Cardiophile for Cardiology Fellows

Infective endarteritis in patent ductus arteriosus (PDA)

Infective endarteritis is less likely in a very small PDA as well as a large PDA. It is more likely in moderate sized PDAs and small PDAs. Hence there is no role for closing very small PDA without continuous murmur. In PDA infective endarteritis, the vegetations occur either at the pulmonary end of the ductus or in the wall of the pulmonary artery opposite the ductus, where the jet strikes.

Why is neonatal myocardium more prone for cardiac failure?

Contractile elements form 30% of the fetal heart while it forms 60% in the adult. Immature myocytes lack sufficient sarcoplasmic reticulum and mitochondria. Hence the neonatal myocardium is more cardiac failure.

Angina in Eisenmenger PDA

In general angina due to right ventricular ischemia is rarer in Eisenmenger PDA compared to other forms of Eisenmenger syndrome. Angina has been reported in Eisenmenger PDA due to compression of left main coronary artery [Am Heart J. 1993;125:1767-71].

Left coronary angiogram in RAO caudal view

Left coronary angiogram in right anterior oblique (RAO) caudal view showing the left main coronary artery (LMCA), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCX). Obtuse marginal (OM) branch of LCX is also seen.

Left coronary angiogram in PA cranial view

Left coronary angiogram in postero-anterior (PA) cranial view showing a proximal plaque (arrow) in LAD, in this case a recanalised vessel after anterior wall myocardial infarction. Septal and diagonal (Diag) branches of LAD are also seen.

Left coronary angiogram in RAO cranial view

Left coronary angiogram in left anterior oblique (LAO) cranial view

Right coronary angiogram in left anterior oblique view

Full length of the right coronary artery is seen in a C shape in the left anterior oblique (LAO) view. Proximally it gives off the right ventricular branches and distally it divides into posterior left ventricular branch and posterior descending coronary artery. The division occurs at the crux, the crossing point of the inter ventricular and atrioventricular grooves posteriorly. The artery which crosses the crux is defined as the dominant coronary artery. Right coronary dominance is much more common than left dominance. Even when the right coronary artery is dominant, the major portion of left ventricular myocardium is supplied by the left coronary artery.

Total occulsion of right coronary artery

Total occulsion of right coronary artery, proximal to the major right ventricular branches can result in inferior wall myocardial infarction and right ventricular infarction. The catheter used in this case is a trans radial Tiger catheter. The contrast reflux into the aorta is also seen. The full right coronary artery with a mild lesion distally is shown below for comparison. In this case the catheter used is a trans femoral Judkins right coronary catheter. RCA: right coronary artery; PDA: posterior descending coronary artery.

Right coronary artery showing right ventrcicular branches and posterior descending artery

What is the most common reason for a patient who has undergone closed mitral valvotomy needing a mitral valve replacement later?

Mitral restenosis with calcification is the common reason for requiring mitral valve replacement later. Other possibilities are inadequate valvotomy and development of progressive mitral regurgitation, which could have developed during the procedure or later on due to recurrence of rheumatic activity.

How will you identify mitral restenosis and differentiate it from inadequate valvotomy? 

Historically there should have been a sustained improvement of at least 2 classes of NYHA for at least 6 months after the mitral valvotomy. Earlier recurrence of symptoms could be due to an inadequate valvotomy. An initial transient improvement is not enough to qualify for a successful valvotomy as even a slight increase in mitral valve area will produce subjective improvement in a patient with critical mitral stenosis and pulmonary congestion. To diagnose mitral restenosis, there should be at least 50% loss of the initial valve area and the absolute valve area should be below 1.5 sq cm. That would be mean that a diagnosis of mild mitral restenosis will not be tenable – mild mitral stenosis being defined as mitral valve area between 1.5 – 2.0 sq cm. Moderate mitral stenosis is defined as mitral valve area between 1.0 to 1.5 sq. cm. Mitral valve area below 1.0 sq cm constitutes critical or severe mitral stenosis. This is the level of obstruction needed to raise the transmitral gradient above 20 mm Hg and left atrial pressure to 25 mm Hg, the threshold for pulmonary edema.

What is chronic rheumatic carditis?

Rheumatic carditis lasting more than 6 months is considered as chronic rheumatic carditis. Evidence of recent streptococcal infection as an essential criteria for the diagnosis of rheumatic carditis cannot be applied in this situation.

What is patient prosthesis mismatch in aortic valve replacement?

An effective orifice area less than 0.7 sq cm per sq m body surface area for the aortic valve is taken as patient prosthesis mismatch in case of aortic valve replacement.

Ventricular tachycardia is defined as three or more consecutive premature ventricular ectopics in a series, at a rate above 100 per minute.

Mechanisms of VT

Reentrant – scar related, bundle branch reentry, fascicular tachycardia

Automatic – acute ischemia, electrolyte imbalance, increased sympathetic tone

Triggered activity – early and delayed after depolarisation, idiopathic right ventricular outflow tract VT

Sustained ventricular tachycardia

Ventricular tachycardia lasting more than 30 seconds or requiring termination before that due to hemodynamic compromise is termed sustained ventricular tachycardia. Unsustained ventricular tachycardia is one which lasts less than 30 seconds.

Idiopathic right ventricular outflow tract VT

Mechanism of idiopathic RVOT VT is triggered activity. It responds to beta-blockers and verapamil, but the current therapy of choice is radiofrequency catheter ablation. Usually there is no structural heart disease associated with this VT.

Bundle branch reentrant tachycardia

Circuit is confined to the left and right bundle branches. Most often the tachycardia has an left bundle branch block (LBBB) pattern and rarely a right bundle branch block (RBBB). Either case, the treatment is ablation of the right bundle. The sinus rhythm ECG can manifest an LBBB pattern. 

Rastelli procedure was intially designed for the repair of d-transposition of great arteries (d-TGA) with ventricular septal defect and pulmonary stenosis. Later it has been used for other conditions with two ventricles, overriding aorta and pulmonary stenosis or atresia. Rastelli procedure can be used for the repair of pulmonary atresia with ventricular septal defect and double outlet right ventricle (DORV) with pulmonary stenosis.

Rastelli procedure involves excision of the obrtructive muscle in the right ventricular outflow tract, suturing an intraventricular baffle connecting the left ventricle to the aorta and closing the ventricular septal defect. The right ventricle is connected to the pulmonary artery by a valved homograft conduit. The procedure is done under cardiopulmonary bypass, preferably under trans oesophageal echo guidance. It is an extensive procedure requiring moderate to long cardiopulmonary bypass time. Post operative inotropic support may be needed. Close monitoring and management of post operative arrhythmias are also needed.

Nitric oxide synthase

 eNOS: endothelial nitric oxide synthase

 iNOS: inducible nitric oxide synthase

 EDHF

 endothelium derived hyperpolarising factor

 Angiotensin II receptors

 AT2 receptor: stimulation of this receptor produces vasodilatation and is anti-proliferative

AT1 receptor: stimulation produces vasoconstriction, is pro-inflammatory

Brachial artery flow mediated vasodilation

A segment of brachial artery is measured by ultrasound and proximal occlusion is applied for a period of 5 minutes. Repeated measurement is taken after 1 minute and within 10 minutes, to assess the flow mediated vasodilation. More than 10% increase in the vessel diameter is taken as a positive response.

Atrial fibrillation with slow ventricular rate, ventricular bigeminy, bidirectional ventricular ectopy

 Click on the image for an enlarged view

Atrial fibrillation with slow ventricular rate, ventricular bigeminy and bidirectional ventricular ectopy. This combination can occur in digoxin toxicity. Ventricular ectopic bigeminy is a feature which can be seen in digoxin toxicity. Bidirectional ventricular tachycardia is another characteristic arrhythmia of digoxin toxicity. Other conditions in which bidirectional ventricular tachycardia can occur are catecholaminergic polymorphic ventricular tachycardia and Andersen-Tawil syndrome.

Atrial fibrillation with fast ventricular rate and  Mobitz type II AV block are two features which are never seen in digitoxicity.

Aortic regurgitation
Coronary anomalies
MAPCAS (major aortopulmonary collaterals)
PDA (patent ductus arteriosus)
Side of the aortic arch