Hiromitsu Gen

Increased thrombin–antithrombin III complex during an episode of paroxysmal atrial fibrillation

Thrombin-antithrombin III complex (TAT) is a marker of thrombin generation, indicating increased coagulability. To investigate whether paroxysmal atrial fibrillation (PAf) is associated with an increased coagulation system, we measured TAT within 24 h after the documentation of PAf in 50 patients with structurally normal hearts. The mean age of the study population was 62 years old. In 32 patients, PAf was documented during routine physical examinations, electrocardiograms or echocardiograms and in the remaining 18 patients, it was reproducibly documented on more than two Holter electrocardiograms. Group I consisted of 38 TAT data sets from 38 patients who did not receive anticoagulant therapy during PAf episodes. At least one week after starting anticoagulant therapy, TAT was measured again in ten patients in whom there was evidence of PAf on the day of measurement. In the remaining 12 patients, PAf occurred while the patients were receiving anticoagulation. Group II consisted of 22 TAT data sets from 22 patients who received anticoagulation during PAf episodes. The average TAT value was 5.8 ng/ml in group I, while it was 2.8 ng/ml in group II (P<0.0001). TAT was greater than 5 ng/ml in 15 of the 38 patients in group I, and in four of the 22 patients in group II. In 20 symptomatic patients, we measured TAT again when the patients maintained sinus rhythm under the same anticoagulant therapy; four patients were receiving and 16 patients were not receiving anticoagulation therapy. TAT decreased from 6.4 to 2.3 ng/ml on average when PAf disappeared and sinus rhythm was maintained (P=0.0009). Increase in the coagulation system occurred transiently during or shortly after PAf episodes in about 40% of PAf patients. As patients with prior anticoagulation had a relatively low TAT value, anticoagulant therapy might be useful in patients with PAf.

Reversible left ventricular dysfunction secondary to rapid atrial fibrillation

We present the cases of four patients with reversible left ventricular dysfunction associated with severe congestive heart failure presumably induced by rapid atrial fibrillation. The mean heart rate was 159 beats/min and the mean left ventricular end-diastolic dimension was 58.5 mm with diffusely impaired left ventricular motion. None of the patients had a history of preceding upper respiratory infection before the acute episode and no signs of inflammation at onset, and all patients were New York Heart Association Class I or II before the acute episode. Left ventriculography, done about 1 month when congestive heart failure and ventricular rate were controlled with digitalis and diuretics, still showed diffusely decreased left ventricular motion; the mean end-diastolic volume was 165 ml and the mean ejection fraction was 30%. Coronary angiography was normal in three patients and one showed moderate left anterior descending artery stenosis. Right ventricular biopsy, done in three patients showed no evidence of myocarditis. Left ventricular wall motion normalized in 5-36 months on follow-up echocardiography. These findings suggest that persistent rapid atrial fibrillation can cause reversible left ventricular dysfunction which can take a considerable period of time to normalize.

Influence of gravity on pulmonary venous flow velocity patterns: Analysis of left and right pulmonary venous flow velocities in left and right decubitus positions

BACKGROUND The pulmonary venous flow signal measured by transesophageal echocardiography is generally recorded from the left upper pulmonary vein in the left lateral decubitus position, whereas that by transthoracic echocardiography is from the right upper pulmonary vein in the left semi-lateral decubitus position. The purpose of this study was to evaluate the influence of the postural change on the peak flow velocities of the left and right pulmonary veins and whether the parameters of the left and right pulmonary venous flow can be used interchangeably. METHODS AND RESULTS The study group consisted of 37 patients with normal left ventricular filling pressure and in whom the systolic forward flow signals from both pulmonary veins recorded in the left and right lateral decubitus positions were clear enough to differentiate as biphasic. The peak early systolic (peak S1) and diastolic velocities were significantly increased when the pulmonary vein was on the recumbent subjects upper side, whereas the peak late systolic velocity (peak S2) was significantly increased when the pulmonary vein was on the recumbent subjects lower side. The peak S1 was higher than the peak S2 when the pulmonary vein was on the recumbent subjects upper side, whereas the reverse relation was seen when the pulmonary vein was on the recumbent subjects lower side. CONCLUSIONS We should take into consideration the body position and the side on which the pulmonary vein is situated in evaluating the peak flow velocities of the pulmonary veins.

Unroofed coronary sinus syndrome: Diagnostic consideration by contrast echocardiography and usefulness of transesophageal echocardiography and magnetic resonance imaging

We present two cases of unroofed coronary sinus syndrome without a left superior vena cava [1]; one is associated with mitral stenosis and the other is an isolated form. The diagnostic clue was a markedly enlarged coronary sinus with color flow within it detected by transthoracic echocardiography. Contrast echocardiography with injection of contrast medium through the left antecubital vein [2] showed a negative jet from the coronary sinus in the right atrium, indicating the presence of a left-to-right shunt through the enlarged coronary sinus. This enlarged coronary sinus was clearly seen lying behind the left atrium by transesophageal echocardiography (TEE) and a communication between the left atrium and the coronary sinus was documented. Echo Doppler gave us additional information about the presence of the flow across the fenestrations. Spin echo magnetic resonance imaging (MRI) demonstrated the fenestration present between the coronary sinus and the left atrium, and cine mode confirmed the flow across these fenestrations. When the coronary sinus is enlarged on transthoracic echocardiography and cannot be filled by contrast echocardiography via the left antecubital vein, further examination for the presence of an unroofed coronary sinus is necessary. T E E and MRI give us useful information in this situation.

The usefulness of contrast echocardiography for detecting right-to-left cardiac shunts during the diagnosis of hypoxemia: 2 case reports

We report two cases in which contrast echocardiography was useful for detecting right-to-left shunt. In case 1, a 53-year-old man was admitted to our hospital after being diagnosed with acute heart failure. Even after improvement of the heart failure, hypoxemia remained. Contrast echocardiography was performed. When contrast medium was injected into the left antecubital vein, it directly drained into the left atrium. When contrast medium was injected into the right antecubital vein, it drained into the right atrium not the left atrium. These findings proved the existence of a right-to-left shunt. In case 2, a 68-year-old man felt dyspnea on mild effort, especially when sitting in an anteflexing posture. In room air, his SpO2 was 95% when sitting in a resting posture and 79% when in an anteflexing sitting posture. Contrast echocardiography was performed. A patent foramen ovale (PFO) was proved using the Valsalva maneuver, and the contrast medium drained from right atrium into the left atrium via the PFO. He underwent patch closure of the PFO, and his symptoms disappeared. Contrast echocardiography should be performed for the diagnosis of chronic hypoxemia for which causes are not detected with routine clinical examinations, in order to confirm right-to-left shunt.

Percutaneous transluminal recanalization for an occluded modified Potts shunt

We performed percutaneous transluminal recanalization successfully for an occluded modified Potts shunt in a 35-year-old man with pulmonary atresia and ventricular septal defect. Percutaneous transluminal recanalization deserves to be considered for occluded shunts if the duration of obstruction is short.