Heart disease is one of the top ten threats to global health in 2019 according to the WHO. Continuous monitoring of ECG on wearable devices can detect abnormality in the user’s heartbeat early, thereby significantly increasing the chance of early intervention which is known to be the key to saving lives. In this paper, we present a set of inter-patient ECG classification methods that use convolutional (CNNs) and spiking neural networks (SNNs). We focused on inter-patient heartbeat classification, in which the model is trained over several patients and then used to infer that for patients not used in training. Raw heartbeat data is used in this paper because most wearable devices cannot deal with complex data preprocessing. A two-steps convolutional neural network testing method is proposed for saving power. For even greater energy-saving, a spiking neural network is also proposed. The latter is obtained from converting the trained CNN model with a less than one percent accuracy drop. The average power of a two-classes SNN is 0.077 W, or 0. 0074× that of previously proposed neural network-based solutions.