B P6 C52 The Dilated, Restrictive, and Infiltrative Cardiomyopathies Flashcards
_____ is characterized by an enlarged left ventricle with systolic dysfunction that is not caused by ischemic or valvular heart disease.
DCM
Due to the prevalence of ischemic cardiomyopathy, the most common clinical and clinical research approach is to sort DCM into _____
Ischemic or nonischemic categories
Electrocardiography in DCM frequently reveals _____
LV hypertrophy
Nonspecific ST-T wave changes
Bundle branch block
Conduction system disease in DCM has specific gene associations (e.g., _____ cardiomyopathy)
LMNA
In advanced cases of DCM with extensive fibrosis, _____ limb leads may be seen.
Low-voltage
Echocardiography in patients with DCM reveals LV _____ that may also show biventricular dysfunction in at least one third of cases, all of which can range from mild to severe.
Systolic dysfunction
In DCM, most commonly, _____ LV hypokinesis is present, but regional wall motion abnormalities may also be seen, particularly septal dyskinesis in those with left bundle branch block
Global
Echo in DCM: A _____ pattern is most commonly seen in patients with volume overload in “decompensated” heart failure and often improves with initiation of diuretic or vasodilator therapy.
Restrictive
Coronary angiography in DCM should be considered in all patients who have risk factors for CAD, most importantly cigarette smoking or a prominent family history of early-onset CAD observed in familial hypercholesterolemia, or in those who are of an age where CAD is commonly observed regardless of added risk factors, conventionally above ___ years in males and above ___ years in females.
Males > 40 years
Females > 45 years
Cardiac magnetic resonance imaging (CMR) in DCM has become foundational for the evaluation of a patient who presents with a recently diagnosed cardiomyopathy. A pattern of _____ suggests a nonischemic cause.
Nontransmural delayed gadolinium enhancement in a noncoronary distribution in a dilated left ventricle
In a significant proportion of patients with DCM, no obvious cause can be found even with a comprehensive clinical evaluation; these patients are assigned a diagnosis of _____
Idiopathic DCM
Patients with DCM typically have an _____ phase for many years before symptomatic heart failure, an arrhythmia, or an embolic event develops later in the course of the disease
Asymptomatic
Truncating variants in the giant scaffolding protein _____ have been shown to be the most common, associated with 10% to 20% of cases of DCM depending upon cohort studied
The only general variation in phenotype commonly recognized is “DCM with prominent conduction system disease,” which has been observed in _____ DCM and some cases of sodium channel (SCN5A) or desmin (DES) DCM
Titin (TTN)
Lamin A/C (LMNA)
Most cases of familial DCM are transmitted via _____ inheritance, with the offspring of a mutation carrier having a 50% chance of inheriting the rare variant
Autosomal dominant
Therapy for DCM is similar to that for all types of _____
HFrEF
_____ is now considered a genetically determined cardiomyopathy that has been historically characterized by lethal arrhythmias in relatively young adults and with fibrofatty replacement of the myocardium, especially of the right ventricle.
ARVC
A recognized misnomer in the ARVC term is that biventricular involvement occurs in up to ___% of cases and a small proportion of cases affect predominantly the left ventricle
50% Biventricular
ARVC is classically conceptualized as having three stages: _____
(1) an early subclinical phase in which imaging studies are negative but during which sudden cardiac death can still occur;
(2) a phase in which (usually) RV abnormalities are obvious without any clinical manifestation of RV dysfunction but with the development of a symptomatic ventricular arrhythmia
(3) progressive fibrofatty replacement and infiltration of the myocardium leading to severe RV dilation and aneurysm formation and associated right-sided heart failure. LV dilation and failure may also arise at this stage or may occur later (sometimes referred to as phase 4)
_____ is a key facilitator of arrhythmias at all stages of ARVC
Exercise
The electrical manifestations of ARVC reflect the pathologic disturbance. In the early stage,_____ may lead to a fatal arrhythmia. As the disease progresses, _____ results in inhomogeneous activation and a further delay in conduction
Early: slow conduction and electrical uncoupling
Progression: fibrofatty infiltration
The predominant site of cardiac involvement in ARVC, known as the triangle of dysplasia, was believed to involve the _____. However, recent data suggest that the RV apex is only involved in advanced disease and that an area involving the _____ and ______ may be most commonly involved
RV outflow tract
Area below the tricuspid valve
RV apex
Basal inferior and anterior RV
Posterolateral LV
Patients with ARVC exhibit a typical monomorphic ventricular tachycardia (VT) characterized by _____. A classic “epsilon wave” in the right precordial leads is a specific but insensitive finding
LBBB morphology with a superior axis
Typical T wave inversions extending to V3 or beyond
The classic hallmark of ARVC, fibrofatty replacement, is now understood to be related to aberrant Wnt signaling of _____ proteins, as well as direct plakoglobin signaling, which transforms myocytes into adipocytes with disease progression.
Desmosomal
Diagnostic Terminology for Revised Criteria of ARVC
Definite:
2 Major
1 Major + 2 minor* (IE criteria -1)
4 mino*
Borderline:
1 major + 1 minor
3 minor
Possible:
1 Major
2 minor