Transcript Introduction to the research project

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
period
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)
Heart diseases
Heart disease is one of the leading causes of death in the world.
Number one in industrialized countries
National 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
etc
http://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_14.pdf
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 lifethreatening.
• 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