Respiratory sigh associated transient autonomic changes detected with a continuous wavelet method of heart rate variability analysis.

•A Morlet CWT transform algorithm for analysis of HRV was written.•Nonstationary signals may be analyzed and transients in autonomic tone may be detected.•A rat model with EKG and respirations with intermittent sighs recordings was analyzed.•Transients in sympathetic and parasympathetic tone associated with sighs was noted.•This algorithm may be useful to evaluate diseases associated with autonomic transients.