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Unravelling the Electropathophysiology of Atrial Fibrillation : a nalysis of morphological characteristics of atrial electrograms during epicardial mapping in coronary artery disease patients

Nijenhuis, L.H. te (2020) Unravelling the Electropathophysiology of Atrial Fibrillation : a nalysis of morphological characteristics of atrial electrograms during epicardial mapping in coronary artery disease patients.

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Abstract:Introduction: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide. Early diagnosis and treatment of AF is desired to prevent progression to severe AF stages. High-resolution epicardial mapping is a promising technique to give insights in the electropathology of the AF and provide a means for early recognition of AF. The aim of this research is to search for morphological characteristics in epicardial electrograms (EGMs) during sinus rhythm, that can describe the duration and area under the curve (AUC) of these electrograms and mark the first signs of AF in patients with coronary artery disease. Methods: High-resolution epicardial mapping with 128 or 192 unipolar electrodes was performed during Coronary Artery Bypass Grafting (CABG) surgery of 81 patients, with and without AF history and post-operative AF (poAF) development. Mapping was performed during sinus rhythm at the right atrium (RA), Bachmann’s bundle (BB), left atrium (LA) and pulmonary vein area (PV). In the obtained epicardial electrograms (EGMs), local activation times were annotated by marking the steepest negative deflection of each atrial potential of each electrogram. Subsequently, peak-to-peak amplitude, atrial complex duration, AUC, normalized AUC (AUCnorm), amplitude ratio, duration ratio and amplitude duration ratio (ADR) were calculated for each atrial complex to describe the morphology. Besides, each potential was classified into a potential type (single, double or complex fractionated). Subsequently each single potential was classified into an amplitude type (R, Rs, RS, rS and S) and a duration type (A, Ab, AB, aB and B). Results: The parameters peak-to-peak amplitude, AUC, AUCnorm and ADR were significantly lower in AF, while duration, amplitude ratio and duration ratio were significantly higher in the AF group. Furthermore, duration was significantly prolonged and duration ratio significantly lower in poAF patients in comparison to no poAF patients at BB. The major part of the 713 520 investigated atrial potentials were single potentials (72.4 %) followed by double (22.6 %) and complex fractionated potentials (5.0 %). More double and complex potentials occurred at BB and in AF patients. The single potentials had the rS morphology as common amplitude type (47.0 %), which was decreased to 43.4 % in AF patients. The duration type shows a shift from A to B morphology in AF and poAF patients in comparison to no AF and no poAF patients. Both the single potential amplitude and duration types showed similar percentages in RA and BB and in PV and LA. Duration, AUC and AUCnorm showed significant differences between single potentials and complex potentials, while amplitude and ADR differed significantly for each potential type. Conclusion: In this study, five new and unique morphological parameters are introduced, which were succesfully able to describe and classify the morphological characteristics of epicardial EGMs. The EGMs were obtained by high-resolution epicardial mapping in coronary artery disease patients. Parameters peak-to-peak amplitude, duration, AUC, normalized AUC, amplitude ratio, duration ratio and amplitude duration ratio are all successful indicators for morphological differences between no AF patients and AF patients. Furthermore, parameters duration and duration ratio show promising results as parameters to indicate differences between patients who develop poAF and patients who do not develop poAF. All investigated parameters are deemed useful to describe the different morphologies of atrial potentials, of which the single potential is the most common. In coronary artery disease patients, the most common amplitude type of these single potentials is the rS morphology, of which the prevalence decreases in AF patients. Moreover, the duration type of these single potentials shows a shift from A to B morphology in AF and poAF patients. The reported insights in morphological differences are expected to be helpful in early diagnosis and therapy of AF and have helped us to unravel the electropathophysiology of atrial fibrillation in coronary artery disease patients to even further extent. Keywords: Atrial fibrillation, Sinus rhythm, High-resolution epicardial mapping, Unipolar electrograms, Coronary artery disease, Coronary Artery Bypass Grafting
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
Link to this item:http://purl.utwente.nl/essays/82770
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