The concentration of hypersensitive cardiac troponin T (TnTsh, upper limit of normal = 14 pg/ml) was at a normal level (9.64 pg/ml). According to the ischemic symptom and previous history, the patient was diagnosed as having unstable angina. Electrocardiogram (ECG) on admission shows a sinus rhythm at 76 bpm, normal conduction, and low amplitude of T wave in multiple leads. Transthoracic echocardiography (TTE) showed a normal left ventricular size and function without regional wall motion abnormalities. On admission, her heart rate was 76 bpm (beats per minute) and her blood pressure was 131/67 mmHg. She was diagnosed as having SSS with 7.97 seconds of asystole and then received a dual-chamber pacemaker (Medtronic Inc., Minneapolis, MN, USA) implantation. One year ago, the patient was admitted to our hospital because of syncope. Then, coronary angiography revealed a severe stenosis of the left anterior descending (LAD), and a stent was implanted into the LAD. Six years ago, she was first admitted to our hospital and diagnosed with unstable angina. Her past history included coronary heart disease and sick sinus syndrome (SSS). Case reportĪ 71-year-old female presented to our hospital complaining of repeated chest pain. Herein, we report the rare case of failure pacing following an acute inferior wall myocardial infarction in a patient with an occlusion of the left circumflex (LCX) that supplied the right ventricular septal. There are few reports describing the pacemaker lost atrial capture as a consequence of an AMI ( 2– 4). However, malfunction of a ventricular lead of a dual-chamber pacemaker following an acute myocardial infarction (AMI) is rare ( 1). There are several causes that contribute to the loss of a permanent pacemaker capture, such as battery depletion, lead dislodgement, and circuit problems. We conclude that the loss of the right ventricular lead pacing occurred in this case of acute coronary syndrome (ACS) induced by an LCX thrombus due to an LCX supplying the right ventricular septal. After reperfusion, the parameters of the right ventricular lead were gradually returned. Emergency coronary angiography revealed that a large filling defect remained due to an extensive thrombus in the proximal left circumflex (LCX) with thrombolysis in myocardial infarction (TIMI) grade 2 flow, and then a repeat thrombus aspiration was performed. Pacemaker lost capture was suspected and was later confirmed by a pacemaker check with a high pacing threshold and a low sensing parameter. On day 7, the patient suddenly suffered cardiopulmonary arrest due to an inferior ST segment elevation myocardial infarction (STEMI). Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, ChinaĪ 71-year-old female with a dual-chamber pacemaker presented to our hospital complaining of repeated chest pain.

Zhihong Wu † Jianjun Tang † Qingyi Zhu Lin Hu Zhenjiang Liu Xuping Li Qiming Liu Shenghua Zhou Mingxian Chen *

Failure to capture pacer spikes