Evaluation of left atrial function by the functional volume change curve derived from Doppler flow spectra

The objective of this study was to clarify the left atrial (LA) reservoir and booster pump function in patients with left ventricular (LV) diastolic dysfunction. To determine LA reservoir and booster pump function, a new algorithm to determine LA functional volume change curve (FVC) was developed from Doppler flow spectra of pulmonary venous flow and LV inflow by transthoracic echocardiography in 110 patients. Patients were classified into normal (N), and abnormal (AB) and pseudonormal (PN) groups on the basis of their Doppler flow patterns. From the indices of FVC, atrial reservoir volume (ARV), passive emptying volume (PEV) and active emptying volume (AEV) were obtained. ARV/stroke volume (SV) was increased in the AB group, but decreased in the PN group compared with N (N, 0.61+/-0.09; AB, 0.73+/-0.10; PN, 0.52+/-0.13, p<0.05). PEV/SV was significantly decreased in AB, but increased in PN compared with N (N, 0.27+/-0.07; AB, 0.19+/-0.07; PN, 0.31+/-0.18, p<0.05). AEV/SV was significantly increased in AB, but decreased in PN compared with N (N, 0.41+/-0.08; AB, 0.56+/-0.10; PN, 0.26+/-0.19, p<0.05). Thus, in patients with an abnormal relaxation pattern, the LA reservoir and booster pump function are augmented, but in patients with a pseudonormal pattern, both LA reservoir and booster pump function are deteriorated, suggesting a vulnerability to pulmonary congestion.

Effect of low-intensity warfarin therapy on left atrial thrombus resolution in patients with nonvalvular atrial fibrillation: a transesophageal echocardiographic study

The presence of left atrial thrombus (LAT) is associated with an increased risk of embolic stroke. However, it has yet to be established definitively whether low-intensity warfarin therapy (INR: 1.5-2.0) can prevent LAT formation in patients with nonvalvular atrial fibrillation (NVAF). The present study analyzed the clinical and transesophageal echocardiography (TEE) features of 123 such patients to identify risk factors for LAT formation and the efficacy of prophylactic low-intensity warfarin therapy. Left atrial thrombi were found in 35 patients (28%) in whom systemic hypertension (49% vs 23%; p<0.01) and ischemic heart disease (17% vs 3%; p<0.01) were more frequent. Left ventricular ejection fraction (54+/-14% vs 60+/-11%; p<0.05), left ventricular end-diastolic dimension (51+/-7 mm vs 48+/-5 mm; p<0.05), spontaneous echo contrast (2.2+/-0.7 vs 1.4+/-0.9; p<0.01), left atrial diameter (50+/-6 mm vs 43+/-7 mm; p<0.01), left atrial appendage blood velocity (22.3+/-8.7 cm/s vs 37.2+/-21.5 cm/s; p<0.01) and the incidence of left ventricular hypertrophy (37% vs 15%; p<0.01) were also significantly different between the groups. Fourteen patients received continuous warfarin therapy (target INR: 1.5-2.0) and on the follow-up TEE study the left atrial thrombus resolved in 10 (71%). There were no thromboembolic events or major hemorrhagic complications in these patients, so it was concluded that low-intensity warfarin therapy is efficacious in treating LAT formation in patients with NVAF.

Quantification of area at risk in acute myocardial infarction by tomographic imaging

The purpose of this study was twofold: to validate, in a phantom heart model, a simple threshold technique for the quantification of defect size using 123I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) imaging and to compare, in patients with acute myocardial infarction, defect size as shown by BMIPP imaging, with the extent of severe hypokinesis shown by left ventriculography.

METHODS

In a phantom study, defect size was calculated using a standard geometric formula. In a clinical study, BMIPP imaging was performed in 20 patients 10 +/- 5 days after the onset of their infarction. Using the centerline method, the area at risk was defined by contrast ventriculography as the percentage of chords with wall motion >2 s.d. below normal.

RESULTS

In the phantom study, a threshold value of 60% yielded the best agreement between true and measured defect size. In the clinical study, the defect size shown by BMIPP imaging was greater in anterior than in inferior infarcts (p < 0.001) and correlated well with the risk area revealed by contrast ventriculography (r = 0.80, p < 0.0001)

CONCLUSION

The above preliminary data, admittedly from a small group of patients, suggest that tomographic BMIPP imaging provides an accurate quantification of defect size by means of a simple threshold technique and, in the subacute phase, permits determination of the amount of myocardium at risk after acute myocardial infarction.

[Acute cardiac tamponade in nonpenetrating injury of proximal aorta: report of a case]

A 21-year-old male admitted to the emergency room with multiple traumatic injuries and shock. Although a chest X-ray showed normal in size of cardiac shadow, echocardiography confirmed cardiac tamponade. A median sternotomy was performed and the pericardial space was evacuated of 600 ml of blood and blood clots. Minor bleeding was identified in the proximal aorta, and complete hemostasis was achieved with manual compression and fibrin glue sealing. One month follow-up showed no pseudoaneurysm formation.