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Electrocardiographic poor R wave progression III. The normal variant
Insights
Poor R wave progression (PRWP) on ECGs can occur in healthy individuals. This study found PRWP in 8% of normal subjects, unrelated to common factors, suggesting normal variations may explain its presence.
Area of Science:
- Cardiology
- Electrocardiography
Background:
- Poor R wave progression (PRWP) is observed in various cardiac conditions, including myocardial infarction and hypertrophy.
- PRWP is also frequently noted in individuals without apparent heart disease, prompting investigation into its underlying causes.
Purpose of the Study:
- To investigate technical and constitutional factors contributing to PRWP in apparently normal individuals.
- To differentiate true PRWP from artifactual changes caused by lead placement or respiratory variations.
Main Methods:
- Prospective analysis of ECGs in 68 hospitalized patients to assess the impact of precordial lead misplacement and respiratory variations.
- Retrospective analysis of ECGs and clinical records of 100 normal individuals and 50 with mitral valve prolapse undergoing cardiac catheterization.
Main Results:
- Superior and inferior lead repositioning created false positive and false negative PRWP, respectively.
- PRWP was identified in 8% of normal individuals (8/100).
- PRWP in normals was not associated with age, sex, body composition, thoracic abnormalities, ECG axis, cholesterol, blood pressure, or mitral valve prolapse.
Conclusions:
- Technical factors like lead misplacement can induce artifactual PRWP.
- A significant proportion of normal individuals exhibit PRWP, likely attributable to normal variations in cardiac electrical signal distribution.
Abstract:
Electrocardiographic poor R wave progression (PRWR) is found in patients with anterior myocardial infarction, left ventricular hypertrophy and right ventricular hypertrophy, and is also seen in apparently normal individuals. Technical and constitutional factors that might contribute to PRWP in normal subjects were examined. Prospective analysis of the effect of precordial lead misplacement and respiratory variation on the surface ECG was performed in 68 hospitalized patients. Both false positive and false negative PRWP were created with superior and inferior lead position change respectively. The incidence and mechansim of true PRWP were analyzed by retrospective analysis of ECGs and records of 100 individuals with normal findings, and 50 additional individuals with mitral valve prolapse, at cardiac catheterization with coronary angiography. PRWP occurred in 8% (8/100) of normals and was not related to age, sex, height, weight, body surface area, ponderal index, thoracic skeletal abnormalities, ECG frontal axis, serum cholesterol, arterial blood pressure or mitral valve prolapse. In view of the voltage changes produced by alteration of lead placement, one tail of a normal distribution of null planes may account for PRWP in subjects without disease.