Jonas Johnson

The prognostic value of mechanical left ventricular dyssynchrony in patients with acute coronary syndrome

BackgroundEchocardiography is a well-established tool for risk stratification in patients with acute coronary syndrome (ACS). ACS has significant impact on LV dyssynchrony, and detrimental effects on systolic function and long term outcome. The aims of this study were to determine whether LV dyssynchrony carries any predictive information in an unselected ACS population and to evaluate if it has any incremental value to the information given from conventional echocardiographic measurements.MethodsThe study included 227 consecutive ACS patients. Primary endpoint was the composite of death, new MI, or rehospitalisation due to heart failure. Dyssynchrony was measured as intersegmental variation of time to peak strain, the post systolic index (PSI) and myocardial performance index (MPI) with the standard deviation and difference between lowest and highest value (delta) expressing the amount of dyssynchrony. Septal-lateral delay was also tested. All dyssynchrony parameters were compared with Ejection fraction (EF).ResultsThe median follow up time was 53 months. 85 patients reached the combined endpoint. Patients with and without a subsequent combined endpoint differed significantly regarding calculated SD: s and delta-value for PSI, time to peak 2D-strain and MPI but not regarding septal-lateral delay. In ROC-analysis none of the dyssynchrony parameters had larger AUC than EF. When adjusting for traditional risk factors none of the dyssynchrony parameters remained associated with outcome, whereas EF still did.ConclusionLV dyssynchrony seem to have significant prognostic information in patient with acute coronary syndrome but in comparison to conventional parameters such as EF there is no incremental value of this information.

The Cardiac State Diagram as a Novel Approach for the Evaluation of Pre- and Post-ejection Phases of the Cardiac Cycle in Asphyxiated Fetal Lambs

The aim of this study was to investigate myocardial wall motion using echocardiography and color-coded tissue velocity imaging and to generate a cardiac state diagram for evaluation of the duration of the pre- and post-ejection phases in asphyxiated fetal lambs. Six near-term lambs were partly exteriorized and brought to cardiac arrest through asphyxia. Echocardiography measurements were recorded simultaneously with arterial blood sampling for lactate and blood gases. All fetal lambs exhibited prolongation of the pre- and post-ejection phases at the time when the most pronounced changes in lactate concentration and pH occurred. The mean change in duration of the pre- and post-ejection phases for all fetal lambs was 36 ± 7 ms (p < 0.002) and 77 ± 17 ms (p < 0.019), respectively, and the percentage change was 50% (p < 0.001) and 38% (p < 0.049), respectively. As asphyxia progressed in fetal lambs, the duration of the pre- and post-ejection phases increased. The cardiac state diagram has the potential to be a comprehensible tool for detecting fetal asphyxia.

Impact of tachycardia and sympathetic stimulation by cold pressor test on cardiac diastology and arterial function in elderly females

Abnormal vascular-ventricular coupling has been suggested to contribute to heart failure with preserved ejection fraction in elderly females. Failure to increase stroke volume (SV) during exercise occurs in parallel with dynamic changes in arterial physiology leading to increased afterload. Such adverse vascular reactivity during stress may reflect either sympathoexcitation or be due to tachycardia. We hypothesized that afterload elevation induces SV failure by transiently attenuating left ventricular relaxation, a phenomenon described in animal research. The respective roles of tachycardia and sympathoexcitation were investigated in n = 28 elderly females (70 ± 4 yr) carrying permanent pacemakers. At rest, during atrial tachycardia pacing (ATP; 100 min(-1)) and during cold pressor test (hand immersed in ice water), we performed Doppler echocardiography (maximal untwist rate analyzed by speckle tracking imaging of rotational mechanics) and arterial tonometry (arterial stiffness estimated as augmentation index). Estimation of arterial compliance was based on an exponential relationship between arterial pressure and volume. We found that ATP produced central hypovolemia and a reduction in SV which was larger in patients with stiffer arteries (higher augmentation index). There was an associated adverse response of arterial compliance and vascular resistance during ATP and cold pressor test, causing an overall increase in afterload, but nonetheless enhanced maximal rate of untwist and no evidence of afterload-dependent failure of relaxation. In conclusion, tachycardia and cold provocation in elderly females produces greater vascular reactivity and SV failure in the presence of arterial stiffening, but SV failure does not arise secondary to afterload-dependent attenuation of relaxation.

Automated analysis of fetal cardiac function using color tissue Doppler imaging

To evaluate the feasibility of automated analysis of fetal myocardial velocity recordings obtained by color tissue Doppler imaging (cTDI).

The early diastolic myocardial velocity: a marker of increased risk in patients with coronary heart disease.

Tissue Doppler imaging (TDI) is a promising echocardiographic modality allowing quantification of myocardial performance. However, the prognostic potential of TDI in patients with acute myocardial infarction (AMI) is not yet investigated. We sought to explore the ability of TDI in identifying patients at risk for new cardiovascular events after AMI.

Automated analysis of fetal cardiac function using color tissue Doppler imaging in the second half of normal pregnancy: Automated analysis of fetal cardiac function

Color tissue Doppler imaging (cTDI) is a promising tool for the assessment of fetal cardiac function. However, the analysis of myocardial velocity traces is cumbersome and time‐consuming, limiting its application in clinical practice. The aim of this study was to evaluate fetal cardiac function during the second half of pregnancy and to develop reference ranges using an automated method to analyze cTDI recordings from a cardiac four‐chamber view.

Right ventricular mechanics and contractility after aortic valve replacement surgery: a randomised study comparing minimally invasive versus conventional approach

Objective Minimally invasive aortic valve replacementsurgery (MIAVR) is an alternative surgical technique to conventional aortic valve replacement surgery (AVR) in selected patients. The randomised study Cardiac Function after Minimally Invasive Aortic Valve Implantation (CMILE) showed that right ventricular (RV) longitudinal function was reduced after both MIAVR and AVR, but the reduction was more pronounced following AVR. However, postoperative global RV function was equally impaired in both groups. The purpose of this study was to explore alterations in RV mechanics and contractility following MIAVR as compared with AVR. Methods A predefined post hoc analysis of CMILE consisting of 40 patients with severe aortic valve stenosis who were eligible for isolated surgical aortic valve replacement were randomised to MIAVR or AVR. RV function was assessed by echocardiography prior to surgery and 40 days post-surgery. Results Comparing preoperative to postoperative values, RV longitudinal strain rate was preserved following MIAVR (−1.5±0.5 vs −1.5±0.4 1/s, p=0.84) but declined following AVR (−1.7±0.3 vs −1.4±0.3 1/s, p<0.01). RV longitudinal strain reduced following AVR (−27.4±2.9% vs −18.8%±4.7%, p<0.001) and MIAVR (−26.5±5.3% vs −20.7%±4.5%, p<0.01). Peak systolic velocity of the lateral tricuspid annulus reduced by 36.6% in the AVR group (9.3±2.1 vs 5.9±1.5 cm/s, p<0.01) and 18.8% in the MIAVR group (10.1±2.9 vs 8.2±1.4 cm/s, p<0.01) when comparing preoperative values with postoperative values. Conclusions RV contractility was preserved following MIAVR but was deteriorated following AVR. RV longitudinal function reduced substantially following AVR. A decline in RV longitudinal function was also observed following MIAVR, however, to a much lesser extent.

Heart rate and dyssynchrony in patients with cardiac resynchronization therapy: a pilot study

Abstract Objectives: The objective of this pilot study was to describe the impact of paced heart rate on left ventricular (LV) mechanical dyssynchrony in synchronous compared to dyssynchronous pacing modes in patients with heart failure. Methods: Echocardiography was performed in 14 cardiac resynchronization therapy (CRT) patients at paced heart rates of 70 and 90 bpm in synchronous- (CRT), and dyssynchronous (atrial pacing + wide QRS activation) pacing modes. LV dyssynchrony was quantified using the 12-segment standard deviation model (Ts-SD) derived from Tissue Doppler Imaging. In addition, cardiac cycle intervals were assessed using cardiac state diagrams and stroke volume (SV) and filling pressure were estimated. Results: Ts-SD decreased significantly with CRT at 90 bpm (25 ± 12 ms) compared to 70 bpm (35 ± 15 ms, p = .01), but remained unchanged with atrial pacing at different paced heart rates (p = .96). The paced heart rate dependent reduction in Ts-SD was consistent when Ts-SD was indexed to average Ts and systolic time interval. Cardiac state diagram derived analysis of cardiac cycle intervals demonstrated a significant reduction of the pre-ejection interval and an increase in diastole with CRT compared to atrial pacing. SV was maintained at the higher paced heart rate with CRT pacing but decreased with atrial pacing. Discussion: Due to the small sample size in this pilot study general and firm conclusions are difficult to render. However, the data suggest that pacing at higher heart rates acutely reduces remaining LV dyssynchrony during CRT, but not during atrial pacing with dyssynchronous ventricular activation. These results need confirmation in a larger patient cohort.

OC18.02: The cardiac state diagram as a novel approach for evaluation of re- and post ejection phases of the cardiac cycle in asphyxiated fetal lambs

Objectives: To investigate whether levels of cell free fetal DNA (cffDNA) assessed at 25 weeks gestation when determining fetal RHD status and PAPP-A from the combined first trimester risk assessment for trisomy 21 can identify women at risk of developing pre-eclampsia and SGA neonates. Methods: A population of 964 singleton pregnant RhD negative women with an RHD positive fetus who participated in the antenatal RHD screening programme in the Capital Region of Denmark. All women had a first trimester nuchal translucency scan and a 20 week malformation scan. Gestational age was based on CRL measurement at first trimester screening, PAPP-A was measured at 8–14 weeks. SGA was calculated using the regression equation constructed by Marsál and co-workers. We used a standard dilution curve to calculate the amounts of cffDNA. Results: A total of 38 women developed pre-eclampsia (3.9%), 15 cases of severe and 23 cases of mild pre-eclampsia. The number of neonates born SGA was 51 (5.3 %). The OR of developing mild pre-eclampsia given a cffDNA level below the 5th centile was 4.1 (95% CI: 1.2–13.2) and the OR of developing severe pre-eclampsia given a cffDNA level above the 90th centile was 10.2 (95% CI: 3.4–30.4). SGA was significantly associated with fetal DNA levels above the 90th centile (P = 0.009). Amongst women diagnosed with pre-eclampsia 46% in the group with cffDNA levels above the 90th centile delivered an SGA neonate compared to 7% in the group with cffDNA levels below the 90th centile. Amongst women not developing pre-eclampsia the numbers were 7.1% versus 4.5%. PAPP-A levels below the 5th centile were associated with mild pre-eclampsia, but not with SGA. Conclusions: Cell free fetal DNA is a marker for pre-eclampsia. High levels were associated with severe pre-eclampsia, low levels with mild pre-eclampsia, thus indicating different placental pathologic mechanisms. High levels of cffDNA is a poor marker of SGA independently of pre-eclampsia.

The Cardiac State Diagram as a novel approach for evaluation of phases of the cardiac cycle in asfyxiated fetal lambs

The Cardiac State Diagram as a novel approach for evaluation of phases of the cardiac cycle in asfyxiated fetal lambsPseudomyxoma Peritone : symptoms, treatment, prognosis and sensitivity to cytostatic drugs in vitro