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C36 Cardiology and Cardiac Surgery
Heart Failure
Toronto Notes 2019
The most common cause of right heart failure is left heart failure
Measuring NT-Pro BNP
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 portion
NT-proBNP levels (pg/mL)
Age HF very likely <50 >450
50-75 >900
>75 >1800
Limitations: Age, body habitus, renal function, pulmonary embolism
Features of Heart Failure on CXR
HERB-B
Heart enlargement (cardiothoracic ratio >0.50) Pleural Effusion
Re-distribution (alveolar edema)
Kerley B lines
Bronchiolar-alveolar cuffing
Patients on β-blocker therapy who have acute decompensated heart failure should continue β-blockers where possible (provided they
are not in cardiogenic shock or in severe pulmonary edema)
Can the Clinical Examination Diagnose Left- Sided Heart Failure in Adults?
From The Rational Clinical Examination JAMA 2009; http://www.jamaevidence.com/ content/3478992
Study: Systematic review of articles assessing the accuracy and precision of the clinical exam in the diagnosis of CHF.
Results: The diagnosis of left ventricular dysfunction in patient after an MI based on the presence of radiographic pulmonary venous congestion with edema, rales one-third up the lung fields in the absence of a chronic pulmonary disease, or a 3rd heart sound had a positive likelihood ratio (+LR) of 3.1 (95% CI 1.7-5.8) and a negative likelihood ratio (-LR) of 0.62 (95% CI 0.46-0.83). In inpatients the combination of clinical findings, ECG, and CXR had a +LR of 2.0 (95%
CI 1.6-2.5) and a –LR of 0.41 (95% CI 0.30-0.56). Female sex (+LR, 1.6 [95% CI 1.2-2.2]) and sBP ≥160 mmHg (+LR, 1.8 [95% CI 1.3-2.6]) were most indicative for diastolic dysfunction. Heart rate ≥100/ min (+LR 0.43 [95% CI 0.28-0.65]) and left atrial ECG abnormality (+LR 0.42 [95% CI 0.26-0.63]) were most indicative for systolic dysfunction. Conclusions: Patients with signs, symptoms, and risk factors for systolic dysfunction should receive an ECG and CXR. Female sex and sBP ≥160 mmHg are suggestive of diastolic dysfunction; heart rate ≥100/min and left atrial ECG abnormality suggest systolic dysfunction.
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■ sympathomimetics ◆ dopamine
– low dose: selective renal vasodilation (high potency D1 agonist)
– medium dose: inotropic support (medium potency β1 agonist)
– high dose: increases SVR (low potency β1 agonist), which is undesirable
◆ dobutamine
– β1-selective agonist causing inotropy, tachycardia, hypotension (low dose) or hypertension
(high dose); most serious side effect is arrhythmia, especially AF ◆ phosphodiesterase inhibitors (milrinone)
– inotropic effect and vascular smooth muscle relaxation (decreased SVR), similar to dobutamine considerpulmonaryarterycathetertomonitorpulmonarycapillarywedgepressure(PCWP)ifpatient is unstable or a cardiac etiology is uncertain (PCWP >18 indicates likely cardiac etiology) mechanicalventilationasneeded
rarelyused,butpotentiallylife-savingmeasures:
■ intra-aortic balloon pump (IABP) - reduces afterload via systolic unloading and improves coronary perfusion via diastolic augmentation
■ left or right ventricular assist device (LVAD/RVAD)
■ cardiac transplant
Long-Term Management
• overwhelmingmajorityofevidence-basedmanagementappliestoHFREF
• currently no proven pharmacologic therapies shown to reduce mortality in HFPEF; control risk factors
(e.g. hypertension)
Conservative Measures
• symptomaticmeasures:oxygeninhospital,bedrest,elevatetheheadofbed
• lifestylemeasures:diet,exercise,DMcontrol,smokingcessation,decreasealcoholconsumption,patient
education, sodium and fluid restriction
• multidisciplinaryheartfailureclinics:formanagementofindividualsathigherrisk,orwithrecent
hospitalization
Non-Pharmacological Management
• fromCCSguidelines(2017update)
• cardiacrehabilitation:participationinastructuredexerciseprogramforNYHAclassI-IIIafterclinical
status assessment to improve quality of life (HF-ACTION trial)
Pharmacological Therapy
1. Renin-angiotensin-aldosterone blockade
■ ACEI: standard of care – slows progression of LV dysfunction and improves survival ◆ all symptomatic patients functional class II-IV
◆ all asymptomatic patients with LVEF <40%
◆ post-MI
■ angiotensin II receptor blockers
◆ second-line to ACEI if not tolerated, or as adjunct to ACEI if β-blockers not tolerated
– combination with ACEI is not routinely recommended and should be used with caution as it may precipitate hyperkalemia, renal failure, the need for dialysis and increase (CHARM, ONTARGET)
◆ combination angiotensin II receptor blockers with neprilysin inhibitors (ARNI) is a new class of medication that has morbidity and mortality benefit over ACEI alone; it has been recommended to replace ACEI or ARBs for patients who have persistent symptoms (PARADIGM HF)
2. β-blockers: slow progression and improve survival
■ class I-III with LVEF <40%
■ stable class IV patients
■ carvedilol improves survival in class IV HF (COMET)
■ note: should be used cautiously, titrate slowly because may initially worsen CHF
3. Mineralocorticoid receptor (aldosterone) antagonists: mortality benefit in symptomatic heart failure and severely depressed ejection fraction
■ spironolactone or eplerenone symptomatic heart failure in patients already on ACEI, β-blocker and loop diuretic
■ note: potential for life threatening hyperkalemia
◆ monitor K+ after initiation and avoid if Cr >220 μmol/L or K+>5.2 mmol/L
4. Diuretics: symptom control, management of fluid overload
■ furosemide (40-500 mg daily) for potent diuresis
■ metolazone may be used with furosemide to increase diuresis
■ furosemide, metolazone, and thiazides oppose the hyperkalemia that can be induced by β-blockers,
ACEI, ARBs, and aldosterone antagonists
5. Digoxin and cardiac glycosides: digoxin improves symptoms and decreases hospitalizations, no effect on mortality
■ indications: patient in sinus rhythm and symptomatic on ACEI, or CHF and AFib ■ patients on digitalis glycosides may worsen if these are withdrawn
6. Antiarrhythmic drugs: for use in CHF with arrhythmia ■ can use amiodarone, β-blocker, or digoxin