To prevent cardiovascular diseases (CVD), the electrocardiogram (ECG) of the patient must be recorded for a long period of time. For an effective diagnostic, the recording system must easily adapt to new patients and function for long periods of time. This paper presents the use of slopes in event-driven signal as a feature to detect beats and arrhythmias in electrocardiograms (ECG) with 98.3% accuracy and adaptability to new patients specification.