Cardiac Rhythum and Electro cardiography

Question 1

The heart contains two basic types of cells, what are they?

Answer 1

Myocardial cells

Conduction cells

Question 2

Which cells are involved in generating autorhythmicity in the heart?

Answer 2

Pacemaker cells in the AVN / SAN

Question 3

What are the four main components of the conductive system in the heart?

Answer 3

SAN
AVN
Bundle of His
Purkinje Fibres

Question 4

What two sympathetic / parasympathetic fibres control the heart rate?

Answer 4

Accelerator nerve (sympathetic) - Speeds HR

Vagus nerve (Parasympathetic) - Slows HR

Question 5

Adrenaline acts on what adrenoreceptors to have what affect on the heart?

Answer 5

B1-adrenoreceptors, to increase chronotropy and ionotropy

Question 6

Give two examples of B1-adrenoreceptor antagonists

Answer 6

Propanolol

Atenolol

Question 7

State what PQRST means?

Answer 7

P = Atrial depolarisation
QRS = Ventricular depolarisation
T = Ventricular repolarisation

Question 8

An elevated ST is indicative of..?

Answer 8

Myocardial Infraction

Question 9

A PR interval greater than 200 ms is indicative of..?

Answer 9

First degree atrioventricular block

Question 10

Bradycardia is having a HR of..?

Answer 10

60 > bpm

Question 11

Tachycardia is having HR of..?

Answer 11

100 < bpm

Question 12

What is Atrial Fibrillation (AF)?

Answer 12

An abnormal heart rhythm characterized by rapid and irregular beating

Question 13

What are the causes of Atrial Fibrillation?

Answer 13

Thyrotoxicosis
Hypertension
Alcohol
Diseased Heart Muscle
Idiopathic
Ischaemic Heart Disease
Valvular Heart Disease

THADIIV

Question 14

What are commonly used drugs to treat Atrial Fibrillation?

Answer 14

Beta blockers i.e. Atenolol / Propanolol

Ca2+ channel antagonists i.e. Verapamil

Digoxin

Warfarin

Question 15

What is the mechanism of Digoxin?

Answer 15

Na+/K+ ATPase antagonist