1. Clk. Alexander L. Gonzales II December 14, 2010

2. EKG Characteristics: Regular narrow-complex rhythm Rate 60-100 bpm Each QRS complex is proceeded by a P wave P wave is upright in lead II & downgoing in lead aVR www.uptodate.com

3.  HR< 60 bpm; every QRS narrow, preceded by p wave

4.  ETIOLOGIES: Normal aging 15-25% Acute MI, esp. affecting inferior wall Hypothyroidism, infiltrative diseases Hypothermia, hypokalemia SLE, collagen vasc diseases Situational: micturation, coughing Drugs

5.  HR > 100 bpm, regular

6.  ETIOLOGIES: Fever Hyperthyroidism Effective volume depletion Anxiety Pheochromocytoma Sepsis Anemia Exposure to stimulants or illicit drugs Hypotension and shock Pulmonary embolism Acute coronary ischemia and myocardial infarction Heart failure Chronic pulmonary disease Hypoxia

7.  Variations in the cycle lengths between p waves/ QRS complexes  Normal p waves, PR interval, normal, narrow QRS

8.  Usually respiratory--Increase in heart rate during inspiration  Exaggerated in children, young adults and athletes—decreases with age  Usually asymptomatic, no treatment or referral  Can be non-respiratory, often in normal or diseased heart, seen in digitalis toxicity

9. All result in bradycardia Sinus bradycardia (rate of ~43 bpm) with a sinus pause Tachy-brady syndrome

10.  ETIOLOGY: Often due to sinus node fibrosis, Sinus Node arterial atherosclerosis, inflammation (Rheumatic fever, amyloid, sarcoid) Occurs in congenital and acquired heart disease and after surgery Hypothyroidism, hypothermia Drugs: digitalis, lithium, cimetidine, methyldopa, reserpine, clonidine, amiodarone Most patients are elderly, may or may not have symptoms

11.  P wave is altered in shape compared to other P waves and comes early.  QRS complex – normal shape and duration  Cycle comes early

12.  Single ectopic beat that originates in the AV node or Bundle of His area of the condunction system  Retrograde P waves immediately preceding the QRS  Retrograde P waves immediately following the QRS  Absent P waves

13.  Digitalis toxicity  Myocardial Infarction  Myocardial Ischemia  Ingestion of caffeine or amphetamines

14.  Regular rhythm with P waves appearing at a rate of 250 to 300 beats/min  P waves are noted for there “saw tooth” pattern, and or flutter waves  Can be in normal hearts or in those with disease  Most likely due to AV block, creating a reentry circuit

15.  In this rhythm the AV node is bombarded with impulses at a rate of 300 + times per min.  P waves are not distinguishable on the ECG, and appear as “fibrillation waves or f waves.”  QRS complexes are irregular in rhythm with normal duration  Causes – mitral valve or coronary artery disease, long standing hypertension is still the most common cause

16.  Rate: 40 to 60 beats/minute (atrial and ventricular)  Rhythm: regular atrial and ventricular rhythm  P wave: usually inverted, may be upright; may precede, follow or be hidden in the QRS complex; may be absent  PR interval: not measurable or less than.20 sec  QRS and T wave : usually normal

17.  CAUSES Digitalis toxicity Inferior wall MI Myocardial Ischemia Increased vagal tone Rheumatic heart disease Valvular disease Organic disease of the SA node Verapamil toxicity Anticholinesterase toxicity May occur immediately after surgery

18.  Rate: 160 to 240 beats/minute  Rhythm: regular atrial and ventricular  P wave: usually inverted, may be upright; may precede, follow or be hidden in the QRS complex; may be absent  PR interval: not measurable or less than.12 sec  QRS and T wave : usually normal

19.  Supraventricular area fails to fire, which results in ventricular ectopic beat  Premature ventricular contraction (PVC) – most common. No visible P wave QRS > 0.12 seconds in length and is bizarre in morphology

20.  Uniform  Multiform  PVC rhythm patterns Bigeminy – PVC occurs every other complex Couplets – 2 PVCs in a row Trigeminy – Two PVCs for every three complexes

21.  Ventricular tachycardia (VTach) 3 or more PVCs in a row at a rate of 120 to 200 beats/min Most likely due to acute infarction and/ or ischemia  Ventricular fibrillation (VFib) Preterminal event in which myocardium is “dying” No visible P or QRS complexes. Waves appear as fibrillating waves