supraventricular arrhythmias claire b. hunter, m.d
TRANSCRIPT
Adverse Effects of Arrhythmias
Depend Upon:
Overall Ventricular Rate
Too High
Too Low
Loss of Atrial “Kick”
Degree of L.V. Dysfunction
Steps In Arrhythmia Analysis 1. Calculate Rate - Ventricular : Atrial 2. Regularity - QRS : P-Waves 3. Evaluate P-waves
a) Presence b) Contour c) Relationship to QRS Complexes
4. P-R Interval 5. Width Of QRS Complex
a) Pre-existing Conduction Defect b) Rate Dependent Aberrancy
Tachycardias
• Sinus Tachycardia• Atrial Tachycardia
– PAT
– MAT
• AV Nodal Tachycardia• Wolff Parkinson White Syndrome• Atrial Fibrillation• Atrial Flutter
Mechanisms for Supraventricular Tachycardia
• Re-Entrant Mechanism 95%– AV Nodal Re-Entry 40
60%– Accessory Bypass Tracts 20 40%– Sinus Node Re-Entry 5%– Intra-Atrial Re-Entry 5%
• Automatic Atrial Tachycardia 5%
Regular Narrow QRS Tachycardia Rate 160+
• Sinus Tachycardia
• Paroxsymal Supraventricular Tachycardia
• Atrial Flutter with 2-1 Conduction
Paroxysmal Supraventricular Tachycardia
• AV nodal reentry Tachycardia
(AVRNT)
• Atrial Tachycardia
• WPW
AV Nodal Reentrant Tachycardia
• 150-250
• No p wave seen
• Normal qrs
• Sudden onset
• Most common PSVT
AVNRT Treatment
• Vagal maneuvers
• Adenosine 6-12 mg IV
• Verapamil 5 mg Q 5 min x 3
• Diltiazem 15-20 mg IV (2min) x 2
• Digoxin, Beta blockers, Ca C1 blockers
• Ablation
Atrial Fibrillation
Ventricular rate variable: depends on
degree of AV Block
Regularity grossly irregular unless
complete AV Block
QRS Complex normal (unless P.E.C.D. or
R.D.A.)
P-waves not identifiable: f-waves
C-S response increase AV Block or none
AF/F: Pathophysiology of Symptoms
• Decreased diastolic filling time
• Decreased diastolic coronary perfusion time
• Exacerbation of angina due to increased oxygen demand (secondary to increase in heart rate)
• Loss of atrial contribution to ventricular filling
AF/F: Treatment Objectives
• Relief of symptoms• Heart rate control• Consider conversion to normal sinus rhythm
– Immediate cardioversion if hypotensive or in pulmonary edema
• Maintenance of sinus rhythm• Prevention of embolic complications
Atrial Flutter
Atrial rate 250 to 350/min Ventricular rate depends on degree of AV block; frequently 150/min Regularity regular of irregular depending on AV block QRS complex normal (unless P.E.C.D. or R.D.A.) P-waves usually saw-tooth in appearance C-S response increase AV block or none
Atrial Flutter (1 - 2%)
• Adverse Effects• Evaluation• Medical Therapy (Control Ventricular Rate)
– Digitalis (Avoid Toxicity)– Propranolol– Verapamil
• Cardioversion• Preventive Therapy
Wolff Parkinson White
• Pre excitation– Short PR interval– Delta waves
• Paroxysmal SVT
• Treatment– Acute– Chronic