Cardiomyopathy: Dilated and Restrictive Types

• Cardiomyopathies are diseases of the heart muscle that can lead to heart failure, arrhythmias, and sudden cardiac death.

Dilated Cardiomyopathy (DCM)

• Characterized by the enlargement and dilation of the heart chambers.
• Most common cause is idiopathic.
• Other causes include pregnancy (peri-partum and post-partum), alcoholism (thiamine deficiency), Beriberi (thiamine deficiency), hemochromatosis, drugs (doxorubicin), genetics (X-linked), and Duchenne Muscular Dystrophy.
• Presents with symptoms and signs of congestive heart failure.
• Leads to systolic failure (decreased Ejection Fraction).
• The apex of the heart is displaced.
• Diagnosed by echocardiography, which reveals an enlarged heart.
• Complications include thrombosis and embolization and arrhythmias.

Treatment of DCM

• Treatment focuses on managing heart failure.
• ICD (implantable cardiac defibrillator) implantation.
• Resynchronization therapy.
• Cardiac transplantation.

Restrictive Cardiomyopathy

• The causes include idiopathic, amyloidosis, sarcoidosis, hemochromatosis, endo-myocardial fibrosis and fibro-elastosis (in children), and Loffler’s syndrome.
• Presents similarly to right-sided heart failure.
• Causes diastolic failure.
• Diagnosed by myocardial biopsy through cardiac catheterization.
• Management includes cardiac transplantation.
• Prognosis is generally very poor.

Hypertrophic Obstructive Cardiomyopathy (HOCM)

• Caused by autosomal dominant mutations in sarcolemma proteins (e.g., myosin binding protein c, tropomyosin, troponin, β myosin heavy chain).
• Can be associated with Friedrich’s Ataxia.
• Symptoms include syncope on exertion, angina, and dyspnea.
• Signs include jerky pulse and double apex beat.
• Ejection systolic murmur is present at the lower part of the sternum.
• Valsalva maneuver or standing from sitting increases the murmur of HOCM, while squatting decreases it; the opposite occurs in aortic stenosis.

Causes of Obstruction in HOCM

• Asymmetrical septal hypertrophy.
• Sub-valvular stenosis.
• Systolic anterior motion (SAM) of mitral leaflets.

Diagnosis of HOCM

• Echo findings include asymmetrical septal hypertrophy, systolic anterior motion of mitral leaflet, and functional mitral regurgitation.
• Exercise test to assess risk of sudden cardiac death.
• Holter ECG monitoring to assess risk of sudden cardiac death.
• HOCM is the most common cause of sudden cardiac death in young athletes.

Factors increasing risk of sudden cardiac death in HOCM

• Young age (less than 14 years).
• Family history of sudden cardiac death.
• Syncope at presentation.
• Septum thickness more than 3 cm by echo (most important factor).
• Abnormal BP changes during exercise.
• Holter monitoring showing short runs of ventricular tachycardia.

Management of HOCM

• Beta blockers are the most important drug.
• Vasodilators are contraindicated.
• Septal myomectomy surgery.
• ICD implantation if there is a high risk of sudden cardiac death.

Ischemic Heart Diseases

• Ischemic heart diseases often present clinically as angina.
• Caused by decreased blood supply to the heart, increased myocardial demands, or decreased oxygen-carrying capacity of the blood.

Criteria for Cardiac Pain

• Central, crushing pain radiating to the jaw or left arm.
• Aggravated by exercise, heavy meals, stress, emotions, and cold.
• Relieved by rest or sublingual nitrates.
• If all three criteria are present, it is typical cardiac pain; if two are present, it is atypical; if one or less, it is non-cardiac pain.

Types of Ischemic Heart Diseases

• Include stable angina, variant angina, and acute coronary syndrome (ACS).
• ACS encompasses unstable angina, non-ST segment elevation myocardial infarction (NSTEMI), ST segment elevation myocardial infarction (STEMI), and sudden cardiac death (SCD).

Stable Angina

• Characterized by fixed atheroma, unlike ACS where the atheroma develops an event.
• In patients with known CAD and typical cardiac pain, treatment should be started immediately without further investigation.
• In patients with known CAD and atypical cardiac pain, functional studies such as exercise echo or thallium scan should be performed.

Management of Stable Angina

• Life style modification
• Symptomatic drugs (monotherapy): sublingual nitrate (GTN), beta blockers, and anti-platelet therapy (e.g., aspirin).
• If not controlled by monotherapy, add calcium channel blockers (CCB).
• If still not controlled, add a fifth drug (potassium channel activator (Nicorandil) or IF channel blocker (Ivabradine)) while waiting for invasive procedures (PCI or CABG).

Percutaneous Coronary Intervention (PCI)

• Also called Percutaneous Transluminal Coronary Intervention (PTCI).
• Complications include ischemia, thrombosis, restenosis, and failure of the procedure.
• Patients undergoing PCI should be given tirofiban before the operation and a drug-eluting stent.
• After the operation, patients must be given aspirin and clopidogrel.

Coronary Artery Bypass Grafting (CABG)

• Used in areas of the heart difficult to reach by PCI.
• Used for osteal disease, distal disease, triple vessel disease or more, and left main stem disease.
• Complications include CNS complications (stroke).

Variant "Prinzmetal" Angina

• Caused by sudden spasm of the coronary artery.
• More common in women and typically occurs at night (at rest).
• ECG shows ST elevation.
• Management includes calcium channel blockers acting on blood vessels (i.e., dihydropyridines).
• Aspirin and beta blockers are contraindicated.

Acute Coronary Syndrome (ACS)

• Differential diagnosis includes unstable angina, NSTEMI, STEMI, and sudden cardiac death (SCD).
• In MI, chest pain lasts more than 20 minutes and there is myocardial cell death with leakage of cardiac enzymes.

Differentiation between Unstable Angina, NSTEMI, and STEMI

• Unstable angina: no ST elevation and no cardiac markers.
• NSTEMI: no ST elevation but cardiac markers are elevated.
• STEMI: ST elevation and cardiac markers are elevated.

Myocardial Infarction (MI)

• Anterior MI: blockage in the left anterior descending artery, most common type, ST elevation in chest leads V1 to V4.
• Lateral MI: blockage in the left circumflex artery, ST elevation in lateral leads V5, V6, aVL, and lead I.
• Inferior MI: blockage in the right coronary artery, ST elevation in aVF, lead II, and lead III; often presents with heart failure with bradycardia and AV block.
• Posterior MI: ST elevation from V1 to V6 in addition to V7, V8, and V9 (back leads).

Criteria for ST elevation

• More than 1 mm in limb leads.
• More than 2 mm in chest leads.

ECG Changes in Order

• Hyper acute T wave (tall T wave).
• Elevation of ST wave.
• T wave inversion.
• Formation of pathological Q wave (indicates an old infarct).

Cardiac Markers

• Myoglobin is the first to rise.
• Troponin is the most sensitive but drops in 7 to 10 days.
• CK-MB is used to detect re-infarction because it drops rapidly (in 3 to 5 days).

Management of Acute Coronary Syndrome

Initial steps

• Give MONA to all patients (Morphine, O2, Nitrates, and Aspirin).
• Serial ECG and serial cardiac markers.

STEMI

• Reperfusion therapy: PCI (ideal time is 90 minutes) or thrombolytic therapy (streptokinase or tPA, optimum time is 30 minutes).
• Streptokinase is used once in a lifetime.

Contraindications to Thrombolytic Therapy

• Hemorrhagic stroke (ever).
• Ischemic stroke in previous 6 months.
• Upper GI bleeding in previous 1 month.
• Major trauma or surgery in previous 3 weeks.
• Pregnancy.
• CNS tumors.
• Severe HTN.
• Bleeding disorders.

No ST Elevation (NSTEMI or Unstable Angina)

• Give MONA, then heparin.
• Assess cardiovascular risk (according to GRACE score).
• If high risk GRACE score; give glycoprotein II B / III A inhibitor, and do angiography in 4 days.

Discharge Medications (for all types of ACS)

• Aspirin for life.
• Beta Blockers for life.
• ACEI for life.
• Statin for life.
• Clopidogrel: 1 month for STEMI, 1 year for NSTEMI or Unstable angina if GRACE score is more than 1.5%.