Cardiac Arrythmias and ECG Guidelines

Understanding the ECG Strip

Arrhythmia	Heart Rate (bpm)	Rhythm	P wave	PR Interval	QRS Complex
Normal Sinus Rhythm	60-100	Regular	Normal	Normal	Normal
Sinus Tachycardia	100-180	Regular	Normal; may be peaked	Normal	Normal
Sinus Bradycardia	<60	Regular	Precedes QRS	Normal	Normal
Premature Atrial Complex	Dependent on rhythm	Irregular due to premature complexes	Same, different or absent	0.12-0.20	1:1
Atrial Tachycardia	160-250	Regular	Normal	0.08 sec	Normal
Atrial Flutter *sawtooth appearance	60-150	Usually regular, may be irregular	Atrial flutter waves		Normal
Atrial Fibrillation *Cardioversion Rx: Betablockers ("lol")	60-180	Irregular	Absent	None	Normal
Premature Ventricular Contraction (PVC)	Present or Absent	Irregular	normal	Not measurable	Distorted >0.12 sec
Ventricular Tachycardia	110-250	Regular	Present or Absent, No relation to QRS complexes	None	Abnormal >0.12 sec
Ventricular Fibrillation *Defibrillation	None	None	Present or Absent	None	Ventricular fibrillation waves
Accelerated Idioventricular rhythm	40-100	Regular	Present or Absent, No relation to QRS complexes	None	Abnormal >0.12 sec
Ventricular Escape Rhythm	<40	Regular	Present or Absent, No relation to QRS complexes	None	Abnormal >0.12 sec
Ventricular Asystole	None	None	Present or Absent	None	None

ECG Strip

0.04 sec – small square

0.20 sec - large square

WAVES	Definition
P wave	Represents depolarization of the right and left atria
QRS complex	Represents depolarization of the right and left ventricles
T wave	Represents ventricular repolarization
U wave	Probably represents the final stage of repolarization of the ventricles
PR interval	Represents the time of progression of the electrical impulse from the SA Node, an ectopic pacemaker in the atria, or an ectopic or escape pacemaker in the AV junction, through the entire electrical conduction system of the heart ventricular myocardium, including the depolarization of the atria
QT interval	Represents the time between the onset of depolarization  and the termination of repolarization of the ventricles
R-R interval	Represents the time between two successive ventricular depolarizations
ST segment	Represents the early part of repolarization of the right and left ventricles
PR segment	Represents the time of progression of the electrical impulse from the AV node through the bundle of His, bundle branches, and Purkinje network to the ventricular myocardium
TP segment	Is the interval between two successive P-QRST complexes, during which electrical activity of the heart is absent

Basic Dysrhythmias, Robert J. Huszar, Revised Third Edition


Basic Heart Drugs:

β-Blockers "olol"- such as metoprolol slow conduction of impulses through the AV node and decrease the heart rate. 

-Propranolol (inderal ): 
Side effect: Audible expiratory wheezes may indicate a serious adverse reaction, bronchospasm.

Calcium channel blockers "dipine" - primarily decrease spasm in cerebral blood vessels

Atropine sulfate will further increase the heart rate and will further decrease the cardiac output.

Lidocaine is useful in suppressing ventricular dysrhythmias.

Warfarin (Coumadin) is administered to clients with atrial fibrillation to prevent clots from forming in the atria it will have no effect in decreasing the ventricular rate or restoring normal sinus rhythm.

Nitroglycerin is a vasodilator and will lower the blood pressure.