the workshop project
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The Workshop Project. Understanding Spiral Waves. The refractory period. E xcitable systems can sustain spiral waves as well as plain waves This is due to the refractory period Three examples of the effect of the refractory period. Induction of spiral waves. - PowerPoint PPT PresentationTRANSCRIPT
The Workshop Project
Understanding Spiral Waves
The refractory period
• Excitable systems can sustain spiral waves as well as plain waves
• This is due to the refractory period– Three examples of the effect of the refractory peri
od
Induction of spiral waves
• Spiral waves can be initiated when tissue has repolarized nearly, but not fully, to the rest state.
• It’s all about timing!
Too late Too early Just right
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Reentrant Spiral Waves: Simulation
Fenton FH et al. Chaos 2002; 12, 852-892.
Belusov-Zhabotinsky Reaction
Oliver Steinbock
Spiral Waves of Electrical Activity in the Heart(Arrhythmias)
Number one in industrialized countries
CDC/StatisticsNational Vital Statistics Report, Vol.49, No.11, October 12, 2006
Deaths and percent of total deaths for the 10 leading causes of death: United States
Rank Cause of death Total Deaths Percentage All causes ...........................................................2,391,399 100.0
1 Diseases of heart ................................................725,192 30.3 2 Malignant neoplasms ...........................................549,838 23.0 3 Cerebrovascular diseases .....................................167,366 7.0 4 Chronic lower respiratory diseases ......................124,181 5.2
etchttp://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_14.pdf
Heart diseases Heart disease is one of the leading causes of death in the world.
Many different types of cardiac arrhythmias• Heart disease is a broad term that includes:
– Coronary heart disease (arteries to heart blocked → heart attack).
– Stroke (arteries to brain blocked or burst).– Congestive heart failure (weakened pumping).– High blood pressure → all of the above.– Arrhythmias (disorders of regular rhythmic beating).
Types of Arrhythmias
• Can occur in upper chambers (atria) or lower chambers (ventricles) or both.
• Heart rate may be increased or decreased.• May be asymptomatic or immediately life-
threatening.• May result from pacemaker dysfunction or
breakdown of electrical activity (reentry)..
Main Types of Fibrillation
• Atrial fibrillation: – Not immediately life-threatening. – 2 million affected, influences lifestyle.– Responsible for 15-20% of all strokes (clotting).
• Ventricular fibrillation: – Contraction no longer coordinated: heart cannot
pump. – 340,000 deaths/year in US. – Tachycardia often immediately precedes fibrillation.
Your project
• Investigate spiral waves forming from the Tusscher-Noble-Noble-Panfilov model:
• For play, the simpler Fitzhugh-Nagumo model is helpful– Try altering the parameters a and b and see how
you can change the spiral tip pattern