Described herein are systems, devices and methods for guiding placement of electrodes, and particularly ECG electrodes on a patient. A picture of the patients body the patient can be analyzed to determine where on the patients body to place electrodes according to a predetermined, conventional or standard placement pattern. The methods, devices and systems may then guide a user in positioning or correcting the position of electrodes on the patient. For example, an image of the patient may be provided showing the correct position of the electrodes, which may act as a patient-specific map or guide. The electrode placement positions can correspond to conventional or standard 12-lead ECG electrode positions.