Use of Electrocardiography to Predict Future Development of Hypertension in the General Population

Significance of blood pressure variability in normotensive individuals as a risk factor of developing hypertension

PURPOSE

Visit-to-visit blood pressure variability is a strong predictor of the incidence of cardiovascular events and target organ damage due to hypertension. The present study investigated whether year-to-year blood pressure variability predicts the risk of hypertension in the Japanese general population.

MATERIALS AND METHODS

This study analysed 2806 normotensive individuals who participated in our physical check-up program for five years in a row from 2008 to 2013. The average, standard deviation, coefficient of variation, average real variability, and highest value of systolic blood pressure in the five consecutive visits were determined and used as baseline data. The participants were followed up for the next 6 years with the development of 'high blood pressure', an average blood pressure level of ≥140/90 mmHg or the use of antihypertensive medications, as the endpoint.

RESULT

During follow-up, 'high blood pressure' developed in 389 participants (13.9%, 29.5 per 1 000 person-years). The incidence increased across the quartiles of standard deviation and average real variability, while the average and highest systolic blood pressure had the most prominent impact on the development of 'high blood pressure'. Multivariate logistic regression analysis adjusted for possible risk factors indicated that the average, standard deviation, average real variability, and highest blood pressure, but not the coefficient of variation of systolic blood pressure, were significant predictors of 'high blood pressure'.

CONCLUSION

Increased year-to-year blood pressure variability predicts the risk of hypertension in the general normotensive population. The highest blood pressure in the preceding years may also be a strong predictor of the risk of hypertension.

Additional prognostic value of electrocardiographic left ventricular hypertrophy in traditional cardiovascular risk assessments in chronic kidney disease

BACKGROUND

Left ventricular hypertrophy (LVH) is a common predictor of the cardiovascular prognosis in chronic kidney disease (CKD). However, whether or not electrocardiography-derived LVH (ECG-LVH) has prognostic value in patients with various degrees of CKD and improves the cardiovascular risk stratification based on traditional risk factors remains unclear.

METHODS

A total of 7206 participants at least 40 years of age who were free from cardiovascular events in a general population were followed for the incidence of cardiovascular events. CKD was confirmed by either the presence of a reduced estimated glomerular filtration rate (eGFR) (<60 ml/min per 1.73 m) or albuminuria, defined as a urinary albumin-to-creatinine ratio (UACR) of at least 30 mg/g Cr.

RESULTS

A total of 1886 (26.2%) had CKD, of which 1471 (78.0%) had a preserved eGFR (CKD stage 1-2). After an average 11.3 years of follow-up, the adjusted hazard ratio for the incidence of cardiovascular events significantly increased for ECG-LVH according to the Sokolow--Lyon voltage, Cornell voltage, or Cornell voltage product among participants with CKD (hazard ratio 1.47, P = 0.002), in contrast to those without CKD (hazard ratio 1.15, P = 0.210). The inclusion of any ECG-LVH parameters improved the accuracy of reclassification in any risk prediction model based on the eGFR, UACR, or Framingham 10-year risk score in the CKD participants (net reclassification improvement = 0.13-0.32, all P values <0.040).

CONCLUSION

In patients with CKD stage 1-5, ECG-LVH is useful for predicting the risk of future cardiovascular events and adds prognostic information to traditional cardiovascular risk assessments.

Indices of left ventricular voltage on electrocardiogram are closely associated with serum cardiac troponin I levels in normotensive Japanese individuals

The high-sensitivity cardiac troponin I (hs-cTnI) in serum can increase due to an increase in left ventricular (LV) overload in individuals with hypertension. Since LV voltage on an electrocardiogram (ECG) reflects LV load, it is possible that LV voltage is closely associated with hs-cTnI in individuals without hypertension. This study investigated the association between LV voltage indices and serum hs-cTnI levels in normotensive Japanese individuals.Subjects who visited the Enshu Hospital for a health check-up were screened for their eligibility. Subjects with renal dysfunction, cancer, active inflammatory disease, or a history of cardiovascular events were excluded, as were subjects with obvious ST segment or T wave abnormality, Wolff-Parkinson-White syndrome, pacemaker implantation, or frequent arrhythmia in the ECG. Exclusion of individuals with hypertension left 803 subjects (54.8 ± 11.3 years) for final inclusion. The R wave voltage in lead V5 (RV5 voltage), the Sokolow-Lyon voltage (a sum of the QRS wave (a complex wave consists of Q, R, and S wave) of the S wave voltage in lead V1 and the R wave voltage in lead V5), and the Cornell product (a product of QRS duration and QRS voltage) were evaluated by ECG as LV voltage indices. Laboratory measurements included serum hs-cTnI levels. Possible associations between indices of LV voltage on ECG and serum hs-cTnI levels were cross-sectionally investigated in the normotensive subjects.The median values [interquartile range] of hs-cTnI and BNP were and 2.1 [1.4-3.0] and 13.8 [7.7-24.9] pg/mL, respectively. Multivariate regression analysis identified that the levels of hs-cTnI, but not BNP, were significantly associated with RV5 voltage (β 0.090, P = .0087), Sokolow-Lyon voltage (β 0.112, P = .0009), and Cornell product (β 0.101, P = .039) after adjustment for possible confounding factors. Moreover, the RV5 voltage, Sokolow-Lyon voltage, and Cornell product were significantly associated with the hs-cTnI levels after adjustment for possible confounding factors including ECG findings (β 0.109, P = .0075; β 0.125, P = .0010; and β 0.096, P = .0116, respectively).Indices of LV voltage in ECG had close associations with serum hs-cTnI levels in normotensive subjects. These findings support that the ECG findings of LV voltage have significant associations with slight myocardial micro-damage even in normotensive subjects.

Comparison of Left Ventricular Hypertrophy by Electrocardiography and Echocardiography in Children Using Analytics Tool

Left ventricular hypertrophy (LVH) is a common finding on pediatric electrocardiography (ECG) leading to many referrals for echocardiography (echo). This study utilizes a novel analytics tool that combines ECG and echo databases to evaluate ECG as a screening tool for LVH. SQL Server 2012 data warehouse incorporated ECG and echo databases for all patients from a single institution from 2006 to 2016. Customized queries identified patients 0-18 years old with LVH on ECG and an echo performed within 24 h. Using data visualization (Tableau) and analytic (Stata 14) software, ECG and echo findings were compared. Of 437,699 encounters, 4637 met inclusion criteria. ECG had high sensitivity (≥ 90%) but poor specificity (43%), and low positive predictive value (< 20%) for echo abnormalities. ECG performed only 11-22% better than chance (AROC = 0.50). 83% of subjects with LVH on ECG had normal left ventricle (LV) structure and size on echo. African-Americans with LVH were least likely to have an abnormal echo. There was a low correlation between V₆R on ECG and echo-derived Z score of left ventricle diastolic diameter (r = 0.14) and LV mass index (r = 0.24). The data analytics client was able to mine a database of ECG and echo reports, comparing LVH by ECG and LV measurements and qualitative findings by echo, identifying an abnormal LV by echo in only 17% of cases with LVH on ECG. This novel tool is useful for rapid data mining for both clinical and research endeavors.

Prognostic Value of Electrocardiographic Left Ventricular Hypertrophy on Cardiovascular Risk in a Non-Hypertensive Community-Based Population

BACKGROUND

The appearance of left ventricular hypertrophy on 12-lead electrocardiography (ECG-LVH) has been clarified to be associated with the risk of incidence of cardiovascular events (CVEs) in hypertensive individuals and the general population, but not enough in non-hypertensive individuals.

METHODS

A total of 4,927 non-hypertensive individuals ≥40 years of age who were free of CVE in the general population were followed for the incidence of CVE. ECG-LVH was defined according to criteria of the Sokolow-Lyon (SL) voltage, Cornell voltage (CV), or Cornell voltage product (CP).

RESULTS

During the average 9.8 ± 2.0 years of follow-up, 267 individuals (5.4%) had their first CVE. The hazard ratio (HR) for the incidence of CVE after full adjustment by potential confounders significantly increased in the individuals with ECG-LVH by any criteria of the SL voltage, CV, and CP (HR = 1.77, P < 0.001) compared to those with no ECG-LVH. This association was also significant in individuals without any of obesity, dyslipidemia, and diabetes mellitus or those with systolic blood pressure (BP) <120 mm Hg and diastolic BP <80 mm Hg. Furthermore, ECG-LVH by each criteria provided the reclassification improvement for the CVE risk prediction model by the Framingham 10-year risk score (the net reclassification improvement = 0.17-0.22, each P value < 0.010).

CONCLUSIONS

In the absence of hypertension, ECG-LVH parameters are associated with the increased risk of developed CVEs independent of the established risk factors and provide the additional prognostic value in an assessment of the CVE risk using the traditional risk factors.

Carotid intima-media thickness is a novel predictor of new onset of hypertension in normotensive subjects

Increased carotid intima-media thickness (IMT) in individuals without hypertension might indicate other factors promoting the atherosclerotic process that are often simultaneously clustered in individuals. The present study tested the hypothesis that carotid IMT predicts new onset of hypertension in the normotensive subjects.A total of 867 participants were enrolled from our yearly physical checkup program and their carotid IMT was measured. After a baseline examination, the subjects were followed up for a median of 1091 days with the endpoint being the development of hypertension.At baseline, the carotid IMT value was 0.75 ± 0.16 mm. Hypertension developed in 184 subjects during the follow-up (76.9/1000 person-years). The incidence of hypertension was increased across the tertiles of the carotid IMT value (39.6, 70.0, and 134.5/1000 person-years in the first, second, and third tertiles, respectively, P < .001 by log-rank test). Multivariate Cox-hazard analysis after adjustment identified carotid IMT, taken as a continuous variable, as a significant predictor of new-onset hypertension (hazard ratio = 7.08, 95% confidence interval = 3.06-15.39). Furthermore, multivariate linear regression analyses indicated a significant correlation between the carotid IMT at baseline and yearly increases in systolic blood pressure during the follow-up period (β = 0.189, P < .001).Carotid IMT is an independent predictor of hypertension onset in normotensive subjects. The findings also suggested a close association between increased carotid IMT and blood pressure.