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Wim B Vletter

Publications and source records attributed to Wim B Vletter.

11 recordsLinked to original sources
PubMed2007

Spectral pulsed-wave tissue Doppler imaging lateral-to-septal delay fails to predict clinical or echocardiographic outcome after cardiac resynchronization therapy.

AIMS: The current study sought to assess if pre-implantation lateral-to-septal delay (LSD) > or =60 ms assessed by spectral pulsed-wave myocardial tissue Doppler imaging (PW-TDI) could predict successful long-term outcome after cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Sixty patients (72% males, mean age 59 +/- 10 years) who were referred for CRT according to the ACC/ESC guidelines were enrolled in the study. All patients underwent spectral PW-TDI before and 1 year after CRT. Two left ventricular (LV) dyssynchrony time intervals, T(O) and T(P) (time to onset and peak of LV myocardial velocity, respectively), LSD were recorded. Left ventricular dyssynchrony was defined as LSD > or =60 ms. Clinical response was defined as an improvement in >1 NYHA class plus improvement in 6-min walk distance (6MWD) > or =25%, echocardiographic response was defined as a > or =15% reduction in LV end-systolic volume (LV-ESV). One year after CRT, 50 patients (83%) were clinical responders and 47 patients (78%) were echocardiographic responders. Both T(O) and T(P) LV dyssynchrony indices failed to predict echocardiographic CRT outcome. In addition, there were no significant differences between 'synchronous' and 'dyssynchronous' patient populations at baseline or follow-up in either clinical (NYHA class and 6MWD) or echocardiographic (LV ejection fraction, LV end-diastolic, and end-systolic) variables. CONCLUSION: The great majority of patients referred for CRT benefit clinically from it. However, spectral PW-TDI failed to predict CRT outcome. When PW-TDI dyssynchrony was applied for selection of proper CRT patients, up to 80-86% of the patients with synchronous LSD that had proven clinical and echocardiographic benefit from CRT would have been denied CRT.

Cardiac Pacing, Artificial↗
PubMed2006

Cardiac involvement in adults with m.3243A>G MELAS gene mutation.

Cardiac data in adults with mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS syndrome) or asymptomatic gene carriers with the mitochondrial deoxyribonucleic acid adenine-to-guanine point mutation at nucleotide pair 3243 are scarce. Twelve subjects (mean age 35 +/- 13 years), 8 with MELAS syndrome (patients) and 4 asymptomatic gene carriers (carriers), were enrolled in the study. Each subject underwent electrocardiography, exercise testing, Holter monitoring, echocardiography, and genetic and biochemical analysis for respiratory chain enzyme activity (complex I rest activity) in skeletal muscle. On electrocardiography and Holter monitoring, none of the subjects had evidence of preexcitation, cardiac arrhythmias, or conduction abnormalities. Patients had significantly lower (42 +/- 17% from normal vs 103 +/- 14%, p <0.02) exercise tolerance. All but 1 of the patients and none of the gene carriers had ragged red fibers on muscle biopsy. The mean percentage of gene mutation in skeletal muscle tended to be higher in patients (53 +/- 19%, range 19% to 73%) compared with carriers (33 +/- 20%, range 15% to 62%). Mean complex I rest activity in patients (36 +/- 18%, range 10% to 58%) was significantly (p <0.01) lower compared with carriers (120 +/- 60%, range 72% to 205%). Left ventricular (LV) abnormalities were confined to patients with MELAS syndrome. Two patients had LV hypertrophy, 5 had LV systolic abnormalities, and 5 had LV diastolic dysfunction. Apart from 1 patient with an isolated LV diastolic abnormality, all patients with LV abnormalities had ragged red fibers. Patients with abnormal systolic LV function had a trend toward a higher percentage of mutated skeletal muscle (59.7 +/- 10.7% vs 35.8 +/- 21.3%, p <0.10) and significantly lower complex I rest activity (26.7 +/- 14.0% vs 97.8% +/- 57.9, p <0.01). In conclusion, none of the MELAS gene carriers had cardiac abnormalities, whereas most patients with the MELAS phenotype, particularly those with ragged red fibers, had LV involvement.

Adolescent↗
PubMed2006

Usefulness of ultrasound contrast agent to improve image quality during real-time three-dimensional stress echocardiography.

Dobutamine stress echocardiography is an accepted tool for the diagnosis of coronary artery disease. Some investigators have claimed that 3-dimensional imaging improves the diagnostic accuracy of dobutamine stress echocardiography. The purpose of the present investigation was to examine the role of contrast echocardiography in the improvement of segmental quality and interobserver agreement during stress real-time 3-dimensional echocardiography (RT3DE). The study comprised 36 consecutive patients with stable chest pain referred for routine stress testing. Three-dimensional images were acquired with an RT3DE system with an X4 matrix-array transducer. All available reconstructed 2-dimensional segments were graded as optimal, good, moderate, or poor. Wall motion was scored as normal, mild hypokinesia, severe hypokinesia, akinesia, or dyskinesia. At peak stress, 466 of the 612 segments (76%) could be analyzed during conventional RT3DE. With contrast-enhanced RT3DE, the number of available segments increased to 553 (90%). The image quality index during conventional RT3DE was 2.2, whereas with contrast-enhanced RT3DE, it was 3.1. With conventional RT3DE, 2 independent observers agreed on the diagnosis of myocardial ischemia in 85 of 108 coronary territories (79%, kappa = 0.26). With contrast-enhanced RT3DE, agreement increased to 95 of 108 coronary territories (88%, kappa = 0.59). Study agreement on myocardial ischemia was present in 26 of 36 studies (72%, kappa = 0.43) with conventional RT3DE and in 32 of 36 studies (89%, kappa = 0.77) with contrast-enhanced RT3DE. In conclusion, during stress RT3DE, contrast-enhanced imaging significantly decreases the number of poorly visualized myocardial segments and improves interobserver agreement for the diagnosis of myocardial ischemia.

Cardiotonic Agents↗
PubMed2006

Real-time three-dimensional echocardiography for regional evaluation of aortic stiffness.

Aortic stiffness is an important predictor of cardiovascular morbidity and mortality. Non-invasive measurement of aortic stiffness is a promising challenge for echocardiography. The most important limitation of previous studies was that regional differences for aortic stiffness were not taken into consideration. In our patient, we demonstrated the usefulness of real-time three-dimensional echocardiography in assessment of regional aortic stiffness.

Adult↗
PubMed2006

Norepinephrine-induced vasoconstriction results in decreased blood volume in dialysis patients.

BACKGROUND: Hypotension during haemodialysis results from an inadequate cardiovascular response to ultrafiltration-induced hypovolaemia. It has been suggested that plasma volume could be increased as a result of systemic vasoconstriction. METHODS: We studied the effect of a norepinephrine (NOR) infusion (30 min), compared with no infusion, on relative blood volume (RBV) in six haemodialysis patients. During infusion we measured RBV, systolic blood pressure (SAP), heart rate (HR), stroke volume index (SI), total peripheral resistance (TPRI), ejection fraction (EF), inferior vena cava diameter (VCD) and core temperature. RESULTS: At the end of the NOR infusion, we observed a significant increase in TPRI (47+/-47% vs 4+/-17%; P<0.01) and SAP (27+/-12% vs 0+/-8%; P<0.01). Norepinephrine-induced vasoconstriction resulted in a significant decrease in RBV (-9+/-3% vs 0+/-1%; P<0.01). No significant changes were seen in SI (-4+/-21% vs 0+/-8%), HR (-5+/-19% vs -4+/-5%), EF (7+/-14% vs -2+/-10%), VCD or temperature. CONCLUSIONS: We conclude that norepinephrine-induced vasoconstriction results in a decrease in RBV. This indicates that improved haemodynamic stability during haemodialysis through vasoconstriction can be accompanied by a decrease in RBV and that part of the variability in blood volume may be due to changes in arterial tone. Such changes must be taken into account if RBV measurements are used to improve the haemodynamic tolerance of dialysis.

Blood Volume↗
PubMed2005

Myocardial contractility does not determine the haemodynamic response during dialysis.

BACKGROUND: LV systolic dysfunction in dialysis patients has been implicated in the genesis of dialysis hypotension. End-systolic elastance (E(es)), a relatively load-independent parameter of myocardial contractility, was assessed by testing the acute left ventricular (LV) response to nitroglycerine (NTG) in hypotension-prone (HP) and hypotension-resistant (HR) patients. METHODS: Routine measurement of ejection fraction (EF) was done before dialysis in 15 patients without significant valvular disease or symptoms of coronary heart disease. Continuous arterial pressure was measured by Finapres, with systolic blood pressure (SBP) as surrogate for LV end-systolic pressure. Simultaneously, LV area was measured using automated border detection. SBP and LV area data were combined online to create pressure-area loops in real time following intravenous NTG bolus. E(es) was determined offline by beat-to-beat analysis of consecutive pressure-area loops. RESULTS: SBP, at baseline 168 mmHg (128-188 mmHg), decreased to 127 mmHg (79-161 mmHg). End-systolic LV area, at baseline 6 cm2 (1-12 cm2), decreased to 4 cm2 (1-10 cm2). E(es) in the HP group (11 mmHg cm(-2); 7-22 mmHg cm(-2)) was not different from E(es) in the HR group (9 mmHg cm(-2); 4-16 mmHg cm(-2)). EF was 61% (45-73%). There was no correlation between E(es) and EF. CONCLUSIONS: In this population of dialysis patients without clinically manifest heart disease, the HP and HR groups had a similar E(es). Therefore, these two types of dialysis patients were not distinguished by a difference in myocardial contractility. The results of this study argue against a role for reduced myocardial contractility in the genesis of intradialytic hypotension.

Adult↗
PubMed2005

Percutaneous versus surgical treatment for patients with hypertrophic obstructive cardiomyopathy and enlarged anterior mitral valve leaflets.

BACKGROUND: The purpose of this study was to compare percutaneous transluminal septal myocardial ablation (PTSMA) and septal myectomy combined with mitral leaflet extension (MLE) in symptomatic hypertrophic obstructive cardiomyopathy patients with an enlarged anterior mitral valve leaflet (AMVL). Both PTSMA and myectomy reduce septal thickness and left ventricular outflow tract (LVOT) gradient; however, an uncorrected enlarged AMVL may predispose to residual systolic anterior motion (SAM) after successful standard myectomy or PTSMA. Myectomy with MLE previously demonstrated superior hemodynamic results compared with standard myectomy, but its value relative to PTSMA is unknown. METHODS AND RESULTS: Twenty-nine patients (aged 44+/-12 years) underwent myectomy with MLE, and 43 patients (aged 52+/-17 years) underwent PTSMA. Mitral leaflet area was similar in both groups (16.7+/-3.4 versus 15.9+/-2.7 cm2, respectively). After PTSMA, 2 patients died, 4 needed a reintervention, and 4 required a permanent pacemaker for complete heart block. After surgery, only 1 patient needed a reintervention. At 1-year follow-up, LVOT gradients did not differ between surgical and PTSMA patients (17+/-14 versus 23+/-19 mm Hg, respectively). Preinterventional mitral regurgitation grade was more severe in the surgical group, but with myectomy combined with MLE, the residual grade was similar to that of PTSMA. Mean SAM grade decreased significantly more after surgery (from 2.9+/-0.3 to 0.5+/-0.7 mm Hg versus from 2.8+/-0.5 to 1.3+/-0.9 [corrected], P<0.05). CONCLUSIONS: PTSMA in these selected patients with hypertrophic obstructive cardiomyopathy had more periprocedural complications and resulted in more reinterventions. Hemodynamic results (SAM grade and reduction in mitral regurgitation) were better in surgical patients.

Adult↗
PubMed2004

Increase in serum ionized calcium during diffusive dialysis does not affect left ventricular diastolic function.

An increase in serum Ca2+ during hemodialysis (HD) may lead to impaired left ventricular (LV) relaxation. Since LV diastolic function assessment in dialysis patients is hampered by preload dependence of Doppler measurements, we tested the effect of HD without ultrafiltration (UF) on these measurements. Transmitral E and A velocities, and mitral annulus e and a velocities were measured in 10 patients before and after 1 h of HD without UF. Dialysate Ca2+ was 1.75 mmol/l. Serum Ca2+ after 1 h (1.31 mmol/l; 1.28-1.46 mmol/l) was higher (p = 0.002) than before HD (1.24 mmol/l; 1.09-1.32 mmol/l). E/A (0.8; 0.4-2.8) and e/a (0.7; 0.4-1.3) after 1 h were not different than E/A (0.8; 0.6-5.1) and e/a (0.7; 0.4-1.8) before HD. The increase in serum Ca2+ does not lead to a change in Doppler parameters of LV diastolic function. Changes in these parameters after combined HD-UF are related to preload, not to serum Ca2+.

Adult↗
PubMed2003

Contrast superharmonic imaging: a feasibility study.

Harmonic imaging provided significant improvement in image quality by taking advantage of the scattered second harmonic (2H) component from contrast bubbles. However, differentiation between contrast and tissue (usually termed contrast-to-tissue ratio, CTR) is sometimes cumbersome and this is mainly due to tissue contamination. We have previously demonstrated, using simulations and in vitro measurements, that CTR increases as a function of the order of the harmonic number. A new contrast imaging method based on the detection of the higher harmonics was developed and termed superharmonic (SH). This technique has been shown to be more sensitive to contrast by increasing the signal from contrast and suppressing that from tissue (high CTR). The purpose of this study was to determine the clinical feasibility and usefulness of SH in patients using a commercially available contrast agent (SonoVue(R)) for quantification of myocardial perfusion. A total of 10 patients with various cardiac diseases were assessed. Apical four-chamber views were acquired using SH in triggered mode before and after contrast injection. The superharmonic was performed with a newly developed probe transmitting at 0.8 MHz with a mechanical index of 0.2. Myocardial perfusion was determined visually and analyzed quantitatively using radiofrequency (RF) processing from different regions of interest. The results showed that, before contrast injection, SH was totally blinded to tissue and no superharmonic components were generated in the image view. After administration of SonoVue(R), myocardial opacification was visualized by SH after contrast entered the myocardium. An increase of more than 15 dB in the myocardial bubbles echo compared to tissue echo was measured. In addition, the technique was used to visualize myocardial perfusion after myocardial septal ablation for hypertrophic cardiomyopathy. The clinical results showed the ability of contrast SH imaging in differentiating low and normal perfusion areas, demonstrating the high sensitivity and specificity of the technique.

Adult↗
PubMed2003

Preload dependence of new Doppler techniques limits their utility for left ventricular diastolic function assessment in hemodialysis patients.

Left ventricular (LV) hypertrophy leads to diastolic dysfunction. Standard Doppler transmitral and pulmonary vein (PV) flow velocity measurements are preload dependent. New techniques such as mitral annulus velocity by Doppler tissue imaging (DTI) and LV inflow propagation velocity measured from color M-mode have been proposed as relatively preload-independent measurements of diastolic function. These parameters were studied before and after hemodialysis (HD) with ultrafiltration to test their potential advantage for LV diastolic function assessment in HD patients. Ten patients (seven with LV hypertrophy) underwent Doppler echocardiography 1 h before, 1 h after, and 1 d after HD. Early (E) and atrial (A) peak transmitral flow velocities, peak PV systolic (s) and diastolic (d) flow velocities, peak e and a mitral annulus velocities in DTI, and early diastolic LV flow propagation velocity (V(p)) were measured. In all patients, the E/A ratio after HD (0.54; 0.37 to 1.02) was lower (P < 0.01) than before HD (0.77; 0.60 to 1.34). E decreased (P < 0.01), whereas A did not. PV s/d after HD (2.15; 1.08 to 3.90) was higher (P < 0.01) than before HD (1.80; 1.25 to 2.68). Tissue e/a after HD (0.40; 0.26 to 0.96) was lower (P < 0.01) than before HD (0.56; 0.40 to 1.05). Tissue e decreased (P < 0.02), whereas a did not. V(p) after HD (30 cm/s; 16 to 47 cm/s) was lower (P < 0.01) than before HD (45 cm/s; 32 to 60 cm/s). Twenty-four hours after the initial measurements values for E/A (0.59; 0.37 to 1.23), PV s/d (1.85; 1.07 to 3.38), e/a (0.41; 0.27 to 1.06), and V(p) (28 cm/s; 23 to 33 cm/s) were similar as those taken 1 h after HD. It is concluded that, even when using the newer Doppler techniques DTI and color M-mode, pseudonormalization, which was due to volume overload before HD, resulted in underestimation of the degree of diastolic dysfunction. Therefore, the advantage of these techniques over conventional parameters for the assessment of LV diastolic function in HD patients is limited. Assessment of LV diastolic function should not be performed shortly before HD, and its time relation to HD is essential.

Adult↗