Abstract: A probe having a temperature sensor on its distal portion is introduced into a fluid-filled body cavity of a subject, and an irrigating fluid passed through the probe. The temperature of the irrigating fluid exiting the probe differs from the temperature of the body cavity. Temperature readings of the irrigating fluid exiting the probe are recorded. A determination is made from the temperature readings that predetermined contact criteria between the probe and the interior wall of the body cavity are satisfied.

Abstract: Apparatus, consisting of a catheter having a distal end and a predefined outer diameter. The apparatus also has a plurality of elastic filaments, each filament having at least one electrode fixed thereto and having two ends fixed within the catheter distal end to hold the filament as a loop. The loop intertwines with one or more other loops of the other filaments so that the plurality of the filaments forms an open lattice, which expands when uncompressed to a lattice diameter at least 5 times greater than the outer diameter of the catheter.

Abstract: A bipolar electrogram and a unipolar electrogram are recorded from electrodes of a probe, and differentiated with respect to time. Peaks are identified in the differentiated bipolar electrogram. An activity window is defined that includes bipolar activity about the peaks. An extreme negative value in the differentiated unipolar electrogram within the activity window is reported as a unipolar activation onset. In one aspect, an annotation is selected from candidate minima in the differentiated unipolar electrogram within the activity window by excluding candidates that fail to correlate with activity in the bipolar electrogram.

Abstract: A bipolar electrogram and a unipolar electrogram are recorded from electrodes of a probe, and differentiated with respect to time. Peaks are identified in the differentiated bipolar electrogram. An activity window is defined that includes bipolar activity about the peaks. An extreme negative value in the differentiated unipolar electrogram within the activity window is reported as a unipolar activation onset. In one aspect, an annotation is selected from candidate minima in the differentiated unipolar electrogram within the activity window by excluding candidates that fail to correlate with activity in the bipolar electrogram.