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
Major criteria in the diagnosis of ARVC
I. Global and/or regional dysfunction and structural alterations
By two-dimensional echocardiography:
- Regional RV akinesia, dyskinesia, or aneurysm and one of the following (end diastole):
– RVOT PLAX>/= 32 mm (19 mm/m2)
– RVOT PSAX>/= 36 mm (21 mm/m2)
OR
- Fractional area change <33%
By MRI:
- Regional RV akinesia, dyskinesia, or dyssynchronous RV contraction and one of the following:
–Ratio of RVEDV to BSA 110 mL/m2 (male) or >/=100 mL/m2 (female) or RVEF </= 40%
By RV angiography:
Regional RV akinesia, dyskinesia, or aneurysm
II. Tissue Characterization of Wall
Residual myocytes <60% by morphometric analysis (or <50% if estimated), with fibrous replacement of RV free wall myocardium in at least one sample, with or without fatty replacement of tissue seen on endomyocardial biopsy
III. Repolarization Abnormalities
Inverted T waves in right precordial leads (V1, V2, and V3) or beyond in individuals >14 years of age (in absence of complete right bundle branch block QRS >/= 120 msec)
IV. Depolarization/Conduction Abnormalities
Epsilon wave (reproducible low-amplitude signals between end of QRS complex to onset of T wave) in right precordial leads (V1–V3)
When a genetic cause can be identified, rare variants in the genes encoding _____ account for most genetic causes of ARVC
Plakophilin 2 (PKP2)
Desmoglein 2 (DSG2)
Desmoplakin (DSP)
The autosomal recessive syndromic _____, so named because it was discovered on the Greek island of Naxos, is manifested as ARVC cosegregating with palmoplantar keratoderma and wooly hair
Naxos disease
ARVC
Plakoglobin
A second autosomal recessive syndromic disease, _____, resembles Naxos disease in that individuals have palmoplantar keratoderma and wooly hair, but individuals with Carvajal syndrome manifest DCM, not ARVC. Carvajal syndrome is caused by a frameshift rare variant in DSP, which encodes desmoplakin.
Carvajal syndrome
DCM
Desmoplakin
The differential diagnosis of ARVC in the early stages (before the onset of visible structural abnormalities) includes _____ VTs.
Idiopathic and RVOT VT
The morphology of the classic ARVC-related VT differs from these entities, and in the presence of _____ during sinus rhythm, ARVC should be the initial diagnosis. Cardiac sarcoidosis may occasionally mimic ARVC morphologically and be indistinguishable, even with multiple imaging modalities.
Precordial T wave inversion during sinus rhythm
Cardiac biopsy in patients with sarcoidosis often fails to show the pathognomonic granulomas but may reveal extensive _____, which may also be confused with ARVC.
Fibrosis
Intense physical exertion is associated with an earlier onset of symptoms and an increased risk of sustained VT, and therefore patients with a diagnosis of ARVC are advised not to participate in _____.
Athletic activity
The classic monomorphic VT in ARVC with predominant RV involvement is generally well tolerated, even at a rapid rate, possibly because of _____ LV function in most patients.
Preserved LV function
Antiarrhythmic drugs may suppress a symptomatic arrhythmia but have not been shown to prevent sudden death. ____ agents may suppress catecholamine-triggered arrhythmia and slow progression of ventricular dysfunction and have been recommended as potentially valuable in all patients with ARVC.
Beta blockers
An _____ is recommended in patients with aborted sudden death, synope, or decreased LV function and may be considered in other patients with ARVCb
ICD
Catheter ablation has not been shown to reduce sudden death in ARVC but is valuable in a patient with an ICD and frequent arrhythmias or in occasional patients with very well-tolerated single-morphology VT.
Ablation appears to be most successful when lesions are made in both the _____t; it should be performed only at centers experienced in the technique, either as a combined procedure or with epicardial ablation reserved for recurrence after endocardial ablation
Epicardial and endocardial surfaces of the heart
Because a history of _____ among carriers of a pathogenic ARVC desmosome rare variant is associated with an earlier onset of symptoms and a higher prevalence of VT or ventricular fibrillation, there is a task force recommendation that persons with definite or suspected ARVC should not compete in most competitive sports.
Vigorous sustained exercise
Class I indication for ICD implantation in ARVC
High Risk:
Aborted SCD due to VF
Sustained VT
Severe dysfunction of RV, LV, or both
Echocardiographic Diagnostic Criteria for Left Ventricular Noncompaction
Chin et al. (California criteria)*
- LVNC is defined by an X/Y ratio </= 0.5
- These criteria evaluate trabeculae at the LV apex on the parasternal short axis and apical views and by using the LV free wall thickness at end- diastole
Jenni et al. (Zurich criteria)†
- Bilayered myocardium consisting of a thin C layer and a much thicker NC layer with deep endomyocardial recesses: NC/C >2
- Predominant location of the pathology is midlateral, midinferior, and at the apex
- Evidence of intertrabecular recesses filled with blood from the LV cavity
- Acquisition of image views: short axis with measurement of the NC/C ratio performed at end-systole
MRI Diagnostic Criteria for LVNC
Petersen et al.
Ratio between NC and C layers >2.3 at end-diastole
Jacquier et al.
Trabeculated LV mass >20% of global LV mass (measurements made at end-diastole)
The “purest” form of tachycardia-induced cardiomyopathy is probably that caused by _____, often in a child or young patient with systolic dysfunction
Incessant or extremely frequent atrial tachycardia or permanent reciprocating junctional tachycardia
The _____ of the arrhythmia, more than the heart rate, is probably a critical factor in tachycardia-induced cardiomyopathy.
Duration
Most patients with PVC-associated tachycardia-induced cardiomyopathy have more than _____ PVCs over a 24-hour period, but the condition has also been described with a lesser frequency of arrhythmia.
> 20,000/24H
Most cases of tachycardia-induced cardiomyopathy improve within _____months after correction of the arrhythmia, but occasionally patients have been seen with late improvement, up to 1 year
3-6 months
Because the rapid, irregular ventricular response to atrial fibrillation is associated with marked beat-to-beat variation in the ejection fraction, the most accurate way to determine whether an improvement in systolic function has really occurred is to evaluate the ejection fraction_____ and then compare it with a reevaluation 3 to 6 months later.
Early after restoration of sinus rhythm
_____ has been defined as DCM that occurs in a temporal relationship to pregnancy
Peripartum cardiomyopathy (PPCM)
Definitive evidence of this was recently shown, where 172 women with PPCM underwent sequencing for DCM genes, with _____ identified in 26 of the 172 (15%)
TTN truncating variants (TTNtvs)
The U.S. incidence is estimated to be between 1 in 1000 and 1 in 4000 live births, with a major risk factor that of _____ ancestry; significantly higher incidence has been reported in countries with predominant African ancestry. _____ are also risk factors.
African ancestry
Preeclampsia
Older age
Multiple-fetus pregnancies
In patients with PPCM, symptoms and signs of heart failure develop during late pregnancy or after delivery, similar to those of any patient with heart failure caused by LV systolic dysfunction. Most diagnoses are made in the _____ months following delivery; prepartum diagnoses are most commonly made in the _____ month of pregnancy.
4 months after delivery
Last month of pregnancy