Significance of Fibrillatory Waves and the P Terminal Force in Idiopathic Atrial Fibrillation

SUMMARY

The amplitude of the fibrillatory waves and the magnitude of the P terminal force in lead V₁ of the electrocardiogram were examined in 30 patients without evident organic heart disease who were diagnosed as having idiopathic atrial fibrillation. Twenty-six patients (86%) had both fine fibrillatory waves and a subsequently normal P terminal force. None of the patients in the series had fibrillatory or P wave abnormalities of the magnitude seen in the majority of patients with known heart disease of the types associated with left atrial hypertrophy. It is concluded that either a fine fibrillatory wave or a normal P terminal force mitigates against the presence of left atrial hypertrophy.