Journal of Clinical and Diagnostic Research. 2018 June, Vol-12(6): OD08-OD09 8 8 DOI: 10.7860/JCDR/2018/33903.11622 Case Report Internal Medicine Section “Electrocardiogram Changes with Elevated Troponins Mimicking MI: All that Glitters is not Gold” MONIKA BHANDARI 1 , PRAVESH VISHWAKARMA 2 , AKSHYAYA PRADHAN 3 , RISHI SETHI 4 Keywords: Bradyarrhythmia, Cardiac memory, Coronary angiogram, ST-T changes, Transvenous pacing ABSTRACT Temporary transvenous pacing is often required as life saving measure in conditions such as Stokes Adams attack and symptomatic bradyarrhythmias. Bradyarrhythmias are also known complications of acute Myocardial Infarction (MI), which can be transient or persistent and often demand temporary pacing too. It is difficult to diagnose underlying MI in the setting of paced rhythm due to secondary ST-T changes. Elevated cardiac enzymes are essential in the scenario of paced rhythm to diagnose underlying acute MI. Remarkable T wave inversion and ST depression {similar to Left Bundle Branch Block (LBBB)} do occur in right ventricular paced ECG and some changes may persist following withdrawal of pacing (cardiac memory T waves) simulating ischaemia. Very rarely arrhythmias can also lead to troponin rise causing diagnostic dilemma in such a setting. Here, we report a case of an elderly female who presented with symptomatic Complete Heart Block (CHB) and developed T wave inversion with Q wave formation in anterior leads in sinus rhythm following temporary pacing. She also demonstrated a dynamic rise in serial cardiac troponin values mimicking an acute coronary syndrome. Ultimately, an invasive coronary angiogram was performed to rule of significant coronary artery disease. [Table/Fig-3]: Coronary angiogram showing normal left coronary artery (left panel) and right coronary artery (right panel). The temporary transvenous pacing lead can also seen in-situ. CASE REPORT A 69-year-old female was admitted in the Emergency Department with complaints of recurrent episodes of syncope for past three days. There was no history of associated chest pain and dyspnea. On examination, she had a pulse rate of 32 beats per minute and blood pressure of 140/96 mmHg. Her Electrocardiogram (ECG) demonstrated complete dissociation of P wave and QRS wave suggesting CHB with a Right Bundle Branch Block (RBBB) type escape rhythm [Table/Fig-1]. Patient was immediately shifted to catheterisation laboratory and temporary transvenous pacemaker was implanted with pacing lead positioned at right ventricular apex under fluoroscopic guidance. The procedure was uneventful and all her blood investigations including renal functions and electrolytes were within normal range. Her cardiac troponin T (high sensitive assay) at admission; however, was 0.021 ng/mL (Normal <0.014 ng/mL, Elecsys assay, Roche diagnostics, Indianapolis, USA). The patient regained sinus rhythm on third day of admission but ECG showed T wave inversion in anterior leads with LBBB along with Q waves which persisted on repeated recordings [Table/Fig-2]. At admission because her troponin was elevated, a repeat assay was ordered to rule out ischaemia. Her second troponin value rose from 0.021 ng/mL to 0.047 ng/mL (almost doubled). However, the echocardiography did not show any Regional Wall Motion Abnormality (RWMA) and left ventricular systolic function was normal. However, in view of patient’s advance age, ECG changes and rising cardiac enzymes Coronary Angiography (CAG) was done which revealed normal coronary arteries [Table/Fig-3]. Finally taking into account all the above findings, patient was considered to be a case of degenerative disease of conduction system of heart and ECG changes were likely to be depolarisation abnormality secondary to pacing. A permanent pacemaker was implanted and patient was discharged in stable condition. At her one month follow- up in pacemaker clinic, her pacing parameters were in range. [Table/Fig-2]: 12 lead electrocardiogram depicting return of spontaneous rhythm with ST elevation and T wave inversion with QS in anterior leads suggestive of LBBB (arrows). [Table/Fig-1]: 12 Lead electrocardiogram at admission demonstrating complete heart block with RBBB type ventricular escape rhythm at rate of <40/min.