We turned our attention to chronic congestive heart failure (CHF) and reviewed “The 2012 Canadian Cardiovascular Society Heart Failure Management Guidelines Update“.
National Institute of Health provided a great summary on CHF for patients and the public: http://www.nhlbi.nih.gov/health/health-topics/topics/hf/
For a basic anatomy review of the circulatory system:
For another diagram showing the heart in relation to the body, click here.
And an over-simplification of the pathophysiology of left vs right heart failure is that when the left ventricle fails, not enough oxygenated blood gets pumps to the body to meet its demand. Instead, blood gets backed up into the lungs and cause fluid buildup in the lungs. This pressure can further back up into the right heart, such that the right ventricle and right atrium cannot accommodate a normal amount of venous return, and fluid can accumulate in the body to cause edema. Wikipedia strikes a good balance of depth and readability on this topic: http://en.wikipedia.org/wiki/Heart_failure
The CCS guideline suggests the following investigations for CHF:
- labs (CBC, electrolytes, creatinine, urinalysis, glucose, thyroid function), and
- further testing (nuclear imaging, catheterization, stress test, MRI, CT, endomyocardial biopsy) if appropriate.
The CCS guideline on treatment of chronic CHF:
ACE inhibitors for:
- all symptomatic HF patients and EF < 40%.
- all patients with an EF < 35%
Angiotensin receptor blocker:
- if patient intolerant to ACEI
- add to ACEI if intolerant or contraindicated for BB
- add to ACEI and BB if patient has NYHA class II-IV HF and EF ≤ 40% deemed at increased risk of HF events
- all HF patients with an EF ≤ 40%
- initiated at a low dose and titrated to the target dose or maximal tolerated dose
Mineralocorticoid receptor antagonist:
- EF <30% and one of the following:
- past MI and HF
- severe chronic HF (NYHA IIIB-IV) despite optimized treatment
- age >55 with HF symptoms on treatment and recent hospitalization for CV disease in the past 6 months (or if QRS duration > 130ms and EF <35%)
- with elevated BNP or NT-proBNP levels
- loop diuretic, such as furosemide, for most patients with HF and congestive symptoms. When acute congestion is cleared, the lowest dose should be used that is compatible with stable signs and symptoms
- persistent volume overload despite optimal medical therapy and increases in loop diuretics, cautious addition of a second diuretic (a thiazide or low dose metolazone) may be considered as long as it is possible to closely monitor morning weight, renal function, and serum potassium
- patients in sinus rhythm who continue to have moderate to severe symptoms, despite optimized HF therapy
- patients with chronic atrial fibrillation (AF) and poor control of ventricular rate
Isosorbide dinitrate and hydralazine:
- black Canadians with HF-REF
- non-black HF patients unable to tolerate an ACE inhbitor or ARB