Most current Holter devices monitor the ECG for 24 to 72 hours. However, for the accurate diagnosis of many cardiac diseases, especially for the wide variety of asymptomatic cases, continuous ECG monitoring for weeks or even months may be required. In this paper, we focus on the issue of ECG compression during long-term monitoring of the patient. The patient may be at home, at work, or even on a trip. A scalable compression scheme is proposed which ensures optimal signal quality given the limited physical storage on the wearable device. When necessary, the signal quality is progressively and gently degraded in order to adapt to environmental and the patient's conditions. Details of the proposed scheme are described and sample results are presented.