cardiomyopathies Flashcards
What are cardiomyopathies?
A group of diseases of the myocardium affecting its mechanical or electrical functions.
Mechanical functions include hypertrophic, dilated, and restrictive cardiomyopathies; electrical functions include long QT syndrome.
What characterizes hypertrophic cardiomyopathy?
Marked ventricular hypertrophy in the absence of abnormal loading conditions.
Abnormal loading conditions include hypertension and valvular diseases.
What is the impact of hypertrophic cardiomyopathy on the diastolic filling phase?
Leads to reduced stroke volume due to impaired diastolic filling.
The filling phase is crucial for adequate heart function.
What is the most common cause of hypertrophic cardiomyopathy?
Most cases are familial, autosomal dominant, caused by mutations in genes encoding troponin T and beta myosin.
These proteins are sarcomeric proteins essential for muscle contraction.
What is a significant risk associated with hypertrophic cardiomyopathy in young people?
Most common cause of sudden death.
This highlights the severity of the condition in this demographic.
What are some clinical features of hypertrophic cardiomyopathy?
Patients may be asymptomatic or have:
* Breathlessness
* Angina
* Syncope
* Jerky pulse
* Ejection systolic murmur
* Pansystolic murmur
* Bisferious pulse
* Double apical pulsation
These features can vary in presentation.
How do standing and Valsalva maneuvers affect murmurs in hypertrophic cardiomyopathy?
They increase the intensity of murmurs.
Conversely, squatting and sustained handgrips decrease murmur intensity.
What complications can arise from hypertrophic cardiomyopathy?
Complications include:
* Sudden death
* Thromboembolism
* Arrhythmias
* Infective endocarditis
* Heart failure
These complications can significantly impact patient outcomes.
What are the key ECG findings in hypertrophic cardiomyopathy?
Signs of left ventricular hypertrophy (LVH):
* Deep S in V1 V2
* Tall R in V5 V6
* Both together > 35 mm
These findings help in diagnosing the condition.
What is the echocardiographic criteria for hypertrophic cardiomyopathy?
Septum 1.5 times the thickness of the posterior wall.
This measurement is critical for diagnosis.
What management options are available for hypertrophic cardiomyopathy?
Management includes:
* Amiodarone
* ICD
* Beta blockers
* Verapamil
* Catheter ablation of the septum
* Surgical myomectomy
Each option addresses different aspects of the condition.
What criteria indicate the need for an ICD in hypertrophic cardiomyopathy patients?
High-risk patients with:
* Massive LVH (>30mm on echo)
* Family history of sudden cardiac death (<50 y/o)
* Non-sustained V. tach on Holter monitoring
* Prior unexplained syncope
* Abnormal BP response on exercise
These criteria help assess the risk of sudden cardiac events.
Why should vasodilators be avoided in hypertrophic cardiomyopathy?
They aggravate the ventricular outflow obstruction and can cause refractory hypotension.
This could worsen the patient’s condition.
Fill in the blank: The most common cause of sudden death in young people is _______.
hypertrophic cardiomyopathy
What is the most common type of cardiomyopathy?
Dilated cardiomyopathy
It results in a dilated, weak, poorly contracting ventricle.
What is usually the first complaint in dilated cardiomyopathy?
Shortness of breath
Other complaints may include arrhythmias, embolism, and heart failure.
What percentage of dilated cardiomyopathy cases are idiopathic?
50%
This means the cause is unknown.
Name two toxic causes of dilated cardiomyopathy.
- Alcohol
- Doxorubicin
Toxic substances can lead to heart damage.
What metabolic conditions can cause dilated cardiomyopathy?
- Uremia
- Hypophosphatemia
- hypo / hyper thyroid
These conditions affect normal heart function.
List two infectious causes of dilated cardiomyopathy.
- Viral infections
- Chagas disease
HIV and Lyme disease are also included.
What are the common diagnostic investigations for dilated cardiomyopathy?
- ECG
- CXR
- Echo
These tests help assess heart function and structure.
What findings on an ECG might suggest dilated cardiomyopathy?
Arrhythmias and T wave flattening
These are nonspecific findings.
What is the main management strategy for dilated cardiomyopathy?
- Remove offending agents
- Digoxin
- Vasodilators
- Diuretics
Anticoagulants may also be considered.
What defines restrictive cardiomyopathy?
Infiltration of the myocardium resulting in a rigid ventricle
This leads to impaired diastolic filling.
