Terminal PV1 Negativity in NHANES III Introduction Deep terminal negativity of P wave in V1 (DTNPV1), defined as negative P prime larger than one small box (1 mm, or 0.1 mV), could be easily detected by simple visual inspection of the resting 12-lead ECG. The objective of this study was to determine the relationship between DTNPV1 and all-cause-, cardiovascular disease (CVD), and ischemic heart disease (IHD) mortality in the National Health and Nutrition Examination Survey III (NHANES III). Methods and Results After exclusion of participants with atrial fibrillation and missing data, DTNPV1 was automatically measured from standard 12-lead ECG in 8,146 participants. Minnesota and Novacode algorithms were used for the determination of major and minor ECG abnormalities. National Death Index was used to identify the date and cause of death. During a median follow-up of 13.8 years, a total of 2,975 deaths (1,303 CVD and 742 IHD deaths) occurred. After adjustment for age, gender, race/ethnicity, IHD, heart failure, chronic obstructive pulmonary disease, cancer, diabetes, body mass index, smoking, dyslipidemia, hypertension, use of antihypertensive and lipid-lowering medications, and ECG abnormalities, DTNPV1 was associated with significantly increased risk of all-cause death (HR [95% CI]: 1.30 [1.10, 1.53]; P = 0.002), CVD death (HR [95% CI]: 1.36 [1.08, 1.72]; P = 0.010), and IHD death (HR [95% CI]: 1.36 [1.00, 1.85]; P = 0.047). Conclusion In a large sample of the adult United States population, DTNPV1 is independently associated with increased risk of death due to all-cause, CVD, and IHD, findings suggesting its potential usefulness as a simple marker to identify individuals at risk of poor outcomes. [ABSTRACT FROM AUTHOR]