A defibrillation system for synchronized cardioversion of a patient includes a first housing that includes a measurement circuit configured to receive electrocardiogram (ECG) signals and measure ECG parameters based on the ECG signals, and a first processor configured to analyze the ECG parameters, and initiate communication of a synchronization signal for a second processor for delivery of one or more defibrillation pulses and further includes a second housing that is separate from and external to the first housing and that includes a shock delivery circuit, and the second processor which is configured to receive the communication of the synchronization signal from the first processor, and control the shock delivery circuit to deliver the one or more defibrillation pulses in response to the synchronization signal.