The voltage Dilemma in electrocardiogram (ECG)

Background

Pericardial effusion involves fluid buildup around the heart, potentially leading to cardiac tamponade—a critical condition that can impair heart function. Symptoms vary widely from mild to life-threatening. An electrocardiogram (ECG) is crucial for initial assessment, but interpreting findings can be challenging, especially when classic signs like low voltage QRS complexes are absent. Recognising new voltage changes from the baseline ECG is crucial even when traditional low voltage criteria are not met. Understanding these nuances and their clinical significance is essential for timely diagnosis and effective treatment, highlighting the importance of careful ECG interpretation by emergency physicians.

Case report

A 57-year-old male, diagnosed with chronic kidney disease and recently initiated on anti-tubercular treatment for pulmonary tuberculosis, presented to the emergency department with worsening shortness of breath. The baseline ECG a month prior revealed normal sinus rhythm with right atrial enlargement (RAE) and left ventricular hypertrophy (LVH). Upon presentation, the ECG revealed sinus tachycardia without P pulmonale or LVH, suggesting a potential dynamic change. Point-of-care ultrasound (POCUS) confirmed moderate pericardial effusion with early right ventricular diastolic collapse.

Why should an emergency physician be aware of this?

A new decrease in QRS voltages and sinus tachycardia should prompt suspicion of pericardial effusion. Emergency physicians need to understand the complexity of new voltage changes in ECGs. The challenge lies in relying solely on standard ECG criteria, emphasising the importance of considering individual baseline variations. Recognising such subtle ECG changes is crucial for diagnosing and treating cardiac tamponade early, leading to better patient outcomes.