Time interval determination from left atrial appendage ejection flow in patients with mitral stenosis

Functional improvement after successful catheter ablation for long-standing persistent atrial fibrillation

Aims

Identifying patients who benefit from restored sinus rhythm (SR) would optimize the selection of candidates for ablation of long-standing persistent atrial fibrillation (LSPAF). This prospective study sought to identify the hitherto unknown factors associated with global functional improvement after successful radiofrequency catheter ablation of LSPAF.

Methods and results

In 171 LSPAF patients (84% of the total consecutive 203 patients) who were examined in SR 12 months after ablation, the individual per cent change from baseline value in maximum oxygen consumption at exercise test (VO2 max), left ventricular ejection fraction (LVEF), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and five-dimensional descriptive system (EQ-5D) of quality-of-life questionnaire were classified in quartiles by 0 (worse) to 3 (best) grades. The individual grades were summed into a composite score (SCORE, 0 … 12) reflecting global functional improvement. Significant improvement in VO2 max (3.4 ± 4.7 mL/kg/min), LVEF (7.5 ± 9.1%), NT-proBNP (-861 ± 809 pg/mL), and EQ-5D (0.7 ± 0.12) was observed (all P < 0.0001). On multivariable analysis, younger age (P = 0.001), male gender (P = 0.02), timely post-ablation left atrial appendage (LAA) outflow (P = 0.005) with improvement in outflow velocity (P = 0.0002), and withdrawal of Class I/III antiarrhythmic drugs (P < 0.05) were positively and independently correlated with the SCORE.

Conclusions

Younger male patients benefited most from catheter ablation of LSPAF. Delayed or non-improved LAA outflow and inability to discontinue Class I/III antiarrhythmic medication reduced the post-ablation functional improvement.

Can left atrial strain and strain rate imaging be used to assess left atrial appendage function?

BACKGROUND

The aim of this study was to evaluate the efficiency of left atrial strain (S) and strain rate (SR) imaging in assessing left atrial appendage (LAA) function.

METHODS

We studied 78 consecutive patients (35 females and 43 males; mean age 38 ± 15 years) referred for transesophageal echocardiography (TEE). LAA late emptying velocity (LAA-EV) was calculated. Real-time color Doppler myocardial velocity imaging (MVI) data were recorded from the LAA by TEE and the lateral wall of the left atrium (LA) by transthoracic echocardiography. Longitudinal S and SR were measured in the mid portion of the lateral LA wall and lateral LAA wall during the contractile period. LAA late systolic velocity (LSV) and LA-LSV were obtained from Doppler analysis.

RESULTS

A significant positive correlation was detected between LAA-EV and MVI parameters (for LAA-S, r = 0.88, p < 0.001; for LAA-SR, r = 0.84, p < 0.001; for LAA-LSV, r = 0.83, p < 0.001; for LA-S, r = 0.84, p < 0.001; for LA-SR, r = 0.79, p < 0.001, and for LA-LSV, r = 0.70, p < 0.001). In addition, a significant positive correlation was detected between LAA-S and LA-S (r = 0.85, p < 0.001).

CONCLUSION

We suggest that LA-S and LA-SR imaging is a beneficial method to evaluate LAA functions noninvasively.

Transthoracic Echocardiographic Predictors of the Left Atrial Appendage Contraction Velocity in Stroke Patients with Sinus Rhythm

Systemic embolization is a potential complication in patients with thrombi situated in the left atrium and particularly, in the left atrial appendage (LAA). Reduced LAA contraction velocities, determined by the transesophageal echocardiography (TEE), are associated with increased risk of LAA spontaneous echocontrast and thrombus formation, and a history of systemic embolism. However, TEE remains a semi-invasive procedure, limiting its serial application as a screening tool. Therefore, it is desirable to obtain information regarding LAA function by transthoracic echocardiography in patients having cardioembolic stroke. The present study was designed to investigate various echocardiographic variables for patients with stroke to predict LAA dysfunction, reflected as reduced LAA contraction velocity. We studied a total of 61 patients with newly diagnosed acute embolic stroke (42 patients) and transient ischemic attack (19 patients). Computerized tomographic scanning was performed for the diagnosis of embolic stroke. Left atrial functional parameters determined by transthoracic echocardiography, such as left atrial active emptying fraction and acceleration slope of mitral inflow A wave, had significant correlations with the LAA contraction velocity (r = 0.57, p < 0.001; r = 0.54, p < 0.001, respectively). Left atrial volume index, left atrial active emptying volume and left atrial fractional shortening were also correlated with LAA contraction velocity (r = -0.44, p < 0.001; r = 0.38, p = 0.003; r = 0.37, p = 0.004, respectively). In conclusion, transthoracic echocardiography can provide valuable and reliable information about the LAA contraction velocity in stroke patients with sinus rhythm. This finding gives new insights for the appropriate strategy in the evaluation of an acute ischemic stroke.

Echocardiographic assessment of the left atrial appendage

The left atrial (LA) appendage is a common source of cardiac thrombus formation associated with systemic embolism. Transesophageal echocardiography allows a detailed evaluation of the structure and function of the appendage by two-dimensional imaging and Doppler interrogation of appendage flow. Specific flow patterns, reflecting appendage function, have been characterized for normal sinus rhythm and various abnormal cardiac rhythms. Appendage dysfunction has been associated with LA appendage spontaneous echocardiographic contrast, thrombus formation and thromboembolism. These associations have been studied extensively in patients with atrial fibrillation or atrial flutter, in patients undergoing cardioversion of atrial arrhythmias and in patients with mitral valve disease. The present review summarizes the literature on the echocardiographic assessment of LA appendage structure, function and dysfunction, which has become an integral part of the routine clinical transesophageal echocardiographic examination.