Atrial thrombi occurring during sinus rhythm in cardiac amyloidosis: evidence for atrial electromechanical dissociation.

Abstract

Thrombus formation in the left atrium is rare in patients in sinus rhythm. In three patients with extensive cardiac amyloidosis transthoracic echocardiography showed large atrial thrombi in or protruding into the body of the left atrium during sinus rhythm. Doppler studies showed no A wave on mitral inflow. Severe atrial and ventricular infiltration by amyloid may have resulted in mechanical atrial standstill with resultant thrombus formation. These findings suggest that patients with severe cardiac amyloidosis may require anticoagulation when atrial function is impaired.

Intracardiac Thrombosis, Embolism and Anticoagulation Therapy in Patients with Cardiac Amyloidosis – Inspiration from a Case Observation

“…LV diastolic dysfunction and low LAA emptying velocity, in addition to AF, were independently associated with intracardiac thrombosis. The Mayo autopsy and TEE studies and prior study support the hypothesis that the combination of systolic and diastolic ventricular dysfunction and chronic amyloid infiltrate in the atria lead to atrial mechanical dysfunction, 17,24 atrial enlargement, and blood stasis. 23,27 Such atrial electrical-mechanical dissociation at least partially explains why some cardiac amyloid patients developed atrial thrombosis while in sinus rhythm.…”

“…Furthermore, the LV diastolic function and atrial mechanical activity were more impaired. Reduced atrial contractility secondary to amyloid infiltration has been reported 17,24 and LV diastolic function is typically impaired before systolic function. 25 The combination of systolic and diastolic ventricular dysfunction, chronic amyloid infiltrate in the atria, and direct toxic effect on myocardium 26 could lead to atrial mechanical dysfunction, atrial enlargement, and blood stasis.…”

“…23,27 Such atrial electrical-mechanical dissociation may partially explain why many cardiac amyloidosis patients developed atrial thrombosis while in sinus rhythm. 17,24,28 It is possible that endomyocardial damage and endothelial dysfunction from amyloid depositions may be responsible. 29,30 Hypercoagulability may also contribute.…”

“…23,27 Such atrial electrical-mechanical dissociation at least partially explains why some cardiac amyloid patients developed atrial thrombosis while in sinus rhythm. 17,24,28 …”

“…13 However, it is possible that autopsy series may over emphasize the frequency of intracardiac thrombosis and there only have been a few anecdotal reports in the literature on intracardiac thrombosis detected by TEE or TTE in live patients. [9][10][11][12][15][16][17] The prevalence of intracardiac thrombus and the effects of anticoagulation in living cardiac amyloid patients has not been reported. Accordingly, we evaluated both TTE and TEE studies from patients with various types of cardiac amyloidosis to determine how frequently detectable intracardiac thrombi are present; the clinical and echocardiographic characteristics associated with their presence; and the effects of therapeutic anticoagulation.…”