cardiovasc system

dysponea

difficult or laboured breathing

what can cause dysponea

left ventricular failure

syncope

fainting or sudden loss of consciousness caused by lack of blood supply to the cerebrum due to a fall in blood pressure

thrombosis

abnormal condition of a blood clot

angina

myocardial ischaemia in patients with stable coronary artery disease that occurs when there is a mismatch between blood supply and demand

ischemia

an inadequate blood supply to an organ or part of the body, especially the heart muscles.

infarction

complete cut off of blood supply to an organ or region of tissue, typically by a thrombus or embolus, causing necrosis

embolism

Obstruction of a blood vessel by a clot of blood or foreign substance

embolus

A clot that breaks lose and travels through the bloodstream.

pulmonary embolism

Blocking of a pulmonary artery due to a blood clot

beta adrenergic stimulation and myocardial contraction

enhances a flux of Ca2+ in myocytes, strengthening the force of contraction

bradycardia

slow heart rate (less than 60 bpm)

tachycardia

rapid heart rate

p wave represents

atrial depolarization

QRS complex represents

ventricular depolarization

T wave represents

ventricular repolarization

PR interval represents

delay of AV node to allow filling of ventricles, time taken for activation to pass from sinus node through atrium, AV node and His-purkinje system to the ventricle

superventricular

arise from atria or AV junction

AV block types

first degree, second degree: mobitz I (wenckebach), mobitz II, third degree

first degree AV block

prolonged PR interval to more than 0.20 seconds

What does a prolonged PR interval indicate?

first degree AV block, each atrial depolarization is followed by a conduction to the ventricles but with a delay

second degree AV block

some P waves conduct, others not followed by QRS

ECG reading second degree AV block: Mobitz Type I (Wenckebach)

-Progressive lengthening of PR interval until a beat is "dropped" (a P wave not followed by a QRS complex).

ECG reading second degree AV block: Mobitz Type II

P wave fails suddenly without preceding prolongation, QRS drops suddenly, usually wide QRS complex

where is blocked in a second degree AV block: Mobitz Type II

infranodal, usually His bundle

third degree AV block

all atrial activity fails to conduct to ventricles

ECG reading third degree AV block

QRSs and the P waves have no relation to each other.

Superventricular Tachycardia types

atrial fibrillation and atrial flutter

ECG atrial fibrillation

irregular PR intervals and absence of organized atrial activity

ECG atrial flutter

sawtooth, visible flutter waves at 300 bpm, usually with 2:1 AV coduction

atrial fibrillation

occurs when the normal rhythmic contractions of the atria are replaced by rapid irregular twitching of the muscular heart wall

atrial flutter

irregular beating of the atria; often described as "a-flutter with 2 to 1 block or 3 to 1 block"

ventricular tachycardia

sustained ventricular tachycardia, extrasystole, ventricular flutter, torsades des pontes, brugada's syndrome

Sustained ventricular tachycardia duration and pulse rate

occurs for more than 30 seconds, rate: 120-220 bpm

presyncope

Feeling of faintness and impending loss of consciousness; often a cardiovascular symptom

normal heart rate

60-100 bpm

ECG of sustained ventricular tachycardia

rapid ventricular rhythm with a broad QRS complex

cardiac enzymes

complex proteins released by heart muscle when it is damaged; taken by blood sample to determine amount of heart disease or damage; most common cardiac enzymes are creatine kinase (CK), glutamic oxaloacetic transaminase (GOT), and lactate dehydrogenase (LDH)

beta blockers

decrease heart rate and dilate arteries by blocking beta receptors

ventricular fibrillation

the rapid, irregular, and useless contractions of the ventricles, patient is pulseless

ECG of ventricular fibrillation

shapeless

treatment of ventricular fibrillation

Defibrillation, CPR and Advanced Critical Life Support drugs (epinephrine, amiodarone, etc.)

ectopic

out of place

extrasystole

premature contraction before the SA node initiates the next contraction

Torsades de pointes

Rate: 120 - 200 usually
P wave: Obscured by ventricular waves
QRS: Wide QRS - "Twisting of the Points"
Conduction: Ventricular only
Rhythm: Slightly irregular

Brugada syndrome

-Autosomal dominant disorder most common in Asian males.
-ECG pattern of pseudo-right bundle branch block and ST elevations in V1-V3.
-increased risk of ventricular tachyarrhythmias and SCD. Prevent SCD with implantable cardioverter-defibrillator (ICD).

acute coronary syndromes

ST-elevation myocardial infarction (STEMI), non-STEMI (NSTEMI), unstable angina (UA)

difference between unstable angina (UA) and non-ST-elevation myocardial infarction (NSTEMI)

NSTEMI has an occluding thrombus, leads to myocardial necrosis and rise in serum troponins or CK-MB.

myocardial infarction (MI)

heart attack, occurs when myocytes die due to myocardial ischaemia

5 types of myocardial infarction (MI)

type I - spontaneous MI with ischaemia, type 2 - MI secondary to ischaemia, type 3 - diagnosis of MI in sudden cardiac death, type 4a - MI related to percutaneous coronary intervention, type 4b - MI related to stent thrombosis, type 5 - MI related to coronary artery bypass grafting (CABG)

type I MI - spontaneous type with ischaemia is due to

a primary coronary event eg. plaque erosion/rupture, fissuring or dissection

type 2 MI - MI secondary to ischaemia is due to

an increased oxygen demand or decreased supply, such as in coronary spasm or embolism, anaemia, arrythmias, hypertension or hypotension

hypertension

persistent high blood pressure in systemic arterial circulation, higher than 140/90 mmHg

hypotension

low blood pressure 90/60 mmHg or lower

percutaneous coronary intervention (PCI)

balloon-tipped catheter is inserted into a coronary artery to open the artery; stents are put in place, used to treat coronary artery disease

stent thrombosis

Blood clot forms in a stent one or more years after it's implanted--can be fatal

stent

wire-mesh tube used to keep arteries open

coronary artery bypass grafting (CABG)

procedure in which a blood vessel from another part of the body is surgically attached to a coronary artery to bypass an area of blockage

why is t-wave positive

the direction of repolarization is opposite the direction of depolarization in the ventricles

unstable angina

chest pain that occurs while a person is at rest and not exerting himself

pathophysiology of acute coronary syndrome (ACS)

Rupture or erosion of the fibrous cap of a coronary artery plaque. This leads to platelet aggregation + adhesion, localized thrombosis, vasoconstriction and distal thrombus embolization.

clinical features of acute coronary syndrome

new onset of chest pain, esp at rest, indigestion, pleuritic chest pain, dysponea

investigations and signs of acute coronary syndrome

ECG: ST depression, T-wave inversions

coronary arteries

blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle

ST Elevation Myocardial Infarction (STEMI)

occurs when cardiac myocytes die due to prolonged myocardial ischaema

pathophysiology STEMI

rupture or erosion of a vulnerable coroanry artery plaque resulting in prolonged occlusion of a coronary artery resulting in myocardial necrosis

clinical features STEMI

severe chest pain lasting more than 20 min, may radiate to left arm, neck, jaw, dyspnoea, fatigue, pre-syncope or syncope, sweaty and pale, thready pulse, hypotension, bradycardia or tachycardia

dyspnoea

difficulty breathing

normal blood pressure

120/80

investigations STEMI

ECG and blood testing and other imaging

ECG STEMI

performed within 10 min, ST elevation

blood tests STEMI

check cardioac troponin I or T levels, blood count, serum electrolytes, glucose and lipid profile

Primary Percutaneous Coronary Intervention (PCI)

Insertion of stent into blocked vessel

complications myocardial infarction

heart failure, myocardial rupture and aneurysmal dilation, ventricular septal defects, mitral regurgitation, cardiac arrhythmias, conduction disturbances

heart failure killip classification

I-IV

killip I

no crackles and no third heart sound

killip II

crackles in <50% of the lung fields or third heart sound

killip III

crackles in >50% of the lung fields

killip IV

cardiogenic shock

What do ACE inhibitors do

inhibits angiotensin-converting enzyme, reduces conversion of angiotensin I to angiotensin II, and prevent angiotensin II medicated vasoconstriciton and sodium and water retention

causes of heart failure

MC: coronary artery disease, ischaemic eart disease, dilated cardiomyopathy, hypertension

diaphoresis

profuse sweating

atherosclerosis

Hardening and narrowing of the arteries due to buildup of cholesterol plaques - atheromas

fibrous cap

a thin layer of tissue over the top of an atherosclerotic plaque

is hypertension a disease of aging

yes

arteriosclerosis

Degenerative changes in the small arteries and arterioles, commonly occurring in individuals over age 50.

systolic

peak blood pressure in the arteries during contraction of the ventricles.

diastolic pressure

lowest arterial pressure reached during arterial relaxation

static measurements of BP

with BP bladder

white coat hypertension

A phenomenon in which patients exhibit elevated blood pressure in the hospital or doctor's office but not in their everyday lives.

masked hypertension

low clinic blood pressure, but elevated ambulatory/home blood pressure

isolated systolic hypertension

a condition most commonly seen in the older adult in which the systolic pressure is greater than 140 mm Hg and the diastolic pressure is within normal limits (less than 90 mm Hg)

orthostatic hypotension

low blood pressure that occurs upon standing up, fall in BP within 3 minutes of standing up of more than 20mmHg systolic or 10mmHg diastolic BP

autonomic neuropathies

diabetes mellitus and parkinson's associated with orthostatic hypotension

variable blood pressure

exaggerated. degree of variability in BP often due to disorders of the autonomic nervous or endocrine system

primary hypertension

high blood pressure from an unidentified cause

main mechanisms affecting BP

vascular volume and tone and cardiac output

resistant hypertension

Uncontrolled BP despite 3 antihypertensives

environmental causes of hypertension

diet, lack of exercise, drugs (eg NSAIDs and alc)

secondary causes of hypertension

hypertension that has an identifiable singular cause, which when removed or reversed leads to normalization of BP