Department of Medicine, Division of Cardiovascular Medicine
Cardiology | Diagnosis | Respiratory Tract Diseases
INTRODUCTION: Pulmonary emphysema causes several electrocardiogram changes, and one of the most common and well known is on the frontal P-wave axis. P-axis verticalization (P-axis > 60 degrees ) serves as a quasidiagnostic indicator of emphysema. The correlation of P-axis verticalization with the radiological severity of emphysema and severity of chronic obstructive lung function have been previously investigated and well described in the literature. However, the correlation of P-axis verticalization in emphysema with other P-indices like P-terminal force in V1 (Ptf), amplitude of initial positive component of P-waves in V1 (i-PV1), and interatrial block (IAB) have not been well studied. Our current study was undertaken to investigate the effects of emphysema on these P-wave indices in correlation with the verticalization of the P-vector.
MATERIALS AND METHODS: Unselected, routinely recorded electrocardiograms of 170 hospitalized emphysema patients were studied. Significant Ptf (s-Ptf) was considered >/=40 mm.ms and was divided into two types based on the morphology of P-waves in V1: either a totally negative (-) P wave in V1 or a biphasic (+/-) P wave in V1.
RESULTS: s-Ptf correlated better with vertical P-vectors than nonvertical P-vectors (P = 0.03). s-Ptf also significantly correlated with IAB (P = 0.001); however, IAB and P-vector verticalization did not appear to have any significant correlation (P = 0.23). There was a very weak correlation between i-PV1 and frontal P-vector (r = 0.15; P = 0.047); however, no significant correlation was found between i-PV1 and P-amplitude in lead III (r = 0.07; P = 0.36).
CONCLUSION: We conclude that increased P-tf in emphysema may be due to downward right atrial position caused by right atrial displacement, and thus the common assumption that increased P-tf implies left atrial enlargement should be made with caution in patients with emphysema. Also, the lack of strong correlation between i-PV1 and P-amplitude in lead III or vertical P-vector may suggest the predominant role of downward right atrial distortion rather than right atrial enlargement in causing vertical P-vector in emphysema.
P-axis, P-terminal force, Emphysema, Interatrial block, Left atrial enlargement, Vertical P-vector
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Copyright 2013 Chhabra et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited.
DOI of Published Version
Chhabra L, Chaubey VK, Kothagundla C, Bajaj R, Kaul S, Spodick DH. P-wave indices in patients with pulmonary emphysema: do P-terminal force and interatrial block have confounding effects? Int J Chron Obstruct Pulmon Dis. 2013;8:245-50. doi: 10.2147/COPD.S45127. Link to article on publisher's site
International journal of chronic obstructive pulmonary disease
Chhabra, Lovely; Chaubey, Vinod; Kothagundla, Chandrasekhar; Bajaj, Rishi; Kaul, Sudesh; and Spodick, David H., "P-wave indices in patients with pulmonary emphysema: do P-terminal force and interatrial block have confounding effects" (2013). University of Massachusetts Medical School Faculty Publications. 217.