Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities
Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using...
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MDPI AG
2021-01-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/2/484 |
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| author | Martijn H. van der Ree Jeroen Vendrik Jan A. Kors Ahmad S. Amin Arthur A. M. Wilde Hanno L. Tan Pieter G. Postema |
| author_facet | Martijn H. van der Ree Jeroen Vendrik Jan A. Kors Ahmad S. Amin Arthur A. M. Wilde Hanno L. Tan Pieter G. Postema |
| author_sort | Martijn H. van der Ree |
| collection | DOAJ |
| description | Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (<i>n</i> = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (<i>n</i> = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, <i>p</i> < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, <i>p</i> < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, <i>p</i> < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined. |
| first_indexed | 2024-03-10T13:26:55Z |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T13:26:55Z |
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| spelling | doaj.art-412d0035f7da488891f2e2f2bd4d38622023-11-21T08:48:25ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-01-0122248410.3390/ijms22020484Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization AbnormalitiesMartijn H. van der Ree0Jeroen Vendrik1Jan A. Kors2Ahmad S. Amin3Arthur A. M. Wilde4Hanno L. Tan5Pieter G. Postema6Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsHeart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsDepartment of Medical Informatics, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, 3015 GD Rotterdam, The NetherlandsHeart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsHeart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsHeart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsHeart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Meibergdreef 9, 1105 AZ Amsterdam, The NetherlandsPatients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (<i>n</i> = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (<i>n</i> = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, <i>p</i> < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, <i>p</i> < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, <i>p</i> < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined.https://www.mdpi.com/1422-0067/22/2/484Brugada syndromevectorcardiogramleft axis deviationventricular arrhythmias |
| spellingShingle | Martijn H. van der Ree Jeroen Vendrik Jan A. Kors Ahmad S. Amin Arthur A. M. Wilde Hanno L. Tan Pieter G. Postema Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities International Journal of Molecular Sciences Brugada syndrome vectorcardiogram left axis deviation ventricular arrhythmias |
| title | Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities |
| title_full | Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities |
| title_fullStr | Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities |
| title_full_unstemmed | Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities |
| title_short | Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities |
| title_sort | left axis deviation in brugada syndrome vectorcardiographic evaluation during ajmaline provocation testing reveals additional depolarization abnormalities |
| topic | Brugada syndrome vectorcardiogram left axis deviation ventricular arrhythmias |
| url | https://www.mdpi.com/1422-0067/22/2/484 |
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