Amiodarone in pregnancy. Case report and review of the literature.

A case of the use of amiodarone in pregnancy is reported and the literature on this subject reviewed. The data available to date show: there is no risk of teratogenic effects, the QT interval is prolonged during infancy (no associated arrhythmias noted), infant bradycardia occurs and should be monitored and thyroid function can be affected and should be monitored at birth. If fetal electrocardiographic monitoring is performed before and during labour and after birth, and thyroid function is assessed, then, to date, there does not appear to be any significant contraindication to the use of amiodarone during pregnancy. In view of the potential side effects, however, the use of amiodarone should be restricted to arrhythmias which are life-threatening or not controlled by conventional therapy.

Detection of coronary artery bypass graft patency as assessed by magnetic resonance imaging.

In a study of 22 patients with 60 coronary artery bypass grafts, magnetic resonance imaging (MRI) correctly assessed graft patency or occlusion in 90% of cases when compared with selective coronary graft angiography and computed tomography. It is concluded that MRI can detect a normally functioning coronary artery bypass graft and could be used as a non-invasive technique to assess graft patency in patients presenting with post-operative angina.

A comparison of angiographic and electrocardiographically gated computed tomographic measurements of left-ventricular function.

Fifty patients with ischaemic heart disease have been studied by electrocardiographically gated computed tomography (CT) and left-ventricular angiography to assess the accuracy of the former in the measurement of left-ventricular volumes and ejection fraction. There was no significant difference in the measurements of end-diastolic volume (p = 0.9, r = 0.81). Computed tomography significantly overestimated end-systolic volume (p less than 0.001, r = 0.89) and significantly underestimated ejection fraction (p less than 0.001, r = 0.74). Although there is some variation between the two sets of measurements, the correlation between the two techniques is good, indicating that electrocardiographically gated CT could be a useful noninvasive technique for assessing left-ventricular function.

Massive right atrial thrombus associated with a Chiari network and a Hickman catheter.

The Chiari network is an embryologic remnant that is said to be present in only 1.5-3% of adults. It is rarely of clinical importance but may, very infrequently, be the site of thrombosis. The authors describe a patient in whom a massive right atrial thrombus formed on a Chiari network, leading to intermittent tricuspid obstruction. The thrombus had formed after the use of a Hickman catheter for the administration of cytotoxic chemotherapy. They can find no previously recorded examples of sufficient thrombus forming on a Chiari network to threaten life by obstructing the flow of blood through the heart.

Identification of intracardiac thrombus: comparison of computed tomography and cross-sectional echocardiography.

Thirty-eight patients with conditions predisposing to intracardiac thrombus have been studied by computed tomography and cross-sectional echocardiography. Computed tomography identified 22 cases of intracardiac thrombus (13 left ventricular, eight left atrial and one right atrial). Cross-sectional echocardiography identified five of these left ventricular thrombi and the right atrial thrombus, but none of the left atrial thrombi. In addition, measurements of thrombus density on computed tomography identified a significant difference (p less than 0.02) between the density of a new compared with an organized thrombus.

Radiation doses and somatic risk to patients during cardiac radiological procedures.

The radiation dose to a series of adult and paediatric patients undergoing cardiac catheterisations and adults having percutaneous transluminal coronary angioplasty has been measured/determined directly using lithium fluoride thermoluminescent dosemeters and indirectly using an air ionisation chamber which indicated exposure-area product. Somatic and genetic risks are estimated from the dosimetry results. It is suggested that the magnitude of the radiation hazard is negligible compared with other clinical hazards associated with these procedures.

Magnetic resonance (MR) cine imaging of the human heart.

A novel approach has been developed for MR cine imaging of the human heart by a modified ECG-gated 2DFT method. A pulse sequence has been devised to minimise the effects of saturation which can be anticipated in sequences that require rapid pulsing. Five frames are produced at the same anatomical level at predetermined intervals during the cardiac cycle. The total time taken to achieve this data is 8 minutes. Additional frames can be interleaved by repeating the sequence with an ECG-gated delay. The anatomical sections, which can be in any orthogonal plane, are then displayed as a cine loop. Cine display in the coronal plane has been used to examine 10 volunteers and 12 patients. In addition to the morphological feature displayed in single slice ECG-gated imaging, areas of dyskinesia can be detected and subjective estimates have been made of left ventricular function.

An investigation of the radiation dose to staff during cardiac radiological studies.

Measurements of radiation distributions in the vicinity of the couch were undertaken for a number of projections commonly employed during cardiac radiological studies. Three types of investigations were considered; cardiac catheterisations, pacemaker implants and percutaneous transluminal coronary angioplasties. The radiation dose to staff involved in these procedures was estimated. For each group of staff, the maximum annual workload and the workload which would necessitate an individual becoming a classified radiation worker may be deduced from an expression given in the text.