An arrhythmia detection device is provided, which includes: a monitoring probe attached to a subject to be examined； a monitoring unit coupled with the monitoring probe； a first displaying unit which displays ECG parameters obtained by the monitoring unit； an ultrasound probe attached onto a body surface of the subject； an ultrasound imaging unit coupled with the ultrasound probe； an arrhythmia triggering unit which triggers the ultrasound imaging unit to scan the heart of the subject when the monitoring unit detects an arrhythmia； and a second displaying unit which displays the images and/or the parameters of the heart obtained by the ultrasound imaging unit.
