy) and diagnosis of exercise-induced arrhythmia (atrial fibrillation, ventricular extrasystoles, ventricular tachycardia, as well as identification of arrhythmias in patients with implantable cardioverter defibrillator).Conclusion: The cardiopulmonary stress test in patients with cardiostimulation should respect certain conditions in conducting the test in order to obtain realistic results of functional capacity. Due to the position of the piezoelectric crystal and the immobilization of the limbs during the cycle ergometer test it is recommended testing using the treadmill.

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