An hiPSC-CM approach for electrophysiological phenotyping of a patient-specific case of short-coupled TdP

Figures

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  Fig. 1. Intervention of ventricular fibrillation as seen on the ICD interrogation of the patient. Electrical signal as detected by the implantable cardioverter defibrillator (ICD) of the patient, consisting of a regular rhythm, independent extrasystoles, a self-terminating ventricular fibrillation (VF), and the intervened VF. 5 subsequent squares represent a timespan of 1 s. The lighting symbol represents the moment of the ICD shock. Letters underneath the interrogation represent sensing (S), tachycardia (T), capacitor charging/charged (C), post-shock pacing (P), unclassified event (•), noise (N)

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  Fig. 2. Occurrence of early after transients in patient hiPSC-CMs. Calcium transient measurements were performed in hiPSC-CMs from the patient and a healthy control during normo- and hyperthermia. A During measurements of hiPSC-CMs of the patient extra calcium releases, termed early after transients (EATs), were observed during normo- and hyperthermia. B Quantification of the EATs highlighted the increased occurrence in the patient, especially after hyperthermia. N = number of measured cell clusters, originating from one clone (healthy) and 3 clones (patient) each with 3–4 hiPSC-CM differentiations

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  Fig. 3. Calcium transient parameters indicating disturbed calcium handling. Calcium transient measurements were performed in hiPSC-CMs from the patient (red) and a healthy control (black) during normo- and hyperthermia. A Definitions of parameters based on the amplitude, and 10% and 90% of the up- and downstroke of the fluorescence intensity. B Number of signals per minute (SPM). C Amplitude of the initial calcium signal, representing the amount of calcium in the initial release. D Rise time of the calcium signal, representing the release time of calcium into the cytosol. E Decay time of the calcium signal, representing the removal time of calcium from the cytosol. F 90% of the calcium transient duration (CTD), representing the duration of the entire calcium transient. N = 34–221 measured cell clusters, originating from one clone (healthy) and 3 clones (patient) each with 3–4 hiPSC-CM differentiations

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  Fig. 4. Shortened action potentials in patient hiPSC-CMs. Action potential measurements were performed in hiPSC-CMs from the patient (red) and a healthy control (black) during normo- and hyperthermia. A Definitions of parameters based on 50% and 90% of the downstroke of the fluorescence intensity. B Number of signals per minute (SPM). C 50% of the action potential duration (APD), representing early repolarization. D 90% of the APD, representing total repolarization. N = 47–135 measured cell clusters, originating from one clone (control) and 3 clones (patient) each with 3–4 hiPSC-CM differentiations

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  Fig. 5. Occurrence of early after transients after pharmacological intervention. Calcium transient measurements were performed in hiPSC-CMs from the patient and a healthy control during hyperthermia after 24 h incubation with either verapamil (5.5 µM), dantrolene (10 µM), flecainide (10 µM), or a vehicle (DMSO). Compared to the prior experiment, the occurrence of early after transients (EATs) after drug administration did not alter in the vehicle group, while the patient had a similar or increased percentage of EATs. N = number of measured cell clusters, originating from one clone (control) and 3 clones (patient) each with 3–4 hiPSC-CM differentiations

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  Fig. 6. Calcium transient parameters after drug administration. Calcium transient measurements were performed in hiPSC-CMs from the patient (red) and a healthy control (black) during hyperthermia after 24 h incubation with either verapamil (5.5 µM), dantrolene (10 µM), flecainide (10 µM), or a vehicle (DMSO). A Number of signals per minute (SPM). B Amplitude of the initial calcium signal, representing the amount of calcium in the initial release. C Rise time of the calcium signal, representing the release time of calcium into the cytosol. D Decay time of the calcium signal, representing the removal time of calcium from the cytosol. E 90% of the calcium transient duration (CTD), representing the duration of the entire calcium transient. N = 15–58 measured cell clusters, originating from one clone (control) and 3 clones (patient) each with 3–4 hiPSC-CM differentiations