Cardiovascular Miscellany II Flashcards
Cardiac arrhythmia
disturbance in heart rhythm due to deranged cardiac electrical signaling
Supraventricular tachycardia
Arrhythmia originating from the atrium
Ventricular tachycardia
Arrhythmia due to reentry around the edge of a scar in the left ventricle, especially a patchy myocardial infarction (of IHD) creating numerous small areas of non-conducting tissue for a cardiac impulse to bounce off of until it finds a path to zing around at a high rate of speed. Huge cause of sudden cardiac death.
Ventricular fibrillation
immediately life-threatening arrhythmia of chaotic ventricular activation at a rapid rate with lack of cardiac pumping
Asystole
lack of electrical activity in the heart
Palpitations
“racing heart”
Syncope
loss of adequate CO due to sustained arrhythmia can produce loss of consciousness
Channelopathy
heart disease of arrhythmias due to defective cardiac myocyte ion channels, usually due to genetic mutations
Long QT syndrome
Phase 2 channelopathy of the left ventricle that causes early after-depolarization (EAD)
Brugada syndrome
Autosomal dominant, sodium channelopathy that leads to shortened/failed APs and localized conduction block in the RV which predisposes to phase 2 re-entrant ventricular tachycardia
Catecholeminergic polymorphic ventricular tachycardia
Familial genetic disease caused by mutations in the cardiac ryanodine receptor (Sarcoplasmic Ca2+ release channel) that causes high cytosolic calcium leading to DAD during phase 4 that predisposes to ventricular tachycardia triggered by high levels of catecholamines
Cardiomyopathy
heterogeneous group of myocardial diseases associated with mechanical and/or electrical dysfunction of the heart
Idiopathic dilated cardiomyopathy
wastebasket category of nonspecific end-stage heart disease with cardiac dilatation and heart failure (systolic dysfunction) and no cause evident (90%)
Hypertrophic Cardiomyopathy
group of genetic diseases with hypertrophy as a compensatory mechanism for mutations in genes (beta-myosin heavy chain) encoding contractile proteins of the cardiac sarcomere (diastolic dysfunction)
Restrictive cardiomyopathy
least common cardiomyopathy that leads to diastolic dysfunction (impaired compliance) due to amyloidosis, radiation-induced fibrosis, or idiopathic
Dystrophin
cell membrane protein that connects the intracellular cytoskeleton to the ECM (mutated in X-linked DCM)
Alcoholic cardiomyopathy
cardiomyopathy caused by alcohol intake (alcohol abuse leads to direct toxic effects on the myocardium by alcohol and its metabolites (like acetylaldehyde) + beriberi heart disease from thiamine deficiency
Peripartum cardiomyopathy
mutlifactorial cardiomyopathy that occurs late in gestation or several weeks postpartum due to pregnancy HTN, volume overload, increased cleavage products of prolactin, etc. that can induce myocardial dysfunction
Arrhythmogenic right ventricular cardiomyopathy
autosomal dominant disorder of cardiac muscle (probably second “hit” being viral infection) with variable penetrance manifesting as right sided heart failure and ventricular rhythm disturbances that can cause SCD
Myocarditis
Myocarditis encompasses a diverse group of clinical entities in which infectious agents and/or inflammatory processes primarily target the myocardium
Cardiac myxoma
Most common primary tumor of adult heart: benign gelatinous mesenchymal neoplasm of endocardium
What is the most common cause of rhythm disorders?
ischemic injury (direct damage or due to dilation of heart chambers with consequent alteration of conduction system firing
What is sudden cardiac death (SCD)?
sudden death typically due to sustained ventricular arrhythmias in individuals with underlying heart disease (CAD) who may or may not have been symptomatic in the past
True or false: SCD is often the first manifestation of IHD.
true!
True or false: frank infarction is a prerequisite for SCD.
FALSE- 80-90% of patients show no evidence of myocardial necrosis after resuscitation
What are 5 general pathways that can lead to end-stage DCM?
1) Genetics (dystrophin mutations)
2) Infection
3) Alcohol or toxins (doxorubicin)
4) Peripartum cardiomyopathy
5) Iron overload
What does a DCM heart look like?
enlarged, flabby heart that is dilated in all chambers. Mural thrombi often present
What is the epidemiology of DCM? What are the presenting symptoms? Why?
20-50 y/o. Manifests as slowly progressive CHF (dyspnea, easy fatigability, poor exertional capacity) due to ineffective contraction