Arrhythmias Flashcards Preview

Cardiovascular Unit 1 > Arrhythmias > Flashcards

Flashcards in Arrhythmias Deck (15):
1

Describe the EKG features of a normal sinus rhythm.

 Sinus Rhythm

  • PR interval (resistance to conduction at the AV node)
  • QRS complex (ventricular depolarization)
  • T wave (ventricular repolarization)
  • Normal sinus rate: 60-100 bpm

  • Normal PR interval is 0.12-0.20 seconds.

2

 Define Sinus Tachycardia

HR > 100bpm

*Beta-blocker is usually effective here

3

Define sinus bradycardia

HR < 60bpm

  • Atropine effective treatment here, if pt becomes v/v

 

Can cause syncope, lightheadedness or fatigue in elderly patients with age-related dysfunction→sick sinus syndrome

4

What is a junctional (nodal) rhythm?

Region surrounding the AV node is often termed the “junction” and rhythms originating there are called junctional rhythms

  • Regular rhythm w/ narrow QRS complexes
  • P waves not seen because they are buried w/in QRS complex
  • Often inverted because they are conducted upward from the AV node rather than downward from the SA node.

5

What are the EKG features of a normal junctional (nodal) rhythm?

Regular, narrow (normal) QRS complex with no antecedent P waves.

6

What are the ECG features of 1st degree A-V Block?

PR interval prolonged, increased junctional delay

  • Causes: drug-induced (beta-blockers, some calcium blockers, digitalis), conduction system disease.
  • EKG features: PR interval is greater than 0.2 seconds (one large block on the EKG).
  • This is a benign condition that can proceed to more serious types of block.

7

What are the ECG features of second degree A-V heart block?

Some P waves conduct and some do not

  • Causes: conduction system disease, high vagal tone, excessive effects of drugs.
  • EKG features: Some P waves conduct normally to ventricles but others do not. Patterns vary.
  • If the rate is too slow to slow to support cardiac output adequately, syncope or confusion may occur requiring a pacemaker.

8

What are the ECG features of third degree A-V block?

Both Ps and QRSs show regular rhythm, but they are at different rates.

  • Causes: av node or junctional failure with aging, infarct or disruption during cardiac surgery—rarely caused by drugs.
  • EKG features: Both Ps and QRSs show regular rhythm, but they are at different rates. With P rate > QRS rate.
  • May cause syncope or sudden death. Usually requires a pacemaker.

9

A-Fib

  • What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: irregularly irregular ventricular rhythm. No p waves.
  • Causes: NI subjects, aging, post-operative, heart disease, hyperthyroidism
  • Clinical manifestations: rapid heart rate (syncope, ischemia, heart failure), loss of atrial kick (heart failure), atrial thrombi (embolic stroke).
  • Treatment: anticoagulation, rate control with drugs, cardioversion—electrical or drugs, ablation.

10

Atrial Flutter

What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: P waves (flutter waves) at rate of 240-320 bpm. Pulse may be regular or irregular. Ventricular rates vary widely—typically rapid if untreated.
  • Complications: atrial flutter has some risk of embolic stroke due to clot in the left atrium, and may result in rapid ventricular rates that are poorly tolerated.
  • Treatment: anticoagulation, rate control with drugs, cardioversion, ablation.

11

Atrial Tachycardia

What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: harrow QRS complex, P waves present, but abnormal. Heart rate may be as high as 180.
  • Causes: abnormal re-entry pathway.
  • Clinical manifestations: rapid heart rate, very uncomfortable and disturbing.
  • Treatment: Adenosine; ablation if recurrent problem.

12

Premature atrial contraction

What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: premature beat, preceded by abnormal P wave, narrow QRS complex.
  • Clinical manifestations: single-beat palpitation, most commonly noticed at rest, when low heart rates permit occurrence of premature ‘skipped beats’ and when distractions are reduced allowing awareness.
  • Treatment: none. Beta-blockers if really annoying.

13

Premature Ventricular Contraction (PVC)

What are the ECG features, causes, clinical manifestations, and treatment?

 

  • EKG features: wide-abnormal QRS, No P-wave.
  • Causes: random single, reentry arrhythmia—short path-length blocks re-entry.
  • Clinical manifestations: single-beat palpitation, most commonly noticed at rest, when low heart rates permit occurrence of premature ‘skipped beats’ and when distractions are reduced allowing awareness.
  • Treatment: none, beta-blockers if really annoying.

14

Ventricular Tachycardia

What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: repetitive wide-abnormal QRS complexes, no p-wave
  • Causes: fibrosis, infiltrate, dilation, long path length permitting reentry.
  • Clinical manifestations: very bad. Abnormal ventricular contraction
  • Treatment: emergency defibrillation.

15

V-Fib

What are the ECG features, causes, clinical manifestations, and treatment?

  • EKG features: abnormal, abnormal, abnormal—all noise, no p waves, no QRS complexes, no T waves.

  • Causes: can progress from ventricular tachycardia. Heart failure.

  • Clinical manifestations: very bad. No ventricular contraction.

  • Treatment: immediate emergency defibrillation.