Case 12 - Cardiac Arrhythmias

Question 1

Role of Ca2+ in vascular smooth muscle contraction

Answer 1

Begins an IP3 signal

Causes actin-myosin formation

Question 2

Role of Ca2+ in cardiomyocyte contraction

Answer 2

Causes calcium-induced-calcium-release

Induced actin-myosin bridging

Question 3

Definition of cardiac failure

Answer 3

Heart failing to pump effectively to meet the body’s oxygen and nutrient demands

Question 4

Features of systolic failure

Answer 4

Weak contraction, reduced ejection fracture

Question 5

Features of diastolic failure

Answer 5

Compromised relaxation, preserved ejection fracture

Question 6

Describe the renin-angiotensin-aldosterone system

Answer 6

When low BP is detected:

angiotensinogen -> angiotensin I -> angiotensin II

This activates the angiotensin II receptors which releases aldosterone and causes blood pressure to increase

Question 7

How do ACE (angiotensin converting enzyme) inhibitors work and give an example

Answer 7

Occupy the active site of the ACE that would normally taken by angiotensin I. Eg, ramipril

Question 8

How do ARBs (angiotensin receptor blockers) work and give an example

Answer 8

Shift the balance of receptors that angiotensin II binds to. If angiotensin I receptors are full then they occupy angiotensin II receptors which has an opposing effect and reduces blood pressure. Eg, Candesartan

Question 9

How do beta blockers work

Answer 9

Beta 1 adrenoceptor blockers than reduce cardiac output by having a negative chronotropic and inotropic effect

Question 10

How does digoxin work and what is it used to treat

Answer 10

Positive inotrope used for elderly/sedentary patients. Used to treat congestive heart failure, atrial fibrillation and atrial flutter

Question 11

How do loop diuretics work and give an example

Answer 11

Inhibits the Na+/K+/2Cl- symporter in the ascending loop. Eg, furosemide

Question 12

How do thiazide diuretics work and give an example

Answer 12

Acts on early distal convoluted tubules and may cause hypokalaemia. Eg, Bendroflumethiazide

Question 13

How do potassium sparing diuretics work

Answer 13

works by competing aldosterone for its mineralocorticoid receptor

Question 14

What is an SVT

Answer 14

Tachycardia not affecting the ventricles alone

Question 15

What is an ILR and what is it used for

Answer 15

An implantable loop recorder used to record heart arrhythmias over a long time

Question 16

Direction of travel of accessory pathways

Answer 16

Atria to ventricles or vice versa

Question 17

Presentation of compensated heart failure

Answer 17

Warm, perfused, stable

Question 18

Presentation of decompensated heart failure

Answer 18

Cold, decreased BP, congested lungs

Question 19

Triggers for cardiac failure decompensation

Answer 19

arrhythmia
non-compliance with medication
infection
acute coronary syndrome

Question 20

Common co-morbidities to cardiac failure

Answer 20

Sleep apnoea
Anaemia
Mitral regurgitation
AF

Question 21

Types of non-ischaemic cardiomyopathy

Answer 21

Hypertrophic
Dilated
Restrictive

Question 22

Causes of non-ischaemic cardiomyopathy

Answer 22

genetics
acquired
idiopathic

Question 23

ECG findings of hypertrophic cardiomyopathy

Answer 23

Sinus rhythm
AF
T wave inversion

Question 24

Features of dilated cardiomyopathy

Answer 24

Cardiac enlargement, reduced systolic function

Question 25

Features of restrictive cardiomyopathy

Answer 25

Normal cardiac size, reduced systolic and diastolic function, bi-atrial enlargement, usually results from myocardial infiltration

Question 26

Symptoms of arrhythmia

Answer 26

``` May be asymptomatic chest pain dizziness breathlessness palpitations syncope sudden death ```

Question 27

Ectopic beats ECG presentation

Answer 27

Atrial - narrow QRS Ventricular - broad QRS May be followed by a compensatory pause

Question 28

Types of AF

Answer 28

Paroxysmal - episodes last less than 48hrs Persistent - episodes last 48hrs-1 week Permanent - Permanent

Question 29

AF ECG presentation

Answer 29

Absent clear P waves

Question 30

Atrial flutter presentation on ECG

Answer 30

Saw-tooth p waves

Question 31

Symptoms of AF

Answer 31

Palpitations, breathlessness, chest pain, cerebral thromboembelotic events

Question 32

Causes of AF

Answer 32

Structural - valvular disease, IHD, cardiomyopathies | Non-structural - severe infections, drugs, caffeine

Question 33

Treatment for AF

Answer 33

Rate and rhythm control drugs | Warfarin/DOACs

Question 34

Indications of accessory pathway on ECG

Answer 34

short PR interval

Question 35

Features of a pacemaker

Answer 35

Requires lifestyle change - can't work as a welder, pilot or diver - requires regular check ups and battery changes

Question 36

Features of heart block

Answer 36

Occurs when conduction from atria -> ventricles is blocked or slowed

Question 37

1st degree heart block on ECG and treatment

Answer 37

Slow conduction at AV node, long PR interval Usually doesnt need treatment

Question 38

2nd degree heart block on ECG and treatment

Answer 38

intermittent conduction from atria to ventricles, P waves may occur with no QRS complexes treatment = pacemaker/drugs

Question 39

3rd degree heart block on ECG and treatment

Answer 39

failed conduction from atria to ventricles. Heart may beat if escape rhythm is present, otherwise causes ventricular asystole treatment = pacemaker/drugs

Question 40

Causes of heart block

Answer 40

age-related, ischaemia, drugs, congenital heart conditions, hypothermia, hypothyroidism

Question 41

Investigations following broad complex tachycardia

Answer 41

echo, cardiac MRI, coronary angiogram

Question 42

Symptoms of broad complex tachycardia

Answer 42

Palpitations, breathlessness, chest pain, cardiac arrest

Question 43

What is an ICD and what does it do

Answer 43

An implantable cardiac defibrillator - constantly monitors heart rhythm - will deliver shock if in abnormal heart rhythm

Question 44

Examples of inherited cardiac diseases

Answer 44

Cardiomyopathies Long QT syndrome Wolff-Parkinsson-White syndrome

Question 45

Which ECG leads look at the inferior aspect of the heart

Answer 45

II III aVF

Question 46

Which ECG leads look at the lateral aspect of the heart

Answer 46

I aVL V5 V6

Question 47

Which ECG leads look at the anterior/septal aspect of the heart

Answer 47

V1 V2 V3 V4

Question 48

Features of long QT syndrome

Answer 48

Long QT syndrome (LQTS) is a condition in which repolarization of the heart after a heartbeat is affected. It results in an increased risk of an irregular heartbeat which can result in fainting, drowning, seizures, or sudden death. These episodes can be triggered by exercise or stress

Question 49

Features of bundle branch block

Answer 49

Left bundle branch block is a cardiac conduction abnormality seen on the electrocardiogram. In this condition, activation of the left ventricle of the heart is delayed, which causes the left ventricle to contract later than the right ventricle

Question 50

Parasympathetic and Sympathetic innervation to the heart

Answer 50

Parasympathetic - vagus nerve | Sympathetic - sympathetic nerve, adrenaline

Question 51

Symptoms of decompensated heart failure

Answer 51

``` • weakness • fatigue • irregular or fast heartbeat • coughing and wheezing • spitting up pink phlegm • decreased ability to concentrate increased weight ```

Question 52

Risk factors for cardiac failure

Answer 52

* High blood pressure. Your heart works harder than it has to if your blood pressure is high. * Coronary artery disease. Narrowed arteries may limit your heart's supply of oxygen-rich blood, resulting in weakened heart muscle. * Heart attack. A heart attack is a form of coronary disease that occurs suddenly. Damage to your heart muscle from a heart attack may mean your heart can no longer pump as well as it should. * Diabetes. Having diabetes increases your risk of high blood pressure and coronary artery disease. * Some diabetes medications. The diabetes drugs rosiglitazone (Avandia) and pioglitazone (Actos) have been found to increase the risk of heart failure in some people. Don't stop taking these medications on your own, though. If you're taking them, discuss with your doctor whether you need to make any changes. * Certain medications. Some medications may lead to heart failure or heart problems. Medications that may increase the risk of heart problems include nonsteroidal anti-inflammatory drugs (NSAIDs); certain anaesthesia medications; some anti-arrhythmic medications; certain medications used to treat high blood pressure, cancer, blood conditions, neurological conditions, psychiatric conditions, lung conditions, urological conditions, inflammatory conditions and infections; and other prescription and over-the-counter medications. * Sleep apnoea. The inability to breathe properly while you sleep at night results in low blood oxygen levels and increased risk of abnormal heart rhythms. Both of these problems can weaken the heart. * Congenital heart defects. Some people who develop heart failure were born with structural heart defects. * Valvular heart disease. People with valvular heart disease have a higher risk of heart failure.

Question 53

Features of Class I anti-arrhythmics

Answer 53

Sodium channel blockers All class I drugs may worsen VTs. Class I drugs also tend to depress ventricular contractility.

Question 54

Features of Class II anti-arrhythmics

Answer 54

Beta blockers adverse effects include lassitude, sleep disturbance, and gastrointestinal upset. These drugs are contraindicated in patients with asthma.

Question 55

Features of Class III anti-arrhythmics

Answer 55

Potassium channel blockers risk of ventricular proarrhythmia, particularly torsades de pointes VT and are not used in patients with torsades de pointes VT

Question 56

Features of Class VI anti-arrhythmics

Answer 56

Calcium-channel blockers side effects including constipation, upset stomach, heart failure, AV block, bradycardia, hypotension, and erectile dysfunction

Question 57

NYHA classification of heart failure patients

Answer 57

* Class I - No symptoms and no limitation in ordinary physical activity, e.g. shortness of breath when walking, climbing stairs etc. * Class II - Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity. * Class III - Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20—100 m).Comfortable only at rest. * Class IV - Severe limitations. Experiences symptoms even while at rest. Mostly bedbound patients.