What is it? An electrocardiogram — abbreviated as EKG or ECG — is a test that measures the electrical activity of the heartbeat. With each beat, an electrical impulse (or “wave”) travels through the heart. This wave causes the muscle to squeeze and pump blood from the heart. A normal heartbeat on ECG will show the timing of the top and lower cha...

Asystole is a terminal rhythm. Asystole is cardiac standstill with no cardiac output and no ventricular depolarization; it eventually occurs in all dying patients. A precursor to asystole may be pulseless electrical activity (PEA), which is when the heart still has electrical activity, but does not have mechanical capture. Do you know that 90% ...

Pulseless Electrical Activity (PEA), formerly known as Electromechanical Dissociation (EMD), is a condition in which there is electrical activity of the heart, but no mechanical capture (no mechanical pumping of the ventricles). Patients in PEA will have a rhythm (it can be any rhythm, technically speaking) on the monitor, but will be pulseless....

Complete heart block, also referred to as third-degree heart block, or third-degree atrioventricular (AV) block, is a disorder of the cardiac conduction system. In this case, there is no conduction through the AV node. There is a complete disassociation of the atrial and ventricular activity of the heart. The ventricular escape mechanism can oc...

These blocks typically arise, as before, from the HIS-Purkinje system of the heart. They are even more dangerous than Wenckebach blocks because of their propensity to go to complete AV blocks (third degree).The normal pattern seem on EKG is a PR interval that does not prolong, however, a beat is dropped at a given, and predictable part of the c...

These blocks typically arise from the HIS- Purkinje system and therefore pose more of a problem for the patient. The typical pattern for this type of block, as seen on EKG, is a PR prolongation leading to a dropped beat. “A type I block manifesting with atypical electrocardiographic findings that result in a misdiagnosis of type II block is not...

A First Degree AV heart block is just about always asymptomatic. It is an EKG finding of a prolonged PR segment. A normal PR interval is from 120-200 msec, and a PR interval on the EKG to more than 200 msec is diagnostic, as well as, definitive. A first degree AV block can arise from delays in the conduction system in the AV node, the His-Purki...

Torsades de pointes, or simply “Torsades”, is a French term that literally means “twisting of the points”. This is a relatively rare variety of ventricular tachycardia that exhibits distinct characteristics on the electrocardiogram (ECG). A typical ECG of Torsades demonstrates a rapid, polymorphic ventricular tachycardia...

“V Fib” is the most common arrhythmia encountered in a patient with sudden cardiac death. It is usually fatal within a few minutes if not treated at once. Ventricular fibrillation is a rapid, grossly irregular ventricular rhythm with marked variability in QRS cycle length, morphology and amplitude. The most common causes are found below. Ischem...

“V Tach” is defined as 3+ successive complexes in duration originating in the ventricle at a rate of greater than 100 bpm (cycle length, less than 60 msec). (5) Many things can precipitate ventricular tachycardia including, but not limited to, myocardial infarctions, Brugada Syndrome, adverse drug reactions, stress, long QT syndrome, hypertroph...

PVCs are the most common ventricular arrhythmia. As with PACs, these are usually benign and not a predictor of future heart disease or problems. They are spurred on by the same stimuli as PACs, for the most part. PVCs are usually only a problem in a patient with sustained PVCs (>6 in a row) or in a patient with significant heart disease. The...

Wolff-Parkinson-White (WPW) Syndrome was first reported in 1930. It is a congenital abnormality seen in up to 1 in 500 otherwise normal EKGs. Electrically active muscle fibers (Kent Bundles) bridge the atria and ventricles and cause pre-excitation of the ventricles (via the HIS-Purkinje system) by bypassing the normal electrical circuitry of th...

Multifocal atrial tachycardia (MAT) is a rapid heart rate that occurs when the atria in the heart get excited or irritated and begin to send multiple signals (electrical impulses) from the atria to the ventricles. In MAT, a typical heart beat is anywhere from 100 to 250 beats per minute. At an increased rate, the heart has less time to fill up ...

These are just as they sound, heart beats that are initiated in the atria at a premature time. They can be caused by an irritated focus (trauma, ischemia, etc) or by aberrant atrial cells that overtake the natural pacemaker. They may be influenced by the same endogenous as well as exogenous stimuli as atrial fibrillation, as detailed above. Mos...

Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of reentrant supraventricular tachycardia (SVT). Because it begins quickly and it’s termination is equally abrupt, a very nonspecific term, paroxysmal supraventricular tachycardia, has been coined to help describe this phenomenon. AVNRT may be functional rather tha...

Atrial flutter can present much like atrial fibrillation; however the EKG findings for this disorder are much different. Instead of having an irregularly irregular set of complexes, with no discernable P-wave activity, you will likely see a characteristic “saw-tooth” appearance of the QRS complexes. (5,6) Another common presenting sign of atria...

The most common type of non-sinus tachyarrhythmia is atrial fibrillation. In this case, disorganized electrical impulses that originate in the atria and pulmonary veins initiate the electrical activity in the conduction system of the heart. This causes what are commonly termed as “irregularly irregular” heart beats. There is chaotic firing from...

Normal Sinus Rhythms are between the rates of 60-100 beats per minute. The beats initiate at the Sinoatrial (SA) Node (AKA the Sinus Node) in the right atrium of the heart, proceed though both atria to the Atrioventricular (AV) Node, through the Bundle of His and ultimately to and throughout the ventricles of the heart. This advancing wave of d...

A “Sinus Arrhythmia” is a normal speeding of the heart rate that happens during inspiration. Though it sounds pathological, it functions in all humans at all times. This is a natural response and is more commonly seen in children than adults. This is not a true “arrhythmia”. It is caused by a slight increase in the heart...