What is new in cardiology? (Part I) by Dr TS Kler.
(Described by Dr SK Kapoor with added inputs).
Despite CAD being a rich man’s disease and US being an affluent country, the incidence of CAD is 2.5 times more in India (w.r.t. US).
Post MI, a damaged heart often generates arrhythmias like AF and VT. These are difficult to treat as the cardiac electrophysiology become complicated due to the scarred tissue hampering the conduction of electrical impulse.
Scarring creates an ‘arrythmial isthmus’ or a narrowing with slowest pace of conduction. This proves to be the best place to ablate in order to terminate the arrhythmia.
A 3-D visualization method for use with electroanatomic mapping of cardiac arrhythmias (Pubmed, NLM) delineates the wave front or the electrical movement of wave.
It displays electrical signals from the heart to show voltage, activation, timing, and morphology at each point within a chamber.
It can help identify:
• Slow conduction channels: These channels can be a substrate for VT. So to define areas of fibrous tissues SUBSTRATE MAPPING is done.
• Tachycardia mechanisms: RIPPLE MAPPING can help identify the mechanisms behind tachycardia.
• Optimal ablation sites: Ripple mapping can help identify the best sites for ablation.
It works by:
1. Importing electrogram locations
2. Constructing a 3D surface
3. Time gating electrograms
4. Displaying electrograms as dynamic bars that extend from the surface
5. Changing the length and color of the bars based on the local electrogram voltage-time relationship
Ripple mapping is an alternative to conventional activation mapping.