Tomoko Machino‐Ohtsuka

BACKGROUND: In patients with atrial fibrillation (AF), most thrombus forms in the left atrial appendage (LAA). However, the relation of LAA morphology with LAA thrombus is unknown. METHODS AND RESULTS: We prospectively enrolled 633 consecutive patients who were candidates for catheter ablation for symptomatic drug-resistant AF. Transesophageal echocardiography (TEE) was performed to assess LAA thrombus. LAA structure was assessed by 3-dimensional TEE. LAA orifice area, depth, volume, and number of lobes were measured on reconstructed 3-dimensional images. Clinical characteristics and echocardiographic measures were compared to determine variables predicting LAA thrombus. Excluded were 69 (10.9%) patients who met the exclusion criteria. Finally, this study comprised 564 patients, of whom LAA thrombus was observed in 36 (6.4%) patients. Multivariate analysis revealed CHADS2 (Congestive heart failure, Hypertension Age>75, Diabetes mellitus and prior Stroke or transient ischemic attack) score (P=0.002), left ventricular ejection fraction (P=0.01), degree of spontaneous echo contrast (P=0.02), left atrial volume (P=0.02), and number of LAA lobes (P<0.001) to be independently associated with thrombus formation. Most patients with LAA thrombus (32/34, 94.4%) had ≥3 LAA lobes, whereas LAA thrombus was observed in only 2 (0.7%) of 296 patients with 1 or 2 lobes. LAA volume significantly decreased in patients maintaining sinus rhythm after catheter ablation (P=0.0009). Number of LAA lobes did not change in any patient. CONCLUSIONS: Complex LAA morphology characterized by an increased number of LAA lobes was associated with the presence of LAA thrombus independently of clinical risk and blood stasis. This study suggests that LAA morphology might be a congenital risk factor for LAA thrombus formation in patients with AF.

INTRODUCTION: An increased left atrial (LA) stiffness reflects the structural remodeling and deterioration of the LA function. This study was designed to estimate LA stiffness by measuring a combination of the strain and LA pressure in patients undergoing pulmonary vein isolation (PVI) of atrial fibrillation (AF) and to evaluate the influence of the LA stiffness on the cardiac function, serum markers, and recurrence of AF after PVI. METHODS: In 155 consecutive patients with AF, the brain natriuretic peptide (BNP) and aminoterminal procollagen type III propeptide (PIIIP) plasma levels were measured before the PVI. The difference between the minimum and maximum LA systolic pressures was directly measured by a transseptal puncture. The ratio of the difference in the LA pressures to the peak systolic LA strain evaluated by speckle-tracking echocardiography was used as an index of the LA stiffness. RESULTS: The calculated LA stiffness index was related to the BNP level (r(s) = 0.444, P < 0.001), E/E' ratio (r(s) = 0.444, P < 0.001), LA volume index (r(s) = 0.370, P < 0.001), and PIIIP level (r(s) = 0.305, P = 0.002). During a mean follow-up period of 33.8 ± 12.2 months, 45 patients (29%) presented with AF recurrences. A Cox proportional hazard regression analysis showed the LA stiffness index was an independent predictor of recurrence of AF (HR 2.88; 95% CI 1.75 to 4.73, P < 0.001). CONCLUSIONS: In patients with AF, the LA stiffness index is related to left ventricular diastolic dysfunction, LA dilatation, and collagen synthesis and may predict AF recurrences after PVI.

BACKGROUND: Although 2-dimensional strain analyses based on speckle tracking echocardiography have been used to detect myocardial deformation, the prognostic impact of 2-dimensional strain is unclear in patients with acute decompensated heart failure (HF). We investigated whether left ventricular and right ventricular (RV) strain parameters assessed by speckle tracking echocardiography provide incremental prognostic information in hospitalized patients because of acute decompensated HF. METHODS AND RESULTS: Six hundred eighteen patients (age, 72±13 years; 38% women; ejection fraction, 46±16%) hospitalized for acute decompensated HF underwent clinical and echocardiographic evaluation just before discharge. We performed strain analyses of left ventricular global longitudinal strain and left ventricular global circumferential strain. We also analyzed RV longitudinal strain only from the free wall (RV-fwLS) and from all segments of the RV global longitudinal strain wall by using Tomtec software. The primary composite end point was cardiovascular death and readmission for HF. There were 34.8% cardiac events during a median follow-up of 427 days. In multivariate Cox models, among echocardiographic parameters, only impaired RV-fwLS (≥-13.1%; hazard ratio, 1.51; 95% CI, 1.12-2.04; P=0.01) was independently associated with cardiac events. Adding RV-fwLS to clinical risk evaluation (age, New York Heart Association class III/IV, blood urea nitrogen, and brain natriuretic peptide) markedly improved prognostic utility and consequently increased net reclassification improvement by 0.30 ( P=0.01). CONCLUSIONS: RV-fwLS is an independent predictor of cardiac events in acute decompensated HF and provides greater prognostic power than standard echocardiographic parameters.