Regarding Article “Ethnic Distribution of Electrocardiographic Predictors of Atrial Fibrillation and Its Impact on Understanding the Ethnic Distribution of Ischemic Stroke in the Atherosclerosis Risk in Communities Study (ARIC)”
To the Editor:
We read with great interest the title-mentioned article published in Stroke.1 We are currently examining the prevalence and characteristics of, and risk factors for, those aged 70 years and over in the Hai District of Northern Tanzania, Africa, and this study has guided us significantly in our thinking about differences in ethnic distribution of atrial fibrillation and stroke. As part of our study, we will examine the prevalence of P wave predictors of atrial fibrillation on 12-lead ECG and validate them in this population with long-term Holter monitoring and follow-up. We will be using the same ECG predictors as described in the ARIC study, as well as P wave dispersion (maximum P wave duration − minimum P wave duration) and P wave initial force in lead V1 (when combined with P wave terminal force). There is good evidence for these measurements in predicting the occurrence of paroxysmal atrial fibrillation.2,–,4
With this in mind, we write to point out the minor but important errors within this report of the ARIC study. These caused us much confusion that was resolved quickly by direct contact with the lead author (Dr Soliman).
In the Methods and Table of Results 2–5, it is stated that the P wave area is measured in microvolts×milliseconds squared. We point out that this should be milliseconds rather than milliseconds squared. In addition, if the voltage was measured in microvolts and then multiplied by milliseconds, then this would give an answer in tens of thousands rather than hundreds (for example, in Table 2 on page 1206, rather than maximum P wave area for blacks being 384.2±115.2, it would in fact be 38 420±11 520 microvolts×milliseconds). We hope this letter will save others wishing to use this important article as a basis for P wave analysis from similar confusion in the future.
Matt Dewhurst, MRCP
North Tyneside General Hospital
North Shields, UK
Phil Adams, BA, FRCP
Royal Victoria Infirmary
Stroke welcomes Letters to the Editor and will publish them, if suitable, as space permits. Letters must reference a Stroke published-ahead-of-print article or an article printed within the past 3 weeks. The maximum length is 750 words including no more than 5 references and 3 authors. Please submit letters typed double-spaced. Letters may be shortened or edited. Include a completed copyright transfer agreement form (available online at http://stroke.ahajournals.org and http://submit-stroke.ahajournals.org).
- © 2011 American Heart Association, Inc.