In order to control real-time sampling and achieve smooth scroll wave in the epicardial mapping system, which has 128 channels and a sampling rate of 2kHz/channel, we have designed a user interface using Direct-Draw in cooperation with multiple-thread technology and extracting method. This method has proven to be feasible in animal experiment.
Algorithms ; Animals ; Artificial Intelligence ; Body Surface Potential Mapping ; methods ; Electrophysiologic Techniques, Cardiac ; instrumentation ; methods ; Pericardium ; physiology ; Signal Processing, Computer-Assisted ; instrumentation ; Software

BACKGROUNDSubstrate modification guided by CARTO system has been introduced to facilitate linear ablation of ventricular tachycardia (VT) after myocardial infarction (MI). However, there is no commonly accepted standard approach available for drawing these ablation lines. Therefore, the aim of the present study was to practically refine this time consuming procedure.

METHODSSubstrate modification was performed in 23 consecutive patients with frequent VTs after MI using the CARTO system. The initial target site (ITS) for ablation was identified by pace mapping (PM) during sinus rhythm and/or entrainment pacing (EM) during VT. According to the initial target site, two approaches were used. The initial target site in approach one has a similar QRS morphology as VT and an interval from the stimulus to the onset of QRS complex (S-QRS) of = 50 ms during PM in sinus rhythm or a difference of the post pacing interval and VT cycle length = 30 ms during concealed entrainment pacing of VT; The initial target site in approach two has an similar QRS morphology as VT and an S-QRS of < 50 ms during PM in sinus rhythm.

RESULTSOverall, 50 lines were performed with a length of (35 +/- 11) mm. Procedure time averaged (232 +/- 56) minutes, fluoroscopy time (10 +/- 8) minutes. Sixteen patients were initially involved into approach one. After completion of 3 +/- 1 ablation lines, no further VT was inducible in 13 patients. The remaining 3 patients were switched to use the alternative approach. However, in none of them the alternative approaches were successful. Approach two was initially used in 7 patients. After completion of 3 +/- 1 ablation lines, no further VT was inducible in only 2 patients. The remaining 5 patients were switched to approach one, which resulted in noninducibility of VT in 4 of them. The initial successful rate was significantly higher in the group of approach one compared to that in the group of approach two (13/16 patients vs 2/7 patients, P = 0.026).

CONCLUSIONSThe approach for substrate modification of VT after MI can be optimized by identifying the appropriate initial target site with specific characteristics within the zone of slow conduction. The refined approach may facilitate linear ablation of VT, and further reduce the procedure and fluoroscopy time.

Aged ; Body Surface Potential Mapping ; instrumentation ; methods ; Catheter Ablation ; methods ; Electrocardiography ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; complications ; Surgery, Computer-Assisted ; methods ; Tachycardia, Ventricular ; physiopathology ; surgery

Using 49 capacitive-coupled electrodes, mattress-type harness was developed to obtain posterior body surface potential map (P-BSPM) in dressed individuals. The aim of this study was to investigate how valuable information P-BSPM could provide, especially in discrimination of old myocardial infarction (OMI). P-BSPM of 59 individuals were analyzed; 23 normal control, 11 right bundle branch block (RBBB), 3 left bundle branch block (LBBB) and 19 OMI patients. Principal component analysis and linear hyper-plane approach were used to evaluate diagnostic performance. The axes of P-BSPM vector potential corresponded well with 12-lead electrocardiogram. During QRS, the end point of P-BSPM vector potential demonstrated characteristic clockwise rotation in RBBB, and counterclockwise rotation in LBBB patients. In OMI, initial negativity on P-BSPM during QRS was more frequently located at lower half, and also stronger in patients with inferior myocardial infarction (MI). The area under the receiver-operating characteristic curve of P-BSPM during QRS in diagnosing overall OMI, anterior MI, and inferior MI was 0.83 (95% confidence interval, 0.70-0.97), 0.71 (0.47-0.94), and 0.98 (0.94-1.0), respectively (P = 0.022 for anterior vs inferior MI groups). In conclusion, the novel P-BSPM provides detailed information for cardiac electrical dynamics and is applicable to diagnosing OMI, especially inferior myocardial infarction.
Adult ; Aged ; Area Under Curve ; Body Surface Potential Mapping/instrumentation/*methods ; Bundle-Branch Block/diagnosis ; Electrocardiography ; Electrodes ; Humans ; Male ; Middle Aged ; Myocardial Infarction/diagnosis ; Principal Component Analysis ; ROC Curve