http://repub.eur.nl/res/aut/15435/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/30284/ 2008-10-01T00:00:00Z Objective: Hypertrophic obstructive cardiomyopathy (HOCM) often leads to heart failure, severe symptoms and death. Percutaneous transluminal septal myocardial ablation (PTSMA) by alcohol injection efficiently reduces left ventricular (LV) outflow tract pressure gradient and improves symptoms. We determined acute changes in haemodynamics and systolic and diastolic LV function after PTSMA. Methods: In 17 consecutive patients with symptomatic HOCM referred for PTSMA, the target vessel was determined by myocardial contrast transthoracic echo-cardiography. An over-the-wire balloon was inflated in the target vessel and multiple 0.5-ml alcohol injections were performed. LV systolic and diastolic function was - assessed by online pressure-volume loops obtained by conductance catheter at baseline and acutely after the procedure. Results: In all patients except two, a single septal branch was treated using a total of 2.0 (0.5) ml ethanol per patient. The rest and post-extrasystolic gradient were significantly decreased after PTSMA (79 (38) to 14 (16) mm Hg and 130 (50) to 34 (33) mm Hg, respectively, both p<0.001). Ejection fraction decreased (78% (9%) to 67% (13%), p<0.001). Cardiac output, heart rate and stroke work were unchanged, but systolic and diastolic volume increased. End-systolic and end-diastolic pressure significantly decreased (166 (27) to 129 (26) mm Hg, p<0.001 and 25 (6) to 21 (7) mm Hg, p = 0.049, respectively). Significant rightward shift (p<0.001) and decreased slope (p = 0.041) of the end-systolic pressure-volume relation indicated reduced contractility, whereas diastolic stiffness, -dP/dtMIN, and tau were significantly improved after the procedure. Conclusions: PTSMA acutely reduced systolic function but promptly improved diastolic function with maintained cardiac output and stroke work. Improved diastolic function and increased end-diastolic volume compensated for the systolic loss and resulted in maintained haemodynamics. http://repub.eur.nl/res/pub/28988/ 2008-04-15T00:00:00Z The aim of the present study was to determine the long-term effects of percutaneous transluminal septal myocardial ablation (PTSMA) on systolic and diastolic left ventricular (LV) functions in patients with obstructive hypertrophic cardiomyopathy (HC). Ten consecutive patients with symptomatic HC despite optimal medical treatment were referred for PTSMA at our center. LV systolic and diastolic functions were assessed by online LV pressure-volume loops obtained by conductance catheter at baseline and at 6 months after the procedure. At follow-up, the mean gradients at rest and after extrasystole were significantly decreased compared with baseline (88 ± 29 to 21 ± 11 mm Hg and 130 ± 50 to 35 ± 22 mm Hg, respectively, p <0.01 for the 2 comparisons). End-systolic and end-diastolic pressures significantly decreased (p <0.01), whereas end-systolic and end-diastolic LV volumes significantly increased (p <0.01 for the 2 comparisons). Cardiac output and stroke volume were unchanged, as were ejection fraction (p = 0.25) and maximum dP/dt (p = 0.13). The slope of the end-systolic pressure-volume relation was not decreased, indicating a preserved contractility. The relaxation constant time, end-diastolic stiffness, projected volume of the end-diastolic pressure-volume relation at 30 mm Hg, and diastolic stiffness constant showed a significant improvement of active and passive myocardial diastolic properties. In conclusion, PTSMA is an effective method in the treatment of symptomatic patients with HC. At 6-month follow-up, the LV-aortic gradient was decreased and active and passive LV diastolic properties were increased. Myocardial contractility was not decreased and general hemodynamics was maintained. http://repub.eur.nl/res/pub/36411/ 2007-09-01T00:00:00Z Objectives: Fluid mechanical forces affect cardiac development. In the chicken embryo, permanent obstruction of the right lateral vitelline vein by clipping reduces the mechanical load on the embryonic myocardium, which has been shown to induce a spectrum of outflow tract anomalies. Insight into the effects of this intervention on the mechanical function of the developing myocardium could contribute to a better understanding of the relationship between hemodynamics and cardiac morphogenesis. We aimed to explore the effects of clipping on intrinsic systolic and diastolic ventricular function at stage 24 in the chicken embryo. Methods: Cardiac pressure-volume relationships enable load-independent quantification of intrinsic ventricular systolic and diastolic properties. We determined ventricular function by pressure-volume loop analysis of in-ovo stage-24 chicken embryos (n = 15) 2 days after venous obstruction at 2.5 days of incubation (stage 17, venous clipped embryos). Control embryos (n = 15) were used for comparison. Results: End-systolic volume was significantly higher in clipped embryos (0.36 ± 0.02 μL vs. 0.29 ± 0.02 μL, P = 0.002). End-systolic and end-diastolic pressure were also increased compared with control animals (2.93 ± 0.07 mmHg vs. 2.70 ± 0.08 mmHg, P = 0.036 and 1.15 ± 0.06 mmHg vs. 0.82 ± 0.05 mmHg, P < 0.001, respectively). No significant differences were demonstrated for other baseline hemodynamic parameters. Analysis of pressure-volume relationships showed a significantly lower end-systolic elastance in the clipped embryos (slope of end-systolic pressure-volume relationship: 2.91 ± 0.24 mmHg/μL vs. 7.53 ± 0.66 mmHg/μL, P < 0.005) indicating reduced contractility. Diastolic stiffness was significantly increased in the clipped embryos (slope of end-diastolic pressure-volume relationship: 1.54 ± 0.21 vs. 0.60 ± 0.08, P < 0.005), indicating reduced compliance. Conclusion: Venous obstruction apparently interferes with normal myocardial development, resulting in impaired intrinsic systolic and diastolic ventricular function. These changes in ventricular function may precede morphological derangements observed in later developmental stages. Copyright http://repub.eur.nl/res/pub/35644/ 2007-01-01T00:00:00Z M-mode echocardiography (using the septal-to-posterior wall motion delay [SPWMD]) and color-coded tissue Doppler imaging (TDI; using the septal-to-lateral delay in peak systolic velocity) have been proposed for assessment of left ventricular (LV) dyssynchrony and prediction of response to cardiac resynchronization therapy (CRT). In this study, a head-to-head comparison between M-mode echocardiography and color-coded TDI was performed for assessment of LV dyssynchrony and prediction of response to CRT. Consecutive (n = 98) patients with severe heart failure (New York Heart Association class III/IV), LV ejection fraction ≤35%, and QRS duration >120 ms underwent CRT. Before pacemaker implantation, LV dyssynchrony was assessed by M-mode echocardiography (SPWMD) and color-coded TDI (septal-to-lateral delay). At baseline and 6 months after implantation, clinical and echocardiographic parameters were evaluated. SPWMD measurement was not feasible in 41% of patients due to akinesia of the septal and/or posterior walls or poor acoustic windows. Conversely, the septal-to-lateral delay could be assessed in 96% of patients. At 6-month follow-up, 75 patients (77%) were classified as responders to CRT (improvement ≥1 New York Heart Association class). The sensitivity and specificity of SPWMD were lower compared with those of septal-to-lateral delay (66% vs 90%, p <0.05; 50% vs 82%, p = NS, respectively). In conclusion, LV dyssynchrony assessment was feasible in 59% of patients with M-mode echocardiography compared with 96% (p <0.05) when color-coded TDI was used. Color-coded TDI was superior to M-mode echocardiography for prediction of response to CRT. http://repub.eur.nl/res/pub/35872/ 2007-01-01T00:00:00Z Aims: At present, 20-30% of patients do not respond to cardiac resynchronization therapy (CRT). In this study, the relation between the extent of viable myocardium and scar tissue vs. response to CRT was evaluated. In addition, the presence of scar tissue in the left ventricular (LV) lead position was specifically related to response to CRT. Methods and results: A total of 51 consecutive patients with ischaemic heart failure and substantial LV dyssynchrony undergoing CRT were included. All patients underwent gated SPECT before CRT implantation to determine the extent of scar tissue and viable myocardium. Clinical and echocardiographic parameters were assessed at baseline and after 6 months of CRT. The results demonstrated direct relations between the response to CRT and the extent of viable myocardium and scar tissue. In addition, the 15 patients (29%) with transmural scar tissue (< 50% tracer activity) in the region of the LV pacing lead showed no improvement after 6 months of CRT. Conclusion: The extent of scar tissue and viable myocardium were directly related to the response to CRT. Furthermore, scar tissue in the LV pacing lead region may prohibit response to CRT. Evaluation for viability and scar tissue may be considered in the selection process for CRT. http://repub.eur.nl/res/pub/13550/ 2005-01-01T00:00:00Z Cardiac pressure-volume relations enable quantification of intrinsic ventricular diastolic and systolic properties independent of loading conditions. The use of pressure-volume loop analysis in early stages of development could contribute to a better understanding of the relationship between hemodynamics and cardiac morphogenesis. The venous clip model is an intervention model for the chick embryo in which permanent obstruction of the right lateral vitelline vein temporarily reduces the mechanical load on the embryonic myocardium and induces a spectrum of outflow tract anomalies. We used pressure-volume loop analysis of the embryonic chick heart at stage 21 (3.5 d of incubation) to investigate whether the development of ventricular function is affected by venous clipping at stage 17, compared with normal control embryos. Steady state hemodynamic parameters demonstrated no significant differences between the venous clipped and control embryos. However, analysis of pressure-volume relations showed a significantly lower end-systolic elastance in the clipped embryos (slope of the end-systolic pressure-volume relation: 5.68 +/- 0.85 versus 11.76 +/- 2.70 mm Hg/microL, p < 0.05), indicating reduced contractility. Diastolic stiffness tended to be increased in the clipped embryos (slope of end-diastolic pressure-volume relation: 2.74 +/- 0.56 versus 1.67 +/- 0.21, p = 0.103), but the difference did not reach statistical significance. The results of the pressure-volume loop analysis show that 1 d after venous obstruction, development of ventricular function is affected, with reduced contractility. Pressure-volume analysis may be applied in the chick embryo and is a sensitive technique to detect subtle alterations in ventricular function.