A system for ablating internal heart tissue in an ablation pattern on a surface of the tissue within the heart. The system includes an ablation catheter with a distal end having an ablating tip portion operative to allow selective ablation of tissue. A guiding device is engageable with the ablation catheter and includes a tissue anchoring portion operable to engage with tissue proximate to the tissue to be ablated so as to temporarily anchor the guiding device relative to the tissue. Engagement of the guiding device with the ablation catheter operates to assist with guiding the ablating tip portion in moving along the pattern. Various devices and methods of use are further disclosed.