Cardiomyocyte Beating Assay

Quantitative analysis of beating uses the digitized data to produce a Beat Score within a user-specified region of interest (e.g., circular region in Motion Analysis). The Beat Score reflects the extent of motion per 16.7ms interval, and each beat consists of a contraction event (early peak) and a relaxation event (late peak). The contraction and relaxation components are quantified by determining the AUC for each component.

In this example, the coefficient of variation for the Contraction and Relaxation scores are 5.6% and 2.4% respectively, indicating consistent beating action over time. The beat-to-beat cycle time is 844ms with a CV of 1.59%.

Isoproterenol, a beta-adrenergic agonist, increases the beating rate.

Astemizole, another hERG channel blocker, causes irregular beating of ES derived cardiomyocytes. Washout of drug restores regular beating (not shown).

Cisapride is a hERG blocker that disrupts rhythmic cardiomyocyte beating. Drug effects can be washed out to restore regular beating to near-baseline levels.

Acetylcholine has negative chronotropic effects on cardiomyocytes.

In the following validation experiments, motion data from the indicated circular regions are analyzed.

Time Domain Analysis of ES Derived Beating Cardiomyocytes

About 1000 ES cells are deposited into each well of 384 well plates and allowed to differentiate by forming Embryoid Bodies. After 9 days of differentiation, cardiomyocytes are detected as beating cells (Brightfield). Time resolved image analysis techniques are used to digitize and track beating cells (Motion Analysis).

Brightfield.

Motion Analysis.