Cardiology

Question 1

Atrial fibrillation (AF)

Answer 1

Rapid, irregularly irregular atrial rhythm. Often asymptomatic, but many patients have palpitations, vague chest discomfort, or symptoms of heart failure (dizziness, dyspnoea, SOB), particularly when the ventricular rate is very rapid (140-160 beats/min). Patients may also show signs of acute stroke or other organ damage due to systemic emboli.

Question 2

Most common causes of AF

Answer 2

• Hypertension.
• Ischaemic or nonischaemic cardiomyopathy.
• Mitral or tricuspid valvular disorders.
• Hyperthyroidism.
• Binge alcohol drinking.

Question 3

Least common causes of AF

Answer 3

• Pulmonary embolism.
• Atrial septal and other congenital heart defects.
• COPD.
• Myocarditis and pericarditis.
• AF without an identifiable cause in patients <60 years is called lone AF

Question 4

Classification: Acute AF

Answer 4

is new-onset AF lasting < 48 hours.

Question 5

Classify: Paroxysmal AF

Answer 5

recurrent AF that typically lasts < 48 hours and that converts
spontaneously to normal sinus rhythm.
( 7 days; may recur with variable frequency)

Question 6

Classify: Persistent AF

Answer 6

lasts > 1 week and requires treatment to convert to normal sinus
rhythm.

Question 7

Classify: Longstanding AF

Answer 7

Long-standing persistent AF: Episodes of continuous AF that last more than 12 months

Question 8

Classify: Permanent AF

Answer 8

cannot be converted to sinus rhythm. The longer AF is present, the less
likely is spontaneous conversion and the more difficult is cardioversion because of atrial remodeling.

Question 9

Treatment objectives overview:

Answer 9

1. Rate control
2. Restore sinus rhythm
3. Decrease risk of Cerebrovascular incident.

Question 10

Tx: rate control, AF associated with rapid rate but with stable hemodynamics. Drugs to slow down ventricular rate

Answer 10

• CCB; Verapamil 2,5 mg repeated until 25-30 mg in 1⁄2-1 hours. Watch BP!
• Beta-blockers: Metoprolol tartrate 5 mg iv, could be repeated.
• Digitoxin 0,6 mg + 0,4 mg after 4 hours.

Question 11

Tx: restoring sinus rhythm (if the arrhythmia has lasted <48hrs)

Answer 11

After the rate is slowed down. The antiarrhythmic drugs used are from class Ia, Ic and III. E.g Ic class drug Flecainide 2mg/kg, max 150 mg, infusion over 30 min.

Question 12

Tx: restoring sinus rhythm (if the arrhythmia has lasted >48hrs)

Answer 12

Synchronized cardioversion (100 joules, followed by 200 and 360) converts AF to normal sinus rhythm in 75-90% of patients, recurrence rate is high. Efficacy and maintenance of sinus rhythm after the procedure is improved with use of class Ia, Ic, or III drugs 24 to 48 h before the procedure.

Question 13

Effectiveness of cardioversion:

Answer 13

Cardioversion is more effective in patients with shorter duration of AF, lone AF, or AF with a reversible cause; it is less effective when the left atrium is enlarged (> 5 cm), atrial appendage flow is low, or a significant underlying structural heart disorder is present.

Question 14

Before cardioversion:

Answer 14

Before conversion is attempted, the ventricular rate should be controlled to <120beats/min, and if AF has been present > 48 hours the patient should be given oral anticoagulant for 3-4 weeks. Alternatively, the patient can be anticoagulated with heparin, and transesophageal echocardiography done; if there is no intra-atrial clot, cardioversion can be done immediately followed by at least 4 weeks of oral anticoagulation as above.

Question 15

Decreasing risk of CVA

Answer 15

Aspirin for those with a CHADS2 of 0 or 1

CHADS2 of >2 should be on anticoagulant therapy

Question 16

New anticoagulant drugs

Answer 16

Several newer anticoagulant drugs (dabigatran, rivaroxaban, and apixaban) have recently been approved for anticoagulant therapy of patients with nonvalvular atrial fibrillation. These drugs have proved to be either equivalent or actually superior in efficacy and safety compared with warfarin. The advantages of the newer agents include obviating the need for INR blood tests and fewer drug–drug or drug–food interactions compared with warfarin.

Question 17

Paroxysmal Tachycardia

Answer 17

refers to a clinical syndrome characterised by a rapid, regular tachycardia with an abrupt onset and termination.

Question 18

Atrioventricular nodal reentrant tachycardia (avNrt)

Answer 18

Is the most frequent form of PSVT and the usual age of onset is beyond the fourth decade of life, female>male. Three types of AVNRT have been described.

Question 19

Typical avNrt (or Slow/Fast)
i.e. the most common

Answer 19

Use the slow pathway for antegrade conduction and the fast pathway for retrograde conduction.

1. Atrial premature complex blocks the fast pathway and proceeds slowly along the slow pathway, the fast pathway has time to recover from refractory period.
2. This allows the impulse to activate the fast pathway retrogradely and return to the atrium, giving rise to an AV nodal reentrant echo beat.
3. The impulse then travels down along the slow pathway again, continuation giving rise to AVNRT.

Question 20

Atypical, either fast/slow OR slow/slow

Answer 20

The fast/slow uses the fast pathway for anterograde conduction and the slow pathway for retrograde conduction. The slow/slow requires presence of two or more slow pathways with different conduction properties and refractory periods; one slow pathway is used for antegrade conduction ant the other slow pathway for retrograde conduction.

Question 21

Clinical features of avNrt

Answer 21

Episodes lasts from seconds to several hours. Patients learn maneuvers to terminate the arrhythmia: carotid sinus massage or the Valsalva maneuver.
Physicians may try to document the tachycardia with an ECG using a 30-day event monitor or tell the patient to seek the emergency department during the next episode.

Question 22

avNrt ECG

Answer 22

during normofrequent sinus rhythm there are no abnormalities. Narrower QRS complex, usually without visible P wave. Visible P wave occurs shortly before or after QRS. Regular rates between 120-200 beats/min.

Question 23

avNrt Tx

Answer 23

Generally a benign condition, it do not influence survival, the main reason for treating is to alleviate symptoms. Self maneuvers, increase vagal tone by Valsalva, gagging, carotid sinus massage, face to ice water.

Question 24

avNrt acute management

Answer 24

1) Adenosine 6 mg IV rapid bolus, can be followed by 2 subsequent 12 mg q 5 min if
first dose is ineffective- purinergic blocking agent that cause acute and transient
AV nodal blockade.
2) Verapamil 5 mg IV or diltiazem 0,25 – 0,35 mg/kg IV are alternatives.

Question 25

avNrt long term management

Answer 25

Catheter ablation of conducting portion of the AV
node using the posterior approach.
2) Medical therapy to depressed AV nodal conduction to reduce the frequent
recurrences of AVNRT

Question 26

avNrt long term management medication

Answer 26

Beta-blockers, calcium channel blockers, class 1a antiarrhythmic (procainamide and disopyramide), class 1c (flecainide) and class III antiarrhythmic (sotalol and amiodarone). Best among these have been class Ic agents.

Question 27

Atrioventricular reentrant Tachycardia (avrt)

Answer 27

Are associated with sudden cardiac death, and may be detected in asymptomatic patients on a routine screening ECG.
AVRT is a reentrant tachycardia with an anatomically defined circuit that consists of two distinct pathways, the normal AV conduction system and an AV accessory pathway, linked by common proximal (the atria) and distal (the ventricles) tissues.

Question 28

Wolff-Parkinson-White: is the most common accessory pathway SVT

Answer 28

Mainly idiopathic, although more common in patients with hypertrophic or other forms of cardiomyopathy, transposition of the great vessels, or Epsteins anomaly. In classic WPW syndrome, antegrade conduction occurs over both the accessory pathway and the normal conducting system during sinus rhythm. The accessory pathway, being faster, depolarizes some of the ventricle early, resulting in a short PR interval and a slurred upstroke to the QRS complex (delta wave). The delta wave prolongs QRS duration to >0,12 seconds.

Question 29

In the most common form of reentrant tachycardia (called orthodromic reciprocating tachycardia)

Answer 29

The circuit uses the normal AV conduction pathway to activate the ventricles, returning to the atrium via the accessory AV connection. The resultant QRS complex is thus narrow (unless bundle branch block coexists) and without a delta wave. Orthodromic reciprocating tachycardia is typically a short RP tachycardia with the retrograde P wave in the ST segment.

Question 30

WPW clinical features

Answer 30

Associated with dyspnea, chest pain, decreased exercise tolerance, anxiety, dizziness or syncope.
Physical examination demonstrates a fast, regular pulse with a constant-intensity first heart sound. Sudden cardiac death in patients wit WPW syndrome is estimated to range from 0,15- 0,39%

Question 31

WPW Tx

Answer 31

For symptomatic WPW syndrome, catheter ablation is considered first line therapy and the
theratment of choice. It is curative in more than 95% of patients and has a low complication rate.

Question 32

WPW medication

Answer 32

Medical therapy: Verapamil, beta blockers, and adenosine modify conduction through
the AV node. While class Ia (procainamide), class Ic(flecainide) and class III(sotalol
and amiodarone) modify conduction across the accessory pathway.