Unstable eigenmodes are possible drivers for cardiac arrhythmias

The well-organized contraction of each heartbeat is enabled by an electrical wave traversing and exciting the myocardium in a regular manner. Perturbations to this wave, referred to as arrhythmias, can lead to lethal fibrillation if not treated within minutes. One manner in which arrhythmias originate is an ill-fated interaction of the regular electrical signal controlling the heartbeat, the sinus wave, with an ectopic stimulus. It is not fully understood how and when ectopic waves are generated. Based on mathematical models, we show that ectopic beats can be characterized in terms of unstable eigenmodes of the resting state.

Download Full-text

Electrocardiographic Changes in Elderly Patients During Endoscopic Retrograde Cholangiopancreatography

Canadian Journal of Gastroenterology ◽

10.1155/2003/620564 ◽

2003 ◽

Vol 17 (9) ◽

pp. 539-544 ◽

Cited By ~ 10

Author(s):

NG Kounis ◽

GM Zavras ◽

PJ Papadaki ◽

SN Kouni ◽

M Batsolaki ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Myocardial Ischemia ◽

Elderly Patients ◽

Endoscopic Retrograde Cholangiopancreatography ◽

Cardiac Arrhythmias ◽

Holter Monitoring ◽

Endoscopic Retrograde ◽

St Segment ◽

Ectopic Beats

BACKGROUND: Cardiorespiratory complications may occur during gastrointestinal endoscopy, and elderly people seem to be more vulnerable to these complications during endoscopic procedures involving the manipulation of abdominal viscera. OBJECTIVES: To determine the incidence of cardiac arrhythmias, changes in oxygen saturation, heart rate and blood pressure during endoscopic retrograde cholangiopancreatography (ERCP) via Holter monitoring in elderly patients older than 70 years of age.METHODS: Holter monitoring and 12-lead electrocardiograms were performed in 30 elderly patients undergoing ERCP and in 30 control subjects undergoing routine chest, abdomen, bone and upper gastrointestinal small bowel follow-through studies. A computerized nontriggered template system was used to analyze the electrocardiograms qualitatively and quantitatively. Arrhythmias, cardiac axis, conduction defects, pauses, ST segment changes, ectopic beats, oxygen desaturation and changes in blood pressure and rate-pressure product were evaluated.RESULTS: Increased heart rate, ST segment changes resulting from myocardial ischemia, oxygen desaturation and transient atrial and ventricular ectopic beats were frequent during ERCP compared with the control group. In one patient, transient left bundle branch block developed and this was attributed to pre-existing hypertension with cardiomegaly. One patient developed ventricular tachycardia and one other sinus bradycardia, but this was attributed to sick sinus syndrome.CONCLUSIONS: Transient myocardial ischemia and various cardiac arrhythmias are frequent in elderly patients undergoing ERCP. Appropriate noninvasive monitoring seems to be justified during this procedure.

Download Full-text

Dynamics of an Array Mechanical Arms Coupled Each to a Fitzhugh-Nagumo Neuron

10.21203/rs.3.rs-276556/v1 ◽

2021 ◽

Author(s):

KOUAMI Nadine ◽

NANA Bonaventure ◽

WOAFO Paul

Keyword(s):

Numerical Simulation ◽

Action Potential ◽

Resting State ◽

Electrical Signal ◽

Pulse Generation ◽

Electromechanical System ◽

Transient Chaos ◽

System Parameters ◽

Potential Flows ◽

Dynamical Behaviors

Abstract In this work, an array of electromechanical systems driven by an electrical line of Fitzhugh-Nagumo neuron is analyzed. It is shown that a single electromechanical system can display different dynamical behaviors such as single and multiple pulse generation, transient chaos, permanent chaos, and antimonotonicity according to the system parameters. In the case of an array of the electromechanical system constituted of a series of coupled discrete Fitzhugh-Nagumo neuron, the numerical simulation shows that as the action potential flows in the discrete array, each electromechanical system executes a pulse-like motion coming at each resting state as the electrical signal passes the node. The electromechanical system analyzed can be seen as a model for multi-periodic actuation processes or a leg model in a millipede system. Furthermore, this line can also carry an envelope of action potential and can be useful for various kinds of information processing systems.

Download Full-text

A history of chaos theory

Dialogues in Clinical Neuroscience ◽

10.31887/dcns.2007.9.3/coestreicher ◽

2007 ◽

Vol 9 (3) ◽

pp. 279-289 ◽

Cited By ~ 10

Keyword(s):

Mathematical Models ◽

Chaos Theory ◽

Cardiac Arrhythmias ◽

Initial Conditions ◽

Fractal Dimensions ◽

Biological Clocks ◽

Deterministic Models ◽

Endogenous Rhythms ◽

History Of ◽

Sensitivity To Initial Conditions

Whether every effect can be precisely linked to a given cause or to a list of causes has been a matter of debate for centuries, particularly during the 17th century, when astronomers became capable of predicting the trajectories of planets. Recent mathematical models applied to physics have included the idea that given phenomena cannot be predicted precisely, although they can be predicted to some extent, in line with the chaos theory. Concepts such as deterministic models, sensitivity to initial conditions, strange attractors, and fractal dimensions are inherent to the development of this theory A few situations involving normal or abnormal endogenous rhythms in biology have been analyzed following the principles of chaos theory. This is particularly the case with cardiac arrhythmias, but less so with biological clocks and circadian rhythms.

Download Full-text

Incidence and predictors of arrhythmias in patients with systemic sclerosis and no overt cardiac disease

European Heart Journal ◽

10.1093/ehjci/ehaa946.3159 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

G Stronati ◽

L Manfredi ◽

C Dichiara ◽

A Dello Russo ◽

A Gabrielli ◽

...

Keyword(s):

Sudden Cardiac Death ◽

Cardiac Disease ◽

Cardiac Arrhythmias ◽

Cardiac Death ◽

Holter Monitoring ◽

Right Atrial ◽

Atrial Volume ◽

Ectopic Beats ◽

Over Time

Abstract Background Cardiac involvement in SSc is frequent, mostly subclinical and represents a negative prognostic factor. Speckle tracking derived measurement global longitudinal strain (GLS) has been able to identify primary heart involvement in patients with SSc and no overt cardiac disease. SSc-related cardiomyopathy, defined as a condition affecting the heart primarily and globally, has been proven to progress over time and seems to be correlated to cardiac arrhythmias. Nonetheless, cardiac arrhythmias represent 6% of the overall causes of death in SSc patients. Purpose The aim of our study was to assess the incidence of cardiac arrhythmias in SSc patients with no overt cardiac disease and to identify potential predictors. Methods Prospective longitudinal study enrolling all consecutive patients with a diagnosis of SSc and no overt cardiac disease or pulmonary hypertension. Echocardiographic parameters and GLS were obtained at baseline and at each follow up. Presence of atrial fibrillation (AF), atrial tachycardia (AT), ventricular ectopic beats >1000/24 h (VEB), supraventricular ectopic beats (SVEB), bundle branch block (BBB) and atrioventricular block (AVB) was assessed through clinical history, ECG and 24-Holter monitoring over time. Results Among 67 consecutive patients with SSc, 11 (16.7%) had at least one episode of AF or AT. Moreover, respectively 12 (17.9%) and 16 (23.9%) had a significant amount of SVEB and VEB at Holter monitoring. Conduction defects were common, with 4 (4.6%) of all patients with grade I AVB, 1 (1.5%) with grade II AVB and 1 (1.5%) with complete heart block. Complete right BBB was seen in 6 (6.9%) of patients. Four patients (4.6%) experienced a sudden cardiac death during follow-up (median 20 months, 1st-3rd quartile 12–24 months). Years from SSc diagnosis (RR 1.10; 95% CI 1.02–1.23; p=0.047) and indexed right atrial volume (iRAV; RR 1.22; 95% CI 1.07–1.39; p=0.004), but not indexed left atrial volume were independently correlated with the diagnosis of AF/AT. The same two variables were independently correlated with any degree of AV block (years from SSc diagnosis: RR 1.11; 95% CI 1.01–1.23; p=0.004; iRAV: RR 1.14; 95% CI 1.02–1.27; p=0.019). Due to the low sample size, we were unable to detect any clinical predictors of sudden cardiac death in our population, however those who died experienced a larger worsening in left ventricle GLS values (4.0±1.6 vs. 0.9±0.4, p=0.056). Conclusions Supraventricular arrhythmias and conduction defects are common in patients with SSc. Time from diagnosis and right atrial volumes are able to predict the incidence of such conditions, supporting the hypothesis that a long-lasting disease and the anatomical remodelling of the right atrium could contribute to the developing of tachy- and bradyarrhythmias in this population. Funding Acknowledgement Type of funding source: None

Download Full-text

Evaluation of Heart Rhythm Variability and Arrhythmia in Children with Systemic and Localized Scleroderma

The Journal of Rheumatology ◽

10.3899/jrheum.080021 ◽

2009 ◽

Vol 36 (1) ◽

pp. 191-196 ◽

Cited By ~ 20

Author(s):

JACEK WOZNIAK ◽

RAFAL DABROWSKI ◽

DARIUSZ LUCZAK ◽

MALGORZATA KWIATKOWSKA ◽

ELZBIETA MUSIEJ-NOWAKOWSKA ◽

...

Keyword(s):

Heart Rate ◽

Cardiac Arrhythmias ◽

Average Rate ◽

Heart Rhythm ◽

Systemic Scleroderma ◽

Localized Scleroderma ◽

Control Group ◽

Healthy Children ◽

Significant Difference ◽

Ectopic Beats

Objective.To evaluate possible disturbances in autonomic regulation and cardiac arrhythmias in children with localized and systemic scleroderma.Methods.There were 40 children included in the study: 20 with systemic and 20 with localized scleroderma. The control group comprised 20 healthy children.Results.In 24-hour Holter recording, the average rate of sinus rhythm was significantly higher in the groups with systemic and localized scleroderma than in the control group, but there was no significant difference between them. The variability of heart rhythm in both groups was significantly decreased. In the group with systemic scleroderma, single supraventricular ectopic beats were observed in 20% and runs were seen in 40% of patients. In the group with localized scleroderma, supraventricular single ectopic beats occurred in 35% of patients and runs in 45% of those studied. Ventricular arrhythmia occurred in 2 children with systemic scleroderma, but in 1 child, it was complex.Conclusion.The most frequent cardiac arrhythmias in both types of scleroderma in children were of supraventricular origin, whereas ventricular arrhythmias did not occur very often. There were no significant differences in autonomic disturbances manifesting as a higher heart rate and decreased heart rate variability between localized and systemic scleroderma.

Download Full-text