Combining field potentials and impedance
Extracellular electrodes record field potentials from cardiomyocyte populations, while impedance measurements provide complementary information about beating-related changes and culture condition. Together, these label-free measurements support functional comparisons before and after drug treatment, continuous monitoring and parallel comparisons across experimental conditions.
Distinguishing three signal types
| Signal | Measurements | Interpretation limits |
|---|---|---|
| Extracellular field potential (EFP) | Frequency, waveform, field potential duration where identifiable, and rhythm abnormalities. | Reflects population-level electrical activity. Field potential duration is not the same as single-cell action potential duration and is not directly equivalent to the clinical QT interval. |
| Beating-related impedance | Beat-associated amplitude, rhythm and related dynamic changes. | Depends on cell motion, morphology and electrode contact; it is not a direct measurement of contractile force. |
| Baseline impedance | Trends related to adhesion, morphology and cell condition before and after dosing. | Influenced by multiple factors. Impedance changes alone cannot be converted into a viability percentage or used to identify a specific toxicity mechanism. |
Available endpoints depend on waveform identifiability and sample suitability. When rate-corrected duration measurements are reported, the correction method and its conditions of applicability must also be stated.
Model and culture compatibility
Assays can be designed around iPSC-derived cardiomyocytes and suitable primary cardiomyocyte cultures. Cell coverage, stable adhesion, baseline beating and electrode contact are important quality-control factors. For three-dimensional cardiac models, feasibility depends on tissue-electrode contact, culture format and signal quality.
Research applications
- Compare concentration-dependent compound effects on cardiac electrical activity and beating-related signals.
- Observe functional changes during acute treatment, extended exposure or recovery.
- Use baseline impedance together with independent measurements of cell condition to help interpret functional changes.
Field potential and impedance assays can be followed by patch-clamp studies, calcium imaging and contractile mechanics analysis to further investigate functional phenotypes identified during screening.
Project design and deliverables
The model, treatment concentrations, exposure times, control conditions and replicate design are agreed according to the study objectives. Results are analyzed alongside sample-condition and quality-control information.
- Culture conditions, baseline quality, dosing design and continuous monitoring records.
- Agreed field potential, beating-related impedance and baseline impedance parameters.
- Integrated interpretation of changes in function and cell condition, with recommendations for supplementary experiments.
