Risk factors for premature ventricular contractions in young and healthy adults.

BACKGROUND: Premature ventricular contractions (PVCs) are associated with an increased risk of morbidity and mortality. Therefore, it was aimed to assess risk factors for the frequency of PVCs in young and healthy adults. METHODS: Our population-based study included 2048 healthy adults from the general population aged 25-41 years. PVC frequency was determined by 24-hour Holter ECG. We performed multivariable regression analysis using stepwise backward selection to identify factors independently associated with PVC frequency. RESULTS: Median age was 37 years, 953 (46.5%) were male. At least one PVC during the 24-hour monitoring period was observed in 69% of participants. Median number of detected PVCs was 2, the 95th percentile was 193. In multivariable regression analyses, we found 17 significant risk factors for PVC frequency. Low educational status (risk ratio (RR) 3.33; 95% CI 1.98 to 5.60), body height>median (1.58, 95% CI 1.11 to 2.24) and increasing levels of waist:hip ratio (2.15, 95% CI 1.77 to 2.61), N-terminal pro brain natriuretic peptide (1.52, 95% CI 1.30 to 1.76) and Sokolow-Lyon Index (1.38, 95% CI 1.15 to 1.66) (all p≤0.01) were associated with a higher PVC frequency. Physical activity (RR fourth vs first quartile 0.51, 95% CI 0.34 to 0.76) and increasing levels of haemoglobin (0.58, 95% CI 0.47 to 0.70) and glucagon-like peptide-1 (0.72, 95% CI 0.64 to 0.82) (all p<0.001) were related to a lower PVC frequency. CONCLUSIONS: PVC occurrence is common even in healthy low-risk individuals, and its frequency is associated with several covariates mainly related to cardiovascular risk factors, markers of cardiac structure and function and socioeconomic status.

Factors independently associated with cardiac troponin I levels in young and healthy adults from the general population.

BACKGROUND: Determinants of cardiomyocyte injury as quantified by high-sensitivity cardiac troponin I (cTnI) in young and healthy individuals, and sex-specific 99th percentiles are largely unknown. METHODS: Our study included 2077 adults from the general population aged 25-41 years without cardiovascular disease. cTnI was measured using a high-sensitivity assay. We performed stepwise backward linear regression analyses to identify variables independently associated with hs-cTnI levels, and calculated narrow-sense heritability from 1638-genotyped participants. RESULTS: Median age was 37 years. cTnI was quantifiable in all but 11 participants (99.5 %). Median (interquartile range) cTnI was significantly higher in men than in women [0.99 (0.71; 1.65) versus 0.47 (0.33; 0.71) ng/L, p < 0.0001]. The 99th percentile of cTnI was 15.79 ng/L in men and 5.11 ng/L in women. Out of 46 variables, 22 independent determinants for cTnI were identified. The strongest associations were observed with sex, age, systolic blood pressure, heart rate, left ventricular mass, N-terminal pro B-type natriuretic peptide, and creatine kinase (all p < 0.0001). The final model explained 36 % of the overall cTnI variability. Heritability of cTnI was estimated to be 29 % (p = 0.005), but became non-significant when the residuals of the multivariable model were used for analysis (5 %, p = 0.36). CONCLUSIONS: Sex, age, and systolic blood pressure belong to the strongest determinants of hs-cTnI in healthy adults. The 99th percentile was three times higher in men compared to women. Hence, sex-specific cut-off values may be preferable when applying hs-cTnI for screening purposes. Our results may also improve the interpretation of cTn levels in daily clinical practice.

Relationships of electrocardiographic parameters with ambulatory hypertension in young and healthy adults.

BACKGROUND: Elevated blood pressure (BP) is a leading cardiovascular risk factor and a major determinant of left ventricular mass. Te aim of this study was to assess electrocardiographic (ECG) changes associated with hypertension in a large cohort of young and healthy adults. METHODS: Healthy individuals aged 25­41 years without known cardiovascular disease were enrolled in a population based cohort study. Resting 12-lead ECG and ambulatory 24-hour BP measurement were obtained using validated devices. Multivariable logistic regression models were constructed to assess the relationships between ECG parameters and daytime hypertension, defined as systolic daytime BP≥140, diastolic BP≥90 mmHg or use of antihypertensive treatment. RESULTS: Daytime hypertension was present among 430 of 2070 (21%) participants. Significant linear relationships were observed between daytime hypertension with RR interval (odds ratio (OR) 95% confidence interval (CI) 0.84 (0.78; 0.92)), R-wave amplitude in leads I and II (OR (95% CI) 2.04 (1.30; 3.19) and 1.61 (1.15; 2.24), and S-wave amplitudes in leads aVR, V1 and V2 with ORs (95% CI) of 3.28 (1.93; 5.59), 2.15 (1.51; 3.08) and 1.47 (1.18; 1.83), respectively. We also observed linear associations between daytime hypertension and T-wave amplitudes in leads V1 (OR (95% CI) 4.83 (2.35; 9.91)), V2 (2.18 (1.43; 3.32)), V4 (0.48 (0.29; 0.80)) and V5 (0.37 (0.19; 0.72)). CONCLUSION: Several ECG parameters are independently associated with daytime hypertension among young and healthy adults. This is one of the first studies to show significant relationships between T wave amplitude and hypertension.