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Toronto Notes 2019 Heart Failure Heart Failure with Reduced Ejection Fraction
• impairedmyocardialcontractilefunction→decreasedLVEFandSV→decreasedCO
Volume Overload and Eccentric Remodelling is the Typical Phenotype
• findings:apexbeatdisplaced,S3,cardiothoracicratio>0.5,decreasedLVEF,LVdilatation • causes
■ ischemic (e.g. extensive CAD, previous MI) ■ non-ischemic
◆ HTN
◆ DM
◆ alcohol (and other toxins)
◆ myocarditis
◆ dilated cardiomyopathy (multiple causes – see Dilated Cardiomyopathy, C40)
Heart Failure with Mid-range Ejection Fraction (HF-mrEF: LVEF 41-49%)
• epidemiologicalstudiesarecurrentlybeingconductedtobettercharacterizeclinicalmanagementof patients in this group
Heart Failure with Preserved Ejection Fraction
• previouslyknownas“diastolicheartfailure”
• concentricremodellingwitha“stiff”leftventricleisthetypicalphenotype
• 1/2ofpatientswithheartfailurehavepreservedEF;conferssimilarprognosistoHRrEF;morecommon
in the elderly and females
• reducedLVcompliancecausesincreasedLVfillingpressures,increasedLApressure/volume,and
pulmonary congestion
• findings:HTN,apexbeatsustained,S4,normal-sizedheartonCXR,LVHonECG/echo,normalEF • causes
■ transient: ischemia (relaxation of myocardium is active and requires ATP) ■ permanent
◆ severe hypertrophy (HTN, aortic stenosis, HCM) ◆ restrictive cardiomyopathy (e.g. amyloid)
◆ MI
High-Output Heart Failure
• causedbydemandforincreasedcardiacoutput
• oftenexacerbatesexistingheartfailureordecompensatesapatientwithothercardiacpathology
• differentialdiagnosis:anemia,thiaminedeficiency(beriberi),hyperthyroidism,A-VfistulaorL-R
shunting, Paget’s disease, renal disease, hepatic disease
Precipitants of Symptomatic Exacerbations
• considernaturalprogressionofdiseasevs.newprecipitant • alwayssearchforreversiblecause
• differentialdiagnosiscanalsobeorganizedasfollows:
■ new cardiac insult/disease: MI, arrhythmia, valvular disease
■ new demand on CV system: HTN, anemia, thyrotoxicosis, infection, etc. ■ medicationnon-compliance
■ dietary indisretion e.g. salt intake
■ obstructive sleep apnea
Investigations
• identifyandassessprecipitatingfactorsandtreatablecausesofCHF
• bloodwork:CBC,electrolytes(includingcalciumandmagnesium),BUN,creatinine,fastingblood
glucose, HbA1c, lipid profile, liver function tests, serum TSH ± ferritin, BNP, uric acid
• ECG:lookforchamberenlargement,arrhythmia,ischemia/infarction
• CXR:cardiomegaly,pleuraleffusion,redistribution,KerleyBlines,bronchiolar-alveolarcuffing
• echo:systolicfunction(LVEF),diastolicfunction(E/Aratio,E/e’),cardiacdimensions,wallmotion
abnormalities, right ventricular systolic pressure (from TR jet), valvular disease, pericardial effusion
• radionuclide angiography: LVEF
• myocardialperfusionscintigraphy(thalliumorsestamibiSPECT)
Acute Treatment of Pulmonary Edema
• treatacuteprecipitatingfactors(e.g.ischemia,arrhythmias)
• L – Lasix® (furosemide) 40-500 mg IV
• M–morphine2-4mgIV:decreasesanxietyandpreload(venodilation)
• N–nitroglycerin:topical/IV/SL-usewithcautioninpreload-dependentpatients(e.g.rightHForRV
infarction) as it may precipitate CV collapse
• O–oxygen:inhypoxemicpatients
• P–positiveairwaypressure(CPAP/BiPAP):decreasespreloadandneedforventilationwhen
appropriate
• P – position: sit patient up with legs hanging down unless patient is hypotensive • in ICU setting or failure of LMNOPP, other interventions may be necessary
■ nitroprusside IV ■ hydralazine PO
Cardiology and Cardiac Surgery C35
A Validated Clinical and Biochemical Score for the Diagnosis of Acute Heart Failure: the ProBNP Investigation of Dyspnea in the Emergency
Department (PRIDE) Acute Heart
Am Heart J 2006;151:48-54
Predictor
Age >75 yr
Orthopnea present
Lack of cough
Current loop diuretic use (before presentation)
Rales on lung exam Lack of fever
Elevated NT-proBNP (>450 pg/mL if <50 yr, >900 pg/mL if >50 yr)
Interstitial edema on chest x-ray Total
Likelihood of heart failure Low = 0-5 Intermediate = 6-8 High = 9-14
Failure Score
Possible Score
1 2 1 1
1 2 4
2 /14
Brain natieuretic peptide (BNP) is secreted by ventricles due to LV stretch and wall tension. Cardiomyocytes secrete BNP precursor that is cleaved into proBNP. After secretion into ventricles, proBNP is cleaved into the active C-terminal portion and the inactive NT-proBNP. The above scoring algorithm developed by Baggish et al. is commonly used. A score of <6 has a negative predictive value of 98%, while scores ≥6 had a sensitivity of 96% and specificity of 84% (p<0.001) for the diagnosis of acute heart failure.
New York Heart Association (NYHA) Functional Classification of Heart Failure • Class I: ordinary physical activity does not
cause symptoms of HF
• Class II: comfortable at rest, ordinary
physical activity results in symptoms • Class III: marked limitation of ordinary
activity; less than ordinary physical activity
results in symptoms
• Class IV: inability to carry out any physical
activity without discomfort; symptoms may be present at rest
Five Most Common Causes of CHF
• CAD (60-70%)
• HTN
• Idiopathic (often dilated cardiomyopathy) • Valvular (e.g. AS, AR, and MR)
• Alcohol (dilated cardiomyopathy)
Precipitants of Heart Failure
HEART FAILED
Hypertension (common) Endocarditis/environment (e.g. heat wave) Anemia
Rheumatic heart disease and other valvular disease
Thyrotoxicosis
Failure to take meds (very common) Arrhythmia (common) Infection/Ischemia/Infarction (common) Lung problems (PE, pneumonia, COPD) Endocrine (pheochromocytoma, hyperaldosteronism)
Dietary indiscretions (common)