Fig. S1
The five-category score of heart function used to identify differences in morphology and heart conduction. Numerical scores ranging from 1-4 (with 1 being nearest wild type) were assigned to 5 parameters of cardiovascular function from anonymized heart videos. Criteria for assigning these scores are outlined in A. Frames from analyzed video files depict hearts scoring progressively higher for all 5 parameters (B-D). Specifically: B is phenotypically normal, while C shows abnormal looping and a minor defect in both atrial and ventricular morphogenesis, and D depicts severe abnormalities in looping, conduction, and morphology. Red and black arrows show atria and ventricles, respectively.