Cardiomyopathies Flashcards
(45 cards)
What is a cardiomyopathy (CM)?
Disease of heart muscle affecting myocardial systolic and/or diastolic function
Cardiomyopathies can be categorized based on various criteria, including etiology and physiology.
How are cardiomyopathies classified?
Classified by etiology as:
* Ischemic CM
* Non-ischemic CM
Ischemic CM is often associated with dilated CM due to ischemic heart disease.
What is the most common classification of cardiomyopathies based on physiology?
Dilated vs. hypertrophic vs. restrictive
This classification is essential for understanding the functional impairments associated with each type.
What is the definition of dilated cardiomyopathy (DCM)?
Dilated – dilated ventricle with impaired inotropy
DCM primarily affects the heart’s ability to contract effectively.
What is the definition of hypertrophic cardiomyopathy (HCM)?
Hypertrophic – abnormally thickened ventricular wall with impaired lusitropy
HCM usually maintains intact systolic function but is characterized by diastolic dysfunction.
What is the definition of restrictive cardiomyopathy (RCM)?
Restrictive – abnormally stiffened myocardium with impaired lusitropy
Systolic function is usually normal or near-normal in RCM.
What are the clinical manifestations of dilated cardiomyopathy (DCM)?
CHF due to reduced contractility
DCM leads to low cardiac output, resulting in congestive heart failure symptoms.
What are the clinical manifestations of hypertrophic cardiomyopathy (HCM)?
CHF and exertional syncope
HCM can lead to sudden death due to arrhythmias.
What are the clinical manifestations of restrictive cardiomyopathy (RCM)?
CHF due to reduced preload and elevated LVEDP
Symptoms arise from the heart’s inability to fill properly.
What is the differential diagnosis of non-ischemic dilated cardiomyopathy (DCM)?
Includes:
* Genetic factors
* Valvular heart disease
* Inflammatory myocarditis
* Toxins (e.g., alcohol, anthracycline chemotherapy)
* Peripartum cardiomyopathy
Non-ischemic DCM can have various underlying causes, including familial and acquired conditions.
What is stress cardiomyopathy (Takotsubo CM)?
Catecholamine-related CM with transient regional systolic dysfunction mimicking IHD
It is characterized by apical ballooning of the left ventricle and occurs often in response to stress.
What triggers stress cardiomyopathy?
Excessive sympathetic response often triggered by emotional or physical stress
It primarily occurs in older women and can be associated with conditions like pheochromocytoma.
How is the diagnosis of Takotsubo CM made?
Diagnosis of exclusion with normal coronary arteries and clinical findings consistent with Takotsubo CM
Clinical findings include wall motion abnormalities and apical ballooning.
What is the prevalence of LVOT obstruction in Takotsubo CM?
25%
LVOT obstruction can complicate the management of Takotsubo CM.
What is the initial management for stress cardiomyopathy?
R/o ACS, supportive therapy for CHF, and consider heparin to prevent thrombus formation
Management may involve inotropic support or other medications depending on the patient’s hemodynamic status.
What is the usual treatment for patients with dilated cardiomyopathy?
Treatment of CHF with:
* Diuretics
* ACEI or ARB
* Beta blockers
* Aldosterone antagonists
* Cardiac resynchronization therapy
These therapies aim to improve heart function and manage symptoms.
What are major risk factors for sudden death in hypertrophic cardiomyopathy (HOCM)?
Includes:
* Prior cardiac arrest
* Non-sustained VT
* Unexplained syncope
* LV thickness > 30 mm
* Abnormal exercise blood pressure
* Family history of sudden death
These factors indicate a higher risk of arrhythmias and sudden cardiac events.
What is the pathophysiology of hypertrophic cardiomyopathy?
Impaired filling due to reduced diastolic relaxation and myocardial ischemia
The condition causes increased LVEDP and oxygen demand, leading to complications.
What is the significance of the Venturi effect in HOCM?
It draws the anterior mitral valve leaflet toward the septum, leading to systolic anterior motion (SAM)
SAM can cause mitral regurgitation and further obstruct left ventricular outflow.
What is the Venturi effect in HCM with ASH?
It is a lower pressure that draws the anterior mitral valve leaflet toward the septum, leading to failure of mitral valve leaflets to coapt.
This phenomenon contributes to left ventricular outflow tract obstruction.
How does HOCM present clinically?
- Dyspnea on exertion (DOE)
- Angina
- Syncope
These symptoms are due to elevated left ventricular end-diastolic pressure (LVEDP), mitral regurgitation (MR), and left ventricular outflow tract (LVOT) obstruction.
What is a distinguishing feature of the HOCM murmur compared to aortic stenosis (AS) murmur?
The HOCM murmur does not radiate to the carotids.
It is also affected by changes in preload.
What do you see on ECG with classic HOCM?
Dagger-like septal Q waves in lateral (I, aVL, V5-6) and sometimes inferior leads, along with left ventricular hypertrophy (LVH) criteria.
These findings are indicative of hypertrophic cardiomyopathy.
How does the degree of LVOT obstruction affect intraoperative management of patients with HOCM?
Systolic LVOT obstruction in HCM is dynamic and increases with decreasing preload and increased contractility.
Management involves volume optimization and avoiding vasodilators.
