[Intravascular ultrasound findings in calcifying arteriosclerosis: in vitro validation using "soft" roentgen images].

Aim: The aim of this study was to validate the detection of calcified arteriosclerotic plaques with intravascular ultrasound (IVUS).

Method: 181 arteries were examined by 20/30 MHz IVUS. The ultrasound cross-sections were compared to the corresponding radiologic (30 kV) and histologic cross-sections.

Aerobic capacity in rate modulated pacing.

Whether heart rate or AV synchrony is the most important factor for an increase in aerobic capacity was evaluated in a comparative study between sinus bradycardia, VVIR, DDD, and DDDR stimulation. Sixteen patients (mean age 67 years) with chronotropic incompetence and implanted DDDR pacemaker (Telectronics META 1250) were randomly studied by cardiopulmonary exercise testing. All patients were exercised to their anaerobic threshold (AT) with the following heart rates: DDD 84 +/- 3, VVIR 110 +/- 5, and DDDR 116 +/- 6 beats/min.