Provisional stenting for symptomatic intracranial stenosis using a multidisciplinary approach: acute results, unexpected benefit, and one-year outcome.

Percutaneous techniques have dramatically changed our approach to coronary and peripheral revascularization. Intracranial atherosclerosis is a highly morbid disease; however, techniques for revascularization are still in evolution. The authors comprise a multidisciplinary team of neurologists, neuroradiologists, and interventional cardiologists who have collaborated in treating fifteen patients with symptomatic intracranial stenosis who have failed medical therapy. The acute success rate (100%) and one-year freedom from death and stroke (93.4%) using balloon angioplasty and provisional stenting are encouraging. A surprising observation in this patient cohort was that 53% of patients had improvement or resolution of a deficit that was chronic and presumed to be permanent and irreversible. This type of chronic but reversible deficit is termed "brain angina". The background, rationale for a multidisciplinary team, techniques, and preliminary results of intracranial angioplasty with provisional stenting are presented.

Intermittent parasystole with exit block.

A 53-year-old patient had a complex ventricular arrhythmia, which most likely was an intermittent pure (nonmodulated) parasystole, due to protection limited to the first part of the cycle coexisting with exit block. However, other interpretations of the observations were possible. Foremost among these was modulated parasystole with partial protection or with an attenuated or nondetectable early delaying phase, with exit block. Interestingly, the parasystole appeared to have fulfilled the dynamic rules regarding the number of sinus beats interposed between manifest parasystolic beats, as has been reported for pure or weakly modulated parasystole. This case corroborates unusual manifestations of an arrhythmia, which because of its newly found complexities and various possible interpretations seems to be discussed with decreasing frequency in most textbooks on general cardiology.

Saphenous vein graft aneurysm presenting as a large mediastinal mass compressing the right atrium.

A patient with a large saphenous vein graft aneurysm is described. This case illustrates the role of magnetic resonance imaging and cardiac catheterization in patients with a mediastinal mass and history of coronary bypass surgery.

High-frequency ultrasound: determination of the lowest frequency required for cellular imaging and detection of myocardial disease.

We have previously demonstrated that a 600 MHz transducer enables the visualization of cellular detail in specimens of myocardium. However, lower-frequency transducers are more practical and provide better tissue penetration for possible in vivo application of this technique. This study was designed to ascertain the lowest frequency at which cellular detail can be imaged. We performed ultrasound imaging of 5 microns sections of 14 samples of myocardium. Each specimen was examined serially with 600 MHz, 400 MHz, 200 MHz, and 100 MHz transducers. Normal cardiac myocytes and pathologic phenomena such as fibrosis, cell fallout, and round cell infiltration were clearly identified with a 600 MHz transducer. Although there was a slight decrease in resolution, normal and pathologic phenomena were also identified with 400 and 200 MHz transducers. However, cellular detail could not be adequately identified with a 100 MHz transducer. In conclusion, transducer frequencies of 600 to 200 MHz enable visualization of cell detail and detection of pathologic changes in the myocardium. A transducer frequency of at least 200 MHz is probably required for possible in vivo application of this technique.