Cardiac Disorders

Gross Structure Hollow, Muscular organ 4 chambers. 2 layered sero fibrous sac-Pericardium. Endocardium. Rt & Lt atria/ventricles. Interatrial septum. Interventricular septum.

Valves Atrioventricular valves:Rt Tricuspid & Lt Mitral.

Pulmonary valve-Rt. Aortic valve-Lt.

Blood Supply Rt & Lt coronary arteries. During diastole. Venous drainage: Coronary sinus  Rt atrium.

Circulation Deoxygenated blood  Rt atrium  Tricuspid

valve  Rt ventricle  Pulmonary valve  Pulmonary circulation. Oxygenated blood  Pulmonary vein  Lt atrium

 Mitral valve  Lt ventricle  Aortic valve  Aorta  Systemic circulation.

Cardiac cycle Sequence of events takes place during a

single beat of the heart. 70 to 75 Bpm. Each beat – 8/10th a second. Atrial systole – 1/10th second. Ventricular systole – 3/10th second. Relaxation – 4/10th second.

Atrial Systole Closes SVC, IVC, Pulmonary veins & Coronary

sinus. AV valves open. Blood enters ventricles.

Ventricular Systole Atria relax. Blood enters into atrium. Closes AV valves. Opens Aortic & Pulmnary valves. S1 – Lubb – AV valve cosure.

Total Diastole Aortic & Pulmonary closure. AV valve opens. S2 – Dup – Closing of Aortic Pulmonary valves.

Contraction of Heart SA node (Rt atrium near to SVC open)  Impulses

 Atrial muscle  AV node (Rt atrium near interatrial septum and ventricle)  Atrioventricular bundle  Purkinji fibres.

Regulation of Heart Beat Automaticity. CNS. Regulation by ANS :– Parasympathetic Vagus nerve & Sympathetic nerves. Cardioaccelerator (sympathetic)&

Cardioinibitor(Parasympathetic) centre -Medulla. Hormones – Adrenal medulla of kidney – ↑rate.

Congestive Cardiac Failure(CCF) Def: “inability of the heart to maintain an

output, at rest or during stress, necessary for the metabolic needs of the body(systolic failure) and inability to receive blood into the ventricular cavities at low pressure during diastole(diastolic failure)”.

Etiopathogenesis Heart failure due to diastolic dysfunction: i. Mitral or tricuspid stenosis ii. Constrictive pericarditis iii. Restrictive cardiomyopathy iv. Acute volume overload(acute aortic or mitral regurgitation) v. Myocardial ischaemia vi. Marked ventricular hypertrophy vii. Dilated cardiomyopathy

Causes of CCF: Infants: Congenital heart disease Myocarditis & primary myocardial disease Paroxysmal tachycardia Anemia Miscellaneous:

1. 2. 3. 4. 5. •

Infections, Upper respiratory infection, Hypoglycemia, Hypocalcemia, Neonatal asphyxia, Persistent fetal circulation

CCF causes: Children: 1.

Rheumatic fever & RHD

2.

CHD complicated by anemia, infection & endocarditis

3.

Hypertension

4.

Myocarditis & primary myocardial disease

5.

Upper respiratory obstruction

Congenital Heart Disease Left to Right shunts: CCF within 6-8 wks of life. at birth pulmonary resistance is high 

pulmonary pressure = systemic pressure.

 Right to Left shunts: CCF does not occur. With pulmonary or tricuspid atresia  CCF

Obstructive lesions: Mild  Late CCF. Severe  CCF. E.g: COA.

Transpositions: Transposition of Great vessels  CCF within 2-3

months. Tachycardia & Anoxic Myocardium  CCF.

CCF in congenital lesion Age

Lesion

Birth-

Pulmonary, aortic & mitral atresias

72hrs 4day-

Hypoplastic left & right heart syndromes, Trans Of Great

1week 1-4weeks

Vessels TOGV, endocardial fibroelastosis, COA

1-

TOGV, endocardial cushion defects, VSD, PDA, Total

2months

anamolous pulmonary venous connection, Anamolous left coronary artery from pulmonary artery

26months

TOGV, VSD, PDA, TAPVC, Aortic Stenosis, COA

Myocardial disease Cause: Coxsackie B infection – age of few hrs

to 7 wks. Primary myocardial diseases: glycogen

storage disease, endocardial fibroelastosis, coronary artery necrosis, anomalous left coronary artery from pulmonary artery.  Left cardiac enlargement , absence of

murmurs, congestive failure, gallop rhythm & ECG showing conduction disturbance,

Arrythmias 3rd important cause of CCF in infancy –

paroxysmal supraventricular tachycardia. 4 months age, male predominate. Heart rate above 180BpmCCF.

Anemia With normal heart hemoglobin 5gm/dl CCF.

With diseased heart hemoglobin of 7-8gm/dl

CCF.

Infections :Upper & Lower respiratory tract 

CCF. Miscellaneous: hypoglycemia, neonatal

asphyxia, hypocalcemia. Rheumatic fever. Anemia and infections complicating CHD. Hypertension: with acute glomerulonephritis,

Clinical Features Symptoms: Slow weight gain. Easy fatiguability Excessive loss of calories for breathing Facial puffiness Pedal edema Irritable infant cry Orthopnea Wheezing Excessive perspiration

Signs Left sided failure

Failure of either

Right sided failure

Tachypnea

side Cardiac enlargement

Hepatomegaly

Tachycardia

Gallop rhythm(S3)

Facial edema

Cough

Peripheral cyanosis

Jugular venous engorgement

Wheezing

Small volume pulse

Rales in chest

Absence of weight gain

Pedal edema

Treatment 1. Reducing cardiac work 2. Augmenting myocardial contractility 3. Improving performance by reducing the

heart size 4. Correcting the underlying cause

Reducing cardiac work Bed rest, Sedatives(morphine, diazepam),

Treatment of fever, anemia, obesity. Vasodilators. Neonates: incubator, 30 degree incline. 36-37degree Celsius temp. Humidified oxygen. Antibiotics. Blood transfusion. Calcium channel blockers.s

Augmenting myocardial contractility Digoxin. Digitalis. Diuretics. Potassium chloride.

Improving performance by ↓heart size Digitalis. Diuretics(frusemide). Potassium supplement. Low sodium diets. Concentrated milk with protein preparations.

Correcting the underlying cause Curative / Palliative operations. Supraventricular tachycardiaverapamil

digoxin. Bed rest, vasodilators. Anticongestive measures. Betablockers. Steroid with immunosuppressants. Tonsillectomy and Adenoidectomy.

Stepwise Management Step one: frusemide, amiloride &

triameterene. Step two: adding digoxin. Step three: adding ACE-inhibitors & stopping diuretics. Step four: adding isosorbid nitrate. Step five: intermittent dobutamine & or dopamine. Step six: myocardial biopsy, steroids, betablockers. Step seven: cardiac transplantation.