Swiss cheese ventricular septal defects
Multiple muscular ventricular septal defects (VSD) are also called ‘swiss cheese’ VSD. Swiss cheese VSDs are difficult to close surgically. It is difficult to locate the openings of the VSD from the right ventricular side. Some may have multiple right ventricular openings for a single left ventricular orifice. When one right ventricular orifice is closed, the VSD may be seen puffing from another orifice. These VSDs require left ventriculotomy for closure which is a problem in a small infant. Due to the difficulty fo surgical closure, often a pulmonary artery banding is all that is done in these cases, to control the excessive pulmonary blood flow and development of pulmonary arterial hypertension. Swiss cheese VSDs are associated with left axis deviation on ECG.
Katz-Wachtel phenomenon / sign on ECG in ventricular septal defect
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The Katz-Wachtel sign is tall diphasic RS complexes at least 50 mm in height in lead V2, V3 or V4 – mid precordial leads [Circulation 1963;27;1118-1127 (Free full text at: http://circ.ahajournals.org/cgi/reprint/27/6/1118.pdf); original description by Katz and Wachtel was published in 1937: Katz LN and Wachtel H. The diphasic QRS type of electrocardiogram in congenital heart disease. Am Heart J; 1937, 13: 202-206]. The sign has been described in ventricular septal defect with biventricular hypertrophy in children. It can be seen with isolated ventricular septal defect as well as complex ventricular septal defect. In fact the Circulation article cited is on Complete Transposition of the Great Vessels: II. An Electrocardiographic Analysis by Larry P et al.
Ventricular septal defect – perimembranous
Perimembraneous ventricular septal defect (VSD)
Medium sized ventricular septal defect in peri-membranous location seen from the apical five chamber view. RV: right ventricle; LV: left ventricle; VSD: ventricular septal defect; Ao: aorta; RA: right atrium; LA: left atrium; IVS: interventricular septum. There is aneurysm of the inteverventricular septum covering the VSD, leaving a small gap. The VSD jet passes through this small defect which is restrictive (below).
VSD Jet on continuous wave Doppler
VSD jet documented by continuous wave Doppler interrogation, showing an interventricular gradient of 61.5 mm Hg, which suggests that the defect is restrictive. Actual gradient may be even more as this jet has an incomplete envelope.
Echocardiographic profile in ventricular septal defect
Ventricular septal defect (subaortic) seen from parasternal long axis view
Parasternal long axis view showing aorta (Ao), left atrium (LA), left ventricle (LV) and a small perimembranous (subaortic) ventricular septal defect. Mitral valve is in the open position and the aortic valve in the closed position.
VSD Jet visualised by colour flow mapping (colour Doppler)
Colour sector in parasternal long axis view shows the mosaic (multi-coloured) VSD jet across the perimembranous VSD from the left ventricle to the right ventricle. It is a high velocity jet because the VSD is restrictive. The neck of the jet almost corresponds to the size of the VSD. VSD jet is seen in a systolic frame.
Continuous wave Doppler interrogation of VSD jet
VSD jet can be picked up in parasternal long axis or short axis view, guided by color Doppler. It may also be picked up from the apical four chamber view, but the allignment may not be good. Pulsed Doppler cannot measure the jet velocity as it is much higher than the Nyquist limit of the pulsed Doppler system. Hence continuous wave Doppler is used for interrogation of the VSD jet. The interventricular gradient is calculated using the Bernoulli equation. A high interventricular gradient indicates that the VSD is restrictive. A low gradient indicates unrestrictive VSD and pulmonary hypertension.
Colour Doppler echocardiogram video in perimembranous ventricular septal defect.
Ventricular septal defect and aortic regurgitation
Aortic regurgitation is more likely to occur in subpulmonic ventricular septal defect (VSD) than perimembranous VSD. Aortic cuspal prolapse occurs in 4 – 9% of VSDs and aortic regurgitation in 2 – 6% of VSDs. But the prevalene of aortic cusp prolapse in subpulmonic VSDs is upto 73% and the occurrence of aortic regurgitation about 52 to 78%. While 62% of those with aortic cusp prolapse along with subaoric VSD have aortic regurgitation, 77% to 90% of those with subaoric VSD and aortic regurgitation have aortic cusp prolapse. A study by Saleeb SF et al Am J Cardiol. 2007;99:1588-92) evaluated 100 patients with subaortic VSD diagnosed in the first year of life, but did not need surgery in infancy were evaluated for the development of aortic regurgitation on follow up. The follow up period ranged from one to twenty four years with a mean of about seven years. Initial VSD size was small in 38 patients, moderate in 50 patients and large in 12 patients. Spontaneous closure of VSD occurred during the follow up period in 4 patients with at a mean age of 6 years with a range of 3.4 to 12.7 years. Three of them had small VSDs and one of them had a moderate sized VSD. Aortic cusp prolapse developed in 14 patients at a mean age of 7.1 years with a range of 0.4 to 18.4 years. The murmur of aortic regurgitation was audible in six patients at mean age of 5.1 ± 3.1 years. All of them had aortic cusp prolapse and underwent surgery with VSD closure and aortic valvuloplasty.
LV – RA shunt: echocardiographic video
A shunt from the left ventricle to the right atrium can occur in three ways: (1) Defect in the atrioventricular septum between the septal attachments of the mitral and tricuspid valves (2) A perimembraneous ventricular septal defect (VSD) with associated fenestration of the septal tricuspid leaflet so that the VSD jet is partly directed from the left ventricle across the interventricular septum through the tricuspid valve into the right atrium (3) Ventricular septal defect with tricuspid regurgitation so that the blood shunted from the left ventricle is passed immediately to the right atrium to produce a step up in oximetry.
A defect in the atrioventricular septum was described by Gerbode F et al in 5 operated cases in 1958 [Gerbode F., Hultgren H., Melrose D., Osborn J. Syndrome of left ventricular-right atrial shunt: successful surgical repair of defect in five cases, with observation of bradycardia on closure. Ann Surg 1958;148(3):433-446]. Anatomically this defect is possible because the septal attachment of the tricuspid valve is distal to that of the mitral valve so that there is a small region of the septum which is between the left ventricle and the right atrium, known as the atrioventricular septum. Usually the defect is congenital. But cases are on record in which the septal defect was acquired due to infective endocarditis. It is mentioned that congenital variety of defect occurs inferior to the tricuspid valve while the aquired variety is superior to the valve.
LV – RA shunt in perimembranous VSD across STL fenestration
The still image shows both the jet from the left ventricle to the right ventricle across the perimembranous VSD and the jet from left ventricle to right atrium across the VSD, through the fenestration in the septal tricuspid leaflet into the right atrium.
Echocardiographic video (color Doppler) showing LV – RA shunt through VSD, across the STL
Initial view shows the mosaic jet from left ventricle to right ventricle across the subaortic VSD as well as another jet traversing the defect in the septal tricuspid leaflet into the right atrium. This second jet resembles a tricuspid regurgitation jet. Second view is the parasternal short axis view of flow from the left ventricule to right ventricle, in the classical location of a perimembranous VSD.
During echocardiographic evaluation, the jet of the Gerbode VSD is likely to be mistaken as a tricuspid regurgitation jet. This will cause misinterpretation as severe pulmonary hypertension while in fact the right ventricular pressures may be low. This can be identified by carefully visualizing the jet origin on colour Doppler. The structural defect can also be seen by careful two dimensional imaging. Pulmonary arterial pressure can be counter checked by using the pulmonary regurgitation jet.
Hepatoclavicular view for left ventriculography
LAO (left anterior oblique) 40 degrees with 40 degrees cranial angulation is known as hepatoclavicular view. It is used to profile inlet ventricular septal defects. Sub pulmonic VSDs may be seen only in RAO (right anterior oblique) views.