Cardiomyopathies Flashcards
(44 cards)
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