scholarly journals Characterizing Spatial Dynamics of Bifurcation to Alternans in Isolated Whole Rabbit Hearts Based on Alternate Pacing

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kanchan Kulkarni ◽  
Ramjay Visweswaran ◽  
Xiaopeng Zhao ◽  
Elena G. Tolkacheva
Keyword(s):  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Cycle Length ◽  
Spatial Dynamics ◽  
Natural Death ◽  
Epicardial Surface ◽  
The Usa ◽  
Collision Mechanism ◽  
Perturbation Size ◽  
Basic Cycle Length

Sudden cardiac death instigated by ventricular fibrillation (VF) is the largest cause of natural death in the USA. Alternans, a beat-to-beat alternation in the action potential duration, has been implicated as being proarrhythmic. The onset of alternans is mediated via a bifurcation, which may occur through either a smooth or a border-collision mechanism. The objective of this study was to characterize the mechanism of bifurcation to alternans based on experiments in isolated whole rabbit hearts. High resolution optical mapping was performed and the electrical activity was recorded from the left ventricle (LV) epicardial surface of the heart. Each heart was paced using an “alternate pacing protocol,” where the basic cycle length (BCL) was alternatively perturbed by ±δ. Local onset of alternans in the heart,BCLstart, was measured in the absence of perturbations (δ=0) and was defined as the BCL at which 10% of LV exhibited alternans. The influences of perturbation size were investigated at two BCLs: one prior toBCLstart(BCLprior=BCLstart+20 ms) and one precedingBCLprior(BCLfar=BCLstart+40 ms). Our results demonstrate significant spatial correlation of the region exhibiting alternans with smooth bifurcation characteristics, indicating that transition to alternans in isolated rabbit hearts occurs predominantly through smooth bifurcation.

scholarly journals Sudden cardiac death after robbery: Homicide or natural death?

2020 ◽  
Vol 75 ◽  
pp. 102057
Author(s):  
Giampiero Bottari ◽  
Silvia Trotta ◽  
Andrea Marzullo ◽  
Giovanni Meliota ◽  
Marco Matteo Ciccone ◽  
...  
Keyword(s):  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Natural Death

scholarly journals Prevention of sudden cardiac death by the implantable cardioverter defibrilator

2011 ◽  
Vol 64 (5-6) ◽  
pp. 291-294 ◽  
Author(s):  
Dragan Kovacevic ◽  
Anastazija Stojisic-Milosavljevic ◽  
Vasilije Topalov ◽  
Bogoljub Mihajlovic ◽  
Dejan Sakac ◽  
...  
Keyword(s):  
Sudden Cardiac Death ◽  
Sudden Death ◽  
Cardiac Death ◽  
Social Insurance ◽  
Heart Rhythm ◽  
Insurance Fund ◽  
Social Insurance Fund ◽  
The Usa ◽  
Rhythm Disorder ◽  
The One

Introduction. Sudden cardiac death or, as it is also called, a modern man?s killer occurs a few hours after the beginning of the disease. Sudden death is the one that happens within an hour from the onset of the subjective discomforts regardless of the existence of any previous disease. According to modern statistics, 450.000 people die suddenly in the USA and 150,000 in Germany. Causes of sudden death. The most frequent causes of sudden death are cardiologic or, in other words, a heart rhythm disorder such as ventricular tachycardia, ventricular fibrillation and bradycardiac rhythm disorder. All these reasons can be efficiently prevented by the implantation of the cardioverter defibrillators. Implantable cardioverter defibrillator. In comparison with the already known medications, the defibrillator seems to be the most efficient in prevention of sudden cardiac death. This fact has been confirmed by large multicentre studies. The implantation itself is a routine procedure. It lasts about an hour and it often passes without any complications. The patient leaves the hospital a few days after the procedure. About 150 of these procedures are performed per year at the Institute of Cardiovascular Diseases Vojvodina. The Social Insurance Fund bears medical costs and the patient only pays the participation fee, which is symbolical if compared to the value and use of the device. Owing to this fact, this device is available to every patient thus making the efficient sudden cardiac death prevention possible.

Parasympathetic effects on cardiac electrophysiology during exercise and recovery

2002 ◽  
Vol 282 (6) ◽  
pp. H2091-H2098 ◽  
Author(s):  
Prince J. Kannankeril ◽  
Jeffrey J. Goldberger
Keyword(s):  
Sudden Cardiac Death ◽  
Refractory Period ◽  
Cardiac Death ◽  
Cardiac Electrophysiology ◽  
Cycle Length ◽  
Recovery Period ◽  
Left Ventricular ◽  
Effective Refractory Period ◽  
Av Block ◽  
Sinus Cycle Length

Depressed parasympathetic tone is associated with an increased risk of sudden cardiac death. Exercise and the postexercise recovery period, which are associated with parasympathetic withdrawal, are high risk periods for sudden death. However, parasympathetic effects on cardiac electrophysiology during exercise and recovery have not been described. Electrophysiology studies were performed using noninvasive programmed stimulation (NIPS) in nine subjects (age 59 ± 18 yr) with implanted dual-chamber devices and normal left ventricular function during multiple bicycle exercise sessions. NIPS was performed at rest, during exercise, and in the early recovery period both before and after parasympathetic blockade with atropine. Parasympathetic effect was defined as the value of the parameter of interest in the absence of atropine minus the value of the parameter in the presence of atropine. During exercise, sinus cycle length, atrioventricular (AV) block cycle length, AV interval, and ventricular effective refractory period shortened; in recovery, the values were intermediate between the rest and exercise values ( P < 0.0001 by ANOVA). Parasympathetic effects on sinus cycle length, AV block cycle length, AV interval, and ventricular effective refractory period were 247 ± 140, 58 ± 20, 76 ± 20, and 8.6 ± 7.5 ms at rest, 106 ± 20, 37 ± 14, 24 ± 13, and 2.6 ± 7.8 ms during exercise, and 209 ± 114, 50 ± 23, 35 ± 21, and 9.5 ± 11.8 ms during recovery, respectively. There was poor correlation among the parasympathetic effects noted at the sinus node, AV node, and ventricle. Further work evaluating parasympathetic effects on cardiac electrophysiology during exercise and recovery in patients with heart disease is required to elucidate its role in modulating the risk of sudden cardiac death noted at these times.

scholarly journals Chloroquine Related to Malaria and its Promising Applications for Covid-19 Treatment

2020 ◽  
Vol 33 (3) ◽  
pp. 125-128
Author(s):  
Alberto Nicodemus Gomes Lopes ◽  
Luciano Barreto Silva
Keyword(s):  
Sudden Cardiac Death ◽  
Qt Interval ◽  
Cardiac Death ◽  
Web Of Science ◽  
Cochrane Library ◽  
Ecg Monitoring ◽  
Pubmed Central ◽  
The Usa ◽  
Online Searches ◽  
The Cochrane Library

Objective: this article described the use of chloroquine as an antimalarial agent with potential antiviral indications for COVID-19 infections. Methods: this article consisted of online searches and gray literature whose database included PUBMED Central, BVS/BIREME, Web of Science, Science Direct, Higher Level Personnel Improvement Coordinator (CAPES), Periodic Door (Portal de Periódicos da CAPES, The Cochrane Library, and PROSPERO). Results: chloroquine and hydroxychloroquine have shown appropriate clinical reports when associated with the antibiotic Azithromycin. It has been authorized for the clinical treatment of severe acute forms of COVID infections by countries such as Brazil and the USA. Conclusions: Chloroquine seems to have potential antiviral properties that may be useful in the treatment of these severe acute forms of COVID-19 associated with Azithromycin. Nevertheless, its indication must include ECG monitoring due to the risk of prolongation of QT interval, leading to sudden cardiac death.

scholarly journals Sudden cardiac death and acute drunken state: Autopsy study

2010 ◽  
Vol 138 (9-10) ◽  
pp. 590-594 ◽  
Author(s):  
Vladimir Zivkovic ◽  
Borislav Miletic ◽  
Slobodan Nikolic ◽  
Fehim Jukovic
Keyword(s):  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Alcohol Intoxication ◽  
Blood Alcohol Concentration ◽  
Alcohol Concentration ◽  
Blood Alcohol ◽  
Acute Alcohol Intoxication ◽  
Natural Death ◽  
Autopsy Study ◽  
Alcohol Abusers

Introduction. Sudden natural death occurs unexpectedly in apparently healthy subjects, or in persons during an apparent benign phase in the course of disease. The most common cause is sudden cardiac death, which is sometimes the first and last manifestation of coronary heart disease. Alcohol directly influences excitation of myocytes, and therefore provokes arrhythmias and possibly, sudden cardiac death. Objective. To establish the frequency of sudden cardiac death in cases of acute alcohol intoxication, to determine blood alcohol concentration at the moment of death, and to determine frequency and level of ethanol intoxication in chronic alcohol abusers, as well as causes of sudden death in those cases. Method. Retrospective autopsy study was performed for a three-year-period. We analyzed cases of sudden natural death, in relation to age and gender, cause of death, and blood alcohol concentration (at least 0.5 g/L). We considered the person to be a chronic alcoholic abuser if gross examination of organs during autopsy showed changes typical for excessive and habitual alcohol consumption. Results. Our sample consisted of 997 cases: 720 men and 277 women, average age 62.0?15.2 years (min=11; max=98). Total of 753 of them died of sudden cardiac death: much more men (?2=167.364; p=0.000), significantly younger than women (t=6.203; p=0.000). We determined acute alcohol intoxication in 73 persons - average blood alcohol concentration 1.85?1.01 g/L (min=0.55; max=3.85), and 61 of them died of cardiovascular diseases (?2=236.781; df=5; p=0.000). Conclusion. In our observed sample, not many persons were under acute alcohol intoxication (around 7%). Most commonly, they were chronic alcohol abusers who died due to exacerbation of chronic heart disease, mildly or moderately intoxicated - the younger, the drunker.

Sign in / Sign up

Export Citation Format

Share Document