UMEM Educational Pearls - By Amal Mattu

Elderly patients should be considered immunocompromised for several reasons:
1. T cell function and reduced cellular immunity occur as we get older.
2. B cell antibody production decreases.
3. Host defenses against infection are reduced with aging, such as reduced circulation and thinning skin.
4. Miscellaneous factors, such as malnutrition and co-existing illnesses contribute to increased risk of infection as well.

[Good reference and suggested reading: Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department: Part I. Emergency Medicine Reports 2010;31(9):103-111.]

The most likely considerations for a regular, narrow complex tachycardia are sinus tachycardia (ST), atrial flutter with 2:1 conduction, and supraventricular tachycardia (SVT, a generic terms that encompasses a few remaining rhythms originating above the ventricle). Atrial flutter is diagnosed when one sees atrial beats at a rate of 250-350/minute.

The distinction between ST and SVT can be difficult at very rapid rates. Here are a few clues that may help in this distinction:
1. Generally the maximal sinus rate that a patient produces will be 220-age. That means that a 20 year old can possibly have a ST up to 200 beats/min, but a 70 year old can only have a ST has fast as 150 beats/min. Rates that exceed that simple formula are extremely unlikely to be ST.
2. If the rate varies with respiration, with positional changes, with relaxation, or with fluid administration, these all favor ST.
3. If the rate reduces slowly, it favors ST. SVT, on the other hand, tends to "break" suddenly.
4. SVT generally will either have no P-waves visible or there may be P-waves just after the QRS complexes. These are referred to as retrograde Ps.
5. History, history, history. Is there a reason for tachycardia, for example a history consistent with dehydration or anxiety? That favors ST. If the patient reports palpitations or other symptoms that were of abrupt onset, that favors SVT.
6. Valsalva maneuvers may gently slow down ST but will either not affect SVT or will abruptly break the SVT....SVT shouldn't gently slow down.

Slight revisions have been made in what is considered to be normal QRS duration.
In children < 4yo, a normal QRS duration is < 90ms.
In children 4-16yo, a normal QRS duration is < 100ms.
Above the age of 16, a normal QRS duration is < 110m.

Consider these numbers when evaluating patients for aberrant conduction (e.g. toxicologic reasons as well) and when defining conduction blocks.

Reference:
Surawicz B, Childers R, Deal BJ, et al. AHA/ACCF/HRS Recommendations for the standardized interpretation of the electrocardiogram, Part III: Intraventricular conduction disturbances. A scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. J Am Coll Cardiol 2009;53(11):976-981.

Three common herbal supplements are reported to be associated with clinically significant hypokalemia: aloe vera, gossypol (used as a male contraceptive), and licorice.

Another popular herbal supplement is reported to be associated with clinically significant hyperkalemia: oleander.

Always ask your cardiac patients (especially those on digoxin) if they are taking any of these herbal supplements!


[Tachjian A, Maria V, Jahangir A. Use of herbal products and potential interactions in patients with cardiovascular diseases. J Am Coll Cardiol 2010;55:515-525.]

Patients with pericarditis are generally treated with high-dose aspirin (e.g. 2-4 gms/day) or other NSAIDs in high dose. However, when myocarditis is also present (e.g. elevated TN levels), lower dosages of aspirin (e.g. 500 mg TID) or other NSAIDS should be used. The higher dosages of anti-inflammatory medications in the setting of myocarditis are thought to exacerbate the myocarditic process and increase mortality (animal studies).

Imazio M, Spodick DH, Brucato A, et al. Controversial Issues in the management of pericardial diseases. Circulation 2010;121:916-928.

Though most causes of acute pericarditis in patients from developed countries are viral or idiopathic, the etiology of pericarditis in patients visiting from developing countries is usually TB, and the TB accounts for > 90% of cases of pericarditis in patients with HIV infection. This group of patients, therefore, should almost always be admitted for a full workup of the cause and for appropriate treatment.

When prescribing quinolones to elderly (e.g. for UTI) patients that are taking iron supplements, advise them to take the antibiotic several hours before taking the iron. Iron will bind the antibiotic in the GI tract and reduce its bioavailability.

[Anderson RS, Liang SY. Infections in elderly patients. Critical Decisions in Emergency Medicine, 2010;24(8):13-18.]

Three groups of patients are at especially high risk of bleeding from excessive anticoagulation with renally-excreted medications: women, the elderly, and patients with chronic renal insufficiency. For all of these patients, ALWAYS dose their renally-cleared medications based on creatinine clearance, NOT just the creatinine.

Which medications in ACS does this apply to?--enoxaparin and G2B3A inhibitors are the most prominent here to consider.

The literature not only demonstrates increased bleeding complications but also increased MORTALITY if you don't dose based on creatinine clearance!

Although supplemental oxygen has long been considered standard care for patients with ACS, the evidence supporting this concept is largely based on animal studies in which acute MI was artificially induced. Should these studies be extrapolated to humans? Maybe not....


Further review of the animal and human literature actually indicates that the routine use of supplemental oxygen and induction of hyperoxia can actually induce adverse hemodynamic consequences such as increased coronary artery tone and reduction in coronary artery blood flow; reductions in cardiac output and increased systemic vascular resistance; and potentially increased infarction size. It certainly seems prudent to treat hypoxia, but if the patient is not hypoxic, skip the supplemental oxygen!

Wijesinghe M, et al. Routine use of oxygen in the treatment of myocardial infarction: systematic review. Heart 2009;95:198-202.
AND
Farquhar H, et al. Systematic review of studies of the effect of hyperoxia on coronary blood flow. Am Heart J 2009;158:371-377.

A recent study of nearly 800 patients with chest pain evaluated symptoms and signs that are most predictive of ruling in for ACS. The following characteristics made acute MI more likely (likelihood ratios in parentheses): observed diaphoresis (5.18), central location of chest pain (3.29), associated vomiting (3.50), radiation of the pain to bilateral arms (2.69), and radiation of pain to the right arm (2.23).

As we've said before, if your patient sweats, it ought to make YOU sweat!

[BodyR, et al. Resuscitation 2010;81:281-286.]

Major and minor clinical prognostic predictors for pericarditis have been described as follows:

Major: fever > 38 degrees C, subacute onset, large effusion, tamponade, lack of response to aspirin or NSAIDs after at least 1 week of therapy

Minor: myopericarditis, immunodepression, trauma, oral anticoagulant therapy

Patients with any of these criteria [major or minor] should strongly be considered for admission. In the absence of these factors, studies show that patients managed as outpatients do well.

[Imazio M, Spodick DH, Brucato A, et al. Controversial issues in the management of pericardial diseases. Circulation 2010;121:916-928.]


 

Many cardiac patients take warfarin...no surprise.
Many patients use herbal supplements...no surprise.
Many herbal supplements can produce increased bleeding risk with warfarin, and some produce decreased effects of warfarin...that may be a bit of a surprise. Here's a few that are worth knowing:

Herbals that increase the bleeding risk of warfarin: alfalfa, angelica (dong quai), bilberry, fenugreek, garlic, ginger, and ginkgo

Herbals that decrease the effect of warfarin: ginseng, green tea

In addition to asking your patients about their prescription medications, specifically ask your patients if they take herbal supplements, over-the-counter products, or green tea (since many patients don't consider green tea to be either an herbal supplement)...especially if the patient takes warfarin. You just might diagnose or prevent a disastrous bleeding complication.

[Tachjian A, Maria V, Jahangir A. Use of herbal products and potential interactions in patients with cardiovascular diseases. J Am Coll Cardiol 2010;55:515-525.]

Missed cases of ACS account for 10% of all malpractice cases in emergency medicine, yet account for 30% of all the money emergency physicians pay out in malpractice cases. This misdiagnosis is the biggest cause of monetary payout in the specialty.

Three main themes account for the majority of missed cases of ACS:
1. Failure to recognize atypical presentations (e.g. dyspnea)
2. Failure to recognize high-risk groups (e.g. women, diabetics)
3. Over-reliance on negative tests (e.g. negative troponin or recent stress test)

Women are more likely to be misdiagnosed than men when they present with acute coronary syndromes. There are several possible reasons for this:
1. Women are more often older and more often have diabetes, both of which are factors involved in atypical presentations.
2. Women present with chest pain less often than men. On the other hand, women are more likely to present with nausea, vomiting, indigestion, malaise, loss of appetitie, or syncope than men.
3. When women do have chest pain, they are more likely to report pain that has atypical features, such as radation to the right arm or shoulder, front neck, or back; and the pain is more often described as sharp, stabbing, or tansient.

The bottom line is something that I've believed since high school: women are confusing...!

[the references for this ACS information comes from many different sources, but if anyone needs a good review on this topic, just email me: amattu@smail.umaryland.edu]

Most people know that the ECG is only diagnostic of ACS approximately in 50% of cases, and in fact patients presenting with ACS can have an initially completely normal ECG in up to 10% of cases. However, traditional teaching is that if the patient is actively having chest pain or other concerning symptoms, the patient with ACS will nearly always have ECG abnormalities. NOT SO, according to a recent study. Researchers from Davis medical center evaluated patients with presumed ACS and normal ECGs, comparing the prevalence of ACS in patients with active symptoms (e.g. chest pain) during the normal ECG vs. patients that were asymptomatic at the time of the ECG. Cutting to the chase, they found no difference in ther rule-in rate between the two groups. In other words, don't be reassured at all if a patients has a normal ECG during symptoms.

This study supports other studies which continually show that an abnormal ECG is excellent at ruling-in disease, but a normal ECG is poor at ruling-out disease. In the absence of a diagnostic ECG, it's all about the HPI, the HPI, and the HPI. And also...the HPI.

[Turnipsee SD, Trythall WS, Diercks DB, et al. Frequency of acute coronary syndrome in patients with normal electrocardiogram performed during presence or absence of chest pain. Acad Emerg Med 2009;16:495-499.]


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Though most people know that therapeutic hypothermia is indicated in resuscitated victims of cardiac arrest, is it safe if that cardiac arrest victim is also being treated for STEMI? Do you need to worry about increased bleeding complications in these patients that are receiving anticoagulants, lytics, PCI, or other standard "bleeding" medications? Are these patients at increased risk for hemodynamic instability with therapeutic hypothermia?

Recent studies have demonstrated that therapeutic hypothermia in acute MI patients receiving other standard treatments (i.e., anticoagulants, etc.) is SAFE: it is associated with no increase in bleeding complications (1), no increase in time to balloon inflation (2), and no increase in hemodynamic instability or malignant arrhythmias (3).

1. Schefold JC, et al. Mild therapeutic hypothermia after cardiac arrest and the risk of bleeding in patients with acute myocardial infarction. Int J Cardiol 2009;132:387-391.
2. Knafelj R, Radsel P, Ploj T, et al. Primary percutaneous coronary intervention and mild induced hypothermia in comatose survivors of ventricular fibrillation with ST-elevation acute myocardial infarction. Resuscitaiton 2007;74:227-234.
3. Wolfrum S, Pierau C, Radke PW, et al. Mild therapeutic hypothermia in patients after out-of-hospital cardiac arrest due to acute ST-segment elevation myocardial infarction undergoing immediate percutaneous coronary intervention. Crit Care Med 2008;36:1780-1786.

  Despite the traditional use of intravenous medications such as vasopressors and antiarrhythmics for victims of cardiac arrest, there is actually very little evidence to support these therapies. On the contrary, 2 recent multicenter center studies demonstrated that the use of intravenous medications that are advocated in standard advanced cardiac life support (ACLS) guidelines are ineffective at improving survival to hospital discharge of patients with primary cardiac arrest. In contrast, these medications have been shown to increase hospital admissions, bed and resource utilization, and costs. The only interventions that have been shown to improve meaningful outcomes are rapid defibrillation for shockable rhythms, good compressions, post-resuscitation therapeutic hypothermia, and there's increasing evidence for post-resuscitation cardiac catheterization as well.

In other words, the best thing you can do early for patients with primary cardiac arrrest is to focus on the basics.

 

Show References

Although we tend to "shotgun" when ordering labs in elderly patients with syncope, the literature actually indicates that we can be very selective in testing with this group, letting the history and PE determine whether any tests are indicated. The most recent literature supporting this concept demonstrated that even cardiac enzyme testing and head CTs in elderly syncope patients were helpful in only 0.5% of cases. The only test that should routinely be obtained is the ECG...a good history and PE should be sufficient to determine when any other tests are indicated.

[Mendu, et al. Yield of diagnostic tests in evaluating syncopal episodes in older patients. Arch Intern Med 2009]

Yet another publication demonstrates that chest pain radiating to the right arm has the highest predictive value for ruling in ACS. In this study, radiation of the pain to the right arm had a higher predictive value than age, gender, comorbidites or traditional risk factors, specific descriptors of pain (e.g. "pressure" or "crushing"), or associated symptoms (e.g. diaphoresis, nausea, dyspnea). The bottom line....beware chest pain that radiates to the right arm!

[Goodacre S, Pett P, Arnold J, et al. Clinical diagnosis of acute coronary syndrome in patients with chest pain and a normal or non-diagnostic electrocardiogram. Emerg Med J 2009;26:866-870.]

When patients present with acute MI, all NSAIDS should be discontinued (e.g. ibuprofen, COX-2 inhibitors, etc.) during the hospitalization. Continued use of NSAIDs during the hospitalization increases the risk of CHF, myocardial rupture, hypertension, reinfarction, and mortality.