Fig. 1

Flow diagram of the study. There were 16 patients excluded due to active cardiac conditions, including 4 patients with tachyarrhythmia, 4 patients on veno-arterial extracorporeal membrane oxygenation support, 3 patients with takotsubo cardiomyopathy, 2 patients were post-resuscitation for cardiac arrest, and 1 patient each with ST elevation myocardial infarction, myocarditis, and pericardial effusion. There were 13 patients excluded based on preexisting cardiac abnormalities, including 5 patients with ischemic cardiomyopathy, 3 patients with dilated cardiomyopathy, 2 with severe aortic stenosis, and 1 patient each with thyrotoxic heart disease, cardiac amyloidosis, and congenital heart disease