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Birke Schneider

Publications and source records attributed to Birke Schneider.

14 recordsLinked to original sources
PubMed2007

Diagnosis of left atrial appendage thrombi by multiplane transesophageal echocardiography: interlaboratory comparative study.

BACKGROUND: Transesophageal echocardiography (TEE) is regarded as the method of choice for imaging left atrial appendage thrombi (LAAT). However, the interobserver variability among 2 independent echocardiographic laboratories in diagnosing LAAT by multiplane TEE has not yet been assessed. METHODS AND RESULTS: The videorecordings of 50 patients in atrial fibrillation (25 from each laboratory) were blindly reviewed by 1 experienced observer from each institution. LAAT were assessed as present, absent or questionable. Indications for TEE were: cardioversion (n=17), valve disease (n=13), endocarditis (n=12), or embolism (n=8). The prevalence of LAAT was 10% (observer 1) vs 12% (observer 2). A questionable LAAT was assessed in 6% vs 12% and a LAAT was excluded in 84% vs 76%, respectively. By head-to-head comparison, disagreement occurred in 11 cases (22%, kappa=0.5). Discrepant results were not related to the echocardiographic equipment. Problems occurred because of reverberation artifacts of the ridge between the left atrial appendage and left upper pulmonary vein (n=5), and in differentiating LAAT from spontaneous echocardiographic contrast (n=4) or an echogenic atrioventricular groove (n=1). The differentiation of pectinate muscles from LAAT was the reason for disagreement in only 1 case. Eliminating the category of questionable thrombi increased the kappa value to 0.65. In 5 patients undergoing cardiac surgery, both observers had agreed on the presence (n=1) or absence (n=4) of LAAT, and intraoperatively the results of TEE were confirmed. CONCLUSION: Even with multiplane TEE, interobserver variability among 2 independent echocardiographic laboratories for diagnosing LAAT remains high because of problems in differentiating LAAT from spontaneous echocardiographic contrast and reverberation artifacts.

Adult↗
PubMed2006

Transient left ventricular dysfunction (tako-tsubo phenomenon): Findings and potential pathophysiological mechanisms.

Tako-tsubo-like left ventricular dysfunction phenomenon (TTP) is characterized by transient left ventricular apical ballooning associated with symptoms, electrocardiographic changes and minimal cardiac enzyme release in the absence of coronary artery disease. Initially described in Japan, TTP occurs worldwide, predominantly in women and frequently after emotional or physical stress. Symptoms include anginal chest pain, dyspnea and syncope. Electrocardiographic ST elevations may be present only for several hours, and are followed by negative T waves that persist for months. Arterial hypertension is found in up to 76% of TTP patients, hyperlipidemia in up to 57% and diabetes mellitus in up to 12%. Potential pathophysiological mechanisms for TTP include catecholamine-induced myocardial stunning or hyperkinesis of the basal left ventricular segments, coronary vasospasm, plaque rupture, myocarditis and genetic factors. TTP patients should be monitored similarly to myocardial infarction patients because organ failure, cardiogenic shock, ventricular fibrillation or rupture may occur. Beta-blockers are indicated, whereas catecholamines and nitrates should be avoided. The long-term prognosis is unknown.

Chest Pain↗
PubMed2005

Surgical closure of the left atrial appendage - a beneficial procedure?

BACKGROUND: Closure of the fibrillating left atrial appendage (LAA) has been recommended during valve surgery to decrease the risk of arterial embolism. However, patients undergoing surgical LAA closure have not systematically been reevaluated for complete LAA obliteration. METHODS AND RESULTS: During a 12-month period, we studied 6 consecutive patients with paroxysmal (n = 3) or permanent (n = 3) atrial fibrillation who underwent surgical LAA closure at the time of valve surgery. Transesophageal echocardiography (TEE) performed 23-159 days (mean 51) postoperatively demonstrated complete LAA closure in only 1 patient. In 5 patients, incomplete LAA closure was found due to disruption of the closure line. The size of the residual LAA orifice ranged from 3 to 20 mm. There was a high flow velocity at the LAA orifice (0.33-2.2 m/s), whereas flow in the LAA body was low (<0.2 m/s). Spontaneous echocardiographic contrast (SEC) in the LAA had newly developed (n = 3) or was much more intense than preoperatively (n = 2). Despite therapeutic anticoagulation 2 patients showed a LAA thrombus which had not been present on the preoperative TEE, and 1 patient with SEC suffered a stroke 4 weeks after attempted LAA closure. CONCLUSION: Surgical LAA closure was incomplete in most patients, resulting in blood stagnation and an increased likelihood of clot formation. Incomplete surgical LAA closure, therefore, may promote rather than reduce the risk of stroke. Intraoperative TEE is mandatory to verify complete LAA obliteration.

Aged↗
PubMed2005

Is surgical closure of patent foramen ovale the gold standard for treating interatrial shunts? An echocardiographic follow-up study.

BACKGROUND: Surgical closure of patent foramen ovale (PFO) has been considered definitive and the gold standard for preventing recurrent paradoxical embolism. However, in contrast to transcatheter PFO closure, patients undergoing operation have not systematically been re-evaluated for residual shunting. This study aimed to assess the efficacy of surgical PFO closure during follow-up by transesophageal echocardiography (TEE). METHODS: Eleven adult patients with diagnosis of a PFO by contrast and/or color Doppler TEE underwent PFO closure by thoracotomy and direct suturing because of paradoxical embolism (n = 4), because of impending paradoxical embolism (n = 1), or during valve operation (n = 6). RESULTS: TEE performed 5 days to 7 months after PFO closure revealed residual shunting in 8 of 11 patients (73%). The shunt size was unchanged in two patients. According to the color Doppler jet width across the atrial septum, the postoperative PFO diameter was smaller in 5 of the remaining 6 patients. Right-to-left shunting by contrast TEE, however, had newly developed (n = 1) or increased (n = 2) for patients with concomitant valve operation. Despite therapeutic anticoagulation a cerebrovascular event occurred in one patient 4 weeks after attempted PFO closure. The mechanism for persistent shunting was incomplete sealing of septum primum and septum secundum by the suture line (n = 6) or a new iatrogenic defect of the fossa ovalis caused by surgical manipulation (n = 2). In two patients a second TEE after 12 and 41 months revealed enlargement of the PFO diameter. CONCLUSIONS: Surgical PFO closure can not be regarded as the gold standard for definitive treatment of interatrial shunts. Residual shunting present in a high proportion of patients may partly explain the recurrence of embolic events.

Adult↗
PubMed2003

Elimination of the left atrial appendage to prevent stroke or embolism? Anatomic, physiologic, and pathophysiologic considerations.

The "elimination" of the left atrial appendage (LAA) seems to be an attractive alternative to oral anticoagulation in the treatment of atrial fibrillation, especially in patients with contraindications to oral anticoagulation therapy. The LAA, however, plays an important role in the maintenance and regulation of the cardiac function, in arterial hypertension, atrial fibrillation, coronary heart disease, valvular heart disease, and heart failure. Data, mainly from animal studies, indicate that elimination of the LAA may impede thirst in patients with hypovolemia, may impair hemodynamic response to volume or pressure overload, may decrease cardiac output, and may promote heart failure. It may have adverse effects in humans as well. Further studies on the hemodynamic and neurohumoral consequences of left atrial appendage elimination are required to advance our understanding of LAA physiology and pathophysiology.

Aged↗