Heart beat is performed when a muscle of cardiac organ is stimulated in consecutive order by an electric signal generated periodically from a portion of cardiac organ. However, if there is something wrong with the electric signal flow, a correct heart beat cannot be carried out. This is so-called cardiac arrhythmia.
Fibrillation of heart is the most common continuous arrhythmia and may increase heart rate up to 100 to 175 per minute or more. Fibrillation of heart may cause the frequency of symptom (e.g., atrial flutter, not normal contraction) to be high and may be linked to various aftereffects such as stroke, blood pooling, blood clot, etc.
Treatment of cardiac arrhythmia was quite changed after the introduction of a catheter ablation using high-frequency current. In the catheter ablation technique, under the X-ray control, an ablation-catheter is inserted into the cardiac organ and the tissue causing arrhythmia is destroyed by high-frequency current. Prerequisite for the success of catheter ablation is to detect the cause of arrhythmia in an atrium accurately. The detection is carried out through an electrophysiological test in which recording is performed in a spatial resolution state, using a mapping-catheter in which electrical potentials are inserted into the atrium.
Various minimum invasion electrophysiological procedures use a catheter which arranges at least one electrode near the target tissue region in the cardiac organ. Such a catheter has a relatively long and flexible axis and has an ablation electrode on the end of the catheter. The proximal end of the catheter is connected to a hand portion which may comprise or may not comprise a steering controller for operating the end portion of the catheter.
However, in a conventional catheter as described in KR laid-open publication No. 10-2007-0027494, an ablation electrode to which high current is applied is disposed on the end of the distal portion of the catheter and a mapping electrode which performs a mapping on a lesion is disposed above the electrode to which high current is applied. In case of removing the lesion which is located deep in the cardiac organ, the ablation electrode is in point-contact with the lesion to remove the lesion. However, due to the heart beat, it is difficult to adjust the position of the catheter stably so as to make the ablation electrode contact with the lesion precisely. Here, the term “point contact” means a portion where the end of the ablation electrode is in contact with the lesion.
That is, a portion of the ablation electrode to which high current is applied must be in contact with the lesion in order to remove the lesion. In a configuration that the ablation electrode is arranged on the end of the distal portion, the end of the ablation electrode is in contact with the lesion in the form of cusp. In the description, for clarity's sake, the portion where the end of the ablation electrode is in contact with the lesion will be referred to as “point-contact”.
Meanwhile, in case that a plurality of monitoring electrodes for detecting lesion region are attached on the distal end, as can be seen in KR Patent 10-0949436, a catheter is not provided with ablation electrodes and therefore it is difficult of a catheter having a plurality of monitoring electrodes to perform both a mapping and an ablation.