MioAtlas
G7: Infections and inflammation

Aortic infective endocarditis with root abscess and fistula to right atrium

Invasive and destructive periannular complication of aortic endocarditis characterized by phlegmonous and abscess extension to the aortic root and fibrous trigone, with transmural erosion and fistula into the right atrium.

Open in 3D simulator

Definition

Invasive and destructive periannular complication of aortic endocarditis characterized by phlegmonous and abscess extension to the aortic root and fibrous trigone, with transmural perforation into the right atrium generating a high-flow aorto-right atrial fistula with continuous left-to-right shunt and added perivalvular aortic regurgitation [C3] [G7-15].

Severity criteria

  • Severity grade: Single grade. Represents an immediate cardiothoracic surgical emergency (Class I indication, Level B according to the ESC 2023 guideline [C3, Sección 11.1, Tabla 14]).
  • Magnitude of fistulous shunt:
    • Continuous systo-diastolic pressure gradient between aortic root and right atrium: systolic 60–90 mmHg, diastolic 30–60 mmHg, generating continuous high-velocity forward flow (> 3–4 m/s) [C3] [G7-15].
    • Pulmonary to systemic flow ratio (Qp:Qs): > 1.5–2.2 depending on fistulous tract diameter [G7-15].
  • Concomitant aortic regurgitation: Moderate to severe grade (EROA ≥ 0.20–0.30 cm²) due to collapse or loss of anatomical support of the abscessed aortic annulus [C3] [V1].

Findings by layer

Hemodynamics

  • Mean right atrial pressure: Severely increased (12–20 mmHg) due to continuous inflow of arterialized blood at high pressure from the aorta [G7-15] [B3].
  • Systemic arterial diastolic pressure: Marked diastolic drop (< 50 mmHg) due to continuous aortocavitary 'steal' phenomenon, with widely widened pulse pressure [G7-15] [B4].
  • Pulmonary blood flow and pulmonary artery pressure: Elevated due to acute left-to-right volume hyperflow (Qp:Qs > 1.5) [G7-15].

Rhythm

  • Default rhythm: First-degree atrioventricular block (first-degree AV block), classic marker of periannular infiltration into the conduction tissue [C3] [G7-15].
  • Alternative rhythms: Second-degree AV block Mobitz II (second-degree AV block) or complete third-degree AV block with junctional or idioventricular escape rhythm [C3] [G7-15] [E2].

ECG

  • Prolonged PR interval (PR interval > 200 ms) or complete atrioventricular dissociation with P waves independent of wide QRS complexes [C3] [E2].
  • Possible complete right bundle branch block or anterior hemiblock due to anatomical proximity of bundle of His branches to the right fibrous trigone [E2].

Heart sounds and murmurs

  • Continuous fistula murmur: Continuous systo-diastolic 'machinery' murmur (similar to patent ductus arteriosus but in an atypical precordial location: 3rd–4th left or right parasternal intercostal space), peaking at end-systole and continuing uninterruptedly throughout diastole [G7-15] [B1].
  • Aortic regurgitation diastolic murmur: Decrescendo component in aortic/Erb area due to intraventricular regurgitation [B1] [C3].
  • Systo-diastolic thrill: Palpable in mesocardium/right sternal border in large-caliber fistulas [G7-15].
  • First and second heart sounds: Muffled or merged within the continuous acoustic turbulence [B1].

Arterial pulse

  • Brisk, collapsing and bounding pulse (Corrigan / water-hammer pulse) with very rapid diastolic collapse due to double systemic runoff (into left ventricle and into right atrium) [B4] [G7-15].

Jugular venous pulse

  • Extreme jugular venous distention with giant systolic and v waves visible in the neck transmitted by the fistulous jet into the superior vena cava and right atrium [B3] [G7-15].

Maneuvers

  • Isometric handgrip: Increases systemic aortic pressure and peripheral resistance, increasing the aorto-atrial gradient and continuous murmur intensity [B1].
  • Valsalva (strain phase): Transiently decreases shunt volume and murmur loudness [B1].

Simulator severity grades

Simulator severity grades: Single grade
Baseline rhythm: First-Degree AV Block

Also known as: Aortic root abscess with fistula · Aorto-cavitary fistula · Aorto-atrial fistula · Periannular aortic abscess · Aorto-right atrial fistula

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. [C3] 2023 ESC Guidelines for the management of endocarditis . Eur Heart J (2023) . DOI: 10.1093/eurheartj/ehad193 PubMed: 37622656
  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. [G7-03] European Heart Rhythm Association (EHRA) international consensus document on how to prevent, diagnose, and treat cardiac implantable electronic device infections-endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), the Latin American Heart Rhythm Society (LAHRS), International Society for Cardiovascular Infectious Diseases (ISCVID) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS) . Europace (2020) . DOI: 10.1093/europace/euz246 PubMed: 31702000
  7. [G7-15] Periannular complications in infective endocarditis involving prosthetic aortic valves . Am J Cardiol (2006) . DOI: 10.1016/j.amjcard.2006.05.066 PubMed: 17056343
  8. [V1] 2025 ESC/EACTS Guidelines for the management of valvular heart disease . Eur Heart J (2025) . DOI: 10.1093/eurheartj/ehaf194 PubMed: 40878295