Heart Failure, Hemodynamics, Nuclear, Channelopathies Flashcards
What is the diagnosis:
- Heart failure with reasonably preserved EF ~ 50%
- Normal coronaries
- LV hypertrophy
- Renal dysfunction
- FH: brother and maternal grandfather also affected by HF
Fabry’s disease
- X-linked disorder
- Alpha-galactosidase A deficiency
Define stroke work of the ventricle
What influences stroke work?
- Represented by the area enclosed by the pressure-volume loop
- Changes in stroke work are influenced by:
- Preload
- Afterload
- Intrinsic contractility
What is the most likely intervention? (A –> B)
Dobutamine (primarily B1-adrenergic agonist)
- Shift in the end-systolic pressure-volume relationship (ESPVR) –>
- consistent with an increase in contractility
- Increase in stroke volume
- difference between EDV and ESV
- EDV is reduced, because the increased contractility of the LV has resulted in a lower ESV before onset of diastolic filling
- difference between EDV and ESV
Define the pressure-volume loop
- depict instantaneous recordings of ventricular pressure against ventricular volume during a single cardiac cycle
- Loop area, which represents stroke work, changes based on varying:
- preload
- afterload
- intrinsic properties of the myocardium
- ESPVR and EDPVR define these properties - remain constant in spite of changing loading conditions of the heart
Describe the diagram
- The end-systolic and end-diastolic pressure-volume relationships (ESPVR, EDPVR) are the boundaries of the PV loop
- End-systolic elastance (Ees): surrogate for cardiac contractility and is represented by the slope of the ESPVR
How can you estimate stroke work?
SV x mean LV or aortic pressure (during ejection) = stroke work
Define ESPVR
End-systolic PV relationship
- linear relationship
- represents the contractile properties of the chamber
- when the myocardium is maximally contracted
Define EDPVR
End-diastolic PV relationship
- nonlinear relationship
- represents the stiffness properties of the ventricular chamber
- when the myocardium is maximally relaxed and undergoing filling
Define end-systolic elastance
- slope of the ESPVR
- surrogate for cardiac contractility
- leftward shift (increased steepness of the slope) of ESPVR
- positively inotropic drugs
- increased HR (pacing, physiologic stimuli)
- “force-frequency relationship”
- rightward shift (decreased steepness of the slope) of ESPVR
- negatively inotropic drugs
How is the EDPVR affected in regards to volume?
Nonlinear
- Low chamber volumes –> increases in volume are associated with minimal changes in pressure
- high LV chamber compliance at low volumes
- High chamber volumes –> increases in volume are associated steep changes in pressure
- chamber compliance has decreased as a result of stretch of elastic elements
Define chamber stiffness (in PV loops)
- ratio of change in pressure to change in volume
- increases as EDV and pressure increase
What causes changes to EDPVR?
Changes in intrinsic properties or composition of the myocardium
- ischemia
- fibrosis
- hypertrophy
- infiltrative disease
What are the components of chamber stiffness?
Examples?
- LV wall volume and Chamber volume
- Hypertrophic Cardiomyopathy –> abnormally increased chamber stiffness
- Normal growth or Athletic hypertrophy –> chamber stiffness not affected
Describe the findings
Positive inotropy
- ESPVR is shifted to the left without change in preload or afterload
- Increased HR as a result of pacing
Describe the findings
Positive Inotropy and Positive Lusitropy
- ESPVR is shifted to the left
- EDPVR is displaced down and to the right
- Inotropes: Epinephrine, Isoproterenol
- Lusitropy: rate of myocardial relaxation
Describe the findings
Increased afterload
- Afterload is elevated without change in contractility or stiffness –> reduce stroke volume
- Phenylephrine
Describe the findings
Decreased afterload
- Afterload is reduced without change in contractility or stiffness, –> increased SV
- Sodium nitroprusside, Hydralazine, ACE
Describe the findings
Increased preload
- Preload is elevated without a change in contractility or stiffness –> increased SV
- IV fluids
Describe the findings
Negative inotropy
- ESPVR is shifted to the right without change in afterload or preload
- BB’s or CCB’s
Describe the findings
Frank-Starling Relationship
- “Length-Tension” Relationship
- increases in EDV –> stretch of ventricular myocytes –> increased tension generation –> stronger contraction
- allows the heart to increase SV when there is increased venous return
- Increasing chamber volume beyond a certain point –> decreases tension generation
What are the Class I recommendations for ICD implantation in patients with Hypertrophic Cardiomyopathy?
- SCD
- VF
- VT (hemodynamically significant)
What are the Class IIa recommendations for ICD implantation in patients with Hypertrophic Cardiomyopathy?
Primary Prevention
-
Family History HCM - SCD
- > 1 first degree relative
- Unexplained syncope (non-neurocardiogenic)
- Massive LVH > 30 mm
Require additional risk factors
- Multiple-repetitive NSVT (on Holter)
- Abnormal exercise BP response
- LGE > 15% of LV mass
*****Require additional risk factors
- End-stage (LVEF < 50%)
- LV apical aneurysm
- LGE > 15% LV mass**
- Marked LVOTO ( > 30mm Hg) at rest
- Modifiable (intense competitive sports, CAD)
- Age > 60 years
- SCD uncommon in this age group
- Alcohol septal ablation (?)
Describe the risk stratification groups in Hypertrophic cardiomyopathy
Describe excitation-contraction coupling
Mechanism by which small amounts of extracellular calcium enter the myocyte (first step**)during the plateau phase of the action potential and lead to larger intracellular calcium release from the SR to initiate myocardial contraction
What is the diagnosis?
- commonly seen in younger individuals
- rapildly progressive (decline in cardiac function - EF 23%)
- often associated with ventricular arrhythmias
- high frequency of autoimmune disorders
Giant cell myocarditis
Describe the features of Giant Cell Myocarditis
- fulminant, rapidly progressive disease that is usually fatal and affects young, otherwise healthy individuals
- associated with autoimmune conditions (but specific cause not known)
- Presentation: (63 GCM patients diagnosed with biopsy)
- fulminant disease that presents within days to weeks
- new heart failure symptoms (75%)
- ventricular arrhythmias (14%)
- heart block (5%)
- fulminant disease that presents within days to weeks
Describe the features of GCM
- Pathophysiology
- Histologically
- Pathophysiology:
- believed to be mediated by T lymphocytes
- can be transferred by T lymphocytes in animal models
- Histologically
- characterized by a diffuse, nongranulomatous infiltrate of T lymphocytes, histiocytes, and eosinophils with myocyte necrosis and little fibrosis
What is the differential diagnosis in a patient with rapidly progressive heart failure and high-grade heart block?
- GCM
- Sarcoidosis
- Lyme disease
- Chagas disease
Diagnose GCM
EMB (RV)
- sensitivity (85%)
- due to diffuse endocardial pattern of inflammation
- If results inconclusive or discordant –>
- re-biopsy of RV or LV EMB should be considered
What is the treatment for GCM?
- GDMT for heart failure
- avoidance of Digoxin (risk of heart block and proarrhythmia)
- Mechanical support (IABP, VADs) –> bridge to recovery or transplant
- 78% of patients on GCM registry with VADs had successful bridging to transplantation
- Immunosuppression
- can see histopathologic improvement, but replacement with fibrosis is common
- cessation –> recurrence (as far as 8 years after diagnosis)
In addition to guideline-directed medical therapy, what intervention for HF patients has also been proven to help reduce rehospitalizations?
Standardized disease education
- 1-hour nurse educator-delivered teaching session at the time of discharge resulted in:
- improved clinical outcomes
- increased self-care and treatment adherence
- reduced cost of care
What are the discharge criteria for HF patients?
What are the discharge criteria for HF patients?
Should be considered for patients with advanced or refractory HF?