Cardiomyopathies Flashcards
define cardiomyopathy
- Heterogenous group of diseases affecting the myocardium
- Not associated with major causes of cardiac disease
A. Ischemic heart disease
B. HTN
C. Pericardial disease
D. Valvular disease
What are the characteristics of cardiomyopathy?
Rhythm&contractilityof heart may be normal, but the stiff walls of heart chambers keep them from adequately filling
↓preload & end-diastolic volume
What are the 3 types of cardiomyopathy?
- Dilated (DCM): most common
- Hypertrophic (HCM)
- Restricted (RCM)
describe DCM
- Results from damage to cardiac muscle fibers
2. Loss of muscle tone grossly dilates all 4 chambers globular shape of heart
Describe hypertrophic CM
Characterized by disproportionate asymmetric thickening of interventricular septum & LVH
Describe RCM
Characterized by restricted ventricular filling due to decreased ventricular compliance & endocardial fibrosis & thickening
What are demographic of DCM?
Most common type (95%)
M>F
African American > Caucasian
What is the etiology of DCM?
- Genetic predisposition
- Excessive alcohol consumption
A. Most common cause - Postpartum
- Chemotherapy
What is the pathophys of DCM?
- Extensive damage to cardiac muscle fibers reduces contractility in left ventricle
- As systolic function declines, stroke volume, EF and CO all fall
What are the sxs of DCM?
1. Dyspnea A. Most common presenting sx 2. Can present with either left or bi-ventricular failure A. Increased JVD B. S3 gallup C. Rales D. Cardiomegaly
What dx studies are used in DCM?
- CXR
- EKG
- ECHO
- Invasive studies prn
What are the results of the CXR in DCM?
Cardiomegaly
Pleural effusion
Pulmonary edema
What are the results of the EKG in DCM?
LBBB
Nonspecific ST-T wave changes
Ventricular or atrial arrhythmias
What are the results of the ECHO in DCM?
Confirms presence of DCM and LV systolic dysfunction
When are invasive studies indicated?
if ischemia is suspected
What is the tx for DCM?
- ACEI
A. Reduces both preload and afterload - Beta blocker: Carvedilol if CHF and renal insufficiency
A. Beta 1 blockade ↓ HR, ↓ contractility ↓ myocardial oxygen demand - Diuretics
A. Reduce preload
B. Reduce pulmonary congestion and edema - Aldosterone antagonist (Spironolactone)
A. Reduce preload - Digoxin
A. Inotropic agent that improves contractility
B. Rate control if pt in A. fib - Avoid alcohol
- 2 gm Na diet
What are the characteristics of HCM?
- Massive hypertrophy of septum
- Small left ventricle
- Diastolic dysfunction
What is the etiology of HCM?
- Genetic predisposition
2. Sudden cardiac death in pts < 30 yrs age
What is the pathophysiology of HCM?
- Autosomal dominanttrait
- Mutated protein in the sarcomere, primary component of themyocyte
- Myocytes ↑ in size → thickening of the heart muscle
- Massive hypertrophy of left ventricle and interventricular septum obstructs left ventricular outflow
- Heart compensates for ↓ CO by ↑ rate & force of contraction
- Hypertrophied ventricle becomes stiff and unable to relax and fill during diastole
- As left ventrical volume ↓ & filling pressures ↑, pulmonary venous pressure ↑ pulmonary congestion & dyspnea
What are the sxs of HCM?
May be asymptomatic 1. Dyspnea A. Most common B. 2° to ↑ stiffness & ↓ filling of the LV 2. CP A. Exertional angina 3. Postexertional syncope A. 2° to ↑ myocardial contractility B. Worsens outflow obstruction 4. Arrhythmias A. Atrial and ventricular 5. Abnormal exercise blood pressure 6. Variable systolic murmur left sternal border A. ↑ with valsalva, ↓ with squatting
What are the dx studies used in HCM?
- CXR
- MRI
- EKG
- ECHO
What are the CXR results in HCM?
unremarkable
What are the EKG results in HCM?
Nonspecific ST-Twave changes, LVH
What are the MRI results in HCM?
LVH, assymetric septal hypertrophy
What are the ECHO results in HCM?
- Asymmetric septal hypertrophy
- Small left ventricle
- Diastolic dysfunction (delayed filling of ventricle)
- Septal wall motion reduced
What is the first line tx in HCM?
- Beta blockers
A. 1st line drug in symptomatic pt’s
B. ↓ HR improves diastolic filling of stiff left ventricle –> ↓ myocardial oxygen demand
C. Treat dyspnea, angina, arrhythmias
Why are diuretics used for HCM?
Reduce high diastolic pressure
Why a dual chamber pacing used in HCM?
May prevent progression of hypertrophy & obstruction
When is an implantable defibrillator indicated in HCM?
- (+) FH premature sudden death
- Prior Hx of cardiac arrest or V Tach or V Fib
- Unexplained syncope
- LV thickness ≥ to 30mm
What are the general characteristics of RCM?
- Results from fibrosis of ventricular wall secondary to collagen defect disease
- Characterized by impaired diastolic filling with reasonably preserved contractile function
- Rarest form of cardiomyopathy
What is the etiology of RCM?
1. Amyloidosis A. Most common cause 2. Radiation 3. Diabetes 4. Post operative change
What is amyloidosis?
- Abnormal protein (amyloid) builds up in tissues and organs
- Can lead to life-threatening organ failure
What is primary amyloidosis?
- Caused by “amyloid light chains”
- Idiopathic
- 2° to Multiple Myeloma
- Affects kidney,heart,liver,intestines, certain nerves
What is secondary amyloidosis?
- 2° to chronic inflammatory disease
SLE,RA, TB, IBD, & certain cancers (MM) - Most commonly affects spleen, kidneys, liver, adrenal gland, and lymph nodes
- Caused by Amyloid type A protein
What are other causes of amyloidosis?
- Dialysis-related
- Genetic (rare)
A. Seen in children - Senile systemic (older males)
What is the pathophys of RCM?
- LVH & endocardial fibrosis limit ventricular relaxation and filling during diastole
- As a result, cardiac output falls
What are the sxs of RCM?
1. Most common symptoms at first may appear to be lung related A. Dyspnea B. Fatigue C. Right sided failure D. Elevated JVD E. Ascites F. Hepatomegaly G. Edema
What are the sxs of RCM in children?
- Hx of “repeated lung infections” or “asthma”
- ↓ Exercise tolerance
- Gallop
- Syncope
- Chest pain w/exercise
What are the dx studies used in RCM?
- EKG
- CXR
- ECHO
What are the results of a EKG in RCM?
- Conduction disturbances frequently present
- LVH
- Atrial hypertrophy
What are the results of a CXR in RCM?
Mild to mod cardiomegaly
What are the results of a ECHO in RCM?
- Small thickened LV
- Rapid early diastolic filling left ventricle
- Biatrial enlargement
- Normal sized ventricles in children
- Pulm HTN in advanced Dz
What is the tx for RCM?
1. Diuretics A. Use with caution to avoid renal dysfunction B. ↓ preload and relieve sx’s of CHF 2. Beta blockers A. Slow heart rate & improve filling B. ↓ Myocardial oxygen demand 3. Calcium channel blockers A. ↑ LV filling time B. Improves ventricular relaxation 4. Heart transplant 5. ACEIs and ARB’s poorly tolerated in patients with amyloidosis
What is a complication of all types of cardiomyopathies?
All CM can lead to HF