阵发性心房颤动射频消融术后左房大小和机械功能变化

目的探讨经导管射频消融术对阵发性心房颤动（房颤）患者左房功能的影响,并比较肺静脉口节段性电隔离（SPVI）和环肺静脉消融（CPVA）两种术式在此方面的异同。方法66例阵发性房颤患者接受射频消融手术治疗。应用经胸心脏超声检查测量患者术前、术后1天、1个月和3个月时的左房前后径、左房面积、舒张晚期跨二尖瓣血流峰速（A峰）和舒张晚期心肌组织运动峰速（A’峰）。结果66例患者中,30例接受SPVI术,36例接受CPVA术。两组患者一般临床情况及术前超声参数相似。术后随访（315±153）d,SPVI组和CPVA组无房性心律失常复发率相似（70％与75％,P=0．650）。两组在手术后左房面积均较术前缩小,SPVI组发生于术后1个月,而CPVA组于术后3个月。SPVI组左房直径也显示出明显缩小（P〈0．05）,而CPVA组术前和术后则差异无统计学意义。左房机械功能方面,CPVA组于术后1天A峰和A’峰明显降低（P〈0．05）,两者均于3个月后较术后1天明显回升,A峰恢复至术前水平,A’峰较术前有明显升高。SPVI组术后1天没有出现A峰和A’峰明显降低;其A峰于术后1个月升高,并保持至3个月;A’峰于术后3个月时升高。结论阵发性房颤经导管SPVI术和CPVA术治疗后3个月,可以出现左房面积缩小和收缩功能改善。CPVA术比SPVI术造成了更多的左房损伤,表现为术后1天左房功能的下降以及术后左房大小、功能参数改善的延迟。     

Left atrial anatomy and function after conversion from atrial fibrillation in hypertrophic hearts

The aim of the study was to evaluate the influence of left ventricular (LV) hypertrophy on left atrial (LA) electrical and mechanical function after cardioversion atrial fibrillation (A-Fib) of brief duration. Study group A included 100 patients with a first diagnosis of hypertension who had a moderate LV hypertrophy. The patient population included 64 men and 36 women with a mean age of 55 +/-7 years who were hospitalized because of A-Fib and were cardioverted with external DC shock. Control group B included 100 patients without cardiac hypertrophy cardioverted because of lone A-Fib. Atrial function and size were assessed by Doppler echocardiography and the following parameters were measured: transmitral peak A velocity, atrial filling fraction, atrial ejection force, peak E velocity, deceleration time, and isovolumic relaxation time, LA maximal and minimal volume, and LV cardiac mass index. Baseline echocardiography showed that LA diameters and volumes were enlarged in all patients during A-Fib. After the restoration of sinus rhythm LA diameters and volumes decreased and the reduction was more evident in group B compared to group A. LA function as a continuous variable was negatively related to LV mass index (r = -0.77), LA diameter (r = -0.66 and r = -0.69 for the superoinferior diameter), LA maximal volume (r = -0.61) and LA minimal volume (r = -0.55) (all p<0.01). Atrial ejection force as a continuous variable was positively related to age (r =0.78), peak A wave velocity (r =0.71), systolic blood pressure (r =0.51), and IVRT (r =0.41) (all p<0.01). Hypertrophy influenced the recovery of atrial function after cardioversion of A-Fib. Atrial function was reduced in patients with LV hypertrophy even after A-Fib of brief duration.     

Pulsed Doppler evaluation of atrial mechanical function after electrical cardioversion of atrial fibrillation

Full recovery of atrial mechanical activity may not occur immediately after successful electrical cardioversion of atrial fibrillation to sinus rhythm. To examine the time course of recovery of left atrial mechanical function, serial two-dimensional, M-mode and transmitral pulsed Doppler echocardiographic studies were performed in 21 patients after elective direct current cardioversion of atrial fibrillation of 3 weeks' to 24 months' duration (mean 5 months). Over 3 months of follow-up, there were significant increases in both peak A wave velocity (p less than 0.005) and percent atrial contribution to total left ventricular filling (p less than 0.005). Compared with values in a normal control population, peak A wave velocity and percent atrial contribution to total left ventricular filling did not return to normal until 3 weeks after cardioversion in patients who remained in sinus rhythm. Left atrial dimension also decreased over the follow-up period (p less than 0.05) in patients with persistent sinus rhythm. These results may have important implications in guiding the appropriate duration of anticoagulant therapy after cardioversion, and in clinically assessing the hemodynamic benefit of restoring sinus rhythm in an individual patient.     

心房颤动自发复律对老年患者左房功能的影响

目的本文探讨老年患者心房颤动自发复律后心房功能恢复的特点.方法采用SONOS 5500型彩色多普勒血流显像仪,观察20例老年对照组和20例非瓣膜病阵发性心房颤动(PAF)患者在心房颤动自发复律后24 h,72 h及7 d左心房收缩功能.观察以下指标:①左房内径LAD和左室内径LVD;②左室射血分数(LVEF);③二尖瓣E峰峰值速度E(cm/s);④二尖瓣A峰峰值速度A(cm/s);⑤取心尖四腔切面AQ技术观察左房:左房最大容积LAVmax,左房最小容积LAVmin,左房收缩期前容积LAVp,左房主动排空容积LAAEV=LAVp-LAVmin,左房主动排空分数LAAEF(%)=LAAEV/LAVp.结果老年PAF组较老年对照组左房内径[(4.24±0.43)cm vs(3.83±0.22)cm,P＜0.05]及左房容积[(70.43±12.70)ml vs(46.2±4.91)ml,P＜0.05]增大;二尖瓣峰流速A(cm/s)在心房颤动自发复律后24 h,48 h明显降低,7 d有所增高,但仍较对照组低[(45.4±12.37)cm/s;(56.64±16.24)cm/s;(65.01±13.58)cm/s vs(74.55±5.97)cm/s,P＜0.05];老年PAF组自发复律后LAAEF(%)降低,至7 d部分恢复,仍较对照组明显降低[(15.72±5.22)%;(16.42±5.20)%;(18.89±7.70)% vs(34.65±7.83)%,P＜0.05].结论老年心房颤动患者左房内径和左房容积增大,心房颤动自发复律7 d时LAAEF仍降低.由于自发复律后仍存在左房收缩功能障碍,且窦性心律难以维持,因此对于左房容积增大的老年PAF患者,抗凝治疗非常重要.     

Left atrial pacemaker dominance after catheter ablation of atrial fibrillation

We report a case of left atrial dominant rhythm demonstrated by electroanatomic mapping. The rhythm occurred after radiofrequency catheter ablation in a patient with persistent atrial fibrillation and structural heart disease.     

Left ventricular function in atrial fibrillation during overdrive pacing

Objective Our purpose was to measure the effect of ventricular pacing in patients with atrial fibrillation (AF) on stroke volume and cardiac output. Background Unceasing variation in cycle length in AF decreases stroke volume and cardiac output. Because ventricular-inhibited pacing after atrioventricular node ablation has been reported to improve left ventricular performance, we tested the hypothesis that overdrive pacing would produce a similar benefit by regularizing cycle length. Methods and Results We studied 18 patients with chronic AF and permanent pacemakers. The aortic time velocity integral (TVI) was measured with continuous-wave Doppler and was used as a surrogate measure of stroke volume (stroke volume = TVI × aortic valve area, and aortic valve area is constant whether in AF or during pacing). For each patient, the linear relation between preceding cycle length and TVI in AF was used to estimate relative stroke volume (TVI compared within each patient) at a preceding cycle length of 666 ms in AF, and a similar comparison between AF and pacing was made at the minimum allowable pacing rate. Relative stroke volume in AF was then compared with relative stroke volume at both the fixed cycle (666 ms) and the minimum allowable rate. During pacing at 666 ms, relative stroke volume increased significantly by 18% (t = 2.8, P = .048), but there was no difference in cardiac output during pacing at the minimum possible rate and the corresponding preceding cycle length in AF. Conclusion Our data suggest that regularization of ventricular rhythm by overdrive pacing in patients with AF only improves stroke volume (and by extension, cardiac output) at pacing rates at the outer limit of and above the normal physiologic range. (Am Heart J 2002;143:827-32.)     

Left atrial flutter after radiofrequency catheter ablation of focal atrial fibrillation

We report an arrhythmic complication in two patients in whom a procedure directed at isolating one or two pulmonary veins had been performed. The complication was related to pulmonary vein disconnection scars after ablation. Both patients developed new clinical tachycardia (atypical atrial flutter) secondary to a reentrant phenomena in the vicinity of a previously ablated pulmonary vein.     

Left atrial reservoir function predicts atrial fibrillation recurrence after catheter ablation: a two-dimensional speckle strain study

Background  

Predictors of atrial fibrillation (AF) recurrence after catheter ablation (CA) are not fully defined. We hypothesized that 2D left atrial (LA) regional strain maps would help identify abnormal atrial substrate that increases susceptibility to AF recurrence post-CA.     

Concomitant recovery of atrial mechanical and endocrine function after cardioversion in patients with persistent atrial fibrillation

OBJECTIVES: The purpose of this study was to evaluate left atrial mechanical function recovery and plasma atrial natriuretic peptide (ANP) release following successful cardioversion of persistent atrial fibrillation (AF). BACKGROUND: Atrial fibrillation is characterized by functional deterioration, loss of atrial contraction, and elevation of plasma ANP levels. The response of ANP release toward atrial mechanical function after cardioversion of AF has not been fully examined. METHODS: We examined 29 patients with successfully cardioverted persistent AF in whom sinus rhythm was maintained for at least 30 days after cardioversion. We assessed mechanical function of the left atrium at 24 h and 7 and 30 days after cardioversion and evaluated plasma ANP level at the same time. Atrial mechanical function was assessed during echocardiographic examination by means of the peak velocity of the transmitral A-wave, early transmitral to atrial flow velocity ratio, and atrial filling fraction (AFF). The plasma ANP level was determined by the radioimmunoassay method. RESULTS: Plasma ANP levels were significantly reduced from 59.4 +/- 16.6 pg/ml to 31.1 +/- 9.2 pg/ml at 24 h after successful cardioversion. Within 30 days, we noted progressive improvement of atrial systolic function (increase in AFF from 21% to 31%, p < 0.05). At the same time, plasma ANP levels gradually increased from 31.1 +/- 9.2 pg/ml at 24 h to 36.9 +/- 12.8 pg/ml on day 30 following cardioversion (p < 0.05). CONCLUSIONS: Plasma ANP levels significantly decreased in patients with persistent AF after successful cardioversion. In the 30 days after cardioversion, gradual elevation of plasma ANP concentration was observed concomitantly with an increase of AFF. Plasma ANP release after successful cardioversion of persistent AF might be due to recovery of atrial mechanical function.