EKG Practice is an Android app. The free demo version has fewer choices. The information below was copied from the Android store.
"ECG practical" is an application designed to help you acquire the basic knowledge of electrocardiography; Knowledge that all healthcare professionals should possess, especially those who work in intensive care units such as CCU, ICU, Operating Rooms, etc.. Electrocardiography is definitely not an "easy" subject of study but with a minimum effort you can acquire the basic informations to be able to detect a critical situation and alert the cardiologist. The electrocardiogram is a simple test, fast, painless, very low-cost, and can definitely save the life of a person. In Italy every year about 120,000 people are affected by myocardial infarction, of these, approximately 25 000 die before reaching the hospital. The diagnosis of myocardial infarction is mainly made with the execution of the ECG. With "ECG practical" you can learn in a simple way the basic principles of electrocardiography, you can calculate your heart rate from the milliseconds or the number of squares between two RR, you can see several examples of ECG tracings, calculate the corrected QT interval, you can easily find the QRS axes or you can make your "diagnosis" simply by answering a few simple questions.
Note: The app does not process the photos taken with the camera or loaded from the gallery to not affect their quality. Loading large images (> 4 mpx) can cause the application to crash, especially in phones with little memory. When taking a photo, choose a lower than 4-megapixel resolution, and shot from a close distance.