Approach to Arrhythmia part 1: Bradycardia

Approach to Arrhythmia part 1: Bradycardia

Bradycardia is defined as heart rate <60/min. To understand the cause of bradycardia we have to understand the structures involved in the production and conduction of cardiac impulse.

The normal cardiac structures involved in electrical activity of the heart are
1. SA node- It is the pacemaker of the heart, because it fires at the highest rate hence predominates over other pacemakers of the heart.
2.AV node – In normal hearts its function is to conduct impulses generated in the SA node to the ventricles through the Bundle of His and bundle branches.It can act as a slow pacemeker when the SA node is diseased
3. Bundle of His and bundle branches- Normally their function is conduction of cardiac impulses. They can act as a slow pacemeker when the proximal structures (SA node & AV node) are diseased.
4. Purkinje fibres
5. Ventricular myocardium- In complete heart block the ventricular myocardium produces escape rhythm at a slow rate of 20-40/min

Disease in any of the structures can lead to bradycardia.

The diagnosis is made from ECG in most of the cases.
Now we will discuss how to systematically analyze an ECG for diagnosing a bradycardia.

Step 1: Calculate the rate first. Bradycardia by definition heart rate <60/min
Step 2: Analysis of rhythm begins with search for P-wave. Normally P-waves are produced by SA node, so absence of P-waves indicate disease of SA node. Which is called as sick sinus syndrome
Step 3: Absent P-waves can be due to
1. Sick sinus syndrome with escape rhythm. (R-R intervals fixed)
2. Atrial fibrillation with slow ventricular rate. (R-R intervals variable)

Sick sinus syndrome: no visible P waves, fixed R-R intervals.

Sick sinus syndrome: no visible P waves, fixed R-R intervals.

 

Step 4: P-waves present
If P-waves are present look for P-P interval, PR-interval and relation between P and R waves.

Step 5: P-P interval variable
Nonconducted APCs
Step 6: P-P interval fixed
The next stepis evaluation of PR-interval and relation between P and R waves

Step 7: PR interval normal and fixed: Sinus bradycardia

Sinus bradycardia

Sinus bradycardia

PR interval prolonged but fixed and each QRS complex is preceeded by P wave: First degree AV block

1st degree AV block: Prolonged fixed PR interval

1st degree AV block: Prolonged fixed PR interval

(ECG courtesy of www.lifeinthefastlane.com)
PR interval lengthens then dropped beat and return with short PR interrval: Mobitz type 1 second degree AV block

Wenckebach block

Wenckebach block

(ECG courtesy of www.lifeinthefastlane.com)
PR interval fixed then dropped beat : Mobitz type 2 second degree AV block
No PR relationship : Third degee AV block

Complete heart block

Complete heart block

(ECG courtesy of www.lifeinthefastlane.com)

 

The flow chart below summarizes the whole approach

ECG  approach to bradycardia

ECG approach to bradycardia

 

Cardiology MCQ 18.5.15

Q. All of the following are effective in the management of reflex syncope except

A. Life style modifications like avoiding triggers

B. Physical counterpressure maneuvers

C. Beta blockers

D. Cardiac pacing in patients with cardioinhibitory reflex syncope

Explanation:

According to ESC guideline 2009, beta blockers are no longer recommended and have been given class III recommendation for the treatment of reflex syncope. The first step in the management of reflex syncope is life style modifications like – avoiding triggers such as crowded places, prolonged standing etc.

-Physical counterpressure maneuvers are emerging as nonpharmacologic treatments for
syncope. These maneuvers include tensing of crossed legs, handgrip and arm tensing, abdominal binders, and support stockings.

-Class IIa recommendations include cardiac pacing for patients with dominant cardioinhibitory, carotid sinus sensitivity, and frequently recurrent reflex syncope after 40 years of age with documented cardioinhibitory responses during monitoring.

-Remember that pacemaker implantation in patients with reflex syncope and no evidence of cardioinhibitory reflexes is not indicated and can be harmful (class III).

Reference:

1. Guidelines for the diagnosis and management of syncope (version 2009) The Task Force for the Diagnosis and Management of Syncope of the European Society of Cardiology (ESC). European Heart Journal (2009) 30, 2631–2671

Answer: C

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical tudents, Electrophysiology,  Syncope

Revised Jones Criteria for Acute Rheumatic Fever – 2015 guideline

Acute rheumatic fever remains a serious healthcare concern for the majority of the world’s population despite its decline in incidence in Europe and North America. This statement reviews the historic Jones criteria used to diagnose acute rheumatic fever in the context of the current epidemiology of the disease and updates those criteria to also taking into account the use of Doppler echocardiography in the diagnosis of carditis as a major manifestation of acute rheumatic fever.

1. Epidemiology:

1. It is reasonable to consider individuals to be at low risk for ARF if they come from a setting or population known to experience low rates of ARF or RHD (Class IIa; Level of Evidence C).
2. It is reasonable that where reliable epidemiological data are available, low risk should be defined as having an ARF incidence <2 per 100 000 school-aged children (usually 5–14 years old) per year or an allage prevalence of RHD of ≤1 per 1000 population per year (Class IIa; Level of Evidence C).
3. Children not clearly from a low-risk population are at moderate to high risk depending on their reference population (Class I; Level of Evidence C).

2. Clinical Manifestations of ARF:

Generally, the clinical profile of ARF in low- and middle-income countries closely resembles that of high-income countries. Universally, the most common major manifestations during the first episode of ARF (the “major criteria” for diagnosis) remain
carditis (50%–70%) and arthritis (35%–66%). These are followed in frequency by chorea (10%–30%), which has been demonstrated to have a female predominance, and then
subcutaneous nodules (0%–10%) and erythema marginatum (<6%), which remain much less common but highly specific manifestations of ARF.

3.Carditis: Diagnosis in the Era of Widely Available Echocardiography:

Classically, as discussed in the 1992 AHA revised Jones criteria statement, carditis as a major manifestation of ARF has been a clinical diagnosis based on the auscultation of typical murmurs that indicate mitral or aortic valve regurgitation, at either valve or both valves. Numerous studies over the past 20 years have addressed the role of echocardiography (compared with purely clinical assessment) in the diagnosis of ARF. More than 25 studies have reported echocardiography/Doppler evidence of mitral or aortic valve regurgitation in patients with ARF despite the absence of classic auscultatory findings. This writing group concludes the following:

1. Echocardiography with Doppler should be performed in all cases of confirmed and suspected ARF (Class I; Level of Evidence B).
2. It is reasonable to consider performing serial echocardiography/ Doppler studies in any patient with diagnosed or suspected ARF even if documented carditis is not present on diagnosis (Class IIa; Level of Evidence C).
3. Echocardiography/Doppler testing should be performed to assess whether carditis is present in the absence of auscultatory findings, particularly in moderate- to high-risk populations and when ARF is considered likely (Class I; Level of Evidence B).
4. Echocardiography/Doppler findings not consistent with carditis should exclude that diagnosis in patients with a heart murmur otherwise thought to indicate rheumatic carditis (Class I; Level of Evidence B).

Evolving role of echogardiography in acute rheumatic fever

Evolving role of echogardiography in acute rheumatic fever

4.Specific doppler criteria for diagnosis of rheumatic valvulitis

Pathological mitral regurgitation (all 4 criteria met)
1.Seen in at least 2 views
2.Jet length ≥2 cm in at least 1 view
3.Peak velocity >3 m/s
4.Pansystolic jet in at least 1 envelope

Pathological aortic regurgitation (all 4 criteria met)
1.Seen in at least 2 views
2.Jet length ≥1 cm in at least 1 view
3.Peak velocity >3 m/s
4.Pan diastolic jet in at least 1 envelope

Morphological Findings on Echocardiogram in Rheumatic Valvulitis

Acute mitral valve changes
Annular dilation
Chordal elongation
Chordal rupture resulting in flail leaflet with severe mitral regurgitation
Anterior (or less commonly posterior) leaflet tip prolapse
Beading/nodularity of leaflet tips

Chronic mitral valve changes: not seen in acute carditis
Leaflet thickening
Chordal thickening and fusion
Restricted leaflet motion
Calcification

Aortic valve changes in either acute or chronic carditis
Irregular or focal leaflet thickening
Coaptation defect
Restricted leaflet motion
Leaflet prolapse

5.Evidence of preceding Streptococcal infection:

Because other illnesses may closely resemble ARF, laboratory evidence of antecedent group A streptococcal infection is needed whenever possible, and the diagnosis is in doubt when such evidence is not available.

Any one of the following can serve as evidence of preceding infection:
Increased or rising anti-streptolysin O titer or other streptococcal antibodies (anti-DNASE B) (Class I, Level of Evidence B). A rise in titer is better evidence than a single titer result.
A positive throat culture for group A β-hemolytic streptococci (Class I, Level of Evidence B).
A positive rapid group A streptococcal carbohydrate antigen test in a child whose clinical presentation suggests a high pretest probability of streptococcal pharyngitis (Class I, Level of Evidence B).

6. Diagnosis of Acute rheumatic fever:

For all patient populations with evidence of preceding GAS infection

Diagnosis: initial ARF: 2 Major manifestations or 1 major plus 2 minor manifestations
Diagnosis: recurrent ARF: 2 Major or 1 major and 2 minor or 3 minor

Major and minor criteria for diagnosis of Acute rheumatic fever

Major and minor criteria for diagnosis of Acute rheumatic fever


Flow charts for diagnosis of rheumatic fever

Flow charts for diagnosis of rheumatic fever

 

7.Rheumatic Fever Recurrences

As stated in the 1992 guidelines, patients who have a history of ARF or RHD are at high risk for “recurrent” attacks if reinfected with group A streptococci. Such an attack is considered
a new episode of ARF, but one in which the complete set of Jones criteria, even as revised, may not be completely fulfilled.

The guideline recommendations for diagnosing rheumatic fever recurrences are:
1. With a reliable past history of ARF or established RHD, and in the face of documented group A streptococcal infection, 2 major or 1 major and 2 minor or 3 minor manifestations may be sufficient for a presumptive diagnosis (Class IIb; Level of Evidence C).
2. When minor manifestations alone are present, the exclusion of other more likely causes of the clinical presentation is recommended before a diagnosis of an ARF recurrence is made (Class I; Level of Evidence C).

8.“Possible” Rheumatic Fever

In some circumstances, a given clinical presentation may not fulfill these updated Jones criteria, but the clinician may still have good reason to suspect that ARF is the diagnosis.
This may occur in high-incidence settings. In such situations the clinicians should use their discretion and clinical acumen to make the diagnosis that they consider most likely and manage the patient accordingly.

1. Where there is genuine uncertainty, it is reasonable to consider offering 12 months of secondary prophylaxis followed by reevaluation to include a careful history and physical examination in addition to a repeat echocardiogram (Class IIa; Level of Evidence C).
2. In a patient with recurrent symptoms (particularly involving the joints) who has been adherent to prophylaxis recommendations but lacks serological evidence of group A streptococcal infection and lacks echocardiographic evidence of valvulitis, it is reasonable
to conclude that the recurrent symptoms are not likely related to ARF, and discontinuation of antibiotic prophylaxis may be appropriate (Class IIa; Level of Evidence C).

Summary:

Jones criteria needed revision to meet current technological advances and clinical needs. Strict application of echocardiography/Doppler findings may be used to fulfill the major criterion of carditis, even in the absence of classic auscultatory findings, providing that ambient loading conditions are taken into consideration. In addition, monoarthritis or polyarthralgia could be accepted as fulfilling the major criterion of arthritis, but only in moderate- to high-risk populations. For low-risk populations, monoarthritis is not included, and polyarthralgia remains a minor criterion. Similarly, the requirement for the presence of fever can be fulfilled with oral, tympanic, or rectal temperature documented at 38°C in moderate- to high-risk populations, but only at ≥38.5°C in others.

Refernce:

1. http://circ.ahajournals.org/content/early/2015/04/23/CIR.0000000000000205.abstract

Cardiology MCQ 26.4.15

All of the following statements about Arrhythmogenic Right Ventricular
Dysplasia/Cardiomyopathy are correct except

A. Pathogenic mutations can be identified in 50% of patients

B. The clinical presentation is between 2nd to 5th decade of life

C. Left dominant arrhythmogenic cardiomyopathy most commonly involves apical septal segment of left ventricle

D.  Left-dominant disease is more commonly seen in patients with desmoplakin mutations

Explanation:

-Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiomyopathy. Although structural involvement of the right ventricle predominates, a left dominant form of ARVD/C has been described

-Ventricular arrhythmias, increased risk of sudden cardiac death, and abnormalities of right ventricular structure and function characterize this disease
-The pathognomonic features are right ventricular myocyte loss with fibrofatty replacement.
-Because a pathogenic mutation can be identified in approximately 50% of affected individuals

-Patients usually present during the second to fifth decades of life with palpitations, light-headedness, syncope, or sudden death. Patients younger than 12 years and those older than 60 years rarely manifest clinical signs or symptoms of ARVD/C

-Cardiac MRI can be to detect involvement of left ventricle in patients with ARVD/C, especially those with advanced disease

-Left-dominant arrhythmogenic cardiomyopathy also occurs in and is defined by early disease of the LV, often affecting the posterolateral wall, in the absence of significant right ventricle (RV) systolic dysfunction. Left-dominant disease is more commonly seen in patients with desmoplakin mutations.

References:

1. Marcus F, Fontaine G, Guiraudon G, et al: Right ventricular dysplasia: A report of 24 adult cases. Circulation 65:384–398, 1982.
2. Corrado D, Basso C, Thiene G, et al: Spectrum of clinicopathologic manifestations of arrhythmogenic right ventricular cardiomyopathy/dysplasia: A multicenter study. J Am Coll Cardiol 30:1512–1520, 1997.
3. Dalal D, Nasir K, Bomma C, et al: Arrhythmogenic right ventricular dysplasia: A United
States experience. Circulation 112:3823–3832,2005.
4. Marcus F, Zareba W, Calkins H, et al: Arrhythmogenic right ventricular cardiomyopathy/dysplasia clinical presentation and diagnostic evaluation: Results from the North American Multidisciplinary Study. Heart Rhythm 6:984–989, 2009.
5. Sen-Chowdhry S, Syrris P, Prasad SK, et al: Leftdominant arrhythmogenic cardiomyopathy: An under-recognized clinical entity. J Am Coll Cardiol 52:2175–2187, 2008.
6. Dalal D, Tandri H, Judge DP, et al: Morphologic variants of familial arrhythmogenic right ventricular dysplasia/cardiomyopathy: A genetics-magnetic resonance imaging correlation study. J Am Coll Cardiol 53:1289–1299, 2009.
7. den Haan A, Tan B, Zikusoka M, et al: Comprehensive desmosome mutation analysis in North Americans with arrhythmogenic right ventricular dysplasia/cardiomyopathy. Circ Cardiovasc Genet 2:428–435, 2009.

Answer: C

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical tudents, Electrophysiology,  Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy, ARVD/C

Cardiology MCQ 22.4.15

 CARDIOLOGY MCQ & REVIEW

Q. All of the following statements about accessory pathways (AP) are correct except

A. Majority of APs conduct both antegradely and retrogradely

B. Around 50% of patients with preexcitation have bypass tracts that conduct only antegradely.

C. Retrograde only conduction is more common than antegrade only conduction via APs

D. In around 10% of patients spontaneous disappearance of preexcitation may be seen

Explanation:

 -The vast majority of A-V bypass tracts conduct both antegradely and retrogradely.

-Less than 5% of patients with preexcitation have bypass tracts that conduct only antegradely (1). This is much less common than the converse situation of retrogradely conducting bypass tracts in the absence of antegrade preexcitation (i.e., so-called concealed bypass tracts).
-In patients who manifest only antegrade conduction over their bypass tract, spontaneous circus movement tachycardia, either antidromic or orthodromic, is not usually observed, but when it is, it is antidromic. The primary rhythm disturbance they manifest is atrial fibrillation 

-Over time antegrade conduction over an A-V bypass tract may disappear. Chen et al. (2) noted a loss of preexcitation in one fifth of symptomatic patients with WPW. Only 7.8% lost retrograde conduction. Spontaneous loss of preexcitation has been observed in one fifth to one half of children with WPW.
References:
1. Hammill SC, Pritchett EL, Klein GJ, et al. Accessory atrioventricular pathways that conduct only in the antegrade direction. Circulation 1980;62:1335–1340.
2. Chen SA, Chiang CE, Tai CT, et al. Longitudinal clinical and electrophysiological assessment of patients with symptomatic Wolff-Parkinson-White syndrome and atrioventricular node reentrant tachycardia. Circulation 1996;93:2023–2032.
Answer: B
Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Atrial fibrillation, WPW syndrome

Cardiology MCQ 21.4.15

CARDIOLOGY MCQ & REVIEW

Q. All of the following statements about atrial flutter – fibrillation in WPW syndrome are correct except

A. Atrial fibrillation can precipitate ventricular fibrillation in patients with accessory pathways

B. The incidence of atrial flutter and/or fibrillation appears to be higher in patients with A-V bypass tracts than in the normal population

C. Prevalence of atrial fibrillation is same in patients with manifest preexcitation and those with concealed preexcitation

D. Atrial flutter-fibrillation may be the presenting arrhythmia in 5% to 10% of patients with A-V bypass tracts

Explanation:

-In patients with WPW syndrome atrial flutter and fibrillation are less common presenting arrhythmias, but they are potentially more life threatening, because they can result in extremely rapid ventricular rates that precipitate ventricular tachycardia and/or fibrillation

-Atrial flutter-fibrillation may be the presenting arrhythmia in 5% to 10% of patients with A-V bypass tracts and occurs even more commonly when orthodromic or antidromic tachycardia also is present

-As many as 50% of patients with symptomatic arrhythmias will have atrial fibrillation of variable duration at some time.

-The incidence of atrial flutter and/or fibrillation appears to be higher in patients with A-V bypass tracts than in the normal population

-Atrial fibrillation appears to be five times more common when overt preexcitation (i.e., WPW) is present than in patients with concealed bypass tracts at similar locations and similar rates of tachycardias

-Patients with atrial fibrillation have a higher incidence of inducible atrial fibrillation than those without the arrhythmia

1. Klein GJ, Bashore TM, Sellers TD, et al. Ventricular fibrillation in the Wolff-Parkinson-White syndrome. N Engl J Med 1979;301:1080–1085.
2. Cosio FG, Benson DW Jr, Anderson RW, et al. Onset of atrial fibrillation during antidromic tachycardia: association with sudden cardiac arrest and ventricular fibrillation in a patient with Wolff-Parkinson-White syndrome. Am J Cardiol 1982;50:353–359.
Answer: C
Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Atrial fibrillation, WPW syndrome

 

Cardiology MCQ 20.4.15

Cardiology MCQ & Review

Q. Which of the following drugs is found to be useful in idiopathic ventricular fibrillation ?

A. Quinidine

B. Bisoprolol

C. Verapamil

D. Sotalol

 

Explanation:

Idiopathic ventricular fibrillation has a high recurrence rate.

The recommended therapy is implantation of implantable cardioverter defibrillator. Currently, recommendations for a specific drug therapy are not available.

Antiarrhythmic agents had no effect on the recurrence rate in the patients from the Unexplained Cardiac Arrest Registry of Europe

In a study by Belhassen et al.,patients with IVF have received oral quinidine guided by serial electrophysiological studies. In patients receiving continuous quinidine treatment, no recurrences of VF were reported during a mean follow-up period of 9.1 ± 5.6 years. In a subset of patients, these promising results were confirmed during longterm follow-up.

Currently pharmacologic therapy serves as an adjunct to ICD therapy in patients with multiple ICD discharges.

 

References:

1.Belhassen B, Viskin S, Fish R, et al: Effects of electrophysiologic-guided therapy with Class IA antiarrhythmic drugs on the long-term outcome of patients with idiopathic ventricular fibrillation with or without the Brugada syndrome. J Cardiovasc Electrophysiol 10:1301–1312, 1999.
2. Belhassen B, Glick A, Viskin S: Excellent longterm reproducibility of the electrophysiologic efficacy of quinidine in patients with idiopathic ventricular fibrillation and Brugada syndrome. Pacing Clin Electrophysiol 32:294–301, 2009.

Answer: A (Quinidine)

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular fibrillation

Cardiology MCQ 18.4.15

Cardiology MCQ & Review

All of the following statements about fascicular reentry ventricular tachycardia are true except

A. Fascicular VTs  account for around 10% of idiopathic VTs

B. Left posterior fascicular VT is the most common, with a narrow right bundle, left inferior axis QRS morphology.

C. Left anterior fascicular VT is less common and has right bundle, right inferior axis QRS morphology.

D.  These tachycardias are also referred to as verapamil-sensitive fascicular tachycardias, given their tendency to slow or terminate with intravenous verapamil.

Explanation:

-Most patients with VT have structural heart disease, 10% have idiopathic VT, occurring in the setting of a structurally normal heart

-Among idiopathic VTs, those arising from the right or left ventricular outflow tract are most common, followed by fascicular VT, which accounts for between 7% and 12% of idiopathic VTs

-Left posterior fascicular VT is the most common, with a narrow right bundle left superior axis QRS morphology.
-Left anterior fascicular VT is less common and has right bundle right inferior axis QRS morphology

-These tachycardias are also referred to as verapamil-sensitive fascicular tachycardias, given their tendency to slow or terminate with intravenous verapamil
-Fascicular VT typically manifests in young adulthood with a slight male preponderance

-Presentation consists of palpitations, presyncope and, rarely syncope, but not sudden cardiac death

-Incessant, fascicular VT has been reported to cause tachycardia-mediated cardiomyopathy

-In some patients, the arrhythmia may manifest only during exercise.

References:

1. Tada H, Ito S, Naito S, et al: Idiopathic ventricular arrhythmia arising from the mitral annulus: A distinct subgroup of idiopathic ventricular arrhythmias. J Am Coll Cardiol 45:877–886, 2005.
2. Lin D, Hsia HH, Gerstenfeld EP, et al: Idiopathic fascicular left ventricular tachycardia: Linear ablation lesion strategy for noninducible or nonsustained tachycardia. Heart Rhythm 2:934–939, 2005.
3. Belhassen B, Rotmensch HH, Laniado S: Response of recurrent sustained ventricular tachycardia to verapamil. Br Heart J 46:679–682, 1981.
4. Bennett DH: Experience with radiofrequency catheter ablation of fascicular tachycardia. Heart 77:104–107, 1997.
5. Nakagawa H, Beckman KJ, McClelland JH, et al: Radiofrequency catheter ablation of idiopathic left ventricular tachycardia guided by a purkinje potential. Circulation 88:2607–2617, 1993.
6. Lee HW, Kim JB, Joung B, et al: Successful catheter ablation of focal automatic left ventricular tachycardia presented with tachycardia-mediated cardiomyopathy. Yonsei Med J 52:1022–1024, 2011.

Answer: B (Left posterior fascicular VT has right bundle branch and left superior axis )

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular tachycardia

MCQ 17.04.2015

All of the following statements about ventricular fibrillation are true except

1.Ninety to ninety-five percent of individuals with ventricular fibrillation reveal underlying structural heart disease.

2. No structural heart disease can be identified in 55% to 60% of patients.

3.According to the results of the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER) among patients with normal left ventricular function, idiopathic ventricular fibrillation (IVF) was diagnosed in 44% of patients with ventricular fibrillation without structural heart disease.

4.The diagnosis of idiopathic ventricular fibrillation (IVF) is based on the exclusion of currently known structural and primary electrical heart diseases following a complete noninvasive, invasive, and genetic workup.

Explanation:

-Ventricular fibrillation in patients without structural heart disease is rare. 90-95% of individuals with ventricular fibrillation reveal underlying structural heart disease

-No structural heart disease can be identified in only 5% to 10% of patients

-According to the results of the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER) among patients with normal left ventricular function, a causal diagnosis
for ventricular fibrillation can be found in 56%. Most diagnoses were primary electrical diseases (catecholaminergic polymorphic ventricular tachycardia [CPVT], long QT syndrome, early repolarization syndrome, and Brugada syndrome [69%]). In 31% of patients, a subtle structural heart disease (i.e., coronary spasm, subclinical arrhythmogenic right ventricular cardiomyopathy and myocarditis) was identified. In addition, idiopathic ventricular fibrillation (IVF) was diagnosed in 44% of patients with ventricular fibrillation without structural heart disease.

-The diagnosis of IVF is based on the exclusion of currently known structural and primary electrical heart diseases following a complete noninvasive, invasive, and genetic workup.

Ref:
1.Krahn AD, Healey JS, Chauhan V, et al: Systematic assessment of patients with unexplained cardiac arrest: Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER). Circulation 120:278–285, 2009.

2. Rosso R, Kogan E, Belhassen B, et al: J-point elevation in survivors of primary ventricular fibrillation and matched control subjects: incidence and clinical significance. J Am Coll Cardiol 52:1231–1238, 2008.

3. Napolitano C, Bloise R, Monteforte N, et al. Sudden cardiac death and genetic ion channelopathies: long QT, Brugada, short QT, catecholaminergic polymorphic ventricular tachycardia, and idiopathic  ventricular fibrillation. Circulation 125:2027–2034, 2012.

Answer : B

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular fibrillation

MCQ 16.04.2015

All of the following arrhythmias are usually seen in structurally normal heart except

A. Right ventricular outflow tract ventricular tachycardia

B. Fascicular reentry ventricular tachycardia

C. Bundle branch reentry ventricular tachycardia

D. Catecholaminergic polymorphic ventricular tachycardia

 

Explanation:

Bundle branch reentry (BBR) ventricular tachycardia (VT) is a unique, fast (200 to 300 beats/min), monomorphic tachycardia associated with hemodynamic collapse, syncope, and/or cardiac arrest.

It is caused by a macroreentry circuit involving the right and left bundle branches, an upper common pathway, and septal ventricular muscle.

BBRoccurs in patients who have dilated cardiomyopathy and in those with coronary artery disease, valvular heart disease, myotonic dystrophy, or even no heart disease with associated His-Purkinje system disease.

The incidence is reported to be 3.5% and 6% of ventricular tachycardias

Classification of ventricular arrhythmias in the absence of structural heart disease

I. Non–life-threatening (typically monomorphic)
A. Outflow tract
Right ventricular outflow
Left ventricular outflow
Aortic sinus of Valsalva
Peri His bundle
B. Idiopathic left ventricular tachycardia
Left posterior fascicle
Left anterior fascicle
High septal fascicle
C. Other
Mitral annulus
Tricuspid annulus
Papillary muscle
Perivascular epicardial
II. Life-threatening (typically polymorphic)
A. Genetic syndromes
Long QT
Brugada
Catecholaminergic polymorphic ventricular tachycardia
Short QT
B. Idiopathic ventricular fibrillation

Answer: C

Ref:

1. Blanck Z, Dhala A, Deshpande S, et al: Bundle branch reentrant ventricular tachycardia: Cumulative experience in 48 patients. J Cardiovasc Electrophysiol 4:253–262, 1993.

2 . Blanck Z, Jazayeri M, Dhala A, et al: Bundle branch reentry: A mechanism of ventricular tachycardia in the absence of myocardial or valvular dysfunction. J Am Coll Cardiol 22:1718–1722, 1993.

3. Eric N. Prystowsky, Benzy J. Padanilam, Sandeep Joshi,  Richard I. Fogel. Ventricular Arrhythmias in the Absence of Structural Heart Disease. J Am Coll Cardiol 2012;59:1733–44

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular tachycardia