Biomedical subjects

Monique R M Jongbloed

Publications and source records attributed to Monique R M Jongbloed.

10 recordsLinked to original sources

PubMed2006

Effect of radiofrequency catheter ablation for atrial fibrillation on left atrial cavity size.

Left atrial (LA) remodeling is associated with atrial fibrillation (AF). Radiofrequency catheter ablation offers a good treatment option for AF, with reasonable long-term results. The purpose of the present study was to assess whether LA reverse remodeling occurs after successful catheter ablation. Fifty-seven consecutive patients (45 men; age 53 +/- 8 years) with symptomatic drug-refractory AF were treated with radiofrequency catheter ablation. The patients were divided into 2 groups on the basis of AF recurrence as determined by Holter monitoring and 12-lead electrocardiographic findings at 6 weeks and 3 months of follow-up (sinus rhythm [SR] group, no recurrence; AF group, AF recurrence). At baseline and 3 months of follow-up, 2-dimensional echocardiography was performed to assess LA size and dimensions. Furthermore, LA volumes were measured at end-systole and end-diastole. After 3 months, 39 of 57 patients (68%) maintained SR. At 3 months of follow-up, the LA anteroposterior diameter showed a significant reduction in the SR group (4.5+/- 0.3 vs 4.2 +/- 0.2 cm, p <0.01), and an additional increase was observed in the AF group (4.5+/- 0.3 vs 4.8 +/- 0.3 cm, p <0.05). Furthermore, the LA end-systolic and end-diastolic volumes decreased significantly in the SR group from baseline to follow-up (59 +/- 12 vs 50 +/- 11 ml, p <0.01, and 37 +/- 9 vs 31 +/- 7 ml, p <0.01, respectively). However, a tendency toward an increase in LA volumes was observed in the AF group. In conclusion, the results of this study have demonstrated that LA reverse remodeling occurs after successful radiofrequency catheter ablation for AF.

Atrial Fibrillation↗

PubMed2006

Histology of vascular myocardial wall of left atrial body after pulmonary venous incorporation.

During embryonic development, the common pulmonary vein (PV) becomes incorporated into the left atrium, giving rise to separate PV ostia. We describe the consequences of this incorporation process for the histology of the left atrium and the possible clinical implications. The histology of the left atrial (LA) wall in relation to PV incorporation was studied immunohistochemically in 16 human embryos and fetuses, 1 neonate, and 5 adults. The PV wall, surrounded by extrapericardially differentiated myocardial cells, was incorporated into the LA body. After incorporation, the composition of PVs and the smooth-walled LA body wall was histologically identical. The LA appendage, however, consisted of endocardial and myocardial layers without a vessel wall component. In 2 adults, the myocardium in the LA posterior wall was absent. At the transition of the LA body and LA appendage, a smooth-walled myocardial zone lacking the venous wall was observed. This zone was histologically identical to the sinus venarum of the right atrium. In conclusion, the LA body arises by incorporation and growth of PVs, presenting with a histologically identical structure of vessel wall covered by extrapericardially differentiated myocardium of PVs. Discontinuity of myocardium may be the substrate for arrhythmias, and absence of myocardium in some patients makes this area potentially vulnerable to damage inflicted by ablation strategies. A border zone between the LA body and LA appendage is hypothesized to be the left part of the embryonic sinus venosus.

Actins↗

PubMed2005

Noninvasive visualization of the cardiac venous system using multislice computed tomography.

OBJECTIVES: We sought to evaluate the value of multislice computed tomography (MSCT) to depict the cardiac venous anatomy. BACKGROUND: During cardiac resynchronisation therapy (CRT), left ventricular (LV) pacing is established by a pacemaker lead in a tributary of the coronary sinus (CS). Knowledge of the CS anatomy and variations may facilitate the implantation of LV leads. METHODS: The MSCT scans of 38 patients (34 men; age 60 +/- 12 years) were studied. Anatomical variants were divided in three groups, dependent on the continuity of the cardiac venous system at the crux cordis. The CS ostium and distances between the main tributaries were measured. RESULTS: The most frequently observed variant had a separate insertion of the CS and the small cardiac vein in the right atrium (24 patients [63%]). In 11 patients (29%), there was continuity of the anterior and posterior venous system at the crux cordis. In three patients (8%), the posterior interventricular vein (PIV) did not connect to the CS. The mean distance from the PIV to the posterior vein of the left ventricle (PVLV) was 42.4 +/- 18.1 mm, from the PVLV to the left marginal vein (LMV) 39.9 +/- 15.6 mm, and from the LMV to the anterior interventricular vein 45.4 +/- 15.3 mm. The diameter of the CS ostium was 12.6 +/- 3.6 mm in anteroposterior and 15.5 +/- 4.5 mm in the superoinferior direction (p < 0.01). CONCLUSIONS: The anatomy of the CS and its tributaries can be evaluated using MSCT. As substantial variation in anatomy was observed, pre-implantation knowledge of the venous anatomy may help to decide whether transvenous LV lead placement for CRT is feasible.

Aged↗

PubMed2005

Multislice computed tomography versus intracardiac echocardiography to evaluate the pulmonary veins before radiofrequency catheter ablation of atrial fibrillation: a head-to-head comparison.

OBJECTIVES: The purpose of this study was to perform a head-to-head comparison between multislice computed tomography (MSCT) and intracardiac echocardiography (ICE). BACKGROUND: Different imaging techniques have been used to visualize the pulmonary veins (PV) before radiofrequency ablation of atrial fibrillation. METHODS: The PV and their atrial insertion were evaluated in 42 patients (35 men, 49 +/- 9 years) admitted for ablation of PV ostia. Ostia were measured in two directions (anterior-posterior and superior-inferior) with MSCT. Two-dimensional (2-D) measurements of PV ostia were performed with ICE. Results were compared, considering MSCT as the gold standard. Venous ostium indexes were calculated by dividing MSCT measurements in the anterior-posterior direction and the superior-inferior direction. RESULTS: Common ostia of left PV were observed in 33 (79%) patients with MSCT and 31 (74%) patients with ICE. Common ostia of right PV were observed in 13 (31%) and 16 (38%) patients, respectively. Additional PV were observed in 13 (31%) patients with MSCT and in 7 (17%) patients with ICE. Ostial diameters by MSCT in the anterior-posterior direction were similar to 2-D measurements by ICE. By contrast, diameters by MSCT in the superior-inferior direction were significantly larger than 2-D diameters measured with ICE. Venous ostium indexes were 0.77 +/- 0.18 and 0.90 +/- 0.15 (p < 0.01) for left and right PV respectively, indicating an oval shape of particularly left PV ostia. CONCLUSIONS: Variation in PV anatomy is frequently observed with both techniques. The sensitivity for detection of additional branches is higher for MSCT. Results of measurements of PV ostia suggest an underestimation of ostial size by ICE. Three-dimensional imaging techniques, such as MSCT, are required to demonstrate an oval shape of PV ostia.

Adult↗

PubMed2005

Atrial fibrillation: multi-detector row CT of pulmonary vein anatomy prior to radiofrequency catheter ablation--initial experience.

PURPOSE: To evaluate multi-detector row computed tomographic (CT) depiction of pulmonary veins to provide a road map for radiofrequency catheter ablation. MATERIALS AND METHODS: For patients, institutional review board (IRB) approval was not required, and consent was obtained for treatment. Control subjects were part of an IRB-approved research protocol at the institution, in which they had consented to participate. Multi-detector row CT was performed in 23 patients (17 men, six women; mean age, 48 years +/- 11 [standard deviation]) with atrial fibrillation who were admitted for isolation of pulmonary veins by means of radiofrequency catheter ablation. Pulmonary vein anatomy was evaluated, and diameters of pulmonary vein ostia were measured. To determine the shape of ostia, a venous ostium index was calculated for all veins by dividing anterior-posterior measurements by superior-inferior measurements. Results were compared with those in a control group of 11 patients (eight men, three women; mean age, 56 years +/- 11) without atrial fibrillation. Images were evaluated by two observers in consensus. RESULTS: Pulmonary veins additional to the four main veins were found in seven (30%) of 23 patients. Common ostia of left and right pulmonary veins were detected in 19 (83%) and nine (39%) patients, respectively. Early branching occurred more often with right than with left veins (19 [83%] vs three [13%] cases, P <.05) in both patients and control subjects. Anterior-posterior diameter of ostia was 12.8 mm +/- 3.3 for left veins, 16.2 mm +/- 3.8 for right veins, and 18.8 mm +/- 7.7 and 28.7 mm +/- 5.1 for left and right common ostia, respectively. Ostia of right pulmonary veins were more round than were ostia of left pulmonary veins (venous ostium index in patients, 0.91 +/- 0.21 vs 0.75 +/- 0.17, P <.05; in control subjects, 0.93 +/- 0.12 vs 0.82 +/- 0.17, P <.05). The CT data were used to determine ablation strategy and guide catheters during radiofrequency ablation. CONCLUSION: Multi-detector row CT provides a valuable road map for pulmonary vein anatomy prior to radiofrequency catheter ablation. Variations in number and insertion of pulmonary veins were observed in a considerable number of patients and control subjects.

Adult↗

PubMed2005

Fusion of multislice computed tomography imaging with three-dimensional electroanatomic mapping to guide radiofrequency catheter ablation procedures.

BACKGROUND: The outcome of catheter ablation procedures of cardiac arrhythmias depends on the ability to evaluate the underlying mechanism and to depict target sites for ablation. Fusion of different imaging modalities within one system may improve electroanatomic modeling and facilitate ablation procedures. OBJECTIVES: The purpose of this study was to study the feasibility of fusion of multislice computed tomography (MSCT) with electroanatomic mapping to guide radiofrequency catheter ablation of atrial arrhythmias. METHODS: Sixteen patients (15 men, age 54 +/- 7 years) with drug-refractory atrial fibrillation (AF) underwent 64-slice MSCT within 2 days before radiofrequency catheter ablation. MSCT data were imported to the Carto electroanatomic mapping system. Using the new CartoMerge Image Integration Module, the MSCT images and the electroanatomic map were aligned. A statistical algorithm provided information about the accuracy of the fusion process. RESULTS: In all patients, MSCT images could be fused with the electroanatomic map. Mean distance between the mapping points and the MSCT surface ranged from 1.7 +/- 1.2 mm to 2.8 +/- 1.8 mm. This resulted in an average of 2.1 +/- 0.2 mm for the patient group as a whole. CONCLUSION: MSCT images can be fused with the three-dimensional electroanatomic mapping system in an accurate manner. Anatomy-based catheter ablation procedures for atrial arrhythmias may be facilitated by integration of different imaging modalities.

Atrial Fibrillation↗

PubMed2004

Left atrial tachycardia originating from the mitral annulus-aorta junction.

BACKGROUND: At the mitral annulus-aorta (MA-Ao) junction, the left atrium is continuous through the subaortic curtain with the musculature of the anterior mitral leaflet. Under experimental conditions, this region can generate abnormal electrical activity. In patients with left atrial tachycardia, we investigated whether this region could be the source of this arrhythmia. METHODS AND RESULTS: In 10 (28%) of 35 consecutive patients with left atrial tachycardia, the arrhythmia originated from the MA-Ao junction. Sustained, self-limited episodes of atrial tachycardia (cycle length, 340+/-56 ms; duration, 125+/-69 seconds) were repeatedly induced. Prematurity of the extrastimulus and time to first atrial tachycardia complex were directly correlated (R=0.66; P<0.001). During tachycardia, bipolar electrograms at the earliest site preceded onset of the P wave by 44+/-14 ms and were of longer duration and lower amplitude than those recorded from nearby left atrial sites (52+/-8 versus 24+/-4 ms, P<0.001; and 0.53+/-0.08 versus 3.45+/-0.96 mV, respectively; P<0.001). Ablation eliminated the tachycardia with no recurrence after a mean follow-up of 24+/-19 months. A comparative study in mouse embryos demonstrated the presence of the developing specialized conduction system in the MA-Ao region starting at embryonic age 11.5. CONCLUSIONS: The MA-Ao junction can be a frequent source of left atrial tachycardia. This previously unrecognized site of origin may explain why catheter ablation has been less successful in eliminating left versus right atrial tachycardias. Remnants of the developing specialized conduction system could be the underlying substrate of this arrhythmia.

Adrenergic beta-Agonists↗

PubMed2004

The neural crest is contiguous with the cardiac conduction system in the mouse embryo: a role in induction?

In this study we present data on the spatial relationship between neural crest-derived cells (NCC) and the specialized cardiac conduction system (CCS) in the developing murine heart. Using Wnt1-Cre/R26R conditional reporter mice that express beta-galactosidase from ROSA26 upon Cre-mediated recombination, two populations of NCC are seen: one migrates through the arterial pole and contributes to the bundle branches, whereas the second population enters by way of the venous pole and provides cells to the sinoatrial and atrioventricular node areas. The CCS/ lacZ construct is found in the myocardium of the early embryonic heart and afterward only persists in the definitive CCS and is acknowledged as a reporter for the developing conduction system. The contiguous expression of both reporters is suggestive for a potential role of cardiac NCC in the induction of the final differentiation of the CCS.

Animals↗

PubMed2004

Anatomical observations of the pulmonary veins with intracardiac echocardiography and hemodynamic consequences of narrowing of pulmonary vein ostial diameters after radiofrequency catheter ablation of atrial fibrillation.

Intracardiac echocardiography was used to explore pulmonary venous (PV) anatomy and to monitor PV stenosis in 31 patients referred for radiofrequency catheter ablation at PV ostia. Interindividual variations in PV anatomy and insertion in the left atrium were observed. Narrowing of PV ostia after radiofrequency catheter ablation did not produce significant hemodynamic changes.

Adult↗

PubMed2004

Embryonic conduction tissue: a spatial correlation with adult arrhythmogenic areas.

INTRODUCTION: The occurrence of arrhythmias in adult patients may arise preferentially in anatomic regions derived from the specialized cardiac conduction system. To examine this hypothesis, we performed a detailed analysis of the developing cardiac conduction system using the recently described CCS-lacZ transgenic mouse strain. METHODS AND RESULTS: Transgenic embryos (E9.5-15.5) were stained for beta-galactosidase activity and co-stained with the myocardial marker HHF35. Results were reconstructed three dimensionally. CCS-lacZ expression was observed in the sinoatrial node, left and right venous valves, septum spurium, right and left atrioventricular ring, His bundle, bundle branches, and right ventricular moderator band. Furthermore, lacZ-positive cells could be demonstrated for the first time in the left atrium, in the posterior wall surrounding the pulmonary venous orifice. and, in later stages, surrounding the pulmonary venous wall. These cells were continuous with the left venous valve in the right atrium. LacZ-positive tissue also could be identified in Bachmann's bundle, running retro-aortically between the right atrium and left atrium. CONCLUSION: Known arrhythmogenic areas including Bachmann's bundle, the pulmonary veins, and sinus venosus derived internodal structures, demonstrate lacZ expression. These data support the hypothesis that areas derived from the developing cardiac conduction system may contribute to the arrhythmogenic substrate in adult hearts.

Animals↗