Wide Complex Irregular Rhythm in a Paced Patient: A Clinical Approach

Background and Clinical Significance: Evaluating wide complex rhythms in patients with permanent pacemakers can be a diagnostic challenge, particularly when the rhythm is irregular. While pacemaker-mediated rhythms are typically regular and predictable, the appearance of wide complex irregular rhythms raises concerns ranging from lead malfunction to life-threatening arrhythmias, such as ventricular tachycardia. Understanding the interplay between intrinsic cardiac activity and device function is crucial for timely and accurate diagnosis in this increasingly common clinical scenario. Case presentation: We report on a 74-year-old female with a VVI pacemaker implanted for binodal disease, who presented with intermittent palpitations and an irregular rhythm. The patient has a recent history of falling on her right shoulder, which is also the site of the device implantation. We used a clinical step-by-step approach to rule out pacemaker malfunction and to establish the need for an unscheduled device interrogation. Conclusions: This case presentation highlights the important role of clinical reasoning and the approach to such a patient, especially when a key method of pacemaker evaluation, such as device interrogation, is not readily available.