UMEM Educational Pearls - Cardiology

Subcutaneous Defibrillator

- The implantable cardioverter-defibrillator (ICD) has evolved from devices through epicardial patch electrodes introduced by thoracotomy to transvenous leads advanced to the right ventricle

- Transvenous ICD (T-ICD) reduced the morbidity associated w/thoracotomy implants, however involves potential complications including: hemopericardium, hemothorax, pneumothorax, lead dislodgement, lead malfunction, device-related infection, and venous occlusion

- Subcutaneous ICD (S-ICD) offers the advantage of eliminating the need for intravenous & intracardiac leads. Clinical trials have proven its effectiveness in detecting and treating ventricular fibrillation/tachycardia; however its major disadvantage is its inability to provide bradycardia rate support and anti-tachycardia pacing to terminate ventricular tachycardia

- No study has directly compared the T-ICD & the S-ICD, however clinical data suggests that its use be considered in relatively younger patients (i.e., age <40 years), those at increased risk for bacteremia, patients with indwelling intravascular hardware at risk for endovascular infection, or in patients with compromised venous access



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Category: Cardiology

Title: Airway management in out of hospital cardiac arrest

Keywords: Out of hospital cardiac arrest, OHCA, Prehospital airway management (PubMed Search)

Posted: 4/13/2014 by Ali Farzad, MD
Click here to contact Ali Farzad, MD

Optimal out of hospital cardiac arrest (OHCA) airway management strategies remain unclear. In the US, 80% of OHCA patients receive prehospital airway management, most commonly endotracheal intubation (ETI). There is growing enthusiasm for use of supra-glottic airways (SGA) by EMS because of ease of insertion, and the thought that use of SGA reduces interruptions in chest compressions. More recently, studies have suggested improved survival without the insertion of any advanced airway device at all. 

A recent secondary analysis of OHCA outcomes in the Cardiac Arrest Registry to Enhance Survival (CARES) compared patients receiving endotracheal intubation (ETI) versus supra-glottic airway (SGA), and also patients receiving [ETI or SGA] with those receiving no advanced airway. 

Of 10,691 OHCA, 5591 received ETI, 3110 SGA, and 1929 had no advanced airway. Unadjusted neurologically-intact survival was: ETI 5.4%, SGA 5.2%, no advanced airway 18.6%. Compared with SGA, ETI achieved higher sustained ROSC, survival to hospital admission, hospital survival, and hospital discharge with good neurologic outcome. Moreover, compared with [ETI or SGA], patients who received no advanced airway attained higher survival to hospital admission, hospital survival, and hospital discharge with good neurologic outcome. 

Conclusion: In CARES, patients receiving no advanced airway exhibited superior outcomes than those receiving ETI or SGA. When an advanced airway was used, ETI was associated with improved outcomes compared to SGA.

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Category: Cardiology

Title: Perinatally Infected HIV & Cardiovascular Disease

Posted: 3/31/2014 by Semhar Tewelde, MD (Emailed: 4/6/2014) (Updated: 4/6/2014)
Click here to contact Semhar Tewelde, MD

Perinatally Infected HIV & Cardiovascular Disease

*Perinatally HIV-infected adolescents are susceptible to aggregate atherosclerotic cardiovascular disease risk, but few studies have quantified risk or developed a scoring system

*A recent study of perinatally HIV-infected adolescents calculated coronary artery and abdominal aorta PDAY (Pathobiological Determinants of Atherosclerosis in Youth) scores using modifiable risk factors: HTN, HLD, smoking, obesity and hyperglycemia

*Significant predictors of a high coronary arteries and abdominal aorta scores include: male sex, Hx AIDS-defining condition, long duration of ritonavir-boosted protease inhibitor, and no prior use of tenofovir

*PDAY scores may be useful in identifying high-risk youth who may benefit from early lifestyle or clinical interventions given their trend of increased aggregate atherosclerotic cardiovascular disease risk factor burden

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Category: Cardiology

Title: Are chest compressions safe in arresting LVAD patients?

Keywords: Cardiac arrest, LVAD, CPR, Chest compressions (PubMed Search)

Posted: 3/23/2014 by Ali Farzad, MD
Click here to contact Ali Farzad, MD

The number of patients with left ventricular assist devices (LVADs) is increasing and development of optimal resuscitative strategies is becoming increasingly important. Despite a lack of evidence, many device manufacturers and hospitals have recommended against performing chest compressions because of fear of cannula dislodgment or damage to the outflow conduit.

A recent retrospective analysis of outcomes in LVAD patients who received chest compressions for cardiac arrest did not support the theory that LVADs would be harmed by conventional resuscitation algorithms.

The study was a limited case series of only 8 LVAD patients over a 4 year period. All patients received compressions and device integrity was subsequently assessed by blood flow data from the LVAD control monitor or by examination on autopsy. Although more research is necessary to determine the utility and effectiveness of compressions in this population, none of the patients in this study had cannula dislodgment and half of the patients had return of neurologic function.

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The HEART Score

Acute coronary syndrome defines a spectrum of diseases (unstable angina, NSTEMI, STEMI), without clear ECG abnormalities the diagnosis and disposition can be challenging

Several scoring systems have attempted to risk stratify patients: TIMI, PURSUIT, and GRACE

The TIMI & PURSUIT scores were designed to identify higher-risk patients and long-term mortality

A pilot/observational study has utilized a novel scoring system to risk stratify low to intermediate risk patients

The HEART (History, ECG, Age, Risk factors and Troponin) score: 

  • 0-3 points ~ 2.5% risk (data supporting discharge)
  • 4-6 points ~20.3% risk (data supporting observation)
  • ≥7points ~ 72.7% risk (data supporting early invasive strategies)

This scoring system is limited given the small study size and requires further study/validation, but may be an easy, quick, and reliable predictor of outcome in chest pain patients

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Category: Cardiology

Title: Suprasternal Notch View...a window to the Aortic Arch?

Keywords: Echo, Aortic Dissection (PubMed Search)

Posted: 3/9/2014 by Ali Farzad, MD (Updated: 3/23/2014)
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Early diagnosis and surgical consultation for dissection of the ascending aorta can be life saving. Emergency physicians are increasingly using focused cardiac ultrasound to assess chest pain patients in the ED. 

The suprasternal notch view (SSNV), may provide additional information in the assessment of thoracic aortic pathology. A recently performed pilot study aimed to determine the accuracy of using the SSNV, in addition to the more traditional parasternal long axis view in assessing aortic dimensions as well as pathology compared to CTA of the chest. 

Using a maximal normal thoracic aortic diameter of 40 mm, diagnostic accuracy in detecting dilation of the aorta was 100%. The study showed that the SSNV is feasible and demonstrates high agreement with measurements made on CTA of the chest. 

The SSNV can be a useful bedside window to help diagnose thoracic aortic pathology such as aortic dissection and coarctation of the aorta. 


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Category: Cardiology

Title: Pulseless Electrical Activity (PEA)

Keywords: PEA (PubMed Search)

Posted: 2/27/2014 by Semhar Tewelde, MD (Emailed: 3/2/2014) (Updated: 3/2/2014)
Click here to contact Semhar Tewelde, MD

Pulseless Electrical Activity (PEA)

ACLS algorithm for PEA focuses on memorizing the “ H's & T's" without a systematic approach on how to evaluate & treat the possible etiologies

A modified approach to PEA focuses on “cause-specific” interventions utilizing two simple tools: ECG and Bedside Ultrasound (US)

Simplified PEA Algorithm

♦1st obtain the ECG and assess the QRS-complex length (narrow vs. wide)

♦ A narrow QRS-complex suggests a mechanical problem:  RV inflow or outflow obstruction

Utilize bedside US to assess for RV collapsibility vs. dilation

A collapsed RV suggests tamponade, tension PTX or mechanical hyperinflation

A dilated RV suggests PE

The above listed etiologies all have a preserved/hyperdynamic LV Tx begins w/aggressive IVF’s followed by “cause-specific” therapy: pericardiocentesis, needle decompression, forced expiration/vent management, and thrombolysis respectively

♦ A wide QRS-complex suggests a metabolic (hyperK/acidosis/toxins), ischemic, or LV problem

Utilize bedside US to assess for LV hypokinesis/akinesis

For metabolic/toxic etiologies treat w/calcium chloride and sodium bicarbonate +/- vasopressors

For ischemia and LV failure treat w/cardiac cath. vs. thrombolysis +/- vasopressors/inotropes

♦Trauma and several other etiologies of PEA that are seldom forgotten in any critically ill patient (hypothermia, hypoxia, and hypoglycemia) are not included in this algorithm.

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Category: Cardiology

Title: Recent Negative Stress Tests in Chest Pain Bouncebacks

Keywords: ACS, Stress Test (PubMed Search)

Posted: 2/23/2014 by Ali Farzad, MD (Updated: 3/23/2014)
Click here to contact Ali Farzad, MD

Over-reliance on stress tests is a common reason for misdiagnosis or delays in diagnosis in patients with ACS.
The utility of a recent negative stress test is limited when it is used to determine the risk for an ACS in patients presenting to the emergency department with symptoms of cardiac ischemia. 
Several studies, including a meta analysis, show that while a positive stress test can be useful in determining the next appropriate step of a patient's care, a negative stress test may not be as useful.
ED patients who bounceback after a negative stress test, represent a much higher risk population that may be at the same risk for ACS as those without previous testing.
Bottom Line:
No test is capable of reliably stratifying a patient’s risk to zero. If you are concerned about an ED chest pain patient with a HPI suggestive of ACS, treat conservatively and do not be misled by a recent negative stress test.
Working in an observation unit and don't know what stress test to order? Check out Dr. Mattu's lecture Non-invasive cardiac stress testing: What every emergency physician needs to know (Need EmedHome subscription for link to work).


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Early Atherosclerosis Detection

50 middle-aged asymptomatic subjects free of vascular disease underwent carotid ultrasound (CUS) for risk stratification were also invited to undergo coronary computed tomography angiography (CCTA) or coronary artery calcium score (CAC) to identify which of the 3 imaging modalities was best at identification of early atherosclerosis

Atherosclerosis was observed in 28%, 78%, and 90% of subjects using CAC, CCTA, and CUS, respectively

36 patients with a CAC score = 0, 69% and 86% had atherosclerosis on CCTA and CUS, respectively

Concordance between modalities was highly variable

CUS and CCTA detection of plaque were significantly more sensitive than CAC 

Considering the prevalence of subclinical disease on CUS and CCTA, the threshold at which to treat warrants further research

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Category: Cardiology

Title: New TWI in aVL

Keywords: ECG, STEMI, aVL (PubMed Search)

Posted: 2/9/2014 by Ali Farzad, MD (Updated: 3/23/2014)
Click here to contact Ali Farzad, MD

The importance of new ST-segment depressions (STD) and/or T wave inversions (TWI) in lead aVL have not been emphasized or well recognized across specialties. Computer-assisted ECG readings typically report these findings as normal or nonspecific. 

There is growing evidence that changes in lead aVL are abnormal, and that paying attention to that lead can be clinically useful. Reciprocal changes presenting as STD or TWI in lead aVL may be indicative of a significant coronary artery lesion and can sometimes be the only ECG manifestation of acute MI.  

STD in lead aVL is considered a sensitive marker for early inferior STEMI, and has been shown to help differentiate STEMI from pericarditis. Another recent retrospective study suggests that TWI in aVL might be associated with significant LAD lesions. 

Bottom Line: Paying close attention to subtle changes and abnormalities in lead aVL may help in early identification and initiation of therapy for patients who are having an acute MI.  

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TWI_in_aVL.pdf (112 Kb)

Myocardial Infarction in Women After Childbirth

World Health Organization reports that obesity is the 5th leading cause of global death with the highest impact on women <65 years of age

The association of obesity and cardiovascular risk in young women is currently being researched

A recent nationwide cohort looking at obesity and future cardiovascular risk looked at Danish women giving birth (2004-2009) and followed them a median time of 4.5 years

This study grouped women via pre-pregnancy body mass index (BMI)

                                            1. Underweight (BMI <18.5)     

                                            2. Normal weight (BMI <25)

                                3. Overweight (BMI <30)

                                4. Obese (BMI >30)

Data revealed that healthy women of fertile age, pre-pregnancy obesity alone was associated with increased risk of myocardial infarction in the years after childbirth

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Category: Cardiology

Title: Extremely Fast & Wide Complex Regular Tachycardia

Keywords: Wide complex tachycardia, ventricular tachycardia (PubMed Search)

Posted: 1/26/2014 by Ali Farzad, MD (Updated: 3/23/2014)
Click here to contact Ali Farzad, MD


A 48 year old woman has acute chest pain and palpitations over the past several hours. She has felt similar palpitations in the past but never sought medical attention. She arrives to your ED alert and anxious. HR = 270, BP=130/100. ECG is below. What’s the diagnosis and treatment?

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JEM.WCT.Jan14.pdf (1,636 Kb)

Pacing Atrioventricular Block

 - Atrioventricular (AV) block is classically treated with restoration of heart rate via right ventricular pacing, however high rates of right ventricular pacing is associated w/ left  ventricular systolic dysfunction  

- A recent multi-center randomized control trial (RCT) assessed the efficacy of right vs biventricular pacing in heart failure w/ AV block [BLOCK HF Trial]

- Primary outcomes of: morbidity, mortality, and adverse left ventricular remodeling were shown to be significantly lower in biventricular vs right ventricular pacing 

- In patients with a high rate of pacing and/or an  abnormally low left ventricular ejection fraction biventricular pacing may be more advantageous than conventional right ventricular pacing


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Category: Cardiology

Title: Origin of premature ventricular beats

Keywords: PVC, Premature ventricular beats, Premature ventricular complexes (PubMed Search)

Posted: 1/12/2014 by Ali Farzad, MD (Updated: 3/10/2014)
Click here to contact Ali Farzad, MD

Differentiation between right and left ventricular origin of premature beats can be useful clinically.

The origin of ectopic ventricular beats are recognized best in lead V1 (oriented to differentiate right vs. left sided cardiac activity).
  • PVCs arising from the right ventricle have a left bundle branch block morphology (dominant S wave in V1)

  • PVCs arising from the left ventricle have a right bundle branch block morphology (dominant R wave in V1)

Left Ventricular premature beats are more often associated with heart disease and may precipitate ventricular fibrillation, whereas right ventricular premature beats are commonly seen in individuals with normal hearts. 


Want more emergency cardiology pearls? Follow me @alifarzadmd

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Assessment of Intermediate Coronary Lesions

- Coronary angiography alone to assess CAD is fraught with subjectivity

- Fractional flow reserve (FFR) has become the standard to assess/quantify obstructive CAD; it determines the myocardial flow in the presence of stenosis identifying the lesion responsible for ischemia

- FFR assesses focal stenosis, but does not consider diffuse atherosclerotic narrowing or microcirculatory dysfunction as contributors of ischemic heart disease

- An index of microcirculatory resistance (IMR) can be concomitantly measured with FFR during cardiac catheterization to specifically evaluate the microvasculature

- Coronary flow reserve (CFR) was the 1st proposed method for assessment of intermediate coronary lesion, but proved suboptimal because of its variability especially in patients with microvascular dysfunction (diabetes, prior MI, etc.)

- Utilization of FFR, IMR, and CFR together support the existence of differentiated patterns of ischemic heart disease & may help to determine future ischemic events 

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Category: Cardiology

Title: How to measure ST elevation

Keywords: ST-elevation, Cardiology, MI (PubMed Search)

Posted: 12/29/2013 by Ali Farzad, MD (Updated: 3/10/2014)
Click here to contact Ali Farzad, MD

There is debate and confusion regarding where and how to measure ST elevation (STE). Do you measure the STE at the J-point? Or at 40 msec after the J-point? And how much STE is considered significant? The current guidelines have clarified this issue.

 - STE should be measured at the J-point.

STEMI is defined by STE ≥ 1 mm in at least 2 contiguous leads, with the exception of leads V2-V3.

STEMI is defined by STE ≥ 2 mm in leads V2-V3 in men.

STEMI is defined by STE ≥ 1.5 mm in leads V2-V3 in women.

For more cardiology pearls from the 2013 literature , check out Amal Mattu's Articles You've Gotta Know!


Want more emergency cardiology pearls? Follow me @alifarzadmd

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Metoprolol Usage Cardioprotective

  • Intravenous (IV) metoprolol is sparingly used in STEMI given concern about precipitation of cardiogenic shock (COMMIT/CCS-2 Trial)
  • A recent study (n=220) looked at usage of IV metoprolol versus controls in patients with STEMI and a killip class II or less prior to primary PCI
  • MRI was preformed 5-7 days after STEMI revealing reduced infarct size and increased left ventricular ejection fraction in the IV metoprolol group
  • IV beta-blockade appears cardioprotective in those with a low killip score and should be considered prior to primary PCI in certain subgroups  

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Category: Cardiology

Title: The HEART score for ED patients with Chest Pain

Keywords: ACS, Chest Pain, HEART score (PubMed Search)

Posted: 12/8/2013 by Ali Farzad, MD (Updated: 3/10/2014)
Click here to contact Ali Farzad, MD

The diagnosis of non-STE ACS can be difficult to exclude in ED patients with chest pain. Consequently, over-diagnosis and unnecessary treatment are common. Risk stratification tools (ie. TIMIGRACE) have been created to help risk stratify ACS patients and predict mortality. However, they are of limited utility in the ED and do not effectively differentiate low to intermediate risk patients in all-comers with chest pain.  
The HEART score was recently prospectively validated in an ED population and was able to quickly and reliably predict risk of major adverse cardiac events (MACE - AMI, PCI, CABG, & Death). 
  • 5 practical considerations (History, ECG, Age, Risk factors, & Troponin) are scored (0,1,or 2 points each) depending on the extent of the abnormality.
  • A HEART score (0-10) can be quickly determined without complex calculations
  • Low scores (0-3) exclude short term MACE with >98% certainty
  • High scores (7-10) have high (>50%) MACE rates
  • The HEART score performed significantly better than TIMI and GRACE scores 

Bottom-line: The HEART score can help to objectively risk stratify ED patients with chest pain into low, intermediate, and high risk groups. Using the HEART score can also facilitate more efficient and effective communication with colleagues.


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International_Journal_of_Cardiology_2013_Backus.pdf (371 Kb)

Neth_Heart_J_2008_Six.pdf (144 Kb)

Category: Cardiology

Title: ECG Following Cardiac Transplant

Keywords: Cardiac Transplant (PubMed Search)

Posted: 12/1/2013 by Semhar Tewelde, MD (Updated: 8/28/2014)
Click here to contact Semhar Tewelde, MD

ECG Following Cardiac Transplant

  • Suturing of donor atria to the corresponding structures of a recipient’s residual atria produces two sets of P-waves:
    • A small native P-wave (often so small it may not been visualized)
    • Followed by a donor P-wave of normal size associated w/ a QRS complex
  • A complete or incomplete right bundle branch develops in >80% transplant recipients
  • ~7–25% of recipients also demonstrate a left anterior fascicular block (LAFB)
  • The transplanted heart contracts faster than the atrial remnant secondary to autonomic denervation frequently resulting in an increased resting heart rate 


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TransplantECG.jpg (160 Kb)

Category: Cardiology

Title: Too early to give hypothermia the cold shoulder

Keywords: Therapeutic Hypothermia, ROSC, Cardiac Arrest, Resuscitation (PubMed Search)

Posted: 11/23/2013 by Ali Farzad, MD (Emailed: 11/24/2013) (Updated: 3/10/2014)
Click here to contact Ali Farzad, MD

Hyperthermia after resuscitation from cardiac arrest is associated with poor outcomes and death. Induced mild hypothermia gained widespread use after two RCT's from 2002 (n=352) showed improved survival & neurological outcomes for select patients with OHCA. 
In a new RCT (n=939), patients with ROSC after arrest were assigned to targeted temperature management at either 33°C or 36°C. Survival (51%) and a good neurologic outcome (47 to 48%) did not differ significantly between groups. However, cooling to 36°C is not the same as not regulating temperature and allowing hyperthermia. 
In contrast to a decade ago, one half instead of one third of these patients can expect to survive hospitalization. Paying attention to temperature makes survival more likely than death when a patient is hospitalized after cardiac arrest. 

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N_Engl_J_Med_2013_Nielsen.pdf (497 Kb)

N_Engl_J_Med_2013_Rittenberger.pdf (317 Kb)

N_Engl_J_Med_2002_Hypothermia_after_Cardiac_Arrest_Study_Group.pdf (172 Kb)

N_Engl_J_Med_2002_Bernard.pdf (102 Kb)

Resuscitation_2013_Gebhardt.pdf (551 Kb)