1. Bence Patocskai et al. JACEP 2017;3:353-363
The Opposite Effects of Ajmaline to Mask or Accentuate the J-Wave (Jw) Depend on the Basal Level of Ito-Mediated Action Potential Notch Traces are as described in Figure 1. The bipolar electrograms (Bip.-EG-Epi) were recorded from the epicardium using 3 different low cut filter settings (10 Hz, 30 Hz, and 100 Hz) and 250 Hz “high cut” filter. When action potential notch was small (A), 10 μM ajmaline produced a decrease in J-wave and action potential notch area (B). The effect was reversible on wash-out (C). However, when the action potential notch was amplified using the Ito agonist NS5806 (D), the same concentration of ajmaline caused a marked accentuation of the J-wave appearing as an ST-segment elevation (E to G). Fragmented electrogram activity developed progressively as the repolarization defects became more pronounced and heterogeneous (D to F). Pronounced action potential notch (without re-entry) produced delayed potentials in a lower frequency range (D), whereas phase 2 re-entry depicted as “high-frequency” spike (E and F). After 15 min of ajmaline, loss of the action potential dome occurred throughout the preparation, which led to disappearance of the late potentials (G). Subendo/Mid = action potential from the subendocardium/midmyocardium; other abbreviations as in Figure 1.
Bence Patocskai et al. JACEP 2017;3:
2017 American College of Cardiology Foundation