Novel methods and apparatus for dynamically monitoring paced and sensed P-wave duration, P-wave end and/or QRS duration and/or S-T segment duration, or length, in a patient having an implantable medical device (IMD) provides diagnostic and clinical benefit allowing for predictions about future arrhythmia, advanced notification, alert and intervention as well as providing acute and chronic information regarding cardiac status, including both possibly declining and/or improving cardiac function. The methods can be performed using a wide variety of IMDs, such as pacemakers, cardiac resynchronization therapy (CRT) device, implantable cardioverter defibrillators (ICDs), and implantable loop recorders (e.g., such as the REVEAL® device manufactured by Medtronic, Inc.).
