Introduction to cardiac conditions PICU cardiac course 2014

Objectives: At the end of this session I will be able to… Describe the normal heart structure Describe common cardiac conditions including; Signs and symptoms Management and treatment Discuss different cardiac shunts

Normal Heart Anatomy

Cardiac pressures and Sa02 This is important for later on when we review different cardiac conditions.

Cardiac Terminology Cardiac output- CO=HR x SV (Heart rate- no of heart beats per minute) x (Stroke volume- the amount of blood expelled by the left ventricle with each contraction) Preload- The stretch on the heart before it contracts Afterload- It refers to the resistance against which the ventricles must work against to eject their blood volume Contractility- Refers to the strength and efficiency of a contraction. Rubber band analogy: Need rubber bands Need balloon with water Show balloon with water to demonstrate preload- good amount of fill, plus low resistnace pushing it out as well as a forceful good contraction from the ventricle

8–10 in 1000 births have some kind of congenital heart abnormality Hear disease is the leading cause of childhood deaths with 1 in 3 children having a CHD

Classification of Congenital Heart Disease Congenital Cardiac Disease Acyanotic 75% Cyanotic 25% Increased pulmonary blood flow Obstruction of flow from ventricles Decreased pulmonary blood flow Mixed blood flow Source: http://www.racgp.org.au/gplearninglinks/ccheartdefects_may2000.htm

Lesions with increased blood flow (Acyanotic) ASD VSD AVSD PDA Why do they have increased blood flow?? What does an unbalanced AVSD indicate? Get particpants to draw defects on the whiteboard

Obstruction to blood flow from ventricles (Acyanotic) Coarctation of the aorta Aortic stenosis Pulmonary stenosis

Decrease pulmonary blood flow (Cyanotic) Tetralogy of fallot Tricuspid atresia

Mixed blood flow (Cyanotic) TGA TAPVD Truncus arteriosus Hypoplastic left heart syndrome Mixed blood flow...purple blood! To pause pictures, right hand click the screen

Atrial Septal Defect An Acyanotic increased pulmonary blood flow lesion. Opening between the atria. * 5-10% of congenital heart disease More common in females than males Atrial septum is divided into 2 parts- the primum, which is a thin mobile tissue which developes forst and then the septum secundum which is thick and muscular and develops second. It contains the PFO. Types of ASD include; Sinus venosus ASD: this occurs at the entrance of the SVC or IVC and close to the opening of the right atrium Coronary sinus ASD: this is also known as unroofing of the coronary sinus- where deoxygenated blood from the heart muscle is returned to the left atrium. This will result in cyanosis. Secundum ASD: this occurs at the PFO level. If the septum primum is normal then the defect is classified as a patent formaen ovale. Primum ASD: Located at the bottom end of the septum, next to the AV valves. Source: www.rch.org.au

Signs & Symptoms Left to right shunting Most patients asymptomatic Present 3 to 6 weeks with soft murmur and can have a large heart on x-ray. Present with poor feeding, lower respiratory tract infection and small amount of heart failure. Cyanosis infrequent. Why left to right shunting?? Effects of left to right?? Why respiratory infection? Why not cyanotic?

Treatment Spontaneous closure likely of small secundum type ASD’s. Device closure. Surgical correction either by pericardium patch or sutures. What is a device closure? How do they do a pericardium patch? Source: www.rch.org.au

Ventricular Septal Defect An Acyanotic lesion with increased pulmonary blood flow. Opening between the right and left ventricle. * 30% of congenital heart disease Associated with Downs Syndrome in approximately 11% of patients. Also linked with parental use of marijuana and cocaine. Why does it have more effects on pulmonary circulation? What are the effects of too much pulmonary blood flow? Why does it shunt left to right? Different types of VSD: Perimembranous VSD: Located within the membrane septum. The majority are classified in this group. Muscular VSD: located anywhere in the muscular portion fo the septum. About 33% are muscular. Inlet VSD: located beneath the AV valves Outlet VSD: located within the septum and limited by the pulmonary valve. Doubly committed VSD: close to the semilunar valves. Source: www.rch.org.au

1, 2, 3: Muscular VSD 4: Perimembranous VSD. Where they can sit posterior in the septum or anterior towards the aortic valve. 5: Doubly committed- where it sits just below the pulmonary and aortic valve

Signs & Symptoms Majority of undiagnosed presentations occur at 6-8 weeks of age as the Pulmonary Vascular Resistance falls. Left to right shunting Small shunt causes patient to be asymptomatic A large shunt will increase pulmonary blood flow, leading to tachycardia, increased respiratory rate, sweating, poor feeding and poor weight gain. Why does it have more effects on pulmonary circulation? What are the effects of too much pulmonary blood flow? Why does it shunt left to right? QP:QS ratio will be determined. If this is less than 2, then the child is at low risk of PHT and therefore, may not be operated on- will usually close spontaneously. QP:QS ration >2 meaning that the ratio of pulmonary blood flow to systemic flow is 2 times greater- increasing risk of PHT. Large VSD: when the VSD is the same size as the aortic valve opening.

Eisenmenger’s Complex Increasing Pulmonary Vascular Resistance to protect overflow of blood. Causes changes to vasculature- irreversible. PVR>SVR= shunt reversal= cyanosis This is for a large VSD which is big enough to cause a large Left to right shunt. If surgical intervention is not performed, the damage to the vessels becomes ireversible and the patient will end up with PHT.

Treatment Medical Therapy i.e.. Lasix, Aldactone Surgical Repair with a device. Source: www.google.com

Patent Ductus Arteriosus A cyanotic heart disease with increased pulmonary blood flow Persistent opening between the main pulmonary artery and aorta. Closure begins 10-15mins after birth. Complete closure 3 weeks post birth. Question to participatns: Do they remember the term persistent fetal circulation? A: when the pulmonary vascular resistance doesn’t naturally fall as it does in a normal baby, and the PVR remains high. Source: Pedheart

5-12% of congenital heart disease Again, more common in females than males if term, More common in premature babies compared to term In fetal circulation, approximately 60% of the normal right heart cardiac output is directed into the duct and aorta. At this stage the duct is as large as the descending aorta. YOUTUBE VIDEO

Signs & Symptoms Left to right shunt controlled by diameter of PDA. Small PDA – Resistance to flow high across ductus. Large PDA – CHF, poor feeding, increased respiratory rate and slow weight gain. When they say left to right what do they mean? Where does it flow?

Failure of the PDA to close Closure depends on: 1) increased oxygenation with first breaths= constriction of the ductal tissue 2) Reduction in naturally occurring prostaglandin= contraction of the muscular ductal tissue. Delayed closure due to; prematurity, mechanical ventilation and diuretics, reduced partial pressure of oxygen, maternal infection Prematurity: the development of contractile tissue only occurs after 30 weeks gestation and the duct is significantly less sensitive to the increase in partial pressure of oxygen resulting in a persistent PDA. Mechanical ventilation and diuretics: triggers an increase in circulating prostaglandins and relaxes the muscular wall of the PDA Reduced partial pressure of oxygen: due to a cyanotic heart condition, living at high altitude, respiratory distress syndrome Maternal infection: for example rubella syndrome/ GBS positive- if become septic can cause increased pulmonary hypertension

Treatment Medical Management Cardiac Catheter Surgical Management – Use of diuretics and fluid restrictions. Cardiac Catheter – Coils or balloons used to ligate PDA via cardiac catheter. Surgical Management - Ligation via thoracotomy with no bypass. Limit fluid, give diuretics...why?? Pre and post ductal Sa02....have a think for the next lectures

Tetralogy of Fallot A cyanotic lesion with decreased blood flow. 2 types of TOF - Pink TOF - Cyanotic TOF Made of 4 components: 1. Stenosis of Pulmonary Artery 2. Ventricle Septal Defect 3. Right sided aorta. 4. Hypertrophic right ventricle. Source: Pedheart.org.au

Signs & Symptoms Right to left shunting Hypoxic Spells or ‘TOF Spells’ - Induced by crying, cyanosis, increased respiratory rate. - Decreased pulmonary blood flow caused by infundibula muscle spasm. - Prolonged hypoxia = Loss of consciousness, brain damage. Why right to left shunting? Why are the pressures all of a sudden higher on the right? Great word...infundibular!! Child cries, tenses, infundibular muscle spams= worsening of pulmonary stenosis= less blood flow to the lungs, therefore less return to the heart= low blood pressure. What do parents do to helpt heir child? Squatting, lift legs and feed to keep calm Therefore, these children are often very well fed!! Pink Tof- not many spells Blue TOF- many TET spells

Treatment Hypoxic Spells – Squatting increases systemic vascular resistance -Morphine, volume - Oxygen and mechanical ventilation. TOF – Surgery – BT Shunt - TOF Repair Squatting increases the SVR, therefore there is more reistance to blood flow to the aorta, and more available for the pulmonary circulation. Parents also feed a TOF to keep them calm, therefore they end up being somewhat chubby! Source: www.rch.org.au

Coarctation of the Aorta Acyanotic heart lesion with obstruction to flow from left ventricle. Discrete Narrowing of the aortic arch. Source: www.rch.org.au

6-12% of Congenital heart disease More common in males than females. 2:1 ratio

Signs & Symptoms Right to left flow across PDA to descending aorta. Higher BP’s in arms than legs. Degree of cyanosis depending on degree of narrowing of coarctation. Severe coarctation will show signs of decreased ventricular function, heart failure, poor feeding etc.

Pre and Post Duct presentation Post ductal is more common Perfusion of the lower limbs depends on coallterals being formed Where does the Sa02 probe go

Treatment Prostin at birth to reopen/ maintain PDA Catheter – Dilation of aorta with balloon. Surgical Repair – Aorta dissected and end-to-end/ end to side anastomosis Source: www.rch.org.au

Transposition of the Great Arteries A cyanotic heart lesion with mixed blood flow. Aorta and Pulmonary artery positioned across ventricle from original position. On average greater than normal birth weight The eggbeater disease- each ahs it’s own circulation- no interaction! What will happen when the PDA closes? What would happen if there was no VSD/ ASD? CCTGA The heart has recognised the abnormal position of the great arteries and so the ventricles grow to accommodate this change. The Right ventricle which is meant to be pumping to the lungs and therefore not as strong becomes the left ventricle and the left ventricle pumps to the lungs- this is an issue as the higher pumping venetricle is now pushing at high pressures to the lungs. Source: Pedheart

4-5% of congenital cardiac disease Second most common lesion More common in males than females withr atio of 3:1 If left untreated, high mortality in first year of life

Treatment At birth – Prostin to maintain PDA Balloon Atrial Septostomy, if no VSD Switch Repair- usually Day 7-10 Reimplantation of the coronary arteries therefore there can be some ischaemic changes- high troponin levels and may need to be commenced on GTN. Source: www.rch.org.au

Hypoplastic Left Heart Syndrome A cyanotic heart lesion with mixed blood flow. Hypoplastic left atrium, left ventricle and aorta arch. 25% chance of death in first week of life. No Systemic flow unless PDA or intra atrial communication is present. Source: rch.org.au and Pedheart

Signs and Symptoms Right to left shunting across PDA to allow systemic blood flow. Falls in pulmonary vascular resistance sees blood diverts to lungs rather than systemic system i.e. SaO2 97-100% Rise in pulmonary vascular resistance sees greater systemic blood flow at a price of hypoxia. Increased systemic resistance drops systemic output leading to shock. Pulmonary congestion can occur if atrial communications are small. Cyanosis present even with PDA.

1-2% of all congenital heart defects Resposible for the highest cause fo death.

Treatment Medical – Prostin used prior to surgery to maintain PDA. Surgical: Norwood – Day 2. - Main pulmonary artery divided to construct aorta. - PDA ligated, BT shunt inserted and ASD maintained. BCPS – aprox 4months Fontan – aprox 4-5yrs Why do they have to wait before moving to the next stage…why no just do fontan from the start???

Types of Shunts Blalock-Taussig shunt (BT Shunt) (Classic and Modified) Bidirectional cavopulmonary shunt (BCPS) Central shunt Fontan

Blalock-Taussig Shunt Alfred Blalock Helen Taussig Vivien Thomas- Surgical tech Source: http://images.google.com.au

“as an utterly miserable, small six-year old boy who was no longer able to walk." His skin was intensely blue, his lips deep purple. Just after the final stitches were tied and the clamps released, the anesthesiologist called out, "The boy's a lovely color now!" Dr. Taussig remembered the thrill of walking around to the head of the operating table to see those "lovely normal pink lips." She reported that after his recovery from the operation he was a happy, active child. This was the first op notes from the BT shunt This was the account of the third child to receive the BT shunt http://www.medicalarchives.jhmi.edu/firstor.htm

Modified Blalock-Taussig Shunt Gortex tube sewn between aorta and pulmonary artery Palliative shunt Steals from systemic blood flow to increase pulmonary blood flow Draw on whiteboard the sharing of systemic and pulmonary blood flow Why do this instead of the central shunt? MBTS is useful when CBTS cannot easily be performed, such as on the same side as the aortic arch. They also maintained that pulmonary artery distortion is less likely than with CBTS.

Central Shunt Graft between ascending aorta and main pulmonary artery High pressures Graft size determines the size of the shunt The advantages of this technique are as follows: Applicability to small children with small peripheral vessels Prevention of distortion of pulmonary arteries Provision of equal pulmonary blood flow to both lungs Lower occlusion rate (compared with the CBTS or MBTS techniques) Avoidance of subclavian artery steal Ease of closure during corrective repair

Bidirectional Cavopulmonary Shunt (BCPS) SVC separated at the join to right atrium SVC anastomose to right pulmonary artery Increases pulmonary blood flow Decrease volume of blood returning to heart Improved arterial oxygenation First stage of Fontan More definitive than the BT shunt. Source: www.rch.org.au

Aims of BT and BCPS/Glenn Palliative measure Growth of Pulmonary arteries Lead up to fontan Reduces cardiac workload/CCF Provides adequate pulmonary flow and better systemic oxygen delivery Usually done at about 6 months, to allow growth of the PA’s to cope with increased blood flow.

Fontan Final stage of palliation Done from 18months of age. Seperates the systemic and pulmonary circulations. Right ventricle has to be the systemic pu,ping chamber. Not definitive!

The Fontan 3rd stage can be performed from 2-16 years of age Systemic blood flow is redirected from both IVC and SVC directly to pulmonary arteries Optimises cardiac output Intracardiac and Extracardiac

Intracardiac A tunnel-like patch is placed inside the atrium so that blood returning from the IVC is directed through this tunnel Atrial Septum removed Less common After many years, it was observed that the right atrium of some of the children who had a Fontan operation was progressively dilating. This dilatation seems to be occurring because of the turbulences of the blood as it was arriving from the veins coming from the body into this collecting chamber. This dilatation was annoying, because it was responsible for the formation of clots in the heart, and some of these patients had fast heart rates that made them sick

Extracardiac Fontan The IVC is sewn directly onto a conduit, and the underside of the pulmonary artery Routing the blood flow outside of the heart The atrial septum is removed if not done already Less complicated Less incidence of effusions and arrhythmias Fenestrated Fontan: Pop off valve for the blood flow. If the pressures are too high in the pulmonary system, blood will pop off into the right atrium- which is actually the systemic atrium so the baby will be bluer and have lower sats.

Fenestrations In either method, a hole or “fenestration” is often made between the Fontan circuit and the right atrium Fenestrated Fontan: This fenestration is like a pop-up valve acting as a safety mechanism. It is known to be particularly useful soon after surgery. If the pressures are too high in the pulmonary system, blood will pop off into the right atrium- which is actually the systemic atrium so the baby will be bluer and have lower sats. It is not yet known whether it is good or not to keep this fenestration open for a long time or not. Some believe that it improves the exercise capacity, because on the peak of maximal exercise, some more blue blood will go to the heart and the heart will then be able to pump more blood through the body. Others think that the heart will not function as well if the blood that the heart ejects is more blue (with less oxygen), and believe that the patients will be able to exercise better with the fenestration closed. We hope that future research will be able to show wether Fontan patients would be better with or without fenestration late after surgery. Circulation Journal (Circulation. 2007;116(suppl 1):1-157-1-164) 

Who qualifies for a Fontan Generally children with single ventricle lesions Tricuspid Atresia HLHS Pulmonary Atresia Double Inlet Left Ventricle Double outlet Right Ventricle (with other defects) Ebstein's Anomaly all children who are born with abnormal hearts that cannot be repaired with two pumping chambers (ventricles

Outcomes Post fontan- Sa02 90’s <4 mortality rates 20% 4-16yo mortality rates 7-8% Limitations Experience can vary greatly on how active they were prior to surgery Still Palliative!! Will need a heart transplant in the future. Results from a study last year announced that almost all children (98%) survived the first 14 years after their Fontan operation. Overall the outcomes of the patients were by far better than all expectations!!! Fontan registry The Fontan Registry is a database collecting health information on Fontan patients living in Australia and New Zealand. It is hoped this will be the largest Fontan database in the world, providing researchers and doctors with information to help improve treatment options and long-term health outcomes for patients. The database does not identify patients, with personal data only accessible to the patient's treating doctor in the same state or country 2 questions the fontan registry needs to answer… How long can the Fontan operation last, and can it last forever? Which are the best drugs to take after a Fontan operation to maintain the best possible health?

http://www.fontanregistry.com/

Questions??