Pregnancy and prosthetic heart valves: a French cooperative retrospective study of 155 cases

A French cooperative retrospective study analysed 155 pregnanciesin 103 women with prosthetic heart valves: 95 mechanical prosthesis(MP) and 60 bioprostheses (BP). Among them 13 MP and 10 BP werebivalvular and four were mixed implants. In all, 182 (108 MPand 74 BP) prostheses were exposed to the risk of pregnancy.Among the 108 MP-bearing patients, 16 thromboembolic accidents(TEA) were recorded: 10 thromboses in 13 mitral, two aorticand one pulmonary MP. TEA were four times more frequent underoral anticoagulant therapy. Among the 74 BP, seven sufferedpremature valve failure. Ninety-nine infants were born to 50MP-bearing women (53%) and 48 BP-bearing patients (80%) (P<0.001).Twenty miscarriages were reported; they occurred more oftenunder anticoagulant treatment (17%) than without it (4%) P<0.02).Coumarin-induced embryopathies were rare (only one definitivelyidentified). Because pregnancy with an MP under anticoagulanttherapy is dangerous for the mother and may effect the fetus,the therapeutic indications for women of child-bearing age mustbe taken into consideration. In a women already with an MP atthe time of conception, the duration of heparin therapy shouldbe limited to the following two periods: from the 6th to the12th week (coumarin-induced embryopathies) and during the last2 weeks of gestation (haemorrhages during delivery and the neonatalperiod).     

Far-Field R Wave Oversensing in a Dual Chamber Arrhythmia Management Device: Predisposing Factors and Practical Implications

WERETKA, S., et al. : Far-Field R Wave Oversensing in a Dual Chamber Arrhythmia Management Device: Predisposing Factors and Practical Implications. Initial experience with the Medtronic Jewel 7250, the ICD designed to detect and treat ventricular and supraventricular tachyarrhythmias, is very promising. Its effectiveness, however, depends on sensing performance, which has not yet been systematically examined. The aim of the study was to determine the incidence of, predisposing factors for, and practical implications of far-field R wave oversensing (FFRWOS) in this dual chamber ICD. During a total follow-up of 797 months in 48 patients who had the Jewel 7250, follow-up strip charts, 12-channel Holter recordings and, in particular cases, Holter recordings with intracardiac markers were analyzed for the presence of FFRWOS. FFRWOS was documented in ten (21.3%) patients. Compared to other lead locations, the right atrial appendage lead position was most frequently associated with FFRWOS (  7/27 vs 3/21, P < 0.05  ). Patients with FFRWOS had significantly more treated and nontreated atrial episodes, many of which were judged to have been detected inappropriately. In one case, inappropriate atrial antitachycardia pacing due to R wave oversensing triggered sustained ventricular tachycardia, terminated eventually with a high energy shock. In dual chamber ICDs, FFRWOS may represent a frequent phenomenon possibly leading to serious consequences. For atrial leads, a lateral atrial wall position seems to be preferable. In most cases, FFRWOS can be eliminated by optimization of atrial sensing parameters. Given the possibility of ventricular proarrhythmia with atrial pacing therapy, the capability of ventricular backup defibrillation in respective devices is at least reassuring.