Workshop on Atrial Fibrillation Group 6 Atrial Fibrillation

Workshop on Atrial Fibrillation Group 6

Atrial Fibrillation � The most common type of arrhythmia (irregular heartbeat) � In AF, atria contract very fast and irregularly. � Atria get pooled by blood. � Blood not being able to go into ventricles completely. � Consequently, atria and ventricles do not work together. � The heart’s electrical signals do not begin in the SA node. � Signals begin in another part of the atria or in pulmonary veins and they don’t travel normally. � The amount of blood pumped by ventricles to the body depends on atrial beats.

Spiral Waves Interesting patterns seen in many experiments. Example: Belousov. Zhabotinsky Usually rotate without changing their shapes The tip traces out a perfect circle After getting destabilized, they either drift or meander.

Inward meandering

Outward meandering

Drifting Spiral Waves

GNa – Conductance for fast Na+ channel k. Na. Ca – Current for Na+/Ca 2+ exchanger- An antiport, where three Na+ are brought in for one Ca 2+, when the Parameters membrane potential is negative and when the cell is depolarized, Na+ leaves and Ca 2+ enters. GNa vs k. Na. Ca

Spiral Wave of Day 1 Maximal INa conductance GNa Maximal INa. Ca KNa. Ca

Path of Day 1 Maximal INa conductance GNa Maximal INa. Ca KNa. Ca

Spiral wave Day 2 Maximal INa conductance GNa Maximal INa. Ca KNa. Ca

Path of Day 2 Maximal INa conductance GNa Maximal INa. Ca KNa. Ca

Day 1 VS. Day 2 Wave Comparison

Day 1 VS Day 2 Trajectory Comparison

Conclusions: • Spiral waves are influenced by the concentration of Ions. • Different shape of the spirals depending on which concentration is changed first. • Low concentration of Sodium Calcium exchanger and high concentration of Sodium produces trajectories that are more chaotic. • High Sodium-Calcium concentration and low Sodium concentration produces spiral trajectories that are tight.

Acknowledgement Nancy Griffeth Flavio Fenton Robert Gilmour Bard Ermentrout Aron Wolinetz Charles Beard Rachel Spratt All participants