A hand-held device for acquiring electrocardiographic (ECG) signals from a patient comprises an electrode array with a gripping handle (15) and four electrodes (11-14). The electrodes typically form a quadrilateral array, the array being adapted for placement on the patients thoracic region without the need for upper clothing or underwear to be removed. The device can be used in a method to rapidly acquire ECG data relating to atrial fibrillation and/or flutter without the need for a conventional 12-lead ECG apparatus. The data can be transmitted to a computer for further manipulation and analysis. A kit for putting the method into effect includes the device, a means for communication with a computer and a computer program for running on the computer.
