ECG lead misplacement review and proposal of a simple identification tool: the IDPC algorithm

Vitor J. de Almeida, Departamento de Cardiologia, Instituto Dante Pazzanese de Cardiologia, São Paulo, Brazil
Claudio H. Costa-Lança, Departamento de Cardiologia, Hospital Geral Dr. Beda, Campos dos Goytacazes, Rio de Janeiro, Brazil
Matheus C. de Souza-Gouveia, Faculdade de Medicina, Faculdade Israelita de Ciências da Saúde Albert Einstein (FICSAE), São Paulo, Brazil
Mariana F. Nogueira-de Marchi, Departamento de Cardiologia, Instituto Dante Pazzanese de Cardiologia, São Paulo; 4Electrocardiology Unit, Instituto Dante Pazzanese de Cardiologia, São Paulo. Brazil
José Nunes-de Alencar, Departamento de Cardiologia, Instituto Dante Pazzanese de Cardiologia, São Paulo; 4Electrocardiology Unit, Instituto Dante Pazzanese de Cardiologia, São Paulo. Brazil

The electrocardiogram (ECG) is a fundamental diagnostic tool in medical practice, especially for cardiovascular evaluation. However, lead misplacement – an under-recognized issue – can produce misleading patterns that mimic serious pathologies and hinder accurate interpretation. This represents a significant threat to patient safety, potentially delaying diagnosis of time-sensitive conditions such as myocardial infarction. Clinicians must be aware of ECG patterns suggestive of electrode swap/misplacement and understand the typical consequences of these errors to promptly identify and correct them. In this narrative review, we explore and demonstrate with ECG tracings all frontal plane lead reversals and the most common precordial leads misplacements, providing strategies for their recognition. In this setting, we propose a step-by-step diagnostic approach – the IDPC algorithm – to help identify the most clinically relevant electrode misplacements.

Keywords: ECG lead misplacement. Electrode reversal. Diagnostic errors. Electrocardiography interpretation. IDPC algorithm.