Tachyarrhythmias such as atrial fibrillation (AF) or atrial flutter (AFL) sometimes invoke life-threatening collapse of hemodynamics in patients with severe heart failure. Recently, landiolol, an ultra-short acting β1-selective antagonist, has been reported to be safe and useful for the treatment of supraventricular tachyarrhythmias with reduced left ventricular function. Here we report a case of advanced heart failure with severe hypotension who was treated successfully by landiolol for rapid AF. The patient was a 20-year old male with dilated cardiomyopathy. He presented with low output syndrome in spite of optimal medical therapy and was referred to our department to consider ventricular assist device implantation and heart transplantation. Soon after admission, he developed rapid atrial fibrillation at 180 beats per minute (bpm) followed by severe hypotension and liver enzyme elevation. Low dose landiolol at 2 μg/kg/minute was started because digoxin was not effective. After landiolol administration, his heart rate decreased to 110 bpm, and finally returned to sinus rhythm without hemodynamic deterioration. Intra-aortic balloon pumping was inserted soon after sinus recovery and he was discharged successfully with an implantable left ventricular assist device.