It depends on the procedure. Essentially all procedures inside the heart do require the heart lung machine (mitral valve repair, mitral valve replacement, atrial septal defect closure, surgery for hypertrophic cardiomyopathy, MAZE procedure, tricuspid valve repair or replacement, atrial myxoma resection and others).
Robotic coronary artery bypass can be done without bypass (off-pump) or with bypass depending on the situation. If off pump the heart is beating during the procedure. We do ligate the left atrial appendage without bypass as an isolated procedure. We also place pacemaker leads without bypass.