Clinically significant cardiac fistulas occur rarely, and which are usually repaired by thoracotomy or the application of an occluder through a catheter. These fistulas may be congenital or acquired, and are usually complications of surgery or endocarditis. Currently, the most reported in clinical practice is acquired left ventricular and left atrial fistula, but congenital left ventricular and left atrial fistula has not been reported. This article is the first report of left ventricular and left atrial fistula, and provides detailed echocardiograms that can provide clues for diagnosis.

We report the case of a 68-year-old male patient, from Longshan, Hunan Province, who went to the local hospital in 2005 due to shortness of breath after activities and repeated edema of both lower limbs, and diagnosed as “coronary atherosclerotic heart disease, ischemic cardiomyopathy, grade III cardiac function.” After diuresis, cardiotonic, anti-ventricular remodeling therapy, the effect was not good, and the symptoms were still repeated, so he came to our hospital for treatment. There was no history of valve replacement, stent implantation, or drug abuse. Physical examination: blood pressure 122/80 mmHg. Cyanosis of lips, jugular venous distention, hepatojugular reflex (+), Musset sign was positive, rough breath sound of both lungs, moist rales could be heard, accentuation of first heart sound, systolic murmur of grade 5 or above could be heard in mitral valve auscultation area, loud diastolic murmur could be heard in tricuspid valve auscultation area, frog belly and moderate pitting edema of both lower limbs. Laboratory examination: Myocardial marker: BNP (type B natriuretic peptide) 2844 pg/mL, troponin and myoglobin examination showed no abnormalities. Blood lipids: total cholesterol 2.32 mmol/L, high-density lipoprotein 0.88 mmol/L, low-density lipoprotein 1.59 mmol/L, others showed not abnormal. Echocardiography: An abnormal channel (0.79*1.59), which connects the left ventricle with the left atrium, in the free wall of the left ventricle was seen under two-dimensional ultrasound (Figure 2). In the short-axis view of the left ventricle at the level of the mitral valve, it can be seen that this channel was located outside the annulus of the anterior mitral valve. The anteroposterior diameter of left atrium, left ventricle, right atrium, and right ventricle were 4.5, 5.6, 6.7, and 5.6 cm, respectively. There was no increase in the inner diameter of the left and right coronary arteries; left ventricular wall thickness was normal and no local motion abnormalities. Color Doppler ultrasound showed that: During the systole of the left atrium, a multicolored blood flow signal (turbulent flow) mainly in blue can be seen, one of which runs along the posterior wall of the left atrium through the mitral valve orifice (considering mitral regurgitation); the other beam comes from the shunt signal of the left atrium and left ventricular abnormal channels, with a peak flow rate of 4.3 cm/s (Figure 1 and Figure 2). Finally, we found an abnormal channel connecting the left ventricle and the left atrium in the free wall of the left ventricle.

The mitral aortic interlaminar fiber is the junction between aortic valve and the left half of the noncoronary apex of aortic valve and the anterior leaflet of mitral valve and one-third of the adjacent left coronary valve tip. The junction between mitral valve and aortic valve is formed by fibrous ring tissue, so it is called mitral valve-aortic valve interlaminar fiber. This area is relatively avascular area, easy to be occupied by organisms [1]. Therefore, most clinical reports on left ventricular and left atrial fistula are secondary to infective endocarditis or valve replacement, while congenital left ventricular and left atrial fistula has not been reported. Congenital left ventricular and left atrial fistula is related to the weakness or defect of congenital infra-aortic annular structure. Combined with pathophysiology and the development of the patient's condition, we make the following guesses for patients with left ventricular fistula: Left ventricle and left atrial fistula lead to left ventricle pumping blood into left atrium through the abnormal channel at the beginning of isovolumic contraction, resulting in the increase of left ventricular diastolic volume load. However, through Frank-Starling mechanism [2], the stroke volume of left ventricle was increased significantly, and the ejection fraction was maintained in the normal range. Therefore, there could be a considerable period of asymptomatic period. However, the long-term increasing of left atrial volume load leads to the elevated left atrial pressure and left atrial diameter, when decompensated, that induces pulmonary congestion, left heart failure, and late pulmonary hypertension, leading to right heart failure. This patient was admitted to our hospital for repeated symptoms of whole heart failure. However, no coronary heart disease associated risk factors such as dyslipidemia, hypertension, and diabetes mellitus were found in the patient's previous medical history and related examinations after admission. Therefore, we are suspicious of the patient's coronary heart disease diagnosis. And heart auscultation indicated structural changes in the patient's heart, so we carried out detailed color Doppler ultrasound examination. Finally, an abnormal channel between left ventricular free wall aortic valve and left atrium was observed, and abnormal blood flow signals were demonstrated. Due to the patient had no previous history of valve replacement, infective endocarditis or myocardial infarction, acquired left ventricular and left atrial fistula was not considered. He was finally diagnosed as congenital left ventricular and left atrial fistula. And this can also explain the development of the patient’s condition. The main symptom of this patient was repeatedly whole heart failure. But cardiac signs were not special except for the abnormal severe mitral and tricuspid regurgitation sound. The clinical diagnosis was once missed, and treatment effect was not satisfactory. Basic reason is that the abnormal channel between left atrium and left ventricle has not been discovered. As for the treatment of the patient, because he refused to further assess the size and location of the fistula by transesophageal ultrasound, and refused to use the occluder to repair the fistula through catheter and thoracotomy, we carried out conservative treatment on the patient. This is the first report of congenital left ventricular and left atrial fistula. It has certain reference value for the diagnosis of patients with right heart failure whose symptoms are difficult to correct after repeated clinical diuretic and cardiac therapy.

Congenital left ventricular and left atrial fistula has not been reported. Early diagnosis and treatment prevent the complications of heart failure. We report a 68-year-old male with congenital left atrium and left ventricular fistula. Because this patient refused to further assess the size and location of the fistula by transesophageal ultrasound, and refused to use the occluder to repair the fistula through catheter and thoracotomy, we carried out conservative treatment on the patient.