MioAtlas
G9: Masses and tumors

Left atrial appendage thrombus

Formation of a mural or mobile thrombus within fundus of left atrial appendage (LAA), caused by critical atrial blood stasis, endothelial dysfunction, and loss of active mechanical contractile function in patients with atrial fibrillation.

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Definition

Formation of a mural or mobile thrombus within the fundus of the left atrial appendage (LAA), caused by critical atrial blood stasis, endothelial dysfunction, and loss of active mechanical contractile function in patients with atrial fibrillation; represents the predominant origin of atrial thrombi in non-valvular arrhythmias, presenting without auscultatory murmur or primary intrinsic hemodynamic impairment [G810-11] [G810-12].

Severity criteria

  • Literal statement from Cresti et al. study [G810-11, Abstract]:
    • «The prevalence and causes of endocavitarian thrombosis have not been investigated in recent large-scale studies»
    • «confirmed its association with a valvular heart disease or a systemic hypercoagulable state»
  • Literal statement from Stoddard et al. study [G810-12, Abstract]:
    • «Left atrial appendage thrombus was present in 20 patients (14%) with acute and 47 patients (27%, p < 0.01) with chronic atrial fibrillation»
    • «Left atrial thrombus does occur in patients with acute atrial fibrillation < 3 days in duration»
  • Atrial contractile function: Absence of active mechanical atrial ejection (contractile function = 0).

Findings by layer

Hemodynamics

  • Cardiac output: 4.0–5.0 L/min (mild reduction due to loss of end-diastolic atrial systolic contribution) [G810-11].
  • Left atrial pressure and pulmonary capillary wedge pressure: normal or mildly elevated (12–15 mmHg) [G810-11].

Rhythm

  • Atrial fibrillation, with chaotic atrial depolarization and irregularly irregular ventricular response [G810-11] [G810-12].

ECG

  • Absence of sinus P waves, presence of fibrillatory 'f' waves, and completely irregular R-R intervals [E1] [E2].

Heart sounds and murmurs

  • First heart sound (S1): S1 intensity variable from beat to beat, dependent on duration of preceding R-R interval [B1].
  • Cardiac murmurs: Absence of intrinsic cardiac murmurs arising from appendage thrombotic mass (negative auscultatory control) [G810-11].

Arterial pulse

  • Complete arrhythmia: peripheral arterial pulses completely irregular in rhythm and amplitude (pulsus irregularis inequalis) [B4].

Jugular venous pulse

  • Disappearance of 'a' wave in jugular venous pressure waveform with presence of blunted 'x' descent and normal 'v' wave [B3].

Maneuvers

  • Physiological responses in accordance with baseline rhythm of atrial fibrillation [B1].

Simulator severity grades

Simulator severity grades: Single grade
Baseline rhythm: Atrial Fibrillation

Also known as: Left atrial appendage thrombus · LAA thrombus · Left atrial appendage thrombosis · Left auricle thrombus

Other pathologies in this group

Sources

  1. [B1] Bedside diagnosis of systolic murmurs . N Engl J Med (1988) . DOI: 10.1056/NEJM198806163182404 PubMed: 2897627
  2. [B3] The jugular venous pressure revisited . Cleve Clin J Med (2013) . DOI: 10.3949/ccjm.80a.13039 PubMed: 24085809
  3. [B4] The Carotid Pulse . Clinical Methods: The History, Physical, and Laboratory Examinations (1990) . PubMed: 21250154
  4. [E1] AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part V: electrocardiogram changes associated with cardiac chamber hypertrophy: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology . Circulation (2009) . DOI: 10.1161/CIRCULATIONAHA.108.191097 PubMed: 19228820
  5. [E2] AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology . Circulation (2009) . DOI: 10.1161/CIRCULATIONAHA.108.191095 PubMed: 19228822
  6. [G810-11] Frequency and Clinical Significance of Atrial Cavities in situ Thrombosis: A Large-Scale Study and Literature Review . J Cardiovasc Echogr (2023) . DOI: 10.4103/jcecho.jcecho_47_22 PubMed: 37772043
  7. [G810-12] Left atrial appendage thrombus is not uncommon in patients with acute atrial fibrillation and a recent embolic event: a transesophageal echocardiographic study . J Am Coll Cardiol (1995) . DOI: 10.1016/0735-1097(94)00396-8 PubMed: 7829800