A survey of pathways for mechano-electric coupling in the atria

Fig. 1. Left atrial strain as a function of time. (Time 0 corresponds to the QRS complex in an electrocardiogram.) A) Global left atrial strain curve, as measured using CINE MRI and echocardiography. Data from (Hoit, 2017). B) Positive left atrial strain inputted into computational models (see below).

Fig. 2. Mechano-electric coupling pathways considered in this study. The effects on atrial EP of the pathways in yellow font are investigated in the current study using computational simulations.

Fig. 3. Transmembrane potential, V, under the effect of constant stretch ranging from 1 to 3% and considering effects of (from top to bottom) of the following MEC pathways: a) ISAC_K, b) ISAC_NS, c) capacitance changes and d) simultaneous effect of pathways a)-c).

Fig. 4. APD90 restitution curves under constant stretch for all considered MEC pathways.

Fig. 5. a) Stretch protocols corresponding to the transmembrane potential, V, curves of the same colour on panel b), ie. blue and red: constant stretch (CS) at different values and yellow: time dependent (TD) stretch following the curve displayed on the right. C) V under time-dependent stretch for all the 4 pathways considered.

Fig. 6. APD90 and CV for time-independent and time-dependent stretches in baseline conditions and under the action of the 4 considered MEC pathways.

Fig. 7. Trajectory of the tip of rotors initiated using a cross-field protocol. a) In the presence of constant 3% stretch, the rotor tip follows an epitrochoidal trajectory, similar to what is observed in the baseline (no stretch) case. b) In the presence of time-dependent stretch (30% stretch at peak), the rotor tip hypermeanders and quickly reaches a tissue boundary where it terminates. The trajectory of the rotor is colour-coded according to the time since the rotor initiation.