UMEM Educational Pearls - By Semhar Tewelde

Bifascicular block

1. Right bundle branch block (RBBB) + left anterior fascicular block (LAFB) 
2. RBBB + left posterior fascicular block (LPFB)
3. Complete left bundle branch block (LBBB)

Incomplete Trifascicular block

1. Bifascicular block w/1^st degree AV block    *classically referred to as “trifascicular block”*
2. Bifascicular block w/2^nd degree AV block
3. Alternating LBBB + RBBB

Complete Trifascicular block

1. Bifascicular block w/3^rd degree AV block 

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Stanford type A (proximal) aortic dissection accounts for ~60% of all aortic dissections

Classic treatment includes direct surgical replacement of the ascending aorta w/prosthetic graft (+/- AV  aortic repair/replacement)

~20-30% of these patients (*institutional dependent) are considered poor candidates for surgery and receive only medical management, which innately results in substandard outcomes

In this study those who were considered poor candidates for surgical repair underwent novel endovascular treatment

Endovascular repair in this study was considered both appropriate and improved traditional medical outcomes in patients who were considered poor candidates 

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• Syncope is a sudden lack of blood supply to the brain typically caused by a problem in the regulation of blood pressure or a problem with the heart
• Syncope can be broadly classified in 3 categories neural reflex (~60%), orthostatic (~15%), and cardiac (~15%) 
• >Even in the absence of a firm diagnosis of cardiac syncope, the presence of known structural heart disease (CAD) or evidence a primary electrical disorder is associated with a poor prognosis
• Cardiac causes of syncope can also be divided into 3 categories: structural heart disease, obstructive lesions, and arrhythmogenic potential
  • Structural: Ischemic heart disease, dilated cardiomyopathy, ARVD, 
  • Obstructive: HCM, aortic/mitral stenosis, atrial myxoma, pulmonary HTN, PE, tamponade
  • • Brady: AV block, sick sinus, sinus arrest/pause
    • Tachy: SVT (AVNRT/AVRT), accessory pathways (WPW), or primary arrhythmias (LQTS, SQTS, CPVT, Brugada) 

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• Mirror-image dextrocardia is the most common form of cardiac malposition and is commonly associated with situs inversus of the abdominal organs
• The anatomic right ventricle is anterior to the left ventricle and the aortic arch curves to the right and posteriorly
• 25% percent of these patients will have associated sinusitis and bronchiactasis (Kartagener’s syndrome)
• ECG changes associated with dextrocardia include:

1. Right-axis deviation
2. Global negativity in leads I and aVL (negative QRS w/inverted P and T waves)
3. Lead aVR similar to the normal aVL (positive QRS)
4. Absent R wave progression in precordial leads/dominant S waves

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• MI without obstructive CAD is common, occurring in 5–10% of patients w/woman most commonly affected
• Mechanisms for MI without obstructive CAD include vasospasm, embolism, myocarditis, dissection, tako-tsubo, and occult plaque rupture
• Recent studies have applied cardiac MRI (CMR) with intravascular ultrasound  (IVUS) to determine the mechanism of MI without obstructive CAD
• In this study plaque disruption frequently occurred when the angiogram was normal or showed minimal atherosclerosis; Plaque rupture was demonstrated on IVUS in ~40% of women studied
• IVUS and CMR identified the potential mechanism of MI in 70%
• Consider theses adjunctive tools in the assessment of all patients with a clinical syndrome of MI who do not have obstructive CAD at angiography

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• The ADAPT (2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker) trial was a prospective observational validation study designed to assess a predefined ADP (Accelerated Diagnostic Protocol)
• A low risk patient in this ADP was defined by TIMI 0, ECG w/no ischemic changes, and negative troponin at 0-and 2-hours after presentation
• Primary endpoint was assessment of any major adverse cardiac event (MACE)
• Of 1,975 patients enrolled, 302 (15.3%) had a MACE
• ADP classified 392 patients (20%) as low risk and only 1 (0.25%) had a MACE
• ADP had a sen 99.7%, NPV 99.7%, spec 23.4%, and PPV 19.0%
• Despite ADP identifying patients as low risk for MACE standard of care still requires rapid early outpatient follow-up or further inpatient testing 

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• Cardiorenal syndrome (CRS) type 1 is the development of acute kidney injury (AKI) in the patient with acute cardiac illness, most commonly acute decompensated heart failure (ADHF)
• Multiple pathophysiological mechanisms result in CRS characterized by a rise in serum creatinine, oliguria, diuretic resistance, and worsening ADHF
• There are a host of predisposing factors that create baseline risk for CRS (DM, HTN, HLD, OSA)
• The final common pathway often results in bidirectional organ injury, drug resistance, and death 
• The combination of worsening renal function, volume overload, and diuretic refractoriness makes the management of CRS challenging
• Current therapies although often ineffective include aggressive diuresis and positive inotropes

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• Postural tachycardia syndrome (POTS) is defined as orthostatic intolerance w/ an increase in heart rate by 30 bpm (or HR>120 bpm) that occurs within 10 mins of standing or upright tilt
• Orthostatic intolerance due to POTS will NOT cause orthostatic hypotension (defined as fall of >20/10 mm Hg on standing); instead patients may display no change, a small decline, or even a modest increase in blood pressure
• Symptoms include: palpitations, fatigue, lightheadedness, exercise intolerance, nausea, diminished concentration, tremulousness, and syncope
• POTS is a heterogeneous group of disorders with similar clinical manifestations  

1. Primary POTS - partial dysautonomia form
2. Secondary POTS - hyperadrenergic form

• Tx varies according to the subtype/etiology of POTS and must be individualized
• *Caveat inappropriate sinus tachycardia (IST) and POTS are two different diagnosis where significant overlap exists, however thebtachycardia in IST is NOT postural 

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• Persistent junctional reciprocating tachycardia (PJRT) occurs in children and is characterized by an incessant & sometimes even permanent narrow complex tachycardia 
• PJRT also occurs in adults but in about half these patients it is paroxysmal rather than incessant/permanent
• PJRT is a form of orthodromic AVRT and is caused by a concealed slowly conducting decremental accessory pathway
• Unlike accessory pathways of Wolff Parkinson White syndrome in children that are associated with a structural heart defect in about 1/3 of patients accessory pathways of PJRT are generally isolated
• PJRT can be a serious arrhythmia, particularly in children because of tachycardia-induced cardiomyopathy (TIC) - deterioration of ventricular contractile function caused by very prolonged periods in tachycardia
• LV dysfunction generally resolves following successful ablation of the tachycardia and is indicated even in the very young when the rate is not controlled and especially in patients with persistent left ventricular dysfunction.

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• Takayasu arteritis (TA) is a granulomatous vasculitis that affects the aorta and its major branches
• Involvement of the aortic arch is associated w/CNS symptoms, claudication, absent peripheral pulses, and cardiac manifestations
• The EULAR/PReS consensus criteria for Dx of childhood TA requires characteristic angiographic abnormalities of the aorta plus 1 of the following:

1. Absent peripheral pulses or claudication
2. Blood pressure discrepancy in any limb
3. Bruits
4. Hypertension
5. Elevated acute phase reactants

• Gold standard for Dx is angiography; however, CT and MR angiograms are less invasive and can detect inflammation & luminal diameter changes 
• Tx is challenging, steroids may induce remission in up to 60%

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• Identifying ST-segment changes in patients with LVH is frequently associated with false-positive diagnoses of acute coronary syndrome
• This study analyzed the ACTIVATE-SF database, a registry of consecutive emergency department STEMI diagnoses from 2 medical centers (411 patients)
• In patients with anterior territory ST-elevation, using a ratio of ST segment to R-S–wave magnitude >25% as a diagnostic criteria for STEMI significantly improved specificity for an angiographic culprit lesion (true positive) 
• Although this rule requires further study in a larger population it may augment current criteria for determining which patients with ECG LVH should undergo PCI

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• HIV infected patients are at higher calculated risk for CHD compared w/the general population of the same age
• HIV is known to promote atherosclerosis through mechanisms related to immune activation, chronic inflammation, coagulation disorders, and lipid disturbances
• Additionally combination anti-retroviral therapy (cART) has an affect on lipid and glucose metabolism demonstrated both in vitro and in vivo 
• The presence of an accelerated process of coronary atherosclerosis in this population is a major concern 
• Practitioners should have a high index of suspicion when confronted by young HIV patients and further data/strategies to prevent early CHD in HIV-infected patients is warranted

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• International guidelines recommend early invasive strategy (<24hrs) for patients with NSTEMI w/high risk factors defined by a GRACE score >140
• A recent meta-analysis based on 7 RCTs & 4 observational studies demonstrated an inconclusive survival benefit with an early invasive strategy 
• Heterogeneity across multiple studies including timing of intervention, definition of MI, patients' risk profiles, major bleeding, and sample size make the interpretation of survival results difficult
• Based on the most recent data the optimal timing of intervention remains unclear and a more definite RCT is warranted to guide clinical practice

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• Sports are associated w/an increased risk for sudden cardiac death (SCD) in athletes who are affected by cardiovascular conditions predisposing to ventricular arrhythmias (VA)
• SCD has substantially decreased in Veneto Italy due to the introduction of a preparticipation screening program that identifies unrecognized cardiovascular conditions
• This study included 145 athletes evaluated for VA using a screening protocol of ECG, exercise testing, echocardiography, holter monitoring, and cardiac MRI
• ECG was normal in most athletes (>85%)
• VA were detected prevalently during exercise testing 
• Cardiac MRI detected right ventricular regional kinetic abnormalities (ARVD) in 9 of 30 athletes 
• A total of 30% of these athletes had potentially dangerous VA
• In asymptomatic athletes w/prevalently normal ECG, most VA's can be identified by adding an exercise test 

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• Symptomatic aortic stenosis if left untreated has a high mortality rate (5 yr mortality rate is 50% w/angina, 3 yr mortality rate is 50% w/syncope, and 2 yr mortaltiy rate is 50% w/CHF)
• Standard tx includes medical therapy +/- balloon aortic valvuloplasty
• A recent study comparing standard therapy to transcatheter aortic-valve replacement (TAVR) revealed rates of death at 2 yrs were 68% in standard therapy group vs. 43.3% in TAVR group (p<0.001)
• At 2 yrs the rate of rehospitalization was 72.5% in standard therapy group vs. 35% in TAVR group
• The rate of stroke was higher after TAVR vs. standard therapy in the 1st 30 days
• In appropriate patients with severe AS who are not surgical candidates TAVR reduced rates of death, hospitalizations, and symptoms at 2 yr follow-up

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-Common life-threatening cardiovascular effects of cocaine intoxication include tachydysrhythmias, ventricular fibrillation, myocardial ischemia, and infarction.

-Emergency management of acute cocaine intoxication relies mainly on supportive and symptomatic treatment, w/liberal use of gamma-aminobutyric acid receptor agonists such as benzodiazepines.

-Intravenous lipid emulsion (ILE) therapy has been used successfully to treat cardiac toxicity associated with a variety of lipid-soluble drugs, such as local anesthetics, calcium/beta-blockers, tricyclic anti-depressants, and cocaine. 

-The current hypothesis, called the “lipid sink” hypothesis, suggest that ILE infusion creates an expanded lipid phase in the plasma that absorbs the circulating lipophilic toxin and decreases the amount of free unbound toxin available to bind to the myocardium.

-When life-threatening cardiac arrhythmias (e.g. wide-complex tachycardia/prolonged QT) are not amenable to standard therapy (e.g. sodium bicarbonate/magnesium) consider ILE as a potential option to the current algorithm. 

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• Early CPR performed by laypersons can double the chances of survival in out-of-hospital cardiac arrest (OHCA)
• A retrospective cohort that combined 2 RCT compared the survival effects of dispatcher CPR instruction consisting of chest compression alone or chest compression with rescue breathing
• There was a lower risk of death after adjustment for confounders (adjusted hazard ratio 0.91, 95% confidence interval 0.83-0.99, p=0.02)
• Findings strongly support a long-term mortality benefit of dispatcher CPR instruction strategy consisting of chest compression alone rather than chest compression plus rescue breathing

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