A 63-year-old female with no PMH or FH of heart disease presented to the ER with dyspnea and pressure-like central chest pain. She reported a 3-week history of cough, sore throat and rhinorrhea. On evaluation, vital signs were T 97.8°F, BP 143/85 mmHg, HR 150/min, RR 20/min and SpO297%. Physical exam was significant for tachycardia with irregular pulse and trace bilateral lower extremity pitting edema. Initial investigation was notable for BNP 317 pg/ml, normal Troponin/CKMB, TFT, BMP, CBC and CXR. EKG revealed AFib w/RVR at 152/min. She was admitted, started on diltiazem and heparin infusion given CHA2DS2-VASc score 2. TTE/TEE revealed dilated chambers with an estimated LVEF 25% and no evidence of intracardiac thrombus. Electrical cardioversion achieved sinus rhythm, and she was given a short course of amiodarone infusion, later followed by metoprolol, digoxin and furosemide. Cardiac catheterization revealed left diagonal artery to LV fistula and otherwise normal coronary arteries in addition to echocardiographic findings. Cardiac MRI revealed cardiomegaly with global hypokinesia and LVEF 21.5% without evidence of ischemic disease, valvulopathy or cardiomyopathy. Given an increased risk of sudden cardiac death, she underwent placement of dual chamber ICD/pacemaker. She remained mostly in sinus rhythm and was eventually discharged home on apixaban, digoxin, metoprolol and furosemide with ACEI deferred due to hypotension.
Discussion:
This case illustrates a previously undiagnosed coronary artery fistula identified in the setting of AFib and heart failure. Coronary artery fistula is an abnormal connection between one of the coronary arteries and a cardiac chamber or great vessel. This rare congenital cardiac anomaly has an estimated incidence of 0.2-0.4% found incidentally on diagnostic cardiac catheterizations. Most reported fistulae originate from the RCA and insert into the RA, RV or PA with no significant effects on cardiac function. Few originate from the LAD or LCX but insertion into the LV as seen in this case is extremely rare. When hemodynamically significant fistulae are present, their effects depend upon their sizes and locations, resulting in clinical symptoms in ~19% of patients <20 years and ~63% of those >20 years. Some reported clinical sequelae include rhythm abnormalities, cardiomyopathy or heart failure, chronic myocardial ischemia or angina, and fistula thrombosis or aneurysm.
Conclusions:
In the case presented here, it is plausible that the coronary artery fistula was part of a spectrum of congenital cardiac anomalies that predisposed the patient to AFib and heart failure which had been compensated for a long time until unmasked by a recent viral illness. The incidence of the reported clinical sequelae described above is unknown and warrants further investigation.