Idiopathic ventricular fibrillation as an inherited channelopathy?
| Authors | |
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| Year of publication | 2022 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Background: Inherited arrhythmias are often associated with variants in genes encoding cardiac ionic channels. Similar genetic variants can be also detected in some patients suffering from “true” idiopathic ventricular fibrillation (VF). Aim: This is a pilot study to reveal proarrhythmic potential of selected genetic variants associated with “true” idiopathic VF in our patients. Two probands are going to be investigated, the first one carrying the Y4734C-RYR2 variant, the second one a combination of two KCNH2 variants, S1021Qfs*98 and A228V. Methods: Patient-specific cardiomyocytes have been prepared from a sample of peripheral blood of Y4734C-RYR2 proband and investigation of the functional defect has been started (whole-cell patch clamp, microelectrode array). The functional analysis of KCNH2 variants expressed in Chinese hamster ovary cells is being prepared, control KCNH2 data are being collected (whole-cell patch clamp). Results: The first experimental data showed a tendency of the patient-specific Y4734C-RYR2 cardiomyocytes to irregular electric activity at specific conditions (e.g., increased temperature, decreased extracellular K+, beta-stimulation). The ongoing analysis comparing properties of the patient-specific cardiomyocytes to control differentiated cardiomyocytes (independent control and “healthy” relative) should elucidate the origin of proarrhythmic activity in the proband. The control KCNH2 data are in agreement with the data published so far. Conclusions: It is surprising to observe a physiological ECG both at rest and during exercise in patients with rare variants in cardiac channel genes, even in a proband with two rare KCNH2 variants and repeated episodes of VF (appearing during alarm ringing). Detailed functional analysis is needed to reveal a possible relationship between the identified genotype and phenotype. It should reveal if the “true” idiopathic VF can be an inherited channelopathy at least in some of our patients. Identification of provoking circumstances that can result in unmasking of the phenotype would be very useful from the clinical point of view. |
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