A dual Doppler technique has been described recently, for simultaneous measurement of E and e’ so that the ratio E/e’ can be calculated in the same beat itself. This avoids the beat to beat variation in these values which would compound a non simultaneous measurement. Short of this novel technique, any measurement in atrial fibrillation would need averaging of values for five to ten cardiac cycles. Mitral diastolic E wave deceleration time of less than 100 milliseconds correlates with a pulmonary wedge pressure of more than 18 mm Hg. Deceleration time is the duration between the peak of the E wave and the upper deceleration slope extrapolated to the baseline. It is usually measured from the apical four chamber view. Pulmonary vein diastolic wave deceleration time is also measured in a similar way from the right upper pulmonary vein in the apical four chamber view.

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

Katz-Wachtel sign / phenomenon

Click on the image for an enlarged view

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.

Myocardial strain: [L - L₀)] / L₀

Strain rate measured as the rate of deformation and the integral of strain rate over time give the strain. Strain rate has high resolution for evaluation of regional myocardial function and is an early indicator of regional myocardial dysfunction. In strain assessment, tissue Doppler technique is used to determine tissue velocities at two adjacent points along with the relative distance between the points. The instantaneous rate of change in the two velocities divided by the instantaneous distance between the two points is the strain rate. Positive values for strain rate indicate active myocardial contraction and negative strain rate indicates relaxation. Strain rate has a unit of sec^-1 while strain is unitless. Strain and strain rate subtracts movement due to tethering effect of adjacent myocardium and hence represents the true regional function. Since they are deformation per unit length, they are also normalized for heart size and hence useful in children with different heart sizes.

Trivial AR on color Doppler echo

Trivial aortic regurgitation (AR) on color Doppler echocardiogram. Such trivial AR jets are quite common and does not usually have any added significance. RA: right atrium; Ao: aorta; LA: left atrium; LV: left ventricle. This is a modified five chamber view.

Aortic arch is visualized by placing the transducer in the suprasternal view. Ascending aorta (Asc Ao), aortic arch (Ao Arch) and descending aorta (Desc Ao) are seen in this view. This view can be used to visualize coarctation of aorta, descending aortic flow reversal in severe aortic regurgitation and to assess the aortic valve gradient from the supra sternal view. It is useful in congenital heart disease to assess the relation between aorta and pulmonary artery as the aorta is always superior in this view.

High dose dobutamine infusion is given at: 20 micrograms/kg/min (twenty micrograms per kilogram body weight per minute)

Ischemic, but viable myocardium will show improvement in wall motion at low dose dobutamine with worsening at high dose dobutamine infusion. There is will be no such response for scarred myocardium which is non viable and it will show akinesia.

Wall motion scoring is graded as follows:

Normally contracting segment: 1
Hypokinetic segment: 2
Akinetic segment: 3
Dyskinetic segment: 4

Wall motion score index (WMSI) can be calculated as an average score of all the visualized segments.