Subcutaneous implantable string shaped defibrillator for providing cardiac resynchronization therapy (CRT), including a flexible elongated body, at least two defibrillation leads, at least one sensor, at least two transition units and at least one epicardial lead, the defibrillation leads for providing at least one cardioversion defibrillation shock, the sensor being positioned on at least one of the defibrillation leads, for determining at least one metric of a heart, the transition units for respectively coupling the defibrillation leads to opposite ends of the elongated body, and the epicardial lead, coupled with the elongated body via at least one of the transition units, for providing at least one CRT pulse, the elongated body including a plurality of linked units, the linked units encapsulating at least one capacitor, at least one power source and a processor, wherein the processor provides at least one signal to the epicardial lead for providing the CRT pulse.
