A medical device includes an insertion shaft, having a longitudinal axis and having a distal end adapted for insertion into a body of a patient. A resilient end section is fixed to the distal end of the insertion shaft and is formed so as to define an arc oriented obliquely relative to the axis and having a center of curvature on the axis. One or more electrodes are disposed along the end section. An ultrasound transducer is fixed to the distal end and is configured to image a vicinity of the arc using ultrasound waves.
