Apparatus and method for ablating cardiac tissue

Apparatus for ablation of cardiac tissue in the myocardium of the heart comprising:

• an ultrasound transducer having a plurality of elements;
• and
• control means for:
• (a) moving said ultrasound transducer to selected positions along a scan path in a region of the myocardium having aberrant electrical pathways at which a plurality of lesions are to be created, and
• (b) energizing said elements of said ultrasound transducer in timed sequences at selected times and for selected periods of time to:
• (1) transmit a focused ultrasound beam to create a plurality of lesions that merge to form a linear lesion in a plane containing the locus of said ultrasound transducer while said ultrasound transducer is at the selected positions along the scan path, and
• (2) scan the focused ultrasound beam along the scan path to create a plurality of lesions that merge to form a plurality of linear lesions in the myocardium in a plane containing the locus of said ultrasound transducer while said ultrasound transducer is at the selected positions along the scan path.

A method for ablation of cardiac tissue in the myocardium of the heart comprising the steps of:

• identifying a region of the myocardium that contains aberrant electrical pathways;
• defining a scanning path that extends along a surface of the myocardium and in which a plurality of lesions are to be created;
• developing a focused ultrasound beam;
• directing the focused ultrasound beam to the scanning path and scanning the focused ultrasound beam along the scanning path while the source of the ultrasound beam is at a first position on the scanning path to create pluralities of lesions that merge to form a first plurality of linear lesions in the myocardium that extend along the scanning path;
• and
• directing the focused ultrasound beam to the scanning path and scanning the focused ultrasound beam along the scanning path while the source of the ultrasound beam is at a second position on the scanning path to create pluralities of lesions that merge to form a second plurality of linear lesions in the myocardium that extend along the scanning path and overlap the first plurality of linear lesions.