Subvalvular aortic stenosis is an abnormality of the subaortic region currently classified as a non-cyanotic congenital heart malformation that causes the partial obstruction of the left ventricle outflow tract. This condition has a progressive and recurrent character.
Subvalvular aortic stenosis is more frequently seen in males  and may be asymptomatic during the early childhood. In this case, it is incidentally discovered during a heart murmur evaluation . Symptoms tend to occur as the patient grows older  and the lesion becomes more severe. Initially, the patient comes with complaints that only install during physical efforts, such as dyspnea, dizziness, presyncope or angina with normal coronary arteries. In more advanced stages, veritable syncope is caused by less intense effort. Additional complaints include orthopnea and other heart failure manifestations. Sudden cardiac death may be the first sign of disease. Orthopnea may signify the presence of pulmonary venous hypertension, while syncope may be due to an arrhythmia, as well.
The stature and ponderal growth of affected children are normal. In cases with other heart malformations, like a ventricular septal defect, patent ductus arteriosus, pulmonic stenosis or aortic coarctation , the physical evaluation may fail to raise subvalvular aortic stenosis suspicion. Jugular inspection reveals a prominent "a" wave, caused by decreased compliance of the right ventricle. Arterial pulses are symmetrical and seldom decreased. Carotid palpation may prove the presence of an arterial thrill, while a precordial thrill may be felt upon palpation of this area. The apical impulse is strong. Auscultation highlights the existence of a narrow or paradoxical split second heart sound, associated with an ejection murmur, best heard in the middle left sternal border, radiating to the upper left border of the sternum, with a longer duration if the obstruction is more severe. The physician can differentiate this murmur from that of valvular aortic stenosis based on the absence of clicks. Other murmurs, like that of aortic or mitral regurgitations, sometimes coexist.
Jaw & Teeth
The COACH program focuses on: Adults with congenital heart disease Pulmonary hypertension Cardiovascular connective tissue disorders Pregnancy in women with heart disease Transition of adolescents with congenital heart disease into adult congenital heart [wexnermedical.osu.edu]
[…] of Adults With Congenital Heart Disease). [wikidoc.org]
Subvalvular aortic stenosis (SAS) is one of the common adult congenital heart diseases, with a prevalence of 6.5%. It is usually diagnosed in the first decade of life. Echocardiography is the test of choice to diagnose SAS. [ncbi.nlm.nih.gov]
Task Force 1: congenital heart disease. J Am Coll Cardiol 1994, 24 :867–873. [link.springer.com]
Canine subvalvular aortic stenosis (SAS) is an abnormal, congenital heart murmur caused by subaortic stenosis (SAS). There is a high incidence of this condition among Rottweiler dogs. [en.wikipedia.org]
In this case, it is incidentally discovered during a heart murmur evaluation. Symptoms tend to occur as the patient grows older and the lesion becomes more severe. [symptoma.com]
Innocent Murmurs in Dogs Heart murmurs sound serious, and often are, but sometimes a heart murmur is classified as an innocent heart murmur. These heart murmurs are not serious and often resolve with time. [akc.org]
I would suggest that any negative response to a mild heart murmur in a dog less than 20 weeks of age is premature and unfounded. [rottclub.ca]
The condition is usually detected during puppy vaccine visits to the veterinarian by hearing a heart murmur during physical examination. A heart murmur is the abnormal sound of blood rushing through one of the heart valves. [web.archive.org]
Causes of Systolic Murmurs in Dogs Most heart murmurs are systolic. The most common cause of systolic murmurs is pulmonic stenosis or subaortic stenosis, which is a narrowing of the blood vessel that causes obstruction of the blood flow. [akc.org]
Carotid palpation may prove the presence of an arterial thrill, while a precordial thrill may be felt upon palpation of this area. The apical impulse is strong. [symptoma.com]
Given that pure subvalvular aortic stenosis is a non-cyanotic congenital heart malformation, blood workup is usually noncontributory. The electrocardiogram depicts the degree of underlying left ventricular hypertrophy in most patients. The strain pattern, as well precordial deep Q waves are rarely seen.
Echocardiography is the diagnostic method of choice. This imaging is able to describe the shape of the left ventricular outflow tract, the degree of obstruction, the existence of associated congenital abnormalities, like aortic coarctation or patent ductus arteriosus  and disease consequences . The color doppler probe placed in the left ventricular outflow tract reveals a turbulent flow , the first obstruction indicator. The M-mode cursor put in the same area demonstrates the presence of early closure and flutter of the aortic valve leaflets. It is important to characterize the length and position of the lesions and their relationship with the mitral and aortic valves and this is done using parasternal, apical and subcostal views. The gravity of the disease is assessed by continuous doppler wave interrogation, based on mean pressure gradient across the left ventricle outflow tract. However, this is not a reliable method in tunnel-like or multiple lesions. In these cases, a cardiac catheterization with pullback pressure measurement is needed.
The echocardiography should be performed several times in order to observe disease progression, to characterize left and right ventricular filling and function and the impact of the condition on the aortic valve in terms of regurgitation  . In cases where the acoustic window is poor, diagnosis is aided by transesophageal echocardiography. This is most useful in severe, symptomatic patients that are going to be referred for surgery . Supplementary information, like the severity of mitral regurgitation, the existence of ventricular septal defects or the exact anatomy of the left ventricle is offered by a left ventriculogram.
Surgical correction is the best treatment modality, and the prognosis is usually excellent. [ncbi.nlm.nih.gov]
To our knowledge, this case report is the first to describe how this new drug combination therapy is an effective treatment of GB from angiodysplasias and can be used to bridge to surgical or endovascular treatment. [pure.au.dk]
Surgical correction is the best treatment modality, and the prognosis is usually excellent. [ncbi.nlm.nih.gov]
What Is the Prognosis for a Dog With a Heart Murmur? Heart murmurs can be serious, but they are not a cause for panic. Many of the causes of heart murmurs are treatable, and in some cases, may resolve on their own. [akc.org]
The health status of the puppy and the advice of the veterinarian may warrant investigative procedures in order to give a prognosis. [rottclub.ca]
Prognosis Although natural history studies have not delineated the annual mortality rate, 2-10% of sudden deaths are reported in untreated individuals with severe left ventricular outflow tract (LVOT) obstruction, including subvalvar aortic stenosis [emedicine.medscape.com]
Etiology The etiology of subvalvar aortic stenosis (SAS) still is not fully understood. [emedicine.medscape.com]
It can be classified as fixed or dynamic type depending on the dynamics of the obstruction.  Epidemiology and Demographics Aortic subvalvular stenosis is the second most common form of congenital left ventricular outflow tract obstruction and occurs [wikidoc.org]
However, the Newfoundland dog has been shown to experience an increased incidence of subaortic membranes, which may in part be secondary to inbreeding and is consistent with an autosomal inheritance.  Epidemiology The approximate incidence of congenital [emedicine.medscape.com]
In this review, we describe the pathophysiology, diagnosis, prognosis, and management of SAS with a focus on different pathophysiologic mechanisms, diagnostic approach, and prognosis of the disease by reviewing the current literature. 2018 Wiley Periodicals [ncbi.nlm.nih.gov]
HOCM (a.k.a. idiopathic hypertrophic subaortic stenosis or IHSS ) is not present at birth and is not considered a congenital lesion.  Pathophysiology There are several varieties of congenital aortic subvalvular stenosis (or subaortic stenosis):  [wikidoc.org]
(See Pathophysiology and Treatment and Management.) Go to Aortic Stenosis for more complete information on this topic. [emedicine.medscape.com]
Consequently, it is reasonable to consider the role of alternative therapies which may help prevent recurrence in selected cases. [ncbi.nlm.nih.gov]
: Prevention of bacterial endocarditis: recommendations by American Heart Association. JAMA 1997, 77 :1794–1801. The most updated American Heart Association guidelines for bacterial endocarditis prophylaxis. CrossRef Google Scholar 17. Elkins RC. [link.springer.com]
One study demonstrated that early intervention before the development of a significant gradient ( 40 mm Hg) may prevent recurrence. 4 The authors from the same study also suggested that a postoperative gradient of 10 mm Hg was associated with an increased [journals.lww.com]
- Kitchiner D, Jackson M, Malaiya N, et al. Incidence and prognosis of obstruction of the left ventricular outflow tract in Liverpool (1960-91): a study of 313 patients. Br Heart J. 1994;71:588.
- De Vries AG, Hess J, Witsemburg M, et al. Management of fixed subaortic stenosis- a retrospective study of 57 cases. J Am Coll Cardiol. 1992;19:1013-7.
- Bezold LI, Smith O, Kelly K, et al. Development and validation of an echocardiographic model for predicting progression of discrete subaortic stenosis in children. Am J Cardiol. 1998;81:314–20.
- Choi JY, Sullivan ID. Fixed subaortic stenosis: anatomical spectrum and nature of progression. Br Heart J. 1991;65:280.
- Lopes R, Lourenco P, Goncalves A, et al. The natural history of congenital subaortic stenosis. Congenit Heart Dis. 2011;6:417–23.
- De Agustin J, Gomez de Diego J, Marcos-Alberca P, et al. Combined subaortic membrane and aortic valve stenosis: additive value of three-dimensional echocardiography. Eur Heart J Cardiovasc Imaging. 2014;15(4):388.
- Piacentini G, Marino B, Digilio M. Familial recurrence of discrete membranous subaortic stenosis. J Thorac Cardiovasc Surg. 2007;134:818–9.
- Warnes C, Williams R, Bashore TM, 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. J Am Coll Cardiol. 2008;52:e143–263.
- Valeske K, Huber C, Mueller M, et al. The dilemma of subaortic stenosis: A single-center experience of 15 years with a review of the literature. Thorac Cardiovasc Surg. 2011;59:293–7.
- Barkhordarian R, Uemura H, Rigby ML, et al. A retrospective review in 50 patients with subaortic stenosis and intact ventricular septum: 5-year surgical experience. Interact Cardiovasc Thorac Surg. 2007;6:35–8.