diff --git a/extensions/dicom-pdf/src/getSopClassHandlerModule.js b/extensions/dicom-pdf/src/getSopClassHandlerModule.js
index e0ef0e2..983e785 100644
--- a/extensions/dicom-pdf/src/getSopClassHandlerModule.js
+++ b/extensions/dicom-pdf/src/getSopClassHandlerModule.js
@@ -5,6 +5,7 @@ const { ImageSet } = classes;
 
 const SOP_CLASS_UIDS = {
   ENCAPSULATED_PDF: '1.2.840.10008.5.1.4.1.1.104.1',
+  TwelveLeadECGWaveformStorage: '1.2.840.10008.5.1.4.1.1.9.1.1',
 };
 
 const sopClassUids = Object.values(SOP_CLASS_UIDS);