Heart disease and infective endocarditis

Question 1

What is Myocardial Infarction? How is it different from angina pectoris? (5)

Answer 1

Myocardial infarction: irreversible death (necrosis) of heart muscle secondary to prolonged lack of oxygen supply (ischemia).

Angina pectoris – chest pain due to insufficient blood supply to the heart muscle from the coronary arteries.

Note: Angina is usually due to obstruction or spasm of the arteries that supply blood to the heart muscle.

Question 2

What are the investigations to take place for myocardial infarction?

Answer 2

Electrocardiogram, blood pressure measurement, blood cholesterol level, angiogram (contrast medium with chest radiograph)

Question 3

What are the risk factors for MI? (3)

Answer 3

Age
Tobacco
High blood pressure
Obesity
Diabetes
Stress

Question 4

List some clinical signs of MI

Answer 4

Fatigue; chest discomfort +/chest pain; malaise

Anson: central crushing chest pain, sweating etc

Question 5

What is the management of MI? (5)

Answer 5

Call 999 –>

1. Assess patient airway, breathing, circulation
2. If none, then proceed to CPR (30 compressions (@100 compressions per minute) + 2 breaths (if there is pump available)
3. Use AED if available
4. Continue CPR until ambulance arrives

Question 6

What is infective endocarditits & the common micro-organisms involved? (3)

Answer 6

Infection of the endocardial surface of the heart
Microorganisms

Staphylococcus aureus
Streptococci
coagulase negative Staphylococci
Enterococci

(S/S: Fever, malaise, fatigue, heart murmur, weight loss, coughing)

Question 7

How could dental extraction lead to IE? Common oral micro-organisms involved (10)

(Anson: as this is a long question therefore covered over question 7, 8, 9)

Answer 7

Dental procedures involving gingival manipulation, periapical and mucosal perforation act as a portal of entry for organisms causing bacteremia

Note that it is almost impossible to have IE without compromised endocardial integrity (e.g. congenital heart defects, heart structural problems)

Question 8

What are the consequences of patient having a heart defect?

Answer 8

Microorganisms in mouth reach heart through circulation

Consequences
1. Colonise the initially sterile vegetation(i.e. the defect on endocardium of the heart, such as defective valves, damaged valves – these have poorer immune defense against vegetation) composed of fibrin and platelets

2. Bacteria grows –> enlarge vegetation –> impede blood flow –> inflammation of endocardium –> IE

Question 9

What are the complications of IE?

Answer 9

Complications: stroke (embolism by vegetation fragment), infection of other organs, heart failure

Question 10

What are the aetiological factors of IE (2 or 3)

Answer 10

Artifical heart valves, congenital heart defects, damaged heart valves (e.g. rheumatic fever)

Question 11

What are the most update guidelines for antibiotic prophylaxis? (5)

Answer 11

Needed for:

Prosthetic heart valves, including bioprosthesis and homografts.

History of prior IE.

Selected congenital heart disease

Question 12

What are the selected congenital heart disease that require antibiotic prophylaxis?

Answer 12

Completely repaired
congenital heart defects with prosthetic material/device, whether placed by surgery or by catheter intervention, during the first 6 months post-procedure.

Repaired congenital heart disease with residual defects at the site or adjacent to the site of the prosthetic device. ( Except for the conditions listed above, PAP is no longer recommended for any other form of congenital heart disease, including VSD and ASD).

Cardiac valvulopathy in a transplanted heart.

Anson: look over page 11 last question

Question 13

Apart from antibiotic cover, what are the precautions in dental treatment?

Answer 13

May be excessive bleeding, poor wound healing, easier to faint or risk of heart attack.

Question 14

What is the investigation for determining cause of murmur?

Answer 14

Auscultation

Echocardiography (ultrasound of the heart) – to detect any atrial enlargement, thickening of valves, and area of orifice

Question 15

Patient is diagnosed with mitral stenosis, what is the most common cardiac complication for patients with cardiac arrhythmias?

Answer 15

• Heart failure
• Heart enlargement
• Atrial fibrillation
• Blood clots
• Pulmonary hypertension

Question 16

What is the potential cardiac problem related to dentistry?

Answer 16

Sudden collapse; Chest pain; Shortness of breath

Question 17

What are the preventive measures for the potential cardiac problems related to dentistry? (question 15, 16, 17 are connected)

Answer 17

For atrial fibrillation: anticoagulants, diuretics, anti-arrhythmic
Antibiotic prophylaxis (if have prosthetic heart valve)

Question 18

Give 2 medications that the patient should take to prevent stroke?

Answer 18

Anticoagulants (warfarin), heart rate control (beta blockers)

Question 19

Name 2 medications to prevent stroke in patient with atrial fibrillation (2marks)

Answer 19

Anticoagulants (warfarin), heart rate control (beta blockers)

Anson: IF AF –> anticoagulate regardless of stroke or not

Anticoagulants are superior to HR control medication (beta blockers)

Question 20

Will you suggest patient taking the medication until the day for operation? (1marks)

Answer 20

Ask physician. Usually just continue taking.

Explain the answer:
Not taking may increase risk of thromboembolism. Can use local hemostatic measures such as gelfoam.

Question 21

What are the causes of coronary heart disease?

Answer 21

Causes

1. Narrowing or blocking of coronary artery that disrupt the balance of oxygen supply and oxygen consumption by cardial cells
2. Deposit of cholesterol –> atherosclerosis
3. Risk factors include smoking, DM, obesity, hypertension

Question 22

What are the significance of coronary heart disease?

Answer 22

Significance

1. Untreated condition can result inlife-threateningheart attack
2. Symptoms can be silent, early detection is important
3. Condition can be prevented and treated in early stage

Question 23

What are the treatments of coronary heart disease?

Answer 23

1. Lifestyle modification (exercise, low cholesterol diet, smoking cessation)
2. Medication (statin, antihypertensive)
3. Coronary artery bypass grafting (using a vein grafted from arm/legs to create new pathway)
4. Percutaneous transluminal coronary angioplasty (PTCA–placing inflating balloon within artery)

Question 24

What is rheumatic heart disease?

Answer 24

Rheumatic heart disease is a condition in which the heart valves have been permanently damaged by rheumatic fever. The heart valve damage may start shortly after untreated or under-treated streptococcal infection such as strep throat or scarlet fever. An immune response causes an inflammatory condition in the body which can result in on-going valve damage.

Question 25

What are the clinical management and precautions for patients with this disease?

Answer 25

• Treatment of RHD involves pharmacological therapy like aspirin and antibiotics
• Caution possible drug interactions
• Reasonable to defer elective dental treatments if patient is under active medical treatment, until after consultation with physician