Cardiomyopathy

• Cardiomyopathy is a disease of the heart muscle affecting its ability to pump blood effectively.
• It causes the heart to enlarge, thicken, or stiffen, leading to symptoms like shortness of breath, fatigue, and irregular heartbeats.
• Causes can be genetic or acquired, resulting from conditions like high blood pressure, coronary disease, infections, or alcohol.

Types of Cardiomyopathy

• Dilated
• Hypertrophic
• Restrictive
• Arrhythmogenic right ventricular dysplasia
• Cardiomyopathies that do not fit into any category

Dilated Cardiomyopathy

• Also referred to as non-ischemic dilated cardiomyopathy.
• Characterized by enlargement and dilation of one or both ventricles.
• Accompanied by impaired contractility or poor ejection fraction (EF < 40%).
• Disease process classified as either primary or secondary dilated cardiomyopathy.
• Primary dilated cardiomyopathy is considered idiopathic, diagnosed after excluding secondary causes.
• DCM has many causes affecting ventricular function to varying degrees.
• Some patients with DCM may be asymptomatic due to compensatory mechanisms.
• Ventricle enlargement leads to a decline in ventricular function.
• Results in conduction system abnormalities, ventricular arrhythmias, thromboembolism, and heart failure.
• Etiology is commonly idiopathic (unknown and without an identifiable cause).
• Can have a familial or genetic predisposition, classified under idiopathic if no clear genetic link is identified.
• Secondary causes are infectious myocarditis (e.g., viral, Chagas disease, Lyme disease), ischemic disease, hypertension, medication-induced.
• Other causes include alcohol abuse, human immunodeficiency virus (HIV), peripartum cardiomyopathy, or infiltrative disease.
• Ischemic cardiomyopathy caused by CAD is most common cause of CHF.
• Classified as its own disease entity, described as a cause of DCM in occult disease in patients without known CAD.
• In a 2013 study, DCM was estimated at 1:250 and HCM was estimated at 1:500.
• Heart failure from DCM resulted from pump failure (70%) caused by dilatation.
• Sudden cardiac death from arrhythmias accounted for 30%.
• Recent improvements in survivability can be attributed to ACE inhibitors, beta blockers, implantable defibrillators, and heart transplants.
• Echocardiographic considerations include left ventricle, left atrium, and pulmonary hypertension.
• Left ventricular dilatation related to increased sphericity of the left ventricular geometry.
• Causes apical and lateral displacement of papillary muscles causing mitral regurgitation.
• Can cause the formation of a left ventricular thrombus.
• Left atrial dilatation causes atrial fibrillation.
• Left atrial thrombus/stasis of blood caused by Virchow's triad.
• Pulmonary hypertension can have tricuspid regurgitation and right ventricular dilatation/dysfunction.

Left Ventricular Non-Compaction Cardiomyopathy (LVNC)

• Rare congenital disease affecting both children and adults.
• Results from abnormal prenatal development of heart muscle.
• Characterized by prominent trabeculae, showing continuity between the deep trabecular recesses and the ventricular cavity.
• LVNC is associated with systolic and diastolic left ventricular dysfunction, arrhythmias, congestive heart failure, and thromboembolic events.
• The age of onset and degree of clinical symptoms depends on the extent of the noncompacted cardiac segments.
• Intravenous ultrasound contrast agents are useful to better depict trabecular spaces in patients with suboptimal acoustic windows.
• CT and MRI: provide better visualization of the trabeculations.
• CT findings: prominent trabeculations and deep recesses in the myocardium, affecting the apical and basal surfaces of the left ventricle.
• Based on MRI criteria, a noncompacted to compacted myocardium ratio (NC/C ratio) of ≥2:1 at end systole or ≥2.3:1 in end diastole supports a diagnosis.
• Image resolution, contrast, and positioning of focus in the apical region are crucial when looking for left ventricular noncompaction.
• Differential diagnoses include thrombi, false tendons, apical hypertrophic cardiomyopathy, fibroma, obliterative processes, intramyocardial hematoma, cardiac metastases and intramyocardial abscesses.

Takotsubo Cardiomyopathy (TTC)

• Called “Broken Heart Syndrome.”
• Characterized by transient left ventricular dysfunction with wall motion abnormalities, most commonly in the form of apical ballooning.
• First described in five Japanese cases by Dote et al in 1990.
• The authors coined the term "takotsubo” to describe the syndrome, like a Japanese octopus fishing trap.
• Diagnosed more commonly in females than males (9:1 ratio).
• Mean age of patients was 66.8 years.
• 71.5% of patients had an obvious trigger for TTC.
• Triggers are emotional (27.7%), physical (36%), or both (7.8%).
• Rest did not have an evident trigger.
• Apical TTC was identified in 81.7% of patients.
• The midventricular form was found in 14.6%, and basal and focal forms were diagnosed in 2.2% and 1.5%, respectively.
• Mimics the clinical picture of acute coronary syndrome with chest pain, ST-segment elevation, cardiac markers elevation, and left ventricle wall motion abnormalities.
• Echocardiographic features: left ventricular dysfunction due to akinesia of mid-apical segments of the left ventricle (apical ballooning).
• Increase in serum catecholamines causing direct myocardial toxicity leads to reversible myocardial inflammation and dysfunction.
• Catecholaminergic surges cause acute multivessel microvascular coronary spasm, myocardial stunning, and excessive transient ventricular afterload.
• Sympathetic overstimulation is caused by emotional or physical stresses, exogenous sympathomimetics (cocaine), or withdrawal of sympathetic antagonists (opioids).

Hypertrophic Cardiomyopathy

• Apical Hypertrophy Variant

Hypertrophic Obstructive Cardiomyopathy (HOCM)

Hypertrophic Obstructive Cardiomyopathy (HOCM)

Hypertrophic Obstructive Cardiomyopathy (HOCM)

• Asymmetrical Septal Hypertrophy

Asymmetrical Septal Hypertrophy

• Systolic Anterior Motion (SAM) of the anterior mitral leaflet.
• Is helpful when using the Valsalva maneuver during dynamic auscultation to help distinguish cardiac conditions.
• Is essential in evaluating left ventricular outflow tract obstruction in HCM patients.

Restrictive Cardiomyopathy (RCM)

• Myocardial disorder resulting from increased myocardial stiffness that leads to impaired ventricular filling (compliance).
• Biventricular chamber size and systolic function normal or near-normal until later stages of the disease.
• RCM can affect either or both ventricles, causing signs or symptoms of left or right heart failure.
• RCM may result from inherited or acquired predispositions and disease, broadly classified as:
  • Infiltrative
  • Storage disease
  • Noninfiltrative
  • Endomyocardial
• Infiltrative Cardiomyopathies:
  • Cardiac Amyloidosis: amyloid proteins
  • Sarcoidosis: collection of tiny immune cells leading to the formation of granulomas; Hemochromatosis: excessive iron
  • Apical sparing: pattern seen in cardiac amyloidosis.
• Refers to abnormal global the left ventricular strain in the mid and basal wallswith normal values in the apex
• Lysosomal Storage Diseases: Fabric Disease
• Non-infiltrative are idiopathic with no cause or cardiac amyloidosis apical sparing (93% sensitive, 82% specific): myocardium appears the same.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

• Also known as ARVD (dysplasia).
• An inherited cardiomyopathy marked by fibrofatty replacement of the right ventricle.
• Predisposes to life-threatening ventricular arrhythmias and right ventricular dysfunction.
• 20% of sudden cardiac death (SCD) patients are under 35 years old and athletes with SCD.
• Characteristics include palpitations, dizziness, syncope, and chest pain.
• Can cause ventricular tachycardia and sudden cardiac death (SCD), usually during exercise.
• Exercise/stress increases right ventricular dilatation and worsens manifestation of ARVC.
• Diseased manifests 12-13 yrs and can cause unstable electrical disorder.
• Can progress to right ventricular failure and biventricular failure/dilated cardiomyopathy, where ARVD > ARVC.
• Echo reveals right ventricle is abnormal and MRI reveals fibrofatty infiltration of right ventricular myocardium.
• EKG shows Epsilon wave, a QRS >110ms V1-V3, and T-wave inversion V1-V3.
• Causes RVOT VT, VT with LBBB morphology.