Chest
Clinical Investigations: Cardiology: ArticlesLeft Atrial Appendage Contractile Function in Atrial Fibrillation: Influence of Heart Rate and Cardioversion to Sinus Rhythm
Section snippets
Patient Population
The study group consisted of 26 patients with chronic AF scheduled for elective direct current electrical cardioversion. The mean age was 65 ± 7 years (range, 50 to 79 years) and duration of AF was 28 ± 22 months (range, 1 week to 7 years). The underlying cardiac disease was dilated cardiomyopathy in four patients, coronary artery disease in five patients, and mitral stenosis in two patients. Hypertension, COPD and diabetes were documented in 10, 3, and 4 patients, respectively. Table 1 lists
Left Atrial Appendage Ejection Fraction vs Heart Rate
During AF in the subset of patients with available transesophageal echocardiographic data both immediately before and immediately after cardioversion, mean heart rate (VRR) was 103 ± 31 beats per minute during AF, and mean LAA ejection fraction was 26 ± 10%. The LAA appeared akinetic with poor to absent excursion of its lateral wall. The LAA ejection fraction during AF did not correlate with either left atrial chamber size (r=–0.014; p=NS) or with the duration of AF (r=–0.04; p=NS). Table 2 is
Discussion
The major findings of our study are twofold: (1) LAA emptying is strongly and inversely related to the VRR during AF but is not related to heart rate following direct current cardioversion to sinus rhythm, and (2) LAA emptying increases significantly immediately after direct current cardioversion from AF to sinus rhythm.
Summary
This study offers evidence that during AF the magnitude of LAA emptying is inversely related to the VRR and that, immediately after direct current cardioversion to sinus rhythm, appendage emptying increases markedly and is not dependent on heart rate. These results support our hypothesis that LAA emptying in AF is dependent on the diastolic volume of the left ventricle which is determined by the VRR. Our data can be taken further to indicate that the increase in LAA emptying immediately after
ACKNOWLEDGMENTS
We thank James A. Brownie from Medical Media for assistance with graphics, Dorothy Robinson for assistance with data management, and Michelle Rene Martin for expert assistance in the preparation of the manuscript.
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Cited by (28)
Thoracoscopic Left Atrial Appendage Clipping: A Multicenter Cohort Analysis
2018, JACC: Clinical ElectrophysiologyCitation Excerpt :Stroke prevention is a cornerstone of AF treatment. The LAA is the main source of thromboembolism in AF patients because of blood stasis and coagulation, thus fulfilling the main conditions of Virchow’s triad (14–18). Oral anticoagulation therapy is the mainstay of stroke prevention in AF, but other strategies are now available and can complement interventional approaches to rhythm control.
The left atrial appendage: An old adversary identified
2006, Heart RhythmDoppler echocardiographic assessment of left atrial appendage flow velocities in normal cats
2005, Journal of Veterinary CardiologyCitation Excerpt :In a study of 46 healthy subjects,18 four distinct flow waves were found in 36 (78%), triphasic flow was reported in six (13%), and biphasic flow in four (9%). The differences in the distribution of flow patterns between our findings and the aforementioned study may be explained in part by the different methods used with TEE being the most sensitive technique of recording LAA flow35 and differences in heart rate and PR interval between cats and man.37 In other human studies, however, only two main flow waves were described in the majority of patients – LAA emptying and filling waves – which is in agreement with our observations.17,38
Obliteration of the left atrial appendage for prevention of thromboembolism
2003, Journal of the American College of CardiologyDoes acute-phase beta blockade reduce left atrial appendage function in patients with chronic nonvalvular atrial fibrillation?
2001, Journal of the American Society of EchocardiographyCitation Excerpt :Because atrial myocardium contains both beta1 and beta2 adrenoceptors,14 it is plausible that beta-blockers may acutely impair LAA function in patients with chronic AF. Previous clinical studies have shown that the LAA emptying velocity is inversely related to heart rate during AF and sinus rhythm.15,16 If this is true, reduction in heart rate caused by beta blockade will result in increased LAA emptying velocity in patients with AF; however, our study demonstrated that acute administration of metoprolol decreased LAA emptying velocities, despite the reduction in heart rate.
A prospective, randomized controlled trial comparing the efficacy and safety of sotalol, amiodarone, and digoxin for the reversion of new-onset atrial fibrillation
2000, Annals of Emergency MedicineCitation Excerpt :The ineffective atrial contractions in AF reduce effective cardiac output, especially during exercise, and substantially increase the risk of stroke as a result of the formation and embolization of atrial thrombus.3 Sustained AF with rapid ventricular rate may also result in reversible tachycardia-induced left ventricular dysfunction,4,5 further increasing left atrial stasis.6 AF increases the risk of ischemic stroke sixfold to approximately 5% per year,7 and embolic strokes related to AF are usually large with death or severe neurologic deficit in 50% to 70% of cases.8
This study was supported in part by the funds from Veterans Affairs Research Service.