Corrected QT Interval in Severe Aortic Stenosis: Clinical and Hemodynamic Correlates and Prognostic Impact.

BACKGROUND: The role of the electrocardiogram for risk stratification in patients with severe aortic stenosis is not established. We assessed the hemodynamic correlates and the prognostic value of the corrected QT interval (QTc) in patients with severe aortic stenosis undergoing aortic valve replacement. METHODS: The QT interval was measured in a 12-lead electrocardiogram in 485 patients (age 74 ± 10 years, 57% male) with severe aortic stenosis (indexed aortic valve area 0.41 ± 0.13 cm2/m2, left ventricular ejection fraction 58 ± 12%) the day prior to cardiac catheterization. Prolonged QTc was defined as QTc >450 ms in men and QTc >470 ms in women. The outcome parameter was all-cause mortality. RESULTS: Patients with prolonged QTc (n = 100; 77 men, 23 women) had similar indexed aortic valve area but larger left ventricular and left atrial size, lower left ventricular ejection fraction, more severe mitral regurgitation, lower cardiac index, and higher mean pulmonary artery pressure, mean pulmonary artery wedge pressure, and pulmonary vascular resistance, as compared with patients with normal QTc (n = 385). After a median follow-up of 3.7 years (interquartile range, 2.6-5.2) after surgical (n = 349) or transcatheter (n = 136) aortic valve replacement, patients with prolonged QTc had higher mortality than those with normal QTc (hazard ratio 2.81 [95% confidence interval, 1.51-5.20]; P < .001). Prolonged QTc was an independent predictor of death along with more severe mitral regurgitation and higher pulmonary vascular resistance. CONCLUSIONS: In patients with severe aortic stenosis, prolonged QTc is a marker of an advanced disease stage associated with an adverse hemodynamic profile and increased long-term mortality after aortic valve replacement.

Bioimpedance cardiography in pregnancy: A longitudinal cohort study on hemodynamic pattern and outcome.

BACKGROUND: Pregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child. Bioimpedance cardiography may provide additional outcome-relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases. METHODS: We performed a prospective longitudinal cohort trial in an outpatient setting and included 242 pregnant women. Cardiac output and concomitant hemodynamic data were recorded from 11(th)-13(th) week of gestation every 5(th) week as well as at two occasions post partum employing bioimpedance cardiography. RESULTS: Cardiac output increased during pregnancy and peaked early in the third trimester. A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes. Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy. Furthermore, an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis. CONCLUSIONS: Cardiovascular adaptation during pregnancy is characterized by distinct pattern described herein. These may be altered in women at risk for preeclampsia or reduced birthweigth. The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks.

Music-induced prolongation of heart rate corrected QT intervals from electrocardiogram recordings of healthy preterm pregnant women.

AIM: Women do have longer QTc intervals compared to men. The aim of this study was to investigate as-yet undocumented effects of music on QTc intervals from electrocardiogram (ECG) recordings compared to various cardiovascular parameters of women in the prenatal phase. METHODS: Forty-four healthy women in pregnancy were exposed to quiet surroundings (Q), self-selected slow music (S), and investigator-provided fast music (F) with different rhythm and frequency characteristics for 3 min each during their routine cardiotocography investigation. QTc intervals from ECG recordings were calculated according to the formulas of Bazett, Fridericia, and Sagie. RESULTS: QTc durations (Bazett) increased from 0.396±0.02 (Q) to 0.401±0.02 s (S) and to 0.407±0.03 s (F). The increase in QTc (delta QTc) value for slow (S) and fast (F) music was found to be 5.3 (S) and 10.1 ms (F, milliseconds) when compared to quiescent (Q) conditions showing a highly significant tripled P-value of 0.002 (Q vs. F). Similar results were found using alternate frequency corrections (Fridericia, Sagie) - QTc (delta QTc): 8.1 (Fridericia) and 7.2 ms (Sagie), quiescent vs. F, with P<0.001. None of the tests for other cardiovascular parameters showed significant differences. CONCLUSIONS: As shown from our data, music with different rhythm and frequency characteristics may prolong QTc intervals in healthy preterm pregnant women and may add to other risk factors (e.g., preexisting QTc prolongation or application of QTc prolonging drugs). These data could prove to be relevant in the primary prevention recommendations for women at risk for arrhythmic patterns during pregnancy.

NT-proBNP is increased in healthy pregnancies compared to non-pregnant controls.

Serum concentrations of the amino-terminal pro-B-type natriuretic peptide (NT-proBNP) may be used to monitor cardiac function during pregnancy but normal values are not established for this purpose. Therefore, we investigated NT-proBNP in normotensive healthy pregnancies compared to a non-pregnant control group. Serum NT-proBNP was measured in 94 normotensive, healthy pregnant women (32+/-6 years) every five weeks beginning from 12th gestational week (GW) in a longitudinal study and compared to a non-pregnant control group of 521 women (32+/-7 years). Pooled median serum NT-proBNP levels (25th; 75th percentile) were significantly higher in pregnant women compared to non-pregnant women (56 (33; 95) pg/ml vs. 38 (22; 62) pg/ml (p<0.001)). NT-proBNP increased during pregnancy to 73 (51; 124) pg/ml in the 11+6 to 15+6 GW (p<0.001). However, NT-proBNP levels from 23+0 GW towards term were comparable to non-pregnant controls. NT-proBNP is significantly elevated in healthy pregnancies until mid-pregnancy. As preeclampsia and gestational hypertension are associated with increased NT-proBNP, our results have to be considered in future diagnostic approaches using NT-proBNP for these pathologic conditions.