Wenckebach

A physiologist of the late 19th and early 20th century, who is responsible for the discovery of the Second Degree AV Block Type I and Type II.

Second Degree AV Block Type I

Metaphorically, picture the junctionConnects the atria to the ventricle and slows the impulse conduction speed sufficiently to allow for atrial kick; the junction consists of the AV node and the bundle of His; the junction is a supraventricular structure. 1. Six Second ECG... as a gate. In 2nd degree AV block type IA cardiac rhythm characterized by occasional P waves without a QRS (lonely Ps) and an observable pattern of progressive lengthening of the PR interval followed by a P wave without a QRS (dropped QRS) – the PR interval then shortens..., the gate slowly closes with the time taken for the impulse to get through the gate progressively getting longer. The PR intervalA period measured on rhythm strip paper that measures a wave and a segment; the distance measured is equal to time taken as an ECG is voltage over time; a PR interval for example is measured from the beginning of... progressively lengthens as a result. Eventually, the gate closes and the atrial wave is not carried to the ventriclesThe larger chambers of the heart (3 times the volume and muscle thickness than the atria), responsible for the pumping of blood to the lungs and the rest of the body. – a lonely P waveA wave generated from the depolarization of the atria; the P wave is upright when originating from the SA node. The P wave represents the depolarization of the right and left atria. The P wave begins with the first deviation... results. With a dropped QRSThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also..., the gate then springs back open to begin the process again (PR interval begins narrow once again).

Second degree AV block type I is recognized by cycles of lengthening PR intervalsThe time and interval measured from the beginning of the P wave to the beginning of the QRS; should be called the PQ interval; normal PR interval is 0.12-0.20 seconds. The PR interval is measured from the start of the... that terminate a lonely P wave. This cycle repeats forming a patternPattern refers to the repeating components of an ECG rhythm in a predicative order. An ECG rhythm that is initiated by one of several intrinsic pacemaker sites of a heart will often generate a regular, even rhythm pattern. This can.... Although the loss of every 3rd or 4th beat impacts cardiac outputWhat is it? Why is it Vital? The amount of blood pumped out of the ventricle in a minute (most often refers to the blood pumped by the left ventricle) What is cardiac output? Simply, cardiac output is the amount... minimally, this rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. does require monitoring. Aggressive treatment is usually not required.

Second degree AV block type I occurs at the AV nodeIs located in the inferior aspect of the right atria; functions to slow the conduction speed to allow for atrial conduction prior to ventricular conduction (atrial kick); also serves as a pacemaker if the SA node fails to fire. The.... Causes of second degree AV block are identical to first degree AV blockThe PR interval is the time from the beginning of the atrial wave to the beginning of myocardial depolarization of the ventricles. Normally this takes 0.12 - 0.20 seconds. When the time taken is over 0.20 seconds, this is called.... Typically, the patient is monitored, placed on oxygen and assessed for signs of cardiac ischemiaThe ability to identify cardiac ischemia, injury and infarction is vital in the management of the majority of cardiac emergencies. Most sudden cardiac deaths are associated with an ischemic episode. Patient deaths due to an acute myocardial infarction (MI) typically....

Second Degree Block Type II

Second degree AV block type II is a significant dysrhythmiaUsed interchangeably with arrhythmia, refers to any abnormal rhythm – not normal sinus rhythm or sinus tachycardia. 1. Six Second ECG Guidebook (2012), T Barill, p. 196 due to 1) its unpredictability; 2) its potential to cause consecutive dropped QRS complexes and 3) its tendency to progress to a complete heart blockAlso known as complete heart block, the supraventricular impulse is blocked at the junction or high in the bundle branches; as a result, the myocardium above the block depolarizes independently of the myocardium below the block; characteristics of this rhythm... (third degree AV block). Second degree AV block is identified with lonely ‘P’ waves and a fixed PR interval. The metaphorical gate is either open or closed.

Second degree AV block type II occurs at the level of the bundle branchesThe bundle of His terminates in the right and left bundle branches, insulated rapidly conducting electrical pathways that connect with the Purkinje network and thus begin depolarizing waves across the ventricles; the left bundle branch splits into three smaller branches... (common) or at the bundle of HisPart of the AV junction, the bundle of His conducts the impulse through the fibrous plate that separates the atria and the ventricle; the bundle of His is also a pacemaker, firing at 40-60/minute. The bundle of His serves as... (much less common). This dysrhythmia often has includes aberrant conductionFor about 15% of rhythms with wide QRS complexes, impaired bundle branch conductivity prolongs ventricular depolarization. Ischemia, infarction, and antiarrythmics can slow or block transmission of an impulse along these bundle branches. The resulting widening of the QRS complex is... through the ventricles. Causes of second degree AV block type II include cardiac ischemiaInsufficient supply of oxygen to meet the oxygen demands of tissue. Anaerobic metabolism becomes increasingly important during periods of ischemia. Ischemia results from an inadequate blood flow that fails to meet the oxygen demands (energy demands) of tissues. If tissues... and an anteroseptal myocardial infarctionWhen combined with congruent clinical findings, a diagnosis of an anteroseptal myocardial infarction (MI) is strongly supported. Since the anteroseptal region of the heart involves the left ventricle, it is prudent to continue the investigation into the lateral region that....

1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 126-127, 209