UMEM Educational Pearls - Cardiology

Category: Cardiology

Title: reflux and ACS misdiagnosis

Keywords: reflux, esophagitis, misdiagnosis, myocardial infarction (PubMed Search)

Posted: 7/20/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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 The most common misdiagnosis in cases of missed acute MI is reflux esophagitis. Various studies have demonstrated the following factors that lead to this misdiagnosis:
1. 20% of patients with acute MI describe their pain using the words "indigestion" or "burning."
2. Almost 50% of patients with acute MI report an increase in belching during their ischemic symptoms.
3. 15% of patients get some relief of their ischemic pain with antacids and 7% of patients get complete relief of their ischemic pain with antacids.
4. 8% of patients report that their ischemic pain began while eating.

Before you ever write "Reflux esophagitis" or "GERD" on the chart of a patient you are about to send home, think twice about the possibility of acute cardiac ischemia.
 



Category: Cardiology

Title: ECG changes in myopericarditis

Keywords: myocarditis, pericarditis, myopericarditis (PubMed Search)

Posted: 7/13/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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The pericardium is electrically silent, and so true acute pericarditis should not be associated with ECG changes. STE actually implies concurrent involvement of the myocardium; i.e. myopericarditis. The greater the degree of myocardium involved, the more ECG changes will develop, including STE, AV blocks, and dysrhythmias. Additionally, myocardial involvement is implied by elevated troponin levels, the magnitude of which is related to the amount of myocardial involvement.

[Imazio M, Trinchero R. Myopericarditis: etiology, management, and prognosis. Int J Cardiol 2008;127:17-26.]



Category: Cardiology

Title: Myopericarditis

Keywords: myocarditis, pericarditis, myopericarditis (PubMed Search)

Posted: 7/7/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Both acute pericarditis and myopericarditis are intensely inflammatory. As a result, CRP testing is extremely sensitive for these conditions and is excellent for evaluating their presence or absence.

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Category: Cardiology

Title: low voltage on ECG

Keywords: low voltage, electrocardiography, effusion (PubMed Search)

Posted: 6/30/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Low QRS voltage on the ECG has various definitions; here's my simple definition for low voltage...either one of the following:
     If the added QRS amplitudes (whole R wave + S wave) in leads I + II + III total < 15 mm, OR
     If the added QRS amplitudes (whole R wave + S wave) in leads V1 + V2 + V3 total < 30 mm.

The potential causes of  low QRS voltage includes pericardial effusions, pleural effusions, obesity, COPD, infiltrative cardiac diseases (e.g. sarcoid, amyloid), end-stage cardiomyopathies, severe hypothyroidism.

If the patient has NEW low voltage compared to an old ECG, the only real possibilities are pericardial effusion, pleural effusion, and severe hypothyroidism (e.g. myxedema).



Category: Cardiology

Title: pericarditis and cancer

Keywords: pericarditis, cancer, pericardial effusion, metastastic (PubMed Search)

Posted: 6/22/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Patients with cancer that present with pleuritic chest pain often have pulmonary emboli, but don't forget about pericarditis. Lung and breast cancer, especially, are known to metastasize to the pericardium and produce pericarditis or pericardial effusions. Anticoagulation for presumed PE in patients with pericardial mets. can produce hemorrhagic tamponade, a disastrous iatrogenic complication, so think twice before starting empiric anticoagulation on patients...make sure your patient doesn't have pericarditis or an pericardial effusion.

The ECG in patients with cancer-related pericarditis or pericardial effusion does not always demonstrate the classic ST elevation wtih PR depression (which is most commonly seen in viral pericarditis). Patients with pericardial effusions often demonstrate low voltage and tachycardia. Electrical alternans, though "classic," only appears in 1/3 of patients with pericardial effusions.



Category: Cardiology

Title: normal or non-specific ECG in acute MI

Keywords: ECG, electrocardiogram, acute myocardial infarction (PubMed Search)

Posted: 6/15/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Just a reminder...an initially normal or non-specific ECG can certainly occur in patients that are actively having chest pain from acute MI. A 2001 study published in JAMA nicely pointed this out:

7.9% of patients having an acute MI had an initial normal ECG.
35.1% of patients having an acute MI had non-specific abnormalities on ECG.
57% of patients having an acute MI had diagnostic changes on ECG.

The greater the abnormality on the ECG, the worse the prognosis, but note that even when the ECG was normal, the in-hospital mortality in acute MI patients was 5.7%.

Although serial ECGs won't detect 100% of acute MIs, the diagnostic yield does certainly increase, and so whenever a patient has a concerning presentation, especially in the presence of on-going pain, make sure to get repeat ECGs!

[ref: Welch RD, et al, JAMA 2001]



Category: Cardiology

Title: chronic kidney disease and ACS

Keywords: renal failure, kidney disease, acute coronary syndrome, myocardial infarction (PubMed Search)

Posted: 6/8/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Chronic kidney disease is a risk factor for accelerated atherogenesis. It is also a poor prognostic factor for patients with ACS or after MI. Elevated serum creatinine has been found to be an independent predictor of death after ACS and also a predictor of recurrent cardiovascular events. Cardiovascular death is 10-30 times higher in dialysis patients with ACS than in the general population.

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Category: Cardiology

Title: cocaine chest pain

Keywords: cocaine, chest pain, myocardial infarction (PubMed Search)

Posted: 6/1/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Just a few quick pearls about cocaine-chest pain and myocardial infarction:
 

  • 0.7%-6% of patients presenting to the ED with chest pain during or immediately after using cocaine will rule in for an MI based on cardiac biomarkers. The 6% figure is the most commonly-quoted number.
  • The risk of MI rises as much as 24-fold during the first hour after cocaine use. Although the risk decreases significantly after that, cocaine-related vasoconstriction can still cause acute MI hours or as many as 4 days later.
  • Chest pain is not reliably present in patients with cocaine-associated MI, with one study reporting that only 44% of patients with cocaine-associated MI had chest pain (Hollander and Hoffman, J Emerg Med 1992). Dyspnea and diaphoresis are other common symptoms that should prompt concern for acute MI if chest pain is not present.

[McCord J, et al. Management of cocaine-associated chest pain and myocardial infarction. Circulation 2008;117:897-1907.]



Category: Cardiology

Title: "Everybody clear!" before shocks

Keywords: cardioversion, defibrillation (PubMed Search)

Posted: 5/26/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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It is well-accepted that good, rapid compressions are one of the best interventions we can employ in managing patients with cardiac arrest. It is imperative that we minimize interruptions. Unfortunately, delivering shocks to a patient is a frequent cause of interruptions in compressions. It now appears that we may not need to discontinue compressions during shocks.

A recent study indicates that if shocks are delivered using the common self-adhesive pregelled pad electrodes and the person performing compressions is wearing gloves, the rescuers do not sense a shock at all. Compressions, therefore, do NOT have to stop during the cardioversion or defibrillation.

Whether this statement is true regarding handheld manual defibrillators also is uncertain.


Lloyd MS, Heeke B, Walter PF. Hands-on defibrillation: An analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation 2008;117:2510-2514.

Kerber RE. "I'm clear, you're clear, everybody's clear:" a tradition no longer necessary for defibrillation? Circulation 2008;117:2435-2436.



Category: Cardiology

Title: The ECG and Rescue PCI

Keywords: electrocardiography, ECG, STEMI, acute myocardial infarction, rescue PCI (PubMed Search)

Posted: 5/18/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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According to the most recent (2007 Updated) ACC/AHA Guidelines for management of STEMI, the ECG is one of the most important tools to assess for successful reperfusion after thrombolytics. The treating physician should assess the ECG at 90 minutes after administration of lytics. Failure of the ST elevation to decrease by at least 50% in magnitude in the lead with the greatest initial amount of ST elevation is an indication of failed thrombolysis...regardless of whether or not the patient has persistent symptoms. In fact, the Guidelines specifically state that signs and symptoms are considered unreliable indicators of successful reperfusion.

Patients with ECG evidence of failed thrombolysis at 90 minutes should be referred for emergent PCI ("rescue PCI").

 



Category: Cardiology

Title: Brugada syndrome and atrial fibrillation

Keywords: Brugada syndrome, atrial fibrillation (PubMed Search)

Posted: 5/11/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Brugada syndrome, believed to be responsible for up to 4-5% of all episodes of cardiac arrest, has now been associated with atrial fibrillation as well (atrial fibrillation is the most common atrial dysrhythmia associated with Brugada syndrome). Patients with atrial fibrillation that have a full or incomplete right bundle branch block with ST segment elevation in leads V1-V2 should be referred to an electrophysiologist for evaluation of Brugada syndrome. The best treatment for these patients is still placement of an ICD.
 



Category: Cardiology

Title: syncope and arrhythmias

Keywords: syncope, arrhythmia (PubMed Search)

Posted: 5/4/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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The three factors that are most predictive of an arrhythmia as the cause of a syncopal episode are, in order:
1. abnormal ECG
2. history of CHF
3. age > 65

Overall, approximately 15-20% of cases of syncope are determined to be caused by an arrhythmia.



Category: Cardiology

Title: ICD site infections

Keywords: internal cardioverter defibrillator, infection (PubMed Search)

Posted: 4/27/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Infections occur in up to 8-9% of ICD sites. Early infections usually occur within the first 2 months of placement and are associated with typical findings...redness, tenderness, systemic symptoms, etc. Late infections, however, are often associated with nothing more than JUST pain.

Lack of diagnosis of ICD site infections is associated with a mortality > 50%.

When infected, the entire ICD (including wires) must be replaced.

The most commor organisms associated with ICD infections are Staph and Strep. Treat them all with vancomycin.



Category: Cardiology

Title: ICD shocks

Keywords: internal cardioverter-defibrillator, shock, defibrillation (PubMed Search)

Posted: 4/20/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Patients with ICDs presenting to the ED reporting that their ICD fired once do not need mandatory ICD interrogation, admission or an extensive ED workup purely based on the single shock. A workup should be initiated purely based on any other associated symptoms...chest pain, dyspnea, etc. If the patient was doing well and had no other symptoms prior to the shock, the patient should simply have close follow up with cardiology.

Patients presenting after multiple shocks, on the other hand, do need a workup and emergent ICD interrogation (most of these cases also are later deemed inappropriate shocks).



Category: Cardiology

Title: Pseudo AMI after ICD shock

Keywords: internal cardioverter defibrillator (PubMed Search)

Posted: 4/13/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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ICD shocks are often associated with ST segment elevation and even positive troponin levels that can simulate acute MI. So how do you know if the patient experienced an acute MI with VF that triggered the ICD shock? Or if there simply was an aberrant ICD shock that triggered STE with positive troponins?

STE that is due purely to the ICD shock generally resolves after only 15-20 minutes. Persistent STE beyond that time should be assumed to be true ischemia.

Troponin elevations that are due purely to an ICD shock are usually mild and normalize within 24 hours. Huge troponin elevations and those that last beyond 24 hours should be assumed to be caused by true infarction.



Category: Cardiology

Title: RSI of the patient with an ICD

Keywords: implantable cardioverter defibrillator, AICD, ICD, succinylcholine, intubation (PubMed Search)

Posted: 4/6/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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NOTE THE CORRECTION TO THIS PEARL BELOW:

If a patient with an implantable cardioverter defibrillator needs to receive a paralytic for rapid sequence intubation, succinylcholine alone is not the best choice. The muscle fasciculations sometimes produced by succ can cause enough electrocardiographic artifact that inappropriate discharges of the ICD can occur.

Therefore, giving defasciculating doses of a paralytic before administering succ is recommended. Alternatively, use a nondepolarizing paralytic. Give 'em the rock!
Yet another reason to go with rocuronium.

AM

Dr. Ron Walls and colleagues emailed me about the pearl above, which was adapted from an article in AJEM [McMullan J, Valento M, Attari M, Venkat A. Care of the pacemaker/implantable cardioverter defibrillator patient in the ED. Am J Emerg Med 2007;25:812-822.]

The authors of the AJEM article reference another article for the statement [Stone KR, McPherson CA. Assessment and management of patients with pacemakers and implantable cardioverter defibrillators. Crit Care med 2004;32(4)Suppl:S155-S165.]. The CCM article actually states that SCH-induced fasciculations may cause artifact which may cause problems with some pacemakers, not ICDs. So it appears that there is no reported problem in using SCH in patients with ICDs. Sorry for the confusion.



Category: Cardiology

Title: cardiac tamponade and pulsus paradoxus

Keywords: cardiac tamponade, pulsus paradoxus (PubMed Search)

Posted: 3/30/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Pulsus paradoxus (exaggerated decrease in BP during inspiration) > 10 mm Hg is a physical exam finding that is often considered diagnostic of cardiac tamponade. The sensitivity of the finding, based on pooled studies, is actually only 82% and specificities are reported as low as 70%. In other words, the presence of the PP does not guarantee the presence of tamponade, and (more importantly) the absence of PP does not rule it out.

Conditions that can mask the presence of PP include hypotension, pericardial adhesions, aortic regurgitation, atrial septal defects, and RVH.

Conditions that can produce a PP in the absence of tamponade include severe COPD, CHF, mitral stenosis, massive PE, severe hypovolemic shock, obesity, and tense ascites.

The bottom line...when you are considering the diagnosis of tamponade, get the bedside ECHO. Don't hang your hat (and the patient's life!) on a pulsus paradoxus.



Category: Cardiology

Title: Cardiogenic Shock and Electrocardiography

Keywords: electrocardiography, EKG, cardiogenic shock, acute myocardial infarction (PubMed Search)

Posted: 3/23/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Here's a nice, simple pearl for cardiogenic shock:
"A normal ECG virtually rules out shock due to myocardial infarction."

Essentially, even though MI may be associated with a normal ECG in approximately 5-8% of cases, if a patient has cardiogenic shock due to MI, the ECG will ALWAYS be abnormal.

Gowda RM, Fox JT, Khan IA. Cardiogenic shock: basics and  clinical considerations. Int J Cardiol 2008;123:221-228.

 

Amal



Category: Cardiology

Title: cardiogenic shock and HCM

Keywords: cardiogenic shock, hypertrophic cardiomyopathy (PubMed Search)

Posted: 3/17/2008 by Amal Mattu, MD (Updated: 3/29/2024)
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Cardiogenic shock associated with LV outflow obstruction is managed best without the use of vasoconstrictive agents and vasopressors. Ideally, patients should be treated with IVF and beta blockade. Alpha agonists (e.g. ISO) can also be added.

Typical vasopressors may actually worsen LV outflow obstruction in these patients.



Category: Cardiology

Title: Post-MI Cardiogenic Shock

Keywords: MI, Cardiogenic Sock (PubMed Search)

Posted: 3/8/2008 by Michael Bond, MD (Emailed: 3/9/2008) (Updated: 3/29/2024)
Click here to contact Michael Bond, MD

Post-MI cardiogenic shock, while traditionally thought to carry a mortality > 80%, actually has perhaps half that mortality when patients are treated aggressively with prompt invasive therapy (PCI, possibly CABG). Fibrinolytics have traditionally been discouraged, but authors now indicate that they should be given if all of the following three conditions are present:

  1. PCI will take greater than 90 minutes,
  2. Less than 3 hours have elapsed since onset of STEMI
  3. No contraindications to lytics are present.

Sent on behalf of Dr. Amal Mattu

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