ACUTE CORONARY SYNDROME

Unstable Angina

NSTEMI

STEMI

Pathogenesis

Arrhythmias in MI

Rhythm Causes

Sinus bradycardia • ↑ vagal tone • ↓ SA nodal artery perfusion

Sinus tachycardia • Pain and anxiety• Heart failure• Volume depletion• Chronotropic drugs e.g dopamine

Atrial premature beats , AF • Heart failure• Atrial ischaemia

Ventricular premature beats , VT , VF • Heart failure• Ventricular ischaemia

AV block (first , second , third degree) • Inferior MI : ↑ vagal tone and ↓ AV nodal artery flow

• Anterior MI : extensive destruction of conduction tissue

HEART FAILURE

Compensatory Mechanisms

• Frank-Starling Mechanism• Neurohormonal Activations• Ventricular Hypertrophy and Remodeling

RHF LHF

Symptoms • Leg swelling• RUQ pain / discomfort

• Dyspnoea• PND• Orthopnoea • Reduced effort tolerance ,

fatigue

Signs • Jugular venous distension (raised JVP)

• Pedal oedema • Congestive

hepatosplenomegaly

• Diaphoresis • Tachycardia , tachypnoea • Pulmonary rales • Loud P2• S3 gallop (systolic

dysfunction) • S4 (diastolic dysfunction)

Question : Explain the mechanism / pathogenesis of the above signs and symptoms ! , causes of pitting vs non-pitting oedema

• Orthopnoea – redistribution of intravascular blood from the gravity-dependent portions of the body (abdomen and lower extremities) towards the lung after lying down.

• PND - gradual reabsorption into the

circulation o lower extremity interstitial edema after lying down, with subsequent expansion

of intravascular volume and increased venous return to the heart and lungs • Pulmonary congestion + Haemoptysis (rupture of

engorged bronchial veins)

Acute Pulmonary Edema

- Acute heart failure , chronic heart failure

- Interstitial edema , alveolar edema

• Lasix (IV furosemide) – to reduce LV preload , lower pulmonary capillary hydrostatic pressure

• Morphine – to reduce anxiety , venodilator• Nitrates – to reduce preload • Oxygen • Position (sit upright ) • Inotropic drugs (dopamine)

HYPERTENSION

Target Organ Damage

Organ System Manifestations

Heart Left ventricular hypertrophy Heart failure Myocardial ischaemia and infarction

Cerebrovascular Stroke

Vascular Aortic aneurysm and/or dissection Arteriosclerosis

Kidney Nephrosclerosis Renal failure

Retina Arterial narrowing Haemorrhages ,exudates ,papilledema