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Cardiovascular

Links

Local

• Sudden cardiac death (pedes)
• Swan-Ganz and Cardiac Catheterization
• Ventilator settings

Remote

• SBE Proph AFP July 1998
• EKG & D/Dx of Acute Pericarditis
• MDConsult texts: Braunwald, Wash Manual

Anticoagulation

Warfarin Excess

• INR > 10 and not bleeding. Prior to 2003 recommendation was Vitamin K at least 3mg S/Q or slow IV, as of 2007 oral vitamin K was preferred. In practice this might depend on how much over 10 the INR was, and the patient's personal bleeding risk factors.
• INR > 10 and bleeding: Vitamin K 10mg slowly IV, fresh frozen plasma 15ml/kg, optionally also add 50 units of prothrombin complex concentrate.

INR

Misc

• derived from a normalization of the Prothrombin Time (PT). PT measures factors II, V, VII, X and fibrinogen - the extrinsic and common pathways. By contrast aPTT measures the intrinsic pathway.

Values

• 1: normal (popn range is 0.8 to 1.2), corresponds to a PT of 12-15 seconds.
• 2-3: most conditions - DVT, PE, afib
• 2.5 - 3.5: mechanical heart valve
• 3-4: thrombophilia due to antiphospholipid syndrome

DVT and Pulmonary Embolus

Well's Score - DVT

(via Wikipedia)

1. Active cancer (treatment within last 6 months or palliative) -- 1 point
2. Calf swelling >3 cm compared to other calf (measured 10 cm below tibial tuberosity) -- 1 point
3. Collateral superficial veins (non-varicose) -- 1 point
4. Pitting edema (confined to symptomatic leg) -- 1 point
5. Swelling of entire leg - 1 point
6. Localized pain along distribution of deep venous system -- 1 point
7. Paralysis, paresis, or recent cast immobilization of lower extremities -- 1 point
8. Recently bedridden > 3 days, or major surgery requiring regional or general anesthetic in past 12 weeks -- 1 point
9. Previously documented DVT -- 1 point
10. Alternative diagnosis at least as likely -- Subtract 2 points

Interpretation: (Possible score -2 to 9)

Score of 2 or higher - deep vein thrombosis is likely -> Duplex Ultrasonography
Score of less than 2 - deep vein thrombosis is unlikely -> d-dimer test to further rule out deep vein thrombosis.

D-Dimer test

• cross-linked fibrin degradation product is an indication that thrombosis is occurring, and that the blood clot is being dissolved by plasmin.
• "Patients with a normal D-dimer test result and a low or moderate clinical risk based on the Wells score have a very low risk of DVT and require no further testing"

Well's Score - PE

(via Wikipedia)

• clinically suspected DVT - 3.0 points
• alternative diagnosis is less likely than PE - 3.0 points
• tachycardia - 1.5 points
• immobilization/surgery in previous four weeks - 1.5 points
• history of DVT or PE - 1.5 points
• hemoptysis - 1.0 points
• malignancy (treatment for within 6 months, palliative) - 1.0 points

Traditional interpretation

• Score >6.0 - High (probability 59% based on pooled data
• Score 2.0 to 6.0 - Moderate (probability 29% based on pooled data
• Score <2.0 - Low (probability 15% based on pooled data

Alternate interpretation

• Score > 4: do Spiral CT with contrast
• Score < =4: D-dimer to rule out PE.

EKG and Rhythm Interpretation

Basic

• cardiac cycle.pdf
• axes: 0.2s horizontal blocks, 0.5mv vertically
• Rate: 300, 150, 100, 75, 60, 50 (pacemakers atria 75, AVN 60, Vent 30-40)
• Rhythm: PR 0.11-0.22, QRS < 0.1, normal QT is 0.4*RRinterval
• Axis: QRS above I, AVG
• Hypertrophy in V1: P < 0.11, R wave for RVH, V1 S wave + V5 R wave > 35mm -> LVH
• Infarction: Q in absence of LBBB - > 0.4s or greater than 1/3 of QRS in lead III, inverted T, elevated ST (if also elevated T then suspect pericarditis). Following localizations are somewhat unreliable, vascularity varies greatly:
  • anterior (anterior descending branch of left coronary artery): Q in V1-V4
  • lateral (circumflex branch of left coronary artery): Q in I and AVL
  • posterior (posterior descending artery, usually off right coronary): large R in V1, significant Q wave in V6, R/S ratio >= 1 in V2
  • inferior (variable, may be right or left or both coronary arteries): Q in II, III, AVF

Pediatric (esp. < 8 yo)

• see Harriet-Lane Handbook
• T wave may always be inverted in V5-V6, even by age 5 may have inversion in V1-V2. Before age 5 may have R > S in V1. Adult pattern emerges @ age 5-8.

Rhythm

• Washington Manual
• Varying: sinus (sick sinus syndrome), wandering, atrial fib
• Extra: paroxysmal (atrial, nodal, ventricular), atrial flutter, ventricular flutter, atrial fib, vfib, pvc
• Unifocal PVC in healthy person: No need to evaluate if healthy, CXR rnormal, no LVH, no BBB, no HTN. Personally, I'd get an echo.

WPW or Wolff-Parkinson-White

• accessory bundle of Kent -> ventricular pre-excitation, shortened PR and longer appearing QRS, delta wave swoop (nike) between P and QRS.
• Most common tachycardia has narrow QRS, but may have rate-related BBB with wider QRS. Major risk is that AFib may induce VFib in pts with WPW since auxiliary pathway doesn't block. Usual pattern is orthodromic -- antegrade through AV node, retrograde through accessory pathway.
• familial variant has no gender predominance, sporadic 2:1 male
• 7-20% have Ebstein's anomaly (tricuspid valve malformation) or other defect
• Cannot interpret exercise stress test and thallium scan can have false positive, difficult to assess symptoms.
• Usually refer to cardiologist, treat if symptomatic with arrhythmias. Radiofrequency ablation is @85% successful, EKG normalizes.

Block

• SA: miss 1-2 cycle but return in step
• AV block
  • Primary: PR more than 0.2 second
  • Secondary (2:1, 3:1, 4:1, etc)
    • Mobitz Type I (Wenckebach): PR progressively increases then drop QRS
    • Mobitz Type II: drop QRS abruptly -- greater risk of complete block.
    • Complete: ventricular pacemaker gives erratic rate of 20-40
• BBB QRS > 0.11s, cannot assess for LVH, if LBBB cannot assess for Q wave.
  • RBBB: rabbit ears --  RsR' in V1 or V3, wide S in V5-V6
  • LBBB: mountain -- RR' in V5 or V6, wide S in V1-V2

Miscellaneous

• large pulmonary infarction RV strain/ischemia pattern: S1Q3, inverted T waves V1-V4, ST depressed II, transient RBBB
• LV aneurysm: anteroseptal infarct on EKG with persistent ST elevation.
• electrolytes: U wave with low K, short QT with high Ca, long QT with low Ca
• dig toxicity
  • short QT, inverted T
  • PAT with block (>1 P for each QRS), AV block, multifocal tachycardia
• quinidine: long QT syndrome/roller coaster

Heart Failure (outpatient)

Valsalva test

• 90% specific, useful if suspect CHF but not confident enough to order ECHO.
• inflate cuff to 15mm above systolic then pt performs Valsalva
• Positive findings: maintain beats throughout Valsalva (abnormal persistence of increased BP) and failure of beats to reappear after Valsalva ended (but cuff still on; BP once down fails to jump up again)

Serum brain natriuretic peptide (BNP)

• helps differentiate heart failure from noncardiac conditions in a patient with dyspnea (70-90% specific depending on level, 400 is very high).
• can't distinguish diastolic from systolic heart failure

Physiology

• volume depletion -> incr renin & decr renal perfusion -> incr Cr, BUN and SIADH -> hyponatremia. If add ACE may get sudden decr BP.
• hyponatremia is marker for hi renin state and poor prognosis. Rx with ACE over 8 days. Watch for incr K, BUN, Cr. in this setting. Alternative is hydralazine

Activity and Symptoms: In class IV failure

• activity —> decr. renal perfusion —> incr. Na/fluid retention —> increased failure sx.
• ‘good day’ followed by bad days due to overactivity.
• titrate diuretics and teach adjusting of activity/meds/diet.

Therapies

• Angiotensin II receptor blockers (Teveten/eprosartan, Micardis/telmisartan, Cozaar/losartan, Diovan/valsartan and about a hundred other "sartans") may be of use, studies pending.

Systolic failure

Desired BP with CHF: sysolic 110. Desire minimal orthostatic Sx if pt class IV.

• ACE inhibitors (first line)
• digoxin for symptomatic relief (fatigue)
  • has 2 phase distribution: may be best given in evening and levels done in am.
  • serum levels related to toxicity, not efficacy
  • rare to go over 0.125 to 0.25 mg per day
• diuretic for symptomatic relief (congestion), thiazide 2-3 times/week for mild CHF, otherwise avoid diuretics if mild
• beta blockers (not class IV) - carvedilol (Coreg) is a now popular beta blocker/alpha-1 antagonist added to ACE, digoxin, diuretics. usually can't go above 12.5 mg BID. Can cause fluid retention, require more diuretics.
• spironolactone (aldosterone receptor antagonist): one large good study showed major benefit in class III/IV when added to ACE inhibitor. 12.5-25 mg qD. Significant hyperkalemia risk. Note Indocin and other NSAIDs can increase K.
• older: isordil (160 mg) + hydralazine (300 mg) -- titrate to target dose
• fluid restriction: 1500 ml/day (old?)

Diastolic Failure

• ref: AFP 2006
• if CHF and EF on U/S > 40% Rx as diastolic
• avoid digoxin (contrary to old habits)
• beta blocker is first line therapy ) (cardevilol, Coreg, see above)
• can be prone to hypotension w/ diuretics, so use with care
• ACE & ARB of course
• Spironolactone (Aldactone) may help
• calcium channel blockers can impair LV function, don't look so great in trials. Vasodilators also not so great.

Homocysteine

• fasting serum homocysteine of 12 umol/l -> odds ratio 4.8
• can also do 4 hour methionine load test if IHD without other risk factors
• Rx. with 1 mg of folic acid day

Hypertension

Urgent Care Evaluation: New BP Elevation

• NSAID, other meds
• fundi, heart
• Cr, K, Uric, BUN, Na, Glu
• EKG, CXR

Supplemental Hypotensive agents

• OS Cal 800 mg qD
• Micro K 30-40 mEq Daily

Diet

• low salt
• regular salt + Ca blocker?

Special cases

• age < 40: ternormin
• difficult HTN in younger person: prazosin/doxazosin + diuretic
• older: diuretic
• alcoholic, tobacco addict: clonidine
• NSAIDS (block many agents)
  • greatest increase in BP: indocin, naprosyn, piroxicam
  • least incr in BP: ibuprofen, aspirin, sulindac
  • (3)
• supplement, esp. renin dependent: clonidine
• resistant HTN
  • tenormin or lopressor + HCTZ + Hydralazine (<200 mg/day)
  • lopressor or labetolol + Lasix + Minoxodil

Lipids and Prevention

NHLBI Guidelines

• The NHLBI Guidelines page contains the full guidelines, incuding the at a glance version.

1. Risk estimation (ATP III, 2004)
   
   The risk estimation guidelines are a mess, because they combine two different models -- a Framingham data based model (Bayesian, see NHLBI risk calculator) and a predictive risk factor model. Diabetes and Family History, for example, are a part of the 2nd and missing from the Framingham model -- probably because the deta was not recorded. LDL is estimated in the Framingham model from HDL and total cholesterol, but is a part of the risk factor approach
   
   This is not good. A 48 yo male with fifteen years of diabetes, but good BP, non-smoker and not-too-bad lipids wouldn't get Statins from the Framingham model, but they would from the Risk Factor model.
   

   Item	Risk calculation model	Risk factor approach
   Age	x	x
   Gender	x	x
   Total Cholesterol	x
   HDL Cholesterol	x	x
   LDL Cholesterol		x
   Smoker	x	x
   Hypertension	x	x
   Family history		x
   Diabetes		x

   * HDL > 60 is a negative risk factor
   Family History is CHD in 1st degree male < 55 or female < 65
   Smoking is undefined - certainly if in past month.
   Age in risk factor model is > 45 for men, > 55 for women.

2. LDL Levels to initiate drug therapy

   This is a compromise model (ATP III) based on LDL results. If someone meets only one of the two model criteria, then my guess is that it's really a matter of patient preference and clinical judgment.

   LDL Level	Risk Factor	Framingham 10 yr risk
   > 100	CHD or "equivalent"*	> 20%
   > 130	2 + (ex. 46 yo male smoker)	10 - 20%
   > 160	2 + (ex. 46 yo male smoker)	< 10%
   > 190	Treat based on LDL alone.

   CHD equivalents include Diabetes, symptomatic carotid artery disease, peripheral arterial disease, and abdominal aortic aneurysm.

General Guidelines

These are old. As of 2003 it's statins all the way, and their effect is only partly due to lowering LDL.

• Beware drug interactions and pregnancy
• Many require monitoring of CBC, LFT, a few CK. Typically q2-6 months.
• Beware muscle pain. It's not clear that we fully understand the effect of statins on muscles, and, incidentally, on the CNS.

Names and classes

Bile Acid Sequestrants

Expensive, taste awful, GI problems, cause vit K and folate deficiency (beware use with Coumadin). Give with vitamins. Must mix with juice.

• Cholestyramine: Cholybar, Questran, Questran Light.
  Try: Questran Lite, 2 scoops in 8 oz water by bedside. Take before bedtime.
• Colestipol: Colestid (monitor LFT, CBC)

HMG CoA Reductase Inhibitors (Statins)

Give with evening meal or at bedtime.

Monitor LFTs +/- CK q6w fo 3 mo, then q8w for 1st year then q6months.

Avoid use with erythromycin, warfarin

Triglyceride Metabolism Modifiers

Nicotinic Acid (Niacin)

Do not substitute, avoid sustained release preparations. Rarely used any more. Very poorly tolerated.

• GI upset, rash, hepatoxic, increased glucose and urea
• ASA 325 mg qD will decrease flushing
• a niacin dose of less than 1000 mg total daily is not worth continuing
• regimen: 100 mg and 500 mg tabs available
  • 100 mg BID x 1 wk
  • 200 mg BID x 1 wk
  • 300 mg BID x 1 wk
  • 500 mg BID x 1 wk (check chem 26, +/- CK)
  • 1000 mg BID (ck chem 26 in 6 weeks, aim for 750-1000mg BID)
• monitor LFT, glucose +/- CK

Fibric Acids

Lopid (gemfibrozil). Very rarely used.

• gallstones, rhabdomyolysis with Mevacor
• need low HDL-cholesterol, elevated LDL-cholesterol, and elevated triglycerides to merit use (per Parke-Davis and FDA)
• baseline LFT then q6-12 months

Dangerous Combinations

• mevacor and lopid (rhabdomyolysis)
• mevacor and niacin (maybe muscle injury)

Effective Combinations

(These are old combinations.)

• lower the LDL: Questran and Niacin or Questran and Mevacor
• lower TRIG: Lopid and Niacin (watch LFTs!)
• Niacin and Colestid
• Lopid and Colestid
• Mevacor and Colestid

Dosages

• Niacin: 3-12 gm qD
• Questran or Questran Light
  • 5 gm = 1 packet = 1 scoop
  • 1-6 times per Day (TID)
• Colestid
  • 5 gm = 1 packet = 1 scoop
  • 3-6 times per Day (TID)
• Lopid
  • 600 mg, 1 tab 30 minutes before breakfast and supper

MI

Markers

• myoglobin: early marker, can be used in d/dx in ED
• troponin I or T: Become elevated in 3-12 hours, remain elevated 7-10 days. Can show a recent MI has occurred. Elevation related to worse prognosis. Has largely replaced CK-MB.

Peripheral Vascular Disease

Ankle-brachial index

Measure at ankle and arm, repeat post treadmill

• 1 - 1.4: Normal
• Less than 0.95, significant narrowing of one or more blood vessels in the legs is indicated.
• Less than 0.8, pain in the foot, leg, or buttock may occur during exercise (intermittent claudication).
• Less than 0.4, symptoms may occur when at rest. * 0.25 or below, severe limb-threatening PAD is probably present.

Pressure Meds (CCM)

afterload and preload reduction: HTN, pulmonary edema

a) intravenous medications:

• NTG: IV 0.2 -20 mcg/kg/min; esp. dec PL, less dec AL. Good if angina.
• NIPRIDE: IV 0.5-10 mcg/kg/min; esp. dec AL, less dec PL. (check thiocynate levels) Onset 3s, durn 3m.
• diazoxide: 50-150 mg IV q5m or 7.5-30 mg/min (onset 5m, durn 4-24h); esp dec AL. Do not need art line, often with beta-blocker and diuretic. (reflex inc HR). Dangerous if aortic dissection, angina, MI. Always give with strong diuretic.
• isosorbide dinitrate 3mg bolus IV q5min has been used in some trials for acute pulmonary edema with improved results (1998)

b) oral medications (or both)

• captopril 6.5-13 mg PO q8h. onset 15m; durn 4-6h. Sublingual Captopril 12.5 repeat in 60 minutes is being used @1997.
• prazosin: 2-5 mg PO q6h; balanced dec PL and AL.
• terazosin
  • good with BPH
  • less s/e than prazosin
• doxazosin
  • good with BPH
  • less s/e than prazosin
• hydralazine: 50-100 mg PO q6h or 10-20 mg IV (onset 10-30 min, durn 2-4 h); esp dec AL, often use with beta blocker (reflex tach).

management of hypertension (not preload/afterload)

a) labetolol (Trandate, Normodyne)

• initial dose 20 mg IV then 20-40 mg q10-30 minutes to pressure better or max 300 mg
• IV infusion: 200 mg in 200 ml D5 at 2 mg/min (stop when BP ok)
• Onset 10-30 min, durn. 3-6h. May continue PO.

b) propranolol: beta block; 1-10 mg IV then 3 mg/hr. Total blockade with 0.1 mg/kg. PO 80-640 mg qD; onset 2h durn 12h.

inotropes and vasopressors

a) DOPAMINE: beta 1 and alpha. typical use 500-1500 mcg/min. At 2-5 mcg/kg/min may have renal vasodilatation (renal dose), at > 15 mcg/kg/min effect is predominantly alpha (vasoconstriction). Esp. good for septic shock. (dopamine = norepinephrine + dobutamine)

b) DOBUTAMINE: beta 1 >> beta 2. typical use 800-2000 mcg/min. In range 5-15 mcg/kg/min greatest affect on CO, small chg PVR (up or down). Esp. for cardiogenic shock, CHF, post MI.

Valvular Disorders

General

• MEDLINEplus: Heart Valve Diseases

Mitral Valve Regurgitation

• Pt Ed: Mitral Valve Regurgitation - Mayo, Valvular Heart Disease - Medem, Mitral Valve Replacement (Soc Thoracic Surgery)
• Mitral Valve Surgery: overview for the surgeon
• Since 1970 the trend has been towards repair rather than replacement (where possible)
  • Yun KL, et al. Mitral valve repair versus re...
  • Onnasch JF, et al. Mitral valve repair versus mi...
  • Knott HW. Clinical study of mitral valv...: 80% 5 year survival, 11% operative mortality in this series of repairs.