Coronary Artery Fistulae and Their Significance







Age: 63 years


Gender: Female


Occupation: Homemaker


Working diagnosis: Endocarditis



HISTORY


The patient was well until approximately 4 months prior to presentation, when she developed exercise intolerance, fever, cough, and generalized malaise. She was evaluated and subsequently treated for presumed pneumonia.


The patient had no improvement after a 2-week course of oral erythromycin. The patient was reevaluated.


CXR revealed cardiomegaly, and an ECG demonstrated LA enlargement and first-degree AV block. Cardiology evaluation was recommended. Prior to the evaluation, the patient developed symptoms consistent with a urinary tract infection. After finishing a complete course of antibiotics, her urinary symptoms resolved. Her cough also improved, as did her feeling of malaise.


She was a lifetime nonsmoker, with no prior history of significant infection. She reported excellent exercise tolerance throughout her life, with no perceived limitations. She had had two pregnancies, which were uncomplicated.





Comments: The prolonged nature of this episode should prompt an evaluation for subacute infections or noninfectious causes of fever.


Cardiomegaly with clear lung fields raises the concern for either pericardial effusion or cardiac disease. First-degree AV block can be seen in age-related degeneration of the conduction system, but can also be related to intracardiac anomalies such as a primum atrial septal defect. A new first-degree AV block can be seen in aortic valve endocarditis with extension of infection into the perivalvular area.





CURRENT SYMPTOMS


The patient complains of generalized fatigue and dyspnea on exertion.


NYHA class: II




CURRENT MEDICATIONS


None




PHYSICAL EXAMINATION





  • BP 135/80 mm Hg, HR 66 bpm, oxygen saturation 100%



  • Height 166 cm, weight 62 kg, BSA 1.69 m 2



  • Surgical scars: None



  • Neck veins: Normal



  • Lungs/chest: Clear to auscultation and percussion



  • Heart: The heart rhythm was regular. There was a normal left ventricular impulse with a 2+ RV impulse. There was a continuous murmur heard best at the left sternal border in the fourth intercostal space. P2 was soft.



  • Abdomen: No hepatosplenomegaly was present, or other masses palpated.



  • Extremities: Peripheral pulses were 4/4 throughout with no radiofemoral delay.






Comments: The pulse pressure was normal, and keeping with a good stroke volume.


Elevated JVP is seen in conditions resulting in increased RV and RA pressure, such as pulmonary hypertension, and RV outflow or inflow obstruction. Volume loading, especially chronic, does not necessarily cause JVP elevation because of increased compliance of the RA and the systemic venous bed.


A prominent right ventricular impulse implies RV volume or pressure overload. A soft P2 implies normal pulmonary artery systolic pressure. This patient likely has a lesion that has resulted in RV volume overload. A continuous murmur can be heard in an adult with PDA, ruptured sinus of Valsalva aneurysm, and coronary arteriovenous fistula. Of these, only ruptured sinus of Valsalva aneurysm and arteriovenous fistula might result in RV volume overload. A ruptured sinus of Valsalva aneurysm with significant shunt would be associated with a wide pulse pressure. Acutely, this could also result in cardiac decompensation. While both of these entities could be associated with endocarditis, given the clinical signs here the most likely underlying lesions would be a form of arteriovenous fistula.



PERTINENT NEGATIVES


No cyanosis, clubbing, or edema. No Osler nodes or Janeway lesions. Normal funduscopic exam.




LABORATORY DATA



















































Leukocytes 6.2 × 10 9 /L (3.5–10.5)
Differential:
Neutrophils 58% (42–75)
Lymphocytes 31% (16–52)
Monocytes 9% (1–11)
Eosinophils 1% (0–7)
Basophils 1% (0–4)
Hemoglobin 10 g/dL (11.5–15.0)
Hematocrit/PCV 31% (36–46)
MCV 90 fL (83–99)
Platelet count 359 × 10 9 /L (150–400)
Sodium 138 mmol/L (134–145)
Potassium 4.3 mmol/L (3.5–5.2)
Creatinine 0.8 mg/dL (0.6–1.2)
Blood urea nitrogen 3.0 mmol/L (2.5–6.5)





Comments: The leukocyte count and differential are normal. This does not exclude subacute bacterial endocarditis, as only 20% to 30% of cases will have a leukocytosis.


A normocytic anemia is demonstrated, likely representing anemia of chronic disease, such as with a chronic infection.



OTHER RELEVANT LAB RESULTS










Erythrocyte sedimentation rate (ESR): 92
Blood cultures: No growth





Comments: There is a significant elevation in erythrocyte sedimentation rate. This is a nonspecific marker, but consistent with the suspected diagnosis of endocarditis. Negative blood cultures are common in patients with endocarditis who have been recently treated with antibiotics. There are also several organisms that cause culture-negative endocarditis. These include Coxiella burnetii , Bartonella, nutritionally variant streptococci, and fungi. Of course, noninfectious causes of endocarditis (marantic endocarditis, Libman-Sacks endocarditis, and antiphospholipid antibody-related vegetation) should be considered in a patient with vegetation and persistently negative cultures while off antibiotics.





ELECTROCARDIOGRAM



Figure 78-1


Electrocardiogram.




FINDINGS





  • Heart rate: 73 bpm



  • QRS axis: +73°



  • QRS duration: 104 msec



  • Normal sinus rhythm with first-degree AV block. LA overload. Nonspecific T-wave abnormality.






Comments: There is no specific diagnosis that can be supported by this surface ECG.

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Sep 11, 2019 | Posted by in CARDIOLOGY | Comments Off on Coronary Artery Fistulae and Their Significance
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