Maze operation could alter P wave morphology in electrocardiogram (ECG), which might prevent exact diagnosis of the cardiac rhythm of patients. However, characteristics of P wave in patients with sinus rhythm after the operation have not been elucidated systematically. Consecutive patients who underwent the modified Cox Maze operation from January to December 2007 were enrolled. The standard 12-lead ECG and echocardiography were evaluated in patients who had sinus rhythm at 6 months after the operation. The average axis of P wave was 65+/-30 degrees. The average amplitude of P wave was less than 0.1 mV in all 12-leads, with highest amplitude in V1. The most common morphology of P wave was monophasic with positive polarity (49%), except aVR lead, which was different from those in patients with enlarged left atrium, characterized by large P-terminal force in the lead V1. There were no significant differences in P-wave characteristics and echocardiographic parameters between patients with LA activity (30.6%) versus without LA activity (69.4%) at 6 months after the operation. In conclusion, the morphology of P wave in patients after Maze operation shows loss of typical ECG pattern of P mitrale: P wave morphology is small in amplitude, monophasic and with positive polarity.
Atrial Fibrillation/*physiopathology/*surgery ; Cardiovascular Surgical Procedures/*methods ; Electrocardiography/*methods ; Female ; Heart Conduction System/*physiopathology/*surgery ; *Heart Rate ; Humans ; Male ; Middle Aged ; Treatment Outcome

Polarity reversal mapping for localization of the left free wall accessory pathway (AP) at the atrial insertion site has been shown to be effective for successful ablation, but this technique requires atrial septal puncture. We evaluated the safety, efficacy, and reproducibility of two dimensional polarity reversal mapping at the ventricular insertion site of the accessory pathway without atrial septal puncture in symptomatic patients with manifested left free wall AP. Polarity reversal mapping under the mitral annulus by transaortic approach was performed in 10 consecutive patients with conventional ablation catheter (6 French, 4 mm tip, 2 mm interelectrode distance), during sinus rhythm or atrial pacing. A low set high, bandpass filter (0.005-400Hz) was used. Radiofrequency (RF) ablation was performed at the site of ventricular electrocardiogram polarity reversal during sinus rhythm. Polarity reversal was identified in all patients at the ventricular side of the mitral annulus. Ablation was successful in all patients without complications. The procedure time was 86.0 +/- 21.1 min, the fluoroscopic exposure time was 16 +/- 12 min, the number of RF applications was 8 +/- 6, the power level 21 +/- 7 watts, and the time to initial AP block was 3.0 +/- 0.9 sec. Polarity reversal mapping is a safe and efficient technique at the ventricular insertion site. This technique might be complementary to the currently-utilized activation mapping technique.
Adult ; Catheter Ablation/methods* ; Electrocardiography ; Electrodiagnosis* ; Female ; Heart Conduction System/physiopathology ; Human ; Male ; Middle Age ; Radiography, Thoracic ; Tachycardia, Supraventricular/surgery* ; Tachycardia, Supraventricular/physiopathology ; Tachycardia, Supraventricular/diagnosis*

Arrhythmia, Sinus ; physiopathology ; Arrhythmias, Cardiac ; physiopathology ; surgery ; Atrioventricular Node ; anatomy & histology ; physiology ; Catheter Ablation ; Electrophysiologic Techniques, Cardiac ; Electrophysiology ; Heart ; anatomy & histology ; physiology ; Heart Atria ; anatomy & histology ; Heart Conduction System ; physiology ; Humans ; Models, Cardiovascular ; Wolff-Parkinson-White Syndrome ; physiopathology