Biomedical subjects

Nico De Jong

Publications and source records attributed to Nico De Jong.

3 recordsLinked to original sources

PubMed2005

Intracardiac echocardiography guidance during percutaneous transluminal septal myocardial ablation in patients with obstructive hypertrophic cardiomyopathy.

BACKGROUND: Percutaneous transluminal septal myocardial ablation (PTSMA) recently emerged as an alternative to myectomy for hypertrophic obstructive cardiomyopathy (HOCM) patients with drug-refractory symptoms. The target septal branch selection is a main point to achieve the therapeutic result. METHODS AND RESULTS: We report about PTSMA performed using intracardiac echocardiography (ICE) to guide the procedure in 9 symptomatic HOCM patients. The target septal branch was chosen on the basis of the risk-area visualized using ICE after injection of a contrast agent. During alcohol administration a backscattered signal enhancement of the infarcted area was detected. The procedures were uncomplicated and effective to reduce the gradient from 78.9+/-20.4 mmHg to 7.8+/-7.9 mmHg (p<0.0001). CONCLUSIONS: In this initial experience ICE monitoring during PTSMA was safe and provided high quality and continuous imaging of the treated segment of the septum during the whole procedure.

Adult↗

PubMed2004

Guiding and optimization of resynchronization therapy with dynamic three-dimensional echocardiography and segmental volume--time curves: a feasibility study.

OBJECTIVE: To assess a new approach for guiding and hemodynamic optimization of resynchronization therapy, using three-dimensional (3D) transthoracic echocardiography. BACKGROUND: Resynchronization therapy for heart failure provides the greatest hemodynamic benefit when applied to the most delayed left ventricular (LV) site. Currently, the ideal LV pacing site is selected according to acute invasive hemodynamic assessment and/or tissue Doppler imaging. METHODS: A total of 16 patients with advanced heart failure and an implanted biventricular pacemaker were included in this study. Transthoracic apical LV images at equidistant intervals were obtained using a prototype, fast-rotating second harmonic transducer to reconstruct 3D LV datasets during sinus rhythm (SR), right ventricular (RV) apical and biventricular pacing mode. A semi-automated contour analysis system (4D LV analysis, TomTec, Germany) was used for segmental wall motion analysis and identification of the most delayed contracting segment and calculation of global LV function. RESULTS: Data acquisition duration was 10 s and analyzable 3D images were obtained in 12 patients. Of these patients, data during SR were available in 9 and during biventricular pacing in 11. The greatest contraction delay during SR was found in the anterior and antero-septal segments in five of nine patients. Biventricular pacing resulted in reduction of the contraction delay in seven of eight patients. The global LV function did not change significantly. CONCLUSION: 3D echocardiography with appropriate analytic software allows detection of the most delayed LV contracting segment and can be used to select the optimal pacing site during resynchronization therapy.

Aged↗

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↗