Transient ST-Segment Elevation and QTc Interval Prolongation in a Patient With Persistent Chest Pain

Abstract

A patient in their 50s with a history of hypertension reported having 30 minutes of persistent chest pain. All vital signs were normal except for an elevated blood pressure of 188/104 mm Hg. Laboratory results (hemogram; serum electrolytes; kidney and hepatic; and levels of troponin I and D-dimer) were all within normal limits. An electrocardiogram (ECG) on admission is shown in theFigure, A. The patient was diagnosed with acute myocardial infarction (AMI) and prescribed 300 mg of aspirin and 600 mg of clopidogrel. The emergency coronary angiography findings were normal. A repeated ECG (Figure, B) after coronary angiography showed sinus rhythm without obvious ST-T deviation. Although the ECG findings had shown a significant improvement, the patient's chest pain still persisted. Over the next 8 hours, serial ECGs remained unchanged, and the troponin I level remained unremarkable. However, D-dimer levels significantly increased to 10.2 μg/mL (reference value, <0.25 μg/mL; to convert to nmol/L, multiply by 5.476).

Is a Shaking Hand or a Trembling Heart Producing Changes in Electrocardiogram Findings?

“…Misinterpreting these artifacts can mean unnecessary or even dangerous treatment or intervention. 2,3 Careful analysis of these signals usually helps to find the source of the artifact, which can then be eliminated.…”

“…This patient’s ECG changes (Figure, A) were caused by muscular tremors that resembled VT in the limb leads (except lead II) and atrial flutter in the precordial leads. Misinterpreting these artifacts can mean unnecessary or even dangerous treatment or intervention . Careful analysis of these signals usually helps to find the source of the artifact, which can then be eliminated.…”

An unexpected ECG finding

“…One bipolar limb lead was unaffected, depending on the limb from which artefacts were generated (the source of the artefact for this patient was the left arm, with lead II unaffected). Disturbances in one limb electrode can affect the remaining leads910…”

Uncovering the Truth of Electromechanical Association Artifact With Limb Lead Electrodes—Reply

“…In Reply We appreciate the insightful comments by Drs Zhao and Han in response to our contribution to the Challenges in Clinical Electrocardiography . They raised a concern and we sincerely apologize for the incorrect wording, ie, “the artifact due to the electrode’s intermittent contact with the patient’s skin during systolic pulsation of the radial artery was recorded on the ECG.” In fact, artifacts should be generated during diastolic rather than systolic pulsation, as Drs Zhao and Han state.…”