Alterations in autonomic function are known to occur in cardiac conditions including sudden cardiac death. Cardiac stimulation via sympathetic neurons can potentially trigger arrhythmias. Dissecting direct neural-cardiac interactions at the cellular level is technically challenging and understudied due to the lack of experimental model systems and methodologies. Here we demonstrate the utility of optical interrogation of sympathetic neurons and their effects on macroscopic cardiomyocyte network dynamics to address research targets such as the effects of adrenergic stimulation via the release of neurotransmitters, the effect of neuronal numbers on cardiac wave behaviour and the applicability of optogenetics in mechanistic in vitro studies. We present novel methodologies to study neuron-cardiomyocyte interactions involving optogenetic selective probing and all-optical electrophysiology to measure electrical activity in an automated fashion, illustrating the power and high-throughput capability of such interrogations. We present new findings on how neurons impact cardiac macroscopic wave properties, the links between neuron density and cardiac firing rates as well as the challenges and benefits of macroscopic co-cultures as experimental model systems.