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Applied Psychophysiology and Biofeedback Sep 2022The psychophysiological coherence model proposes that a heart rhythm pattern, known as heart rhythm coherence (HRC), is associated with dominant parasympathetic activity...
The psychophysiological coherence model proposes that a heart rhythm pattern, known as heart rhythm coherence (HRC), is associated with dominant parasympathetic activity and the entrainment of respiratory function, blood pressure, and heart rhythms. Although the HRC pattern has primarily been assessed during wakefulness, changes in cardiac and autonomic activity that occur during sleep stages can also be associated with the HRC pattern. The objective of this study was to examine whether any differences in the HRC pattern could be detected among various sleep stages. Eighteen healthy young individuals participated in this study. Two consecutive polysomnographic (PSG) recordings were obtained from each participant, several segments of cardiac activity were obtained from the second PSG. The HRC pattern was quantitatively evaluated by calculating the HRC ratio (HRCR). The highest peaks in the coherence band (Coher-Peak), 0.1-Hz index, respiratory sinus arrhythmia (RSA), and heart rate (HR) were evaluated. A Friedman test showed significant differences among sleep stages in the Coher-Peak, 0.1-Hz index, RSA, and HR; the Coher-Peak and RSA values were lower in rapid eye movement (REM) sleep, while the 0.1-Hz and HR values were higher in REM sleep. Post hoc analyses identified significant differences between the N2 and REM sleep stages. Among the various sleep stages, HR and RSA measurements behaved independently of the HRC pattern, and the HRC pattern did not appear to be associated with the 0.1 Hz frequency. Further studies are required to identify the characteristics of the HRC pattern during sleep.
Topics: Autonomic Nervous System; Heart Rate; Humans; Pilot Projects; Polysomnography; Sleep; Sleep Stages
PubMed: 35503195
DOI: 10.1007/s10484-022-09542-6 -
European Journal of Anaesthesiology Sep 1985Cardiac dysrhythmias occur in 60% or more of anaesthetized patients. While most are not immediately life-threatening, they are serious when 1) accompanied by... (Review)
Review
Cardiac dysrhythmias occur in 60% or more of anaesthetized patients. While most are not immediately life-threatening, they are serious when 1) accompanied by atrioventricular (A-V) dyssynchrony and impaired myocardial performance, 2) a favourable myocardial oxygen balance is jeopardized, or 3) there is likelihood of progression to life-threatening dysrhythmias. Partial A-V dyssynchrony occurs with non-sinus origin supraventricular and A-V junctional rhythms, and complete A-V dyssynchrony with ventricular rhythms and advanced heart-block. Any tachydysrhythmia may increase the myocardial oxygen demand, and possibly reduce oxygen supply as well. Certain supraventricular tachydysrhythmias and most sustained ventricular rhythm disturbances are likely to predispose to life-threatening dysrhythmias. Thus, any cardiac rhythm disturbance should be of concern to the anaesthetist since it is a departure from normal and a sign of an untoward drug effect or altered physiological state. The purpose of this article is to summarize our current understanding of cardiac electrophysiological mechanisms, particularly how these apply to dysrhythmias that occur during anaesthesia, and to review the actions of, and indications for, antidysrhythmic drugs. A better understanding of electrophysiological mechanisms by anaesthetists should lead to improved patient management; hence, a reduced likelihood that dysrhythmias will occur that require specific drug or electrical management.
Topics: Action Potentials; Adrenergic beta-Antagonists; Anesthesia; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Bretylium Compounds; Calcium Channel Blockers; Heart; Heart Conduction System; Humans; Membrane Potentials; Phenytoin; Refractory Period, Electrophysiological
PubMed: 2866093
DOI: No ID Found -
Otolaryngologia Polska = the Polish... 2003The nasocardiac reflex is a little known reaction of nasomucosal origin. The nasocardiac reflex itself may lead to severe bradycardia or can even procure a very dramatic...
The nasocardiac reflex is a little known reaction of nasomucosal origin. The nasocardiac reflex itself may lead to severe bradycardia or can even procure a very dramatic cardiac arrest following irritation or stimulation of the nerves in the nasal cavities or paranasal sinuses. To clarify the rules and mechanisms of the stimulation of the nasal mucosa influencing heart function, 80 healthy volunteers underwent the experiment. After stimulation of the nasal mucosa on the media turbinates by means of 25% ammonia, almost all individuals revealed a significant decrease in the heart rate. In 11 volunteers, disturbances in heart rhythm occurred after a short period of apnoea. Investigations were performed also in 54 persons before and after local anesthesia of the nasal mucosa by means of 2% lignocaine. In 80% of investigated the local anesthesia did not influence the nasocardiac reflex. Analyzing the influence of the preoperative premedication in 26 patients, it was observed, that the reflective reaction after premedication was more expressed than before. Because laryngectomy changes the conditions and physiology of the nose as the first part of the respiratory tract, the nasocardiac reflex in 38 laryngectomized patients was also analyzed. Tests were carried out preoperatively and postoperatively several days, months and years after surgery. Respiratory and heart function were registered synchronically, a flowmeter before operation was placed in one nostril and postoperatively in the tracheostomy tube. May be that such speedy heart reaction on nasal mucosa stimulation is connected with the participation of vagal nerve branches in the spheno-palatine ganglion.
Topics: Adolescent; Adult; Aged; Bradycardia; Female; Heart; Humans; Male; Middle Aged; Nasal Cavity; Nasal Mucosa; Reflex
PubMed: 14994602
DOI: No ID Found -
CJC Open Nov 2022The Apple Watch Series 4 (AW4) and the KardiaMobile single bipolar lead model (KM) are 2 of the most popular US Food & Drug Administration (FDA)-approved commercial...
BACKGROUND
The Apple Watch Series 4 (AW4) and the KardiaMobile single bipolar lead model (KM) are 2 of the most popular US Food & Drug Administration (FDA)-approved commercial heart trackers. However, a lack of knowledge remains regarding their rhythm-detection accuracy in real-life clinical situations. This paper aims to determine the practicality of using an AW4 or a KM in modern medical practice, by assessing the accuracy of each in identifying heart rhythms and heart rate.
METHODS
Participants from the Toronto Heart Centre clinic were enrolled from January 2019 to December 2019. They had a 12-lead electrocardiogram (ECG), followed by wearing the AW4 watch (OS 5.3), and pressing on the KM electrode plates, within the span of 5 minutes of one another. Each session involved a 12-lead ECG, an ECG from each device, and AW4's photoplethysmography function (APPG).
RESULTS
Of 200 participants, 162 (81%) were in sinus rhythm, and 38 (19%) had atrial fibrillation. The rhythm-detection accuracy for sinus rhythm was 100% for the AW4, and 99.03% for the KM. For atrial fibrillation, accuracy was 90.48% for the AW4, and 100% for the KM. The heart rate accuracy for sinus rhythm was 94.39% for the KM, 90.65% for the APPG, and 96.26% for the Apple ECG function. The heart rate accuracy for atrial fibrillation was 91.30% for the KM, 82.61% for the APPG, and 86.96% for the Apple ECG function.
CONCLUSIONS
Both the AW4 and the KM could reliably detect rhythm and heart rate in real-life clinical situations. However, a nonsignificant trend occurred toward better rhythm detection and accuracy with KM, compared with AW4. The difference is mainly due to artifacts (eg, tremors) and the fit of the strap for AW4. The findings have important implications for how these consumer devices can be used in real-life clinical settings.
PubMed: 36444370
DOI: 10.1016/j.cjco.2022.07.011 -
American Heart Journal Mar 1989Antitachycardia devices need more accurate means to identify arrhythmias. Previous studies have found that sinus rhythm can be distinguished from a variety of...
Antitachycardia devices need more accurate means to identify arrhythmias. Previous studies have found that sinus rhythm can be distinguished from a variety of tachyarrhythmias by algorithms that are based on time-domain and frequency-domain analysis of intracardiac electrograms. Amplitude distribution analysis (time-domain) and power density spectral analysis (frequency-domain) are two of the techniques that have seemed to hold promise. However, previous studies have not evaluated whether lead maturation or drugs such as lidocaine, propranolol, verapamil, or isoproterenol can interfere with the ability of these algorithms to distinguish among cardiac rhythms. In the present study, five dogs had permanent atrial pacing leads placed. On a series of days, recordings were made from the atrial leads during sinus rhythm and induced sustained atrial fibrillation, both before and after administration of cardioactive drugs. For up to 1 month after implantation, progressive lead maturation did not prevent differentiation of atrial fibrillation from sinus rhythm by either amplitude distribution analysis or power density spectral analysis. However, the difference between the power density spectra of sinus rhythm and atrial fibrillation became progressively less with time. Isoproterenol, lidocaine, verapamil, and propranolol had no consistent effects on amplitude distribution analysis of atrial electrograms during sinus rhythm or atrial fibrillation. However, there were marked effects of drugs on amplitude distribution characteristics in individual dogs. Propranolol and lidocaine produced consistent changes in power density spectra during sinus rhythm and atrial fibrillation, respectively; both drugs reduced the ability of power density spectral analysis to differentiate sinus rhythm from atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Algorithms; Animals; Anti-Arrhythmia Agents; Atrial Fibrillation; Cardiac Pacing, Artificial; Dogs; Electric Countershock; Electrocardiography; Electrodes, Implanted; Heart Conduction System; Heart Rate; Isoproterenol; Lidocaine; Propranolol; Signal Processing, Computer-Assisted; Verapamil
PubMed: 2919537
DOI: 10.1016/0002-8703(89)90731-x -
Academic Emergency Medicine : Official... May 2015The objective was to analyze the cardiac arrest rhythms presenting during asphyxial cardiac arrest (ACA).
OBJECTIVES
The objective was to analyze the cardiac arrest rhythms presenting during asphyxial cardiac arrest (ACA).
METHODS
Asphyxial cardiac arrest was induced in 30 Landrace large white piglets, aged 12 to 15 weeks and with a mean (±SD) weight of 20 (±2) kg. After the onset of cardiac arrest, the animals were left untreated for 4 minutes, after which cardiopulmonary resuscitation was commenced. Heart rhythms were monitored from the onset of asphyxia until return of spontaneous circulation or death.
RESULTS
After endotracheal tube clamping and prior to cardiac arrest, normal sinus rhythm was noted in 14 animals, atrial fibrillation in two animals, Mobitz II atrioventricular block in 10 animals, and third-degree atrioventricular block in four animals. At the onset of cardiac arrest, seven animals had ventricular fibrillation (VF), two had asystole, and 21 had pulseless electrical activity (PEA). During the 4-minute period of untreated arrest, however, significant changes in the monitored rhythm were noted; at the end of the fourth minute, 19 animals had VF, two animals had asystole, and nine animals had PEA.
CONCLUSIONS
The most common rhythm after 4 minutes of untreated ACA was VF, while in 57% of animals, PEA was spontaneously converted to VF during the cardiac arrest interval.
Topics: Animals; Asphyxia; Atrial Fibrillation; Cardiopulmonary Resuscitation; Disease Models, Animal; Female; Heart Arrest; Male; Swine; Ventricular Fibrillation
PubMed: 25903291
DOI: 10.1111/acem.12643 -
The American Journal of Physiology Oct 1986A mathematical model is proposed for ventricular parasystole. In this model, there are two separate rhythms, a sinus rhythm and a ventricular ectopic rhythm. An ectopic...
A mathematical model is proposed for ventricular parasystole. In this model, there are two separate rhythms, a sinus rhythm and a ventricular ectopic rhythm. An ectopic beat will occur if the ectopic depolarization falls during a time interval when the ventricles are not refractory. Following an ectopic beat there is a compensatory pause. Analysis of this model, utilizing numerical simulation and techniques in number theory, demonstrates several new rules for parasystole. Specifically, for any set of fixed values for the sinus and ectopic frequencies and the ventricular refractory time, there are at most three different values for the number of sinus beats between ectopic beats. One and only one of these values is odd, and the sum of the two smaller values is one less than the larger value. The variation in the allowed values of the number of sinus beats between ectopic beats, as a function of the parameters of the model, is classified. Clinical cases found in the literature display certain aspects of the predictions of the theoretical model. Theoretical analysis of this kind provides new approaches to assessing the mechanism of complex ventricular arrhythmias.
Topics: Arrhythmias, Cardiac; Humans; Models, Cardiovascular
PubMed: 3766761
DOI: 10.1152/ajpheart.1986.251.4.H841 -
Heart and Vessels Apr 2017This study aimed to examine the discrete impacts of peak oxygen consumption (VO) and brain natriuretic peptide (BNP) levels on future heart failure (HF) events in sinus... (Comparative Study)
Comparative Study
This study aimed to examine the discrete impacts of peak oxygen consumption (VO) and brain natriuretic peptide (BNP) levels on future heart failure (HF) events in sinus rhythm (SR) and atrial fibrillation (AF). A total of 1447 patients who underwent symptom-limited cardiopulmonary exercise testing and whose BNP values were determined simultaneously were analysed (SR, N = 1151 and AF, N = 296). HF events were defined as HF hospitalization or HF death. Over a mean follow-up period of 1472 days, 140 HF events were observed. A high BNP value (dichotomized by median value) was independently associated with HF events in SR (HR 8.08; 95 % CI 4.02-16.26; p < 0.0001), but not in AF patients (HR 1.97; 95 % CI 0.91-4.28; p = 0.087) with a significant interaction between the rhythms. By contrast, low-peak VO was independently associated with HF events in both rhythms (AF; HR 5.81; 95 % CI 1.75-19.30; p = 0.004, SR; HR 2.04; 95 % CI 1.19-3.49; p = 0.009), with a marginal interaction between them. In bivariate Cox models, low-peak VO had much stronger predictive power for HF events than high-BNP in AF, whereas high-BNP was more powerful than low-peak VO in SR. The prognostic value of BNP and peak VO for future HF events seemed to be different between SR and AF.
Topics: Aged; Arrhythmia, Sinus; Atrial Fibrillation; Exercise Test; Female; Heart Failure; Humans; Japan; Linear Models; Male; Middle Aged; Multivariate Analysis; Natriuretic Peptide, Brain; Oxygen Consumption; Prognosis; Proportional Hazards Models; Stroke Volume
PubMed: 27550341
DOI: 10.1007/s00380-016-0887-x -
Aerospace Medicine and Human Performance Aug 2017Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular...
INTRODUCTION
Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure.
CASE REPORT
A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time.
DISCUSSION
While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.
Topics: Accelerated Idioventricular Rhythm; Adult; Aerospace Medicine; Asymptomatic Diseases; Centrifugation; Electrocardiography; Humans; Hypergravity; Male; Remission, Spontaneous; Space Simulation
PubMed: 28720191
DOI: 10.3357/AMHP.4896.2017 -
Pacing and Clinical Electrophysiology :... Jul 1978The effects of the occlusion of the two main atrial arteries irrigating the sinus node on sinus rhythm and postpacing sinus recovery were studied in 12 anesthetized...
The effects of the occlusion of the two main atrial arteries irrigating the sinus node on sinus rhythm and postpacing sinus recovery were studied in 12 anesthetized dogs. Records of spontaneous rhythm and of postpacing sinus recovery were taken at control and hourly for 6 hours after the occlusion. The spontaneous cycle length (AA interval) was 335 +/- 11 ms at control and 416 +/- 17 ms (mean +/- SE) (p less than 0.005) one hour after the occlusion. It remained nearly unchanged during the following 5 hours of observation. The occlusion also shortened atrioventricular conduction time (AV interval) and reduced P-wave amplitude in ECG lead II in 9 of these dogs. While the control postpacing sinus recovery time was 397 +/- 13 ms, the 1-hour value was 715 +/- 165 ms. This prolongation persisted during the first four postocclusion hours but was less marked during the last two hours of observation. Moreover, the postpacing mode of return of the AA intervals to their prepacing value (sinus recovery pattern) became characteristically slow and progressive after occlusion, complete postpacing recovery often occurring only after 100 or more beats. Sequences of escape atrial and/or AV junctional rhythms were frequently seen during this recovery. Atrial extrasystoles and short sequences of atrial tachycardias were observed in most dogs after occlusion. Conversely, none of these changes occurred during a 6-hour experimental time in 5 control dogs in which the same protocol, occlusion excepted, was repeated. These observations show that the sinus node function in the dog is consistently affected by impairing its blood supply. Ischemic dysfunctions include sinus slowing, pacemaker shift, prolonged sinus recovery time, delayed postpacing recovery and supraventricular tachyarrhythmias.
Topics: Animals; Arrhythmia, Sinus; Cardiac Complexes, Premature; Coronary Disease; Coronary Vessels; Dogs; Heart Atria; Ligation; Sinoatrial Node; Tachycardia; Time Factors
PubMed: 82949
DOI: 10.1111/j.1540-8159.1978.tb03486.x