Authors’ Reply: “Electrocardiography in a Patient with Deep Brain Stimulation”

Dear Editor, We thank Goyal et al.[1] for their interest in our manuscript[2] and for the opportunity to further elaborate on the electrocardiographic findings. We take this opportunity to highlight the differences between the electrocardiography (ECG) changes described in our case and those seen in atrial flutter. In the presented illustration [Figure 1a], lead II demonstrates clearly discernible P waves preceding each QRS complex with a 1:1 atrioventricular conduction pattern. The ventricular rate is approximately 75 beats per minute, which is not consistent with atrial flutter, in which atrial activity typically occurs at approximately 250–300 beats per minute with variable atrioventricular conduction, commonly 2:1 or 3:1.[3] Furthermore, classical atrial flutter is characterized by a continuous sawtooth pattern of flutter waves with loss of an isoelectric baseline, particularly in the inferior leads II, III, and aVF, which is not observed in our ECG.Figure 1: Twelve-lead electrocardiography in a patient with deep brain stimulation. (a) Neurostimulator operating in a unipolar configuration; (b) neurostimulator switched off; (c) neurostimulator operating in a bipolar configuration. Blue arrows highlight lead II, demonstrating clearly discernible P waves preceding each QRS complex with a 1:1 atrioventricular conduction pattern. Red circles indicate high-frequency, sharp, regular spikes seen prominently in leads I, II, aVR, aVL, aVF, and V1–V2, consistent with stimulation-related artifactsThe waveforms in our case consist of sharp, high-frequency, regular spikes superimposed on the baseline [Figure 1a], differing in morphology from the broader, undulating flutter waves. Importantly, the disappearance of these artifacts when the neurostimulator was switched off [Figure 1b], along with their absence in bipolar configuration [Figure 1c], strongly supports their origin from deep brain stimulation-related electromagnetic interference. We also wish to highlight that, at standard ECG recording speeds (25 mm/s), individual high-frequency artifact spikes may not be distinctly resolved. Recording at higher sweep speeds can help delineate discrete spikes and improve characterization of rapid deflections.[4] We further acknowledge that several strategies have been described to improve ECG interpretability in patients with deep brain stimulation, including switching to bipolar configuration, temporary deactivation of the neurostimulator, and the use of filtering techniques or alternative lead placements.[5] Among these, changing to a bipolar configuration or transient deactivation remains the most practical and reliable approach in routine clinical settings. In situations of diagnostic uncertainty, ECG findings should be interpreted with caution and, where feasible, reassessed after temporarily modifying the stimulation settings. Our primary intention was to emphasize the potential for deep brain stimulation-related artifacts to mimic cardiac arrhythmias and lead to misinterpretation. We appreciate the insightful comments and believe that this discussion reinforces the importance of careful ECG interpretation in patients with implanted neurostimulation devices. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.