A pacemaker goes rogue: cardiac arrest due to r-on-t phenomenon

SESSION TITLE: Critical Care Case Report Posters 42 SESSION TYPE: Case Report Posters PRESENTED ON: 10/10/2023 09:40 am - 10:25 am INTRODUCTION: R-on-T phenomenon occurs due to extra ventricular contractions that occur when an ectopic beat is superimposed on the T wave of the previous beat. This has been noted to be associated in patients with myocardial infarctions, ischemia and those who underwent percutaneous interventions. We present a case of R-on-T phenomenon on a patient status post coronary artery bypass grafting with epicardial pacemaker leads. CASE PRESENTATION: A 57-year-old male presented to the ED with complaints of dyspnea on exertion and chest pain. He underwent a cardiac stress test which was positive for myocardial ischemia and subsequent cardiac catheterization showed multivessel disease. The patient underwent coronary artery bypass grafting involving 3 vessels and an atrial and ventricular epicardial pacing leads placed. On post-op day 2, patient went into sudden witnessed cardiac arrest due to ventricular fibrillation. ACLS, including defibrillation, resulted in ROSC. An intra-aortic balloon pump was placed by cardiology at bedside and removed few days later without complications. Telemetry event confirmed ectopic beats in the preceding T waves supporting R-on-T phenomenon as the cause of a sustained tachyarrhythmia which lead to the arrest (Figure 1). DISCUSSION: Polymorphic ventricular tachycardia (PVT) is an arrhythmia usually noted to be associated either with long QT interval or normal QT interval. PVT with normal QT relates to myocardial ischemia (MI), amongst other causes, and in the setting of MI. Ischemia triggers ventricular extra systoles with very short coupling intervals that are not pause-dependent. Other causes relates, such in our patient to undersensing of temporary pacing wires placed commonly present on immediate post cardiac surgery patients.. R-on-T phenomenon has been described as a superimposed ectopic beat on the T wave of a preceding beat. It has been noted to initiate sustained tachyarrhythmias and poses an infrequent yet catastrophic risk of sudden cardiac death as seen in our case. Temporary atrio-ventricular epicardial pacemaker malfunctioning poses an increased risk of cardiac arrhythmias in the post-op cardiac surgical patient. Sudden changes in epicardial-lead pacemaker adequacy or effectiveness could trigger fatal complications that clinicians should account for when caring for this critically ill population. CONCLUSIONS: Epicardial pacing R-on-T phenomenon is a rare but fatal complication seen during the care cardiac surgery patients. Clinicians should be aware of undersensing and oversensing phenomena related to pacemaker activity and for prompt identification and intervention. REFERENCE #1: Engel TR, Meister SG, Frankl WS. The "R-on-T" phenomenon: an update and critical review. Ann Intern Med. 1978 Feb;88(2):221-5. doi: 10.7326/0003-4819-88-2-221. PMID: 75705. REFERENCE #2: CARDIAC ARREST SECONDARY TO R ON T PHENOMENON IN A POST PCI PATIENT JAD SARGI KIRAN ZAMAN MUDITA PATEL KARTHIK VEERAPANENI SAIKRISHNA PATIBANDLA SAHAR TAKKOUCHE WAEL KALAJI MICHEAL GRILLO AND LOUIS GEROLEMOU REFERENCE #3: Marrouche NF, SippensGroenewegen A, Yang Y, Dibs SR. R-on-T Phenomenon. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459379/ DISCLOSURES: No relevant relationships by Christian Almanzar Zorrilla No relevant relationships by Ruben Cabrera No relevant relationships by Mauricio Danckers No relevant relationships by Raiko Diaz No relevant relationships by Manjot Malhi No relevant relationships by Ana Martinez Nunez No relevant relationships by Rafael Miret No relevant relationships by Kishankumar Patel No relevant relationships by Shany Quevedo