Research included 100 adult patients (48 men (48%) and 52 women (52%)) with persistent and long-standing persistent forms of atrial fibrillation and valve pathologies (see tab. 1). Average age of patients – 59,3±10,2 years with dispersion from 21 to 77 years. Existence of AF was confirmed by a surface electrocardiogram in 12 standard assignments or 24-hour Holter ECG monitoring. Duration of AF from 1 year to 17 years, with average 4±4,2 years (see fig. 1). To all patients antiarrhythmic therapy was tried out, but proved to be ineffective. At 15% of patients attempts of restoration of a sinus rhythm by means of the electric cardioversion were applied, however it was not possible to control a normal sinus rhythm in long perspective. All patients had an organic pathology of the mitral valve with an average duration in 21,8±12.8 years. Also at 80% of patients tricuspid valve insufficiency was revealed. The functional class of heart failure on NYHA 2,7±0,75. The average size of the left atrium was 5,1±1,5 cm, average left ventricular ejection fraction - 61±8,6%, and a cardiothoracic index - 58,6±4,7%. 12% of patients had the anamnesis of thromboembolic complications. 9% of 100 patients had aorto-coronary artery bypass graft surgery earlier, 16% of patients had arterial hypertension and 5% – diabetes.
Distribution of CSNRT values in the research. The normal value is supposed to be less than 525 msec
Distribution of Sinoatrial Conduction Time values in the research. The normal value is supposed to be less than 215 msec
Electrophysiological Examination Results
During the research all the patients retained normal sinus rhythm with a frequency from 45 to 94 bpm (see tab. 2). The average duration of P wave 128,0±24,2 ms, PQ interval - 220,1±36,5 ms, QRS complex width - 118,6±20,1 ms. The time of carrying out an impulse from sinus node to His bundle (AH interval) and from His bundle to ventricles (HV interval) made 88,2±34,8 ms and 48,3±15,5 ms respectively. Average atrial conduction delay was 84,7±27,3 ms. Average intra-atrial conduction delay was 106,3±18,4 ms. Average sinus node recovery time (SNRT) was 1426,2±346,4 ms, corrected sinus node recovery time (CSNRT) - 425,7±147,1 ms, and sinoatrial conduction time - 174,4±72,8 ms. The value of the functional refractory period (FRP) of the right atirum made 290,0±45,4 ms. The average relative refractory period (RRP) of the right atrium - 360,3±24,0 ms. And the average effective refractory period (ERP) of the right atrium - 258±33,6. For the left atrium indicators of refractory periods were: FRP - 278±24,2 ms, RRP - 323±25,6 ms and ERP - 231,5±37,1 ms. Average values of a refractory periods of AV-node: FRP - 256±33,7 ms, RRP - 380,9±130,4 ms and ERP - 225,6±25,2 ms. Antegrade Wenckebach point was 365,0±86,5 ms. Average retrograde ERP of AV-node - 316,2±76,4 ms.
At 11% of patients pathological lengthening of CSNRT – 900,3±300,6 msec was revealed. And at 13% - pathological lengthening of sinoatrial conduction time (SACT) – 340,2±80 msec (see fig. 2-fig. 4). At 11% of patients pathological lengthening of SACT was followed by pathological lengthening of CSNRT, but at 2% of patients other signs sinus node dysfunction (SND), except lengthening of SACT was not discovered.
Distribution of SND
Thus, total 13% of patients with AF and sinus node dysfunction (SND) were initially diagnosed (see figure 5).
The study of refractivity of various areas of the atria has shown that the ERP of AV-node was minimum in comparison with other areas and had mean value 225,6±25,2 msec. The longest ERP was found in the HRA area - 258±33,6 msec, that is significantly higher, than in the AV-node (p<0,01). In the area of the coronary sinus the ERP had intermediate value, on average 231,5±37,1 msec. This is significantly lower, than the ERP in HRA (p<0,01), but no statistically significant differences were found from the value of ERP of the AV-node (see figure 6).
The mean duration of PQ interval was 220,1±36,5 mm. The mean atrial conduction time was 84,7±27,3 msec, the mean AV-node conduction in the anterograde direction (AH) and the mean time of conduction of His-Purkinje system (HV) - 88,2±34,8 msec and 48,3±15,5 msec respectively. Thus, the lengthening of PQ interval was a consequence of the impulse conduction delay through the atria and AV-node.
Therefore, it is possible to draw a conclusion that patients with AF had decrease in functional ability of the AV-node.
Cryomodification Of Maze III Procedure In Combination With Rfa Of The Right Atrium During Mitral Valve Surgery Results
Consequently, by results of Maze III procedure with valve disease correction disposal of AF was observed at 95% of patients. At 46% of patients at the moment of discharge from the hospital the stable sinus rhythm remained. At 24% of patients the atrial rhythm with the maximum heart rate 80-110 bpm was observed (by the results of 24-hour Holter ECG monitoring). 25% of patients needed permanent pacemaker implantation. At the same time, by results of EP-study, initially before surgical treatment 13% of patients suffered from sinus node dysfunction. From the remained 12% at 9% of patients the indication for pacemaker implantation were the nodal rhythm with low heart rate and pauses more than 3 sec long, one patient had episodes of transient AV block (second degree, second type) and SA block (second degree, second type), one patient had a complete heart block and at the last one – atrial rhythm with pauses more than 3 sec long.
Duration of the effective refractory periods of various areas of atria. HRA – high right atrium, CS – coronary sinus, AV-node – atrioventricular node
At 13% of patients with the atrial rhythm and normal heart rate in the early postoperative period typical atrial flutter has developed. To all of them the radio-frequency ablation of cavo-tricuspid isthmus with creation of the bidirectional block was performed, and further recurrence of atrial flutter wasn’t observed.