Conduction Disorders pt. 2 - Clin Med

What does this refer to

• A 68-year-old male presents with palpitations, lightheadedness, and weakness.

• These symptoms appear to worsen with increased alcohol intake.

• Medical history is significant for hypertension being treated with hydrochlorothiazide.

• On physical exam, the patient appears uncomfortable.

• There is an irregularly irregular pulse when palpating the radial artery.

• On cardiac auscultation, the first heart sound (S1) is of variable intensity.

• There is mild bibasilar crackles on pulmonary auscultation and an absence of peripheral edema.

• An electrocardiogram is obtained.

Atrial Fibrillation (A-Fib)

What does this refer to

• Supraventricular Tachyarrhythmia due to uncoordinated atrial contractions

• Quivering or irregular (arrhythmia)

• Types

  • Normal rate < 100 bpm

  • Rapid Ventricular Response (RVR) = ventricular rate > 100 bpm

• A-fib is irregularly irregular

Atrial Fibrillation (A-Fib)

What does this refer to

normal ventricular response (< 100 bpm)Atrial Fibrillation (A-Fib)

What does this refer to

rapid ventricular response (RVR) > 100 bpm)Atrial Fibrillation (A-Fib)

Atrial Fibrillation

What does this refer to

• Atrial fibrillation (AF) is the most frequently encountered cardiac arrhythmia

• Prevalence

  • < 55 yo 0.1%

  • > 60 yo 3.8%

  • > 80 yo 10%

• M > F

• Caucasians > AA

• May occur in the absence of comorbidities

Epidemiology of Atrial Fibrillation (A-Fib)

What does this refer to

• Structural abnormalities – left atrial enlargement

  • Mitral and aortic stenosis, mitral and aortic regurgitation

• Conduction abnormalities

  • WPW

• Medications

  • Theophylline and Digitalis

• Cardiac function abnormalities

  • MI, PE or CAD

• Hyperthyroidism

• Electrolyte disturbance

• Cardiomyopathies

EtiologyAtrial Fibrillation (A-Fib)

What does this refer to

• Supraventricular tachyarrhythmia due to uncoordinated atrial contractions

• Often due to atrial enlargement, inflammation or infiltrative diseases of the atrium

• Non-repetitive pattern of the RRi

• Strong associations with other cardiovascular diseases

• Risk Factors

  • Hemodynamic stress

  • Atrial ischemia

  • Inflammation

  • Alcohol – drug use

  • Endocrine disorders

  • Neurologic disorders

  • Genetic factors

Etiology of Atrial Fibrillation (A-Fib)

What does this refer to

• Asymptomatic OR symptomatic

  • Palpitations

  • Dyspnea/DOE

  • Syncope

  • Fatigue

  • Dizziness

  • Angina

  • Decompensated heart failure

Clinical history of Atrial Fibrillation (A-Fib)

What does this refer to

Physical exam of Atrial Fibrillation (A-Fib)

What does this refer to

• Atrial flutter

• Multifocal atrial tachycardia

• Premature atrial contractions

• SVT

• Wolff-Parkinson-White (WPW)

Differential diagnosisAtrial Fibrillation (A-Fib)

What does this refer to

Workup for atrial fibrillation (A-Fib)

What does this refer to

• Assess atrial size and ventricular

  • Function

  • Thickness

  • Size

• Assess valvular and pericardial disease

• Measure peak right ventricular pressure

Transthoracic echo (TTE)

What does this refer to

“More sensitive to detect thrombi in L atrium”

Transesophageal echo (TEE)

What does this refer to

• New Onset

  • Hemodynamically stable

    • Admit to telemetry bed (Med-Surg Tele)

  • Cardiology consult

  • Unstable

    • ICU

Disposition/managementAtrial Fibrillation (A-Fib)

What does this refer to

• Hemodynamically stable?

• Hemodynamically unstable

  • Synchronized cardioversion

• Catheter ablation

Clinical management of Atrial Fibrillation (A-Fib)

What does this refer to

• Rate control is # 1

  • Start here

• THEN Rhythm?

  • Even with rate control

    • High risk patients should also have rhythm control

      • Who is high risk?

        • CAD

        • HF

        • Young patients

• Everyone gets some type of anticoagulant/blood thinner

  • ASA +/- Clopidogrel (Plavix) [remember the score] OR

  • Warfarin (Coumadin)

  • Dabigatran (Pradaxa)

  • Rivaroxaban (Xarelto)

  • Apixaban (Eliquis)

Do we treat rate, rhythm or both?Atrial Fibrillation (A-Fib)

Just know it

What does this refer to

AntiarrhythmicsAtrial Fibrillation (A-Fib)

What does this refer to

• New onset A-fib and hemodynamically stable

  • BB or CCB

• Long term management (rate)

  • BB or CCB

    • BB w. hx CAD

  • Digoxin w. hx HF w. reduced EF

• Long term management (rhythm)

  • Drug choices based on patient comorbidities

Clinical managementAtrial Fibrillation (A-Fib)

What does this refer to

• New onset (acute) A-fib

  • Beta blockers

  • CCB

• A-fib RVR

  • Diltiazem (Cardizem) or Metoprolol (Lopressor) IV

• Anticoagulation

  • New onset

    • If cardioversion required – LMWH +/- Warfarin (Coumadin)

Acute Clinical managementNew Onset – Atrial Fibrillation (A-Fib)

What does this refer to

Long term anticoagulation riskAtrial Fibrillation (A-Fib)

What does this refer to

Anticoagulation

• Warfarin (Coumadin)

• Dabigatran (Pradaxa)

• Rivaroxaban (Xarelto)

• Apixaban (Eliquis)

• Edoxaban (Savaysa)

Rate control (B-blockers)

• Metoprolol

Antiarrhythmics (CCB)

• Verapamil (Calan)

• Diltiazem (Cardizem)

• HFrEF —> digoxin preferred therapy

Long term managementAtrial Fibrillation (A-Fib)

What does this refer to

• 1.5 – 2x higher risk of death

  • Most often due to the strong association between AF and thromboembolic events

  • Dislodgement or fragmentation of a clot can then lead to embolic phenomena, including stroke

• High risk for development of HF

• High risk of Renal infarct

Prognosis of Atrial Fibrillation (A-Fib)

What does this refer to

• A 64-year-old woman presents to the emergency room for several hours of lightheadedness and palpitations.

• Her past medical history includes hypertension, mitral valve regurgitation, and chronic obstructive pulmonary disease.

• On physical exam, her pulse is around 150/min.

• An electrocardiogram is administered, revealing a narrow complex tachycardia and sawtooth-like waves in leads II, III, and aVF.

Atrial flutter

What does this refer to

Non-dihydropyridine calcium channel blocker

What does this refer to

• One atrial foci firing at a fast rate

• Rate usually > 300 bpm

Atrial Flutter (A-Flutter)

What does this refer to

• Risk factors/Associated conditions

  • Chronic obstructive lung disease

  • Heart disease

  • Alcohol use

  • Diseases of mitral valve

EpidemiologyAtrial Flutter (A-Flutter)

What does this refer to

Etiology of Atrial Flutter (A-Flutter)

What does this refer to

• Palpitations

• Dizziness +/- syncope

• Fatigue

• Dyspnea/DOE

• Chest pain

Clinical historyAtrial Flutter (A-Flutter)

What does this refer to

Physical exam Atrial Flutter (A-Flutter)

What does this refer to

• Atrial fibrillation

• Atrial tachycardia with AV block

• Multifocal atrial tachycardia

Differential diagnosis atrial flutter (A-flutter)

What does this refer to

• CBC w/ diff

• CMP

• Cardiac biomarkers + EKG

• BNP (HF)

• 2 view CXR

• Echocardiogram

Workup for Atrial Flutter (A-Flutter)

What does this refer to

Clinical intervention Atrial Flutter (A-Flutter)

What does this refer to

Clinical Management of a Stable patient in atrial flutter (A-Flutter)

What does this refer to

“Morbidity and mortality usually related to syncope and HF”

Prognosis of Atrial Flutter (A-Flutter)

What does this refer to

• A 17-year-old girl presents to the emergency room with lightheadedness and palpitation.

• Her pulse is 250/min and she is hemodynamically stable.

• An electrocardiogram shows an antidromic atrioventricular reentrant tachycardia.

• She is given procainamide with a resolution of the arrhythmia.

• Now in sinus rhythm, she is found to have a widened QRS, delta wave, and shortened PR interval on the electrocardiogram.

Wolff-Parkinson-white (WPW)

What does this refer to

The delta wave

What does this refer to

• Atria and ventricles are electrically isolated

• Conduction of electrical impulses from the atria to the ventricles normally occurring via the atrioventricular node and His-Purkinje system

• NOT the case with WPW

Normal AV Conduction

What does this refer to

• Pre-excitation manifest on an ECG and symptomatic arrhythmias involving the accessory pathway

• Ventricular myocardium is activated early as a result of this bypass pathway, prior to activation via the normal AV node/His-Purkinje pathway

Etiology Wolff-Parkinson-white (WPW)

What does this refer to

• Have an additional pathway —> accessory pathway (AP)

• Directly connects atria and ventricles, allowing electrical activity to bypass AV node

• Tissue in the accessory pathways, congenital in origin

• Typically conducts electrical impulses more quickly than the AV node, resulting in shorter PR interval on ECG

Patients with pre-excitation syndrome (Wolff-Parkinson-white (WPW) Syndrome)

What does this refer to

• 1-3/1000 people affected

• Most have no other evidence of heart disease

• 80% of patients with WPW have reciprocating tachycardia such as A-fib/A-Flutter

• Mitral Valve Prolapse (MVP) has an association with WPW

• Effects all ages, but bimodal distribution

  • Infancy

  • School age children and adolescence

  • Incidence decreases with age

• M > F

• No racial predilection

• Family history probably greatest risk factor

EpidemiologyWolff-Parkinson-white (WPW)

What does this refer to

• Accessory pathway outside of the AV node “preexcites” the ventricles

• AV node is bypassed

• Pathology

  • Bypassing AV node causes ventricles to depolarize earlier than normal

EtiologyWolff-Parkinson-white (WPW)

What does this refer to

Tachycardia

What does this refer to

SVT

What does this refer to

Anatomy and physiology of Wolff-Parkinson-White (WPW)

What does this refer to

• Symptoms are the result of tachycardia

• Palpitations

• Lightheadedness and/or dizziness

• Syncope or pre-syncope/near syncope

• Chest pain

• Sudden cardiac death

Clinical historyWolff-Parkinson-white (WPW)

What does this refer to

• Usually requires only an electrocardiogram (ECG)

  • Typically an incidental finding for another clinical indication

• Identification of a short PR interval and a delta wave is usually adequate to confirm the diagnosis of WPW pattern*

• *Rarely, invasive electrophysiology testing to confirm the diagnosis (competitive athletes)

How’s it diagnosed?Wolff-Parkinson-white (WPW)

What does this refer to

• 12-lead showing WPW pattern

  • W – wave (delta) (arrow on image)

  • P - PR interval (<0.12 seconds) short

  • W – wide QRS

Wolff-Parkinson-white (WPW) Syndrome

What does this refer to

• Myocardial infarction

• PVC

• Bundle branch block

• Congenital heart defect

• Hypertrophic cardiomyopathy

Differential diagnosisWolff-Parkinson-white (WPW)

What does this refer to (very important)

• Complains of 1-2 symptoms

  • Chest Pain/Short of Breath/Dizzy

• Awake

• Oriented

• Speak in full sentences

Hemodynamically Stable

What does this refer to (Very important)

Symptoms are a result of an abnormal rhythm

• Altered Mental Status (AMS)

• Loss of Consciousness (LOC)

• Shock

• Hypotension

• Pulmonary Edema

• Poor Perfusion

Hemodynamically unstable

What does this refer to

CCB and Digoxin CONTRAINDICATED in (true) WPW

• Calcium channel blockers or digoxin will worsen a supraventricular tachycardia (SVT) caused by WPW syndrome

Clinical pharmacotherapeuticsWolff-Parkinson-white (WPW)

What does this refer to

• Impulse traveling in the opposite direction to what is normal in that nerve fiber

Antidromic Atrioventricular Reciprocating Tachycardia (Wolff-Parkinson-White)

What does this refer

• Impulse that is traveling in the normal direction in a nerve fiber

• More common

Orthodromic Atrioventricular Reciprocating Tachycardia (Wolff-Parkinson-White)

This is the clinical management for what?

• Synchronized cardioversion

Unstable Orthodromic narrow QRS complex (Wolff-Parkinson-White)

What is the first line of treatment for a patient with stable orthodromic wide QRS complex (Wolff-Parkinson-White)

Procainamide (Procan)

What is the treatemnt for a patient with orthodromic narrow QRS complex only (Wolff-Parkinson-White)

IV adenosine (6 mg)

What does this refer to

• 1st Line Treatment for Stable patients

  • Vagal maneuvers

    • Carotid sinus massage

    • Valsalva maneuver

• 1ST line WIDE QRS COMPLEX

  • Procainamide (Procan)

• 2nd line NARROW QRS COMPLEX ONLY

  • IV adenosine (6mg)

• 3rd line

  • IV verapamil OR diltiazem

Clinical management for orthodromic narrow QRS complex for stable (Wolff-Parkinson-White)

What clinical management is this for

• Edison before medicine

• Synchronized cardioversion

Unstable antidromic wide QRS complex

What clinical management is this for

• MEDICINE BEFORE EDISON

• 1st Line Treatment for Stable patients

  • Procainamide

  • Ibutilide

Stable antidromic wide QRS complex

What is this referring

Preferred long-term treatment

• Catheter-based radiofrequency ablation is definitive

Clinical management of Wolff-Parkinson-White (WPW)

What does this refer to

• Patient placed in a supine or semi-recumbent position

• Instructed to exhale forcefully against a closed glottis after a normal inspiratory effort

• Signs of adequacy → Are they doing it right?

• Neck vein distension, increased tone in abdominal muscles, flushed face

• Patient should maintain the strain for 10-15 seconds

• Then release and resume normal breathing

• Have patient blow into 10 mL syringe just enough to move the plunger around 40 mmHg pressure

Vagal Maneuvers Wolff-Parkinson-white (WPW)

What does this refer to

• Placed supine with neck extended (chin away from chest)

• Carotid sinus located inferior to angle of mandible at level of thyroid cartilage

• Pressure applied to one carotid sinus for 5-10 seconds

  • Pressure via vigorous circular motion may be more effective, steady pressure recommended (may be more reproducible)

• If expected response not obtained

  • Repeat on other side after a one- to two-minute delay

• Contraindications

  • Avoided if prior TIA/stroke and in patients with carotid bruits

Carotid Sinus Massage Wolff-Parkinson-white (WPW)

What does this refer to

• A 28-year-old woman presents to the emergency department for palpitations and lightheadedness.

• She reports that her symptoms began approximately 20 minutes ago and it has not subsided.

• Medical history is significant for hyperthyroidism.

• Vital signs are significant for a blood pressure of 135/95 mmHg and a pulse of 155/min.

• An electrocardiogram is performed that shows a narrow QRS-complex tachyarrhythmia.

• Carotid sinus massage is performed and her symptoms do not improve.

• Vagal maneuvers do not improve her symptoms

• Intravenous adenosine is administered and her pulse decreases to 79/min.

Supraventricular tachycardia (SVT)

What does this refer to

• Rapid heartbeats that begin in or involve the upper chambers (atria) of the heart

• Usually sudden onset

• Common forms of SVT —> NARROW COMPLEX

  • Paroxysmal Supraventricular Tachycardia (PSVT)

  • Atrial Fibrillation

  • Atrial Flutter/Atrial Tachycardia

  • WPW

Supraventricular Tachycardia (SVT)

What does this refer to

• Type of “short-circuit” arrhythmia

• Age > 50yo

• Coronary Artery Disease (CAD)

• Previous heart surgery

Epidemiology Supraventricular Tachycardia (SVT)

What does this refer to

EtiologySupraventricular Tachycardia (SVT)

What does this refer to

• Fluttering sensation in the chest

• Rapid heartbeat (palpitations)

• Shortness of breath

• Lightheadedness or dizziness

• Sweating

• Pounding sensation in the neck

• Syncope/Near Syncope

Clinical historySupraventricular Tachycardia (SVT)

What does this refer to

Physical exam supraventricular tachycardia (SVT)

What does this refer to

Workup for supraventricular tachycardia

What does this refer to

• Time of onset

  • Very sudden/abrupt

• Identified trigger

• Previous episodes/treatment

• EKG findings [per the 2015 ACLS guidelines]

  • Narrow complex tachycardia

  • Rate > 150

  • Absent or “buried P waves”

Diagnosis of Supraventricular Tachycardia (SVT)

What does this refer to

• Atrial Fib

• Atrial Flutter

• Ventricular Tachycardia

Differential diagnosis of supraventricular tachycardia (SVT)

What does this refer to

• In stable patients, perform vagal maneuvers

Clinical intervention for regular supraventricular tachycardia (SVT)

What is the first line of treatment for supraventricular tachycardia (SVT)

adenosine

What does this refer to

Clinical management for stable supraventricular tachycardia (SVT)

What does this refer to

• Synchronized cardioversion

Clinical management of unstable supraventricular tachycardia

What does this refer to

• Symptomatic Wolff-Parkinson-White Syndrome (WPW) syndrome

  • Small risk of sudden death.

• Prognosis in paroxysmal SVT is dependent on any underlying structural heart disease

• Patients with a structurally normal heart have an excellent prognosis

• May result in heart failure/pulmonary edema/myocardial ischemia/ myocardial infarct

Prognosis of supraventricular tachycardia (SVT)

How many boxes should your PR interval be in a normal healthy heartbeat? (beginning of P to end of R)

4 boxes

How many boxes should your PR segment be in a normal healthy heartbeat? (end of P to beginning of R)

2 boxes

How many boxes should your QT interval be in a normal healthy heartbeat? (beginning of Q to end of T)

11 boxes

How many boxes should your ST segment be in a normal healthy heartbeat? (beginning of S to beginning of T)

4 boxes

What does this refer to

• A disorder of myocardial repolarization

• Characterized by a prolonged QT interval

• Qtc >0.44 in men considered prolonged (normal < or = 0.44)

• Qtc >0.47 in women considered prolonged (normal 0.45-0.47)

Long QT syndrome

What does this refer to

• Incidence difficult to determine accurately

• Congenital LQTS estimated at 1 in 3000 in general population

Epidemiology of Long QT syndrome

What does this refer to

• May be either congenital or acquired

• Congenital

  • Jervell and Lange-Nielsen Syndrome

    • Autosomal recessive

    • Associated with congenital sensorineural deafness

  • Romano-Ward Syndrome

    • Autosomal dominant

    • No sensorineural deafness

• Acquired _______

  • Drug therapy

  • Electrolyte imbalance

Etiology of Long QT syndrome

What does this refer to

• Major classes of drugs that prolong the QT interval

  • Antiarrhythmic drugs (Quinidine)

  • Certain non-sedating antihistamines (terfenadine)

  • Macrolide antibiotics (Azithromycin)

  • Certain psychotropic medications (Haloperidol)

  • Certain gastric motility agents (cisapride)

  • A COMMON “EVERY DAY USE” DRUG? ONDANSETRON (ZOFRAN)

• Lists of drugs that prolong QT interval @ www.crediblemeds.org/

Drug classes Long QT Syndrome

Which congenital Long QT syndrome is the below

• Autosomal recessive

• Associated with congenital sensorineural deafness

Jervell and Lange-Nielsen Syndrome

What does this refer to

• Autosomal dominant

• No sensorineural deafness

Romano-Ward Syndrome

What does this refer to

• class IA Antiarrhythmics (quinidine, procainamide, and disopyramide)

• class III Antiarrhythmics (sotalol and ibutilide)

• antiBiotics

• antipsyChotics

• antiDepressants

• antiEmetics

• diuertics (e.g., furosemide)

Etiology Drugs (ABCDEF) Long QT Syndrome

What does this refer to

• Clinical manifestations of congenital LQTS highly variable

• Many have no symptoms

  • ASYMPTOMATIC

• Symptoms (generally from an arrhythmia)

  • Palpitations/tachycardia

  • Pallor

  • Syncope

  • Seizures

  • Cardiac arrest

Clinical history/physical exam Long QT Syndrome

What does this refer to

• QTi often measured in Lead II of a 12 Lead

• Measured from onset of Q to end of T wave

• QT varies inversely with heart rate, therefore a corrected QT (QTc) is obtained

• Qtc > 0.44 in men considered prolonged

• Qtc > 0.47 in women considered prolonged (normal 0.45-0.47)

• > 0.50 considered highly abnormal (increasing danger)

Diagnosis Long QT Syndrome

What does this refer to

• Patients with a possible overdose of a QT-prolonging drug should be evaluated for risk of Torsades de Pointes (TdP)

• Cornerstone of management of acquired LQTS?

  • Identify and stop any precipitating drug

• A permanent pacemaker may be required in the occasional patient with a chronic bradyarrhythmia

• Mild QT prolongation

  • Without TdP or syncope may be tolerated and monitored as an outpatient

Clinical intervention Long QT Syndrome

What does this refer to

• CBC w. diff

• CMP

• EKG/cardiac biomarkers

• CXR

Workup Long QT Syndrome

What does this refer to

• LQTS associated with an increased risk of a characteristic life-threatening cardiac arrhythmia

• Torsades de pointes (tōr-sad' dĕ pwant'), (TdP)

• An atypical, rapid, and bizarre form of ventricular tachycardia

Long QT Syndrome (Gone Wrong)

What does this refer to

• Torsade de pointes is an uncommon and distinctive form of polymorphic ventricular tachycardia (VT) characterized by a gradual change in the amplitude and twisting of the QRS complexes around the isoelectric line

• Typical HR 150-250 bpm

• Associated with prolonged QT syndrome

  • Acquired

  • Congenital

Torsades de Pointes

What does this refer to

• Total incidence and prevalence of TdP is unknown

  • Often manifests as syncope or sudden cardiac death (SCD)

• Women (longer QT) > Men

• Wide age range, most frequently in 35-50 yo

Epidemiology Torsades de Pointes

What does this refer to

• Many cases present as sudden cardiac death

• Recurrent palpitations, syncope, dizziness

• Nonspecific symptoms

  • Nausea

  • Chest pain

  • Dyspnea

  • Diaphoresis

• Obtaining a good drug history is essential and includes*

  • Prescription drugs

  • OTC drugs

  • Illicit drugs

  • Herbal medications

Clinical history of Torsades de Pointes

What does this refer to

Physical exam for Torsades de Pointes

What does this refer to

Etiology of Torsades de Pointes

What does this refer to

• Many cases present as sudden cardiac death

• Recurrent palpitations, syncope, dizziness

• Nonspecific symptoms

  • Nausea

  • Chest pain

  • Dyspnea

  • Diaphoresis

• Obtaining a good drug history is essential and includes*

  • Prescription drugs

  • OTC drugs

  • Illicit drugs

  • Herbal medications

Clinical History of Torsades de Pointes