[Coronary CTA evaluation of the relationship between mitral valve annulus and coronary circulation: implications for percutaneous mitral annuloplasty]. / Etude de la relation entre l'anneau mitral et la circulation coronaire dans l'insuffisance mitrale par scanner cardiaque: implications dans l'annuloplastie mitrale percutanée.

PURPOSE: To evaluate anatomical relationships between mitral annulus (MA), coronary arteries and coronary sinus (CS) in two groups of patients with and without moderate mitral insufficiency on coronary CTA to identify candidates to percutaneous mitral valve annuloplasty via the coronary sinus without risk of coronary artery occlusion. MATERIALS AND METHODS. Fifty-one ECG-gated coronary CTA examinations, obtained during injection of iodinated contrast material on a 16 MDCT were retrospectively reviewed. The mitral valve annulus diameter, anatomical relationships between CS and coronary arteries and MA-CS distance were compared between both patient groups. RESULTS: The group with mitral insufficiency included 16 patients and the control group included 35 patients. The AP diameter of the MA was 45,7+/-5,2 mm in the group with mitral insufficiency, significantly larger (p=0.0009) compared to the control group (39,3+/-5,9 mm). In 70.4% of cases, the CS was located next to a coronary artery in an overlapping configuration. The unfavorable anatomical configuration with regards to annuloplasty appeared related to mitral insufficiency (p=0.0539). The distance between MA and CS was greatly variable with the CS routinely extending over the left atrial surface: the distance was significantly (p=0.0002) greater for all patients along the posterior surface (8,1+/-3,8 mm) compared to the lateral surface (5,2+/-4,6 mm) with this différence persisting within both groups: p=0.004 for patients with mitral insufficiency and p=0.0001 for control patients. CONCLUSION: Our results demonstrate the value of coronary CTA in selecting candidates to percutaneous mitral annuloplasty. In 70.4% of cases, the CS overlaps a coronary artery with risk of compression at the time of annuloplasty.

[An evaluation of the effectiveness of applying 16-slice computed tomography (CT) to coronary arteries in preoperative aortic valve replacement]. / Evaluation du scanner 16 coupes des artères coronaires dans le bilan préopératoire du rétrécissement valvulaire aortique.

UNLABELLED: An evaluation of the effectiveness of applying 16-slice Computed Tomography (CT) to coronary arteries in preoperative aortic valve replacement. PURPOSE: To evaluate the effectiveness of using 16-slice CT to diagnose a significant stenosis in coronary arteries in patients with severe aortic valve stenosis. MATERIAL AND METHODS: 50 patients were included in the study. After a medium contrast injection, CT images of the arteries were taken using 0.75 mm slices. We paired the images with an ECG. Segments smaller than 1.5 mm were discarded, and the results were compared to those from the coronary angiography. RESULTS: A satisfactory visualization of the coronary network was obtained for 80% (40/50) of the patients. For these 40 patients, 23 of the 29 patients without coronary stenosis were correctly classified but 4 of the 11 patients with coronary lesions were not recognized. The sensitivity of the multi-slice CT in detecting a least one significant coronary stenosis is 63.6%, the specificity 79.3%, positive predictive value 53.8% and negative predictive value 85.2%. CONCLUSION: the 16-slice CT is a relatively effective and minimally invasive tool to highlight before valve replacement significant coronary stenosis in arteries greater than 1.5 mm in diameter in patients with severe aortic valvular stenosis. CT technology is currently insufficient for diagnosis, but we hope that with advances in multi-slice CT engineering, its use will help patients avoid invasive coronary angiographies.

[A rare cause of myocardial infarction: papillary fibroelastoma of the aortic valve]. / Cause rare d'infarctus du myocarde: le fibro-élastome papillaire de la valve aortique.

Papillary fibroelastoma is a rare, benign endocardial tumour usually located on the cardiac valves. Before echocardiography, these tumours were chance findings either at surgery or at autopsy. With the advent of echocardiography, the diagnosis has become commoner and they are often the cause of systemic embolism justifying surgical ablation. In this case, an aortic valve papillary fibroelastoma presented with myocardial infarction in a 78 year old woman with normal coronary angiography. The diagnosis was strongly suspected at echocardiography and confirmed by histological analysis of the surgically excised tumour.

Transgenic mice overexpressing human KvLQT1 dominant-negative isoform. Part II: Pharmacological profile.

OBJECTIVE: The acquired long QT syndrome results most often from the action of I(Kr) blocking-drugs on cardiac repolarization. We have evaluated a transgenic (TG) mouse (FVB) overexpressing a dominant-negative KvLQT1 isoform, as an in vivo screening model for I(Kr) blocking drugs. RESULTS: In TG mice, six-lead ECGs demonstrated sinus bradycardia, atrioventricular block, and QTc prolongation. Various drugs were injected intraperitoneally after blockade of the autonomic nervous system and serial ECGs were recorded. The end of the initial rapid phase of the T wave corrected for heart rate using a formula for mouse heart (QTrc), was used as a surrogate for the QT interval. Dofetilide, a specific I(Kr) blocker, did not prolong the QTrc interval either in TG or in wild-type (WT) mice but dose-dependently lengthened the sinus period in TG mice but not in WT mice. Other I(Kr) blockers including E 4031, haloperidol, sultopride, astemizole, cisapride and terikalant behaved similarly to dofetilide. Tedisamil, a blocker of the transient outward current, dose-dependently prolonged the QTrc in WT mice but not in TG mice and also reduced the sinus rhythm in both WT and TG mice. Lidocaine dose-dependently shortened the QTrc interval in TG mice and also lengthened the P wave duration. Nicardipine dose-dependently shortened QTrc and also produced sinus arrest in both WT and TG mice. CONCLUSIONS: We conclude that KvLQT1-invalidated TG mice discriminates in vivo drugs that blocks I(Kr) from drugs that block the transient outward current, the sodium current or the calcium current.