Systems, apparatus, and methods for ablation therapy are described herein, with a processor for confirming pacing capture or detecting ectopic beats. An apparatus includes a processor for receiving cardiac signal data captured by a set of electrodes, extracting a sliding window of the cardiac signal data, identifying a peak frequency over a subrange of frequencies associated with the extracted sliding window, detecting ectopic activity based at least on a measure of the peak frequency over the subrange of frequencies, in response to detecting ectopic activity, sending an indication of ectopic activity to a signal generator configured to generate pulsed waveforms for cardiac ablation such that the signal generator is deactivated or switched off from generating the pulsed waveforms. An apparatus can further include a processor for confirming pacing capture of the set of pacing pulses based on cardiac signal data.