INTRODUCTION: Andersen-Tawil syndrome (ATS) due to Kir2.1mutations typically manifests as periodic paralysis, cardiac arrhythmias and developmental abnormalities but is often difficult to diagnose clinically. This study was undertaken to determine whether sarcolemmal dysfunction could be identified with muscle velocity recovery cycles (MVRCs). METHODS: Eleven genetically confirmed ATS patients and 20 normal controls were studied. MVRCs were recorded with 1, 2, and 5 conditioning stimuli and with single conditioning stimuli during intermittent repetitive stimulation at 20 Hz, in addition to the long exercise test. RESULTS: ATS patients had longer relative refractory periods (P < 0.0001) and less early supernormality, consistent with membrane depolarization. Patients had reduced enhancement of late supernormality with 5 conditioning stimuli (P < 0.0001), and less latency reduction during repetitive stimulation (P < 0.001). Patients were separated completely from controls by combining MVRC and repetitive stimulation. CONCLUSIONS: MVRCs combined with repetitive stimulation differentiated ATS patients from controls more effectively than the conventional long-exercise test.
INTRODUCTION: Andersen-Tawil syndrome (ATS) due to Kir2.1mutations typically manifests as periodic paralysis, cardiac arrhythmias and developmental abnormalities but is often difficult to diagnose clinically. This study was undertaken to determine whether sarcolemmal dysfunction could be identified with muscle velocity recovery cycles (MVRCs). METHODS: Eleven genetically confirmed ATS patients and 20 normal controls were studied. MVRCs were recorded with 1, 2, and 5 conditioning stimuli and with single conditioning stimuli during intermittent repetitive stimulation at 20 Hz, in addition to the long exercise test. RESULTS: ATS patients had longer relative refractory periods (P < 0.0001) and less early supernormality, consistent with membrane depolarization. Patients had reduced enhancement of late supernormality with 5 conditioning stimuli (P < 0.0001), and less latency reduction during repetitive stimulation (P < 0.001). Patients were separated completely from controls by combining MVRC and repetitive stimulation. CONCLUSIONS: MVRCs combined with repetitive stimulation differentiated ATS patients from controls more effectively than the conventional long-exercise test.
Authors: S Veronica Tan; Werner J Z'graggen; Delphine Boërio; Christopher Turner; Michael G Hanna; Hugh Bostock Journal: Muscle Nerve Date: 2016-05-24 Impact factor: 3.217
Authors: Michael G Thor; Vinojini Vivekanandam; Marisol Sampedro-Castañeda; S Veronica Tan; Karen Suetterlin; Richa Sud; Siobhan Durran; Stephanie Schorge; Dimitri M Kullmann; Michael G Hanna; Emma Matthews; Roope Männikkö Journal: Sci Rep Date: 2019-11-26 Impact factor: 4.379
Authors: Karen J Suetterlin; S Veronica Tan; Roope Mannikko; Rahul Phadke; Michael Orford; Simon Eaton; Avan A Sayer; Miranda D Grounds; Emma Matthews; Linda Greensmith; Michael G Hanna Journal: JCSM Rapid Commun Date: 2021-05-05