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 Table of Contents  
CASE REPORT
Year : 2017  |  Volume : 14  |  Issue : 2  |  Page : 103-105

Stress-induced ischemia caused by conus branch of right coronary to right atrial coronary cameral fistula during treadmill test


Department of Cardiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India

Date of Web Publication26-Oct-2017

Correspondence Address:
Ramachandra Barik
Department of Cardiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njc.njc_12_17

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  Abstract 

A 28-year-old apparently healthy young male working in Border Security Force referred to our institute for annual master health checkup. The routine biochemical tests, 12-lead electrocardiogram (EKG), chest X-ray, and echo were normal. His exercise ECG was remarkable for significant horizontal ST depression in lead I, AVL, V4–V6 during treadmill test at 15 METs. He had usual breathlessness during exercise. Coronary angiogram revealed conus branch of right coronary artery to right atrial coronary cameral fistula draining into right atrium which may be an unusual reason for inducible ischemia at high-intensity exercise as the other coronary arteries were normal. He is now under regular follow-up for need–based, catheter-based intervention in the future because of asymptomatic presentation and small size fistula. A period of 12-month follow-up was uneventful.

Keywords: Coronary angiogram, coronary cameral fistula, coronary stealing, stress-induced ischemia, treadmill test


How to cite this article:
Barik R. Stress-induced ischemia caused by conus branch of right coronary to right atrial coronary cameral fistula during treadmill test. Nig J Cardiol 2017;14:103-5

How to cite this URL:
Barik R. Stress-induced ischemia caused by conus branch of right coronary to right atrial coronary cameral fistula during treadmill test. Nig J Cardiol [serial online] 2017 [cited 2020 Nov 28];14:103-5. Available from: https://www.nigjcardiol.org/text.asp?2017/14/2/103/217269


  Introduction Top


Independent conus artery or conus branch of right coronary is seen in ≥90% of computed tomographic coronary angiogram (CT-CAG).[1] It is important for cardiothoracic surgeons because it crosses right ventricular outflow tract [2] and it is important to cardiologists because it forms Vieussens arterial ring.[3],[4],[5] Conus artery or conus branch very rarely forms coronary cameral fistula (CCF).[6] It may present as exertional angina due to coronary steal.[7] It is very rare or has not been reported to have exercise-induced ischemia during treadmill test due to CCF.[8] The interesting finding in this case report is that incidental detection of conus artery CCF to right atrium causing significant horizontal ST depression in chest lead even though the patient was clinically asymptomatic which is a usual feature of the most of the CCF.[9]


  Case Report Top


A 28-year-old male, working as an armed Border Security Force (BSF) appeared for annual fitness checkup. He was asymptomatic in routine life and during duty. There was no history of cardiac illness. Body mass index was 25.4 kg/m 2. His clinical examination including cardiovascular system examination was normal. There was no room air desaturation. Routine tests such as blood sugar, lipid profile, thyroid function, and renal function were normal. Chest X-ray and echocardiography were normal. A 12-lead electrocardiogram (EKG) suggested minor T-wave inversion in lead III. Exercise EKG during treadmill test showed more than 2 mm horizontal ST depression in V4–V6 at 15 METs with usual breathlessness without any angina and/or syncope. He was suggested CT-CAG to rule out the possibility of congenital coronary anomaly. Immediately, CT-CAG could not be done due to technical reason in our institution. Therefore, a routine CAG was performed using right radial approach. CAG revealed normal and dominant left coronary artery [Figure 1]. There was difficulty in selective hooking of the nondominant right coronary artery because of repeated interference of conus branch [Figure 2]. Inadvertently, the selective and deep engagement of tiger catheter into conus branch disclosed the conus branch to right atrial CCF [Video 1]. The fistula was opening exactly opposite to the opening of the coronary sinus. Then, right coronary artery was selectively hooked with deep engagement showed as if the right coronary artery is normal [Figure 3]. He was discharged on the same day after 4 h of uneventful observation.
Figure 1: Left coronary angiogram in left anterior oblique-cranial (60-30) view shows normal coronary arteries with dominant left circumflex coronary artery

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Figure 2: Selective and deep hooking of conus branch during right coronary angiogram showed conus branch to right atrial coronary cameral fistula

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Figure 3: Selective right coronary angiogram with deep intubation shows no apparent coronary cameral fistula because of relatively inadequate contrast flow into conus branch

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He was instructed to continue his duty in BSF because of the asymptomatic presentation, incidental detection during annual health checkup, and small size of the fistula. A period of 12-month follow-up was uneventful.


  Discussion Top


Most of the patients of CCF are detected incidentally during evaluation for other illness.[10] The intensity of murmur in CCF may vary from Grade II to VI depending on the size of the shunt.[9] Therefore, there was no murmur during auscultation because of small shunt. Coronary CT angiography is extremely useful for atypical chest pain and low and/or intermediate probability for coronary artery disease in treadmill test.[11] In this case, a CT-CAG would have served better [12] which could not be done because of technical issue. A hemodynamic study to pinpoint the shunt size could have been done, but we did not feel it is necessary because of obvious small size of shunt (asymptomatic and clinically no murmur). Recommendations for CCF with asymptomatic presentation are variable. Some authors recommend that even small CCF should be treated to prevent future complications.[13] In some other studies, the long-term regular follow-up of cases with small CCF is usually uneventful.[14] There is a Class IIa recommendation that transcatheter occlusion is reasonable for the management of patients with moderate or large coronary artery fistula without clinical symptoms (level of evidence: C),[15] whereas all the large fistula should be closed by surgery irrespective of shunt size and asymptomatic patients with insignificant shunts should followed up.[14]


  Conclusion Top


Core tip: Conus branch of right coronary artery or conus artery directly arising from anterior sinus has been implicated in supporting collaterals to the left anterior descending coronary artery through Vieussens' arterial ring. It is rarely reported that a conus branch of right coronary artery to right atrial fistula can be the reason for significant ST depression during exercise EKG test. This is a rare and interesting case report, wherein an asymptomatic young adult when was undergoing master health checkup, incidentally found to have conus branch of right coronary artery to right atrial CCF responsible for exercise-induced ischemia at high-intensity exercise.

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Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Rao A, Pimpalwar Y, Yadu N, Yadav RK. A study of coronary artery variants and anomalies observed at a tertiary care armed forces hospital using 64-slice MDCT. Indian Heart J 2017;69:81-6.  Back to cited text no. 1
[PUBMED]    
2.
Dabizzi RP, Caprioli G, Aiazzi L, Castelli C, Baldrighi G, Parenzan L, et al. Distribution and anomalies of coronary arteries in tetralogy of fallot. Circulation 1980;61:95-102.  Back to cited text no. 2
    
3.
Plácido R, Almeida AG, Canas da Silva P, Pinto F. Left main ostial agenesis and right coronary artery occlusion: The importance of the 'Vieussens' arterial ring'. Eur Heart J 2016;37:1170.  Back to cited text no. 3
    
4.
Barik R, Damara S. Hide and seek of double right coronary artery. Niger J Cardiol 2016;13:157.  Back to cited text no. 4
    
5.
Wynn GJ, Noronha B, Burgess MI. Functional significance of the conus artery as a collateral to an occluded left anterior descending artery demonstrated by stress echocardiography. Int J Cardiol 2010;140:e14-5.  Back to cited text no. 5
    
6.
Moodi F, Tayebi S, Soltani J, Saleh FS, Ashraf H, Nezhad AF. Coronary artery fistula: A huge conus branch aneurysm. Kardiochir Torakochirurgia Pol 2014;11:441-3.  Back to cited text no. 6
    
7.
Oshiro K, Shimabukuro M, Nakada Y, Chibana T, Yoshida H, Nagamine F, et al. Multiple coronary LV fistulas: Demonstration of coronary steal phenomenon by stress thallium scintigraphy and exercise hemodynamics. Am Heart J 1990;120:217-9.  Back to cited text no. 7
    
8.
Ali A, Colledge J, Sri I, Missouris C. CT: The imaging of choice in the diagnosis of coronary artery fistulae. BJR| case reports. 2016;28:20150492.  Back to cited text no. 8
    
9.
Challoumas D, Pericleous A, Dimitrakaki IA, Danelatos C, Dimitrakakis G. Coronary arteriovenous fistulae: A review. Int J Angiol 2014;23:1-10.  Back to cited text no. 9
    
10.
Mangukia CV. Coronary artery fistula. Ann Thorac Surg 2012;93:2084-92.  Back to cited text no. 10
    
11.
Lau GT, Wei H, Wickham J, To AC. The significance of equivocal exercise treadmill ECG for intermediate risk chest pain assessment – Insight from coronary CT angiography data. Heart Lung Circ 2017. pii: S1443-950630080-X.  Back to cited text no. 11
    
12.
Ghadri JR, Kazakauskaite E, Braunschweig S, Burger IA, Frank M, Fiechter M, et al. Congenital coronary anomalies detected by coronary computed tomography compared to invasive coronary angiography. BMC Cardiovasc Disord 2014;14:81.  Back to cited text no. 12
    
13.
Ata Y, Turk T, Bicer M, Yalcin M, Ata F, Yavuz S. Coronary arteriovenous fistulas in the adults: Natural history and management strategies. J Cardiothorac Surg 2009;4:62.  Back to cited text no. 13
    
14.
Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Develop Guidelines on the Management of Adults with Congenital Heart Disease). Developed in Collaboration With the American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol 2008;52:e143-263.  Back to cited text no. 14
    
15.
Feltes TF, Bacha E, Beekman RH 3rd, Cheatham JP, Feinstein JA, Gomes AS, et al. Indications for cardiac catheterization and intervention in pediatric cardiac disease: A scientific statement from the American Heart Association. Circulation 2011;123:2607-52.  Back to cited text no. 15
    


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  [Figure 1], [Figure 2], [Figure 3]



 

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