Rapid 12-lead ECG Interpretation


Presentation Description

Easiest way to rapidly interpret ECG


By: drnpv (62 month(s) ago)

good presentation.thank you sir

Presentation Transcript

Rapid 12-Lead ECG Interpretation:

Rapid 12-Lead ECG Interpretation Dr.Ashutosh Kawade, MD[Medicine] 4/8/2012 12:56 AM


INTRODUCTION Rate Rhythm Axis Hypertrophy Infarction Other Clinical Aspects 4/8/2012 12:56 AM

ECG Interpretation :

ECG Interpretation Electrocardiography (ECG or EKG) is a transthoracic interpretation of the electrical activity of the heart over time captured and externally recorded by skin electrodes. It is a noninvasive recording produced by an electrocardiographic device.

1 small box = 1 mm = 0.1 mV:

1 small box = 1 mm = 0.1 mV 5 Large squares = 1 second Time 1 Large square = 0.2 second 1 Small square = 0.04 second 2 Large squares = 1 cm 6.1 4/8/2012 12:56 AM Horizontal axis - 1 and 3 sec marks 1 small box = 1 mm = 0.04 sec. Every 5 lines (boxes) are bolded Vertical axis- voltage ECG Graph Paper


RATE Our main objective is to rapidly determine the heart rate from the ECG. First: Find a specific R wave that peaks on a heavy black line (our "start" line ). Next: Count off "300, 150, 100" for every thick line that follows the start line, naming each line as shown. Remember these numbers; we will use them throughout our career . Then: Count off the next three lines after "300, 150, 100" as "75, 60, 50." Now: Memorize these ‘Triplets’ & make certain that we can say the triplets without using the picture . Where the next R wave falls, determines the rate. It's that simple! 4/8/2012 12:56 AM

PowerPoint Presentation:

Rate Determine Rate by Observation START ” 50 ” 00 “1 ” Using the triplets: Name the lines following the “Start” line . Fine division/rate association: reference 300 250 214 187 167 “3 ‘’100 “75” “60” “50” 150 136 125 115 100 94 88 83 79 75 71 68 65 62 60 107 May be calculated : 1500 = RATE mm. between similar waves Bradycardia (slow rates) C • Cycles/6 second strip ✕ 10 = Rate • When there are 10 large squares between similar waves, the rate is 30/minute. Sinus Rhythm: origin is the SA Node (“Sinus Node”), normal sinus rate is 60 to 100/minute. • Rate more than 100/min. = Sinus Tachycardia • Rate less than 60/min. = Sinus Bradycardia Determine any co-existing, independent (atrial/ventricular) rates: • Dissociated Rhythms: A Sinus Rhythm (or atrial rhythms) may co-exist with an independent rhythm from an automaticity focus of a lower level. Determine rate of each. Irregular Rhythms: • With Irregular Rhythms (such as Atrial Fibrillation) always note the general (average) ventricular rate (QRS’s per 6-sec. strip ✕ 10) or take the patient’s pulse. 4/8/2012 12:56 AM


NORMAL ECG WAVES 4/8/2012 12:56 AM

PowerPoint Presentation:

Rhythm ★ Identify basic rhythm… … then scan entire tracing for pauses, premature beats, irregularity, and abnormal waves. ★ Always: • Check for: P before each QRS. QRS after each P. • Check: PR intervals (for AV Blocks). QRS interval (for BBB). • Has QRS vector shifted outside normal range? (to rule out Hemiblock). Irregular Rhythms Sinus Arrhythmia Irregular rhythm that varies with respiration. All P waves are identical. Considered normal. Wandering Pacemaker Irregular rhythm. P waves change shape as pacemaker location varies . Rate under 100/minute … …but if the rate exceeds 100/minute, then it is called Multifocal Atrial Tachycardia Atrial Fibrillation Irregular ventricular rhythm. Erratic atrial spikes (no P waves) from multiple atrial automaticity foci. Atrial discharges may be difficult to see. 4/8/2012 12:56 AM

PowerPoint Presentation:

Rhythm continued Escape The heart’s response to a pause in pacing pause fail sinus evoke automaticity Atrial Escape Beat or Junctional Escape Beat Then… the SA Node usally resumes pacing. or Ventricular Escape Beat Atrial Escape Rhythm Rate 60-80/min. or Junctional Escape Rhythm Rate 40-60/min. or + + + + + + + + + + + + + + + + + + cease causing “ escape” status. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + (“ idiojunctional rhythm”) Ventricular Escape Rhythm Rate 20-40/min. C (“ idioventricular rhythm”) Premature Beats • focus discharge, From an irritable automaticity focus Premature Atrial Beat Premature Junctional Beat Premature Ventricular Contraction PVC’s may be: multiple, multifocal, in runs, or coupled with normal cycles. 4/8/2012 12:56 AM


PVC’s 4/8/2012 12:56 AM

PowerPoint Presentation:

Rhythm continued Tachyarrhythmias 150 250 “focus” = automaticity focus 350 450 Rates: Paroxysmal Tachycardia Flutter Fibrillation multiple foci discharging Paroxysmal (sudden) Tachycardia …rate: 150-250/min. “Supraventricular Paroxysmal Atrial Tachycardia An irritable atrial focus discharging at 150-250/min. produces a normal wave sequence, if P' waves are visible . • P.A.T. with block Same as P.A.T. but only every second (or more) P' wave produces a QRS . Paroxysmal Junctional Tachycardia AV Junctional focus produces a rapid sequence of QRS-T cycles at 150-250/min . QRS may be slightly widened . Paroxysmal Ventricular Tachycardia Ventricular focus produces a rapid (150-250/min.) sequence of (PVC-like) wide ventricular complexes. Flutter …rate: 250-350/min. Atrial Flutter A continuous (“saw tooth”) rapid sequence of atrial complexes from a single rapid-firing atrial focus. Many flutter waves needed to produce a ventricular response. Ventricular Flutter also see “Torsades de Pointes” A rapid series of smooth sine waves from a single rapid-firing ventricular focus; usually in a short burst leading to Ventricular Fibrillation . Fibrillation …erratic (multifocal) rapid discharges at 350 to 450/min. Atrial Fibrillation Multiple atrial foci rapidly discharging produce a jagged baseline of tiny spikes. Ventricular (QRS) response is irregular . Ventricular Fibrillation Multiple ventricular foci rapidly discharging produce a totally erratic ventricular rhythm without identifiable waves. Needs immediate treatment . 4/8/2012 12:56 AM fusion

PowerPoint Presentation:

Rhythm: (“heart”) blocks Sinus (SA) Block the Sinus Node usually resumes pacing, but the pause may evoke an “escape” response from an automaticity focus. An unhealthy Sinus (SA) Node misses one or more cycles (sinus pause)… AV Block Blocks that delay or prevent atrial impulses from reaching the ventricles. 1 ° AV Block 2 ° AV Block … prolonged PR interval PR interval is prolonged to greater than .2 sec (one large square). … some P waves without QRS response cycle until the last P wave in the series does not produce a QRS. Wenckebach … PR gradually lengthens with each Mobitz … some P waves don’t produce a QRS response. If “intermittent,” an occasional QRS is droped. More advanced Mobitz block may produce a 3:1 (AV) pattern or even higher AV ratio 2:1 AV Block … may be Mobitz or Wenckebach. PR length and QRS width or vagal maneuvers help differentiate. 3 ° (“complete”) AV Block … no P wave produces a QRS response 3 ° Block: P waves—SA Node origin. QRS’s—if narrow, and if the ventricular rate is 40 to 60 per min., then origin is a Junctional focus. P waves—SA Node origin. QRS’s—if PVC-like, and if the ventricular rate is 20 to 40 per min ., then origin is a Ventricular focus. C 3 ° Block: Bundle Branch Block Right BBB ★ Always Check: • is QRS within 3 tiny squares? R R ' … find R,R' in right or left chest leads With Bundle Branch Block the criteria for ventricular hypertrophy are unreliable . Left BBB R R ' Caution: With Left BBB infarction is difficult to determine on EKG . QRS in V 1 or V 2 QRS in V 5 or V 6 Hemiblock ★ Always Check: • has Axis shifted outside Normal range? … block of Anterior or Posterior fascicle of the Left Bundle Branch. Anterior Hemiblock Axis shifts Leftward ➞ L.A.D. look for Q 1 S 3 Posterior Hemiblock Axis shifts Rightward ➞ R.A.D. look for S 1 Q 3 4/8/2012 12:56 AM “WILLIAM MORROW” W i l lia m : ‘ W ’ in V1 & ‘ M ’ in V6: LBBB M o r ro w : ‘ M ’ in V1 & ‘ W’ in V6: RBBB

PowerPoint Presentation:

Axis General Determination of Electrical Axis Is QRS Positive ( ) or Negative ( ) in leads I and AVF? First Determine Axis Quadrant I I Is Axis Normal? QRS in lead I …if the QRS is Positive (mainly above baseline), then the Vector points to positive (patient’s left) side . Lead I AVF L . AVF A Normal: { QRS upright in I and AVF “ two thumbs-up” sign I Ex.R.A.D QRS in lead AVF Lead AVF . . D …if the QRS is mainly Positive, then the Vector must point downward to positive half of the sphere. R.A.D . Normal I AVF AVF Axis in Degrees (Frontal Plane) After locating Axis Quadrant, find limb lead where QRS is most isoelectric: Extreme Right Axis Deviation lead Axis I –90 ° -150 AVL –120 ° III –150 ° AVF –180 ° -180 o -90 o -120 o -90 o -60 o o . L. A. D. 0 o 0 o -30 o Left Axis Deviation lead Axis I –90 ° AVR –60 ° II –30 ° AVF 0 ° Normal Range lead Axis AVF 0 ° III +30 ° AVL +60 ° I +90 ° Right Axis Deviation lead Axis AVF +180 ° II +150 ° AVR +120 ° I +90 ° +180 o +150 o A. D. +120 o +90 o +90 o +30 o +60 o R. Axis Rotation (left/right) in the Horizontal Plane Find transitional (isoelectric) QRS in a chest lead. transitional QRS is “isoelectric” Patient’s Right V 1 Rot ation n Rightwards Leftwards Normal Range Patient’s Left V 2 V 3 V 4 V 5 V 6 4/8/2012 12:56 AM Normal Ex.R.A.D


Axis Axis refers to the Mea n Frontal Plane QRS axis (or vector) during ventricular depolarization. As we recall when the ventricles depolarize (in a normal heart) the direction of current flows leftward and downward because most of the ventricular mass is in the left ventricle. We like to know the QRS axis because an abnormal axis can suggest disease such as pulmonary hypertension from a pulmonary embolism. Abnormalities of axis can hint at: Ventricular enlargement Conduction blocks (i.e. hemiblocks ) Determining the Axis: The Quadrant Approach The Equiphasic Approach 4/8/2012 12:56 AM Predominantly Positive Predominantly Negative Equiphasic Leads I and aVF LEFT Axis Deviation LVH LBBB WPW High diaphram, pregnancy WNL – obese, elderly RIGHT Axis Deviation RVH RBBB LV PVCs Pulmonary- emphysema, PE WNL – thin, young Determine which lead contains the most equiphasic QRS complex. The fact that the QRS complex in this lead is equally positive and negative indicates that the net electrical vector (i.e. overall QRS axis) is perpendicular to the axis of this particular lead. Examine the QRS complex in whichever lead lies 90° away from the lead identified in step 1. If the QRS complex in this second lead is predominantly positive, than the axis of this lead is approximately the same as the net QRS axis. If the QRS complex is predominantly negative, than the net QRS axis lies 180° from the axis of this lead.

PowerPoint Presentation:

Hypertrophy Atrial Hypertrophy Right Atrial Hypertrophy • large, diphasic P wave with tall initial component Initia l component Left Atrial Hypertrophy • large, diphasic P wave with wide terminal component terminal component Ventricular Hypertrophy Right Ventricular Hypertrophy C • R wave greater than S in V 1 , but R wave gets progressively smaller from V 1 - V 6 . • S wave persists in V 5 and V 6 . • R.A.D. with slightly widened QRS. • Rightward rotation in the horizontal plane. Left Ventricular Hypertrophy S wave in V 1 (in mm.) + R wave in V 5 (in mm.) Sum in mm. is more than 35 mm. with L.V.H. • L.A.D. with slightly widened QRS. • Leftward rotation in the horizontal plane. Inverted T wave: slants downward gradually, but up rapidly. 4/8/2012 12:56 AM ‘P’ PULMONALE ‘P’ MITRALE


LVH 4/8/2012 12:56 AM Several Criteria for determining LVH Sokolow-Lyon indices — There are two criteria with these widely used indices:1) Sum of S wave in V1 and R wave in V5 or V6 3.5 mV (35 mm)and/or 2) R wave in aVL 1.1 mV (11 mm )


LAD V1,2 deep S and V5,6 tall R >35mm aVL “R” > 12mm Secondary ST depress Most frequently seen with hypertension RAD V1 R + V6 S >10mm V1 rSr’ (incomplete RBBB) Secondary ST depress Usually will be seen with pulmonary pathology HYPERTROPHY LVH RVH 4/8/2012 12:56 AM

PowerPoint Presentation:

Q wave = Necrosis • Significant Q wave is one millimeter (one small square) wide, which is .04 sec. in duration … … or is a Q wave 1/3 the amplitude (or more) of the QRS complex. • Note those leads (omit AVR) where significant Q’s are present … see next page to determine infarct location, and to identify the coronary vessel involved. • Old infarcts: significant Q waves (like infarct damage) remain for a lifetime. To determine if an infarct is acute, see below . Q ST (segment) elevation = (acute ) Injury (also Depression) • Signifies an acute process, ST segment returns to baseline with time. • ST elevation associated with significant Q waves indicates an acute (or recent) infarct. • A tiny “non-Q wave infarction” appears as significant ST segment elevation without associated Q’s. Locate by identifying leads in which ST elevation occurs (next page). elevation • ST depression (persistent) may represent “subendocardial infarction,” which involves a small, shallow area just beneath the endocardium lining the left ventricle. This is also a variety of “non-Q wave infarction.” Locate in the same manner as for infarction location (next page). T wave inversion = Ischemia • Inverted T wave (of ischemia) is symmetrical (left half and right half are mirror images). Normally T wave is upright when QRS is upright, and vice versa. T • Usually in the same leads that demonstrate signs of acute infarction (Q waves and ST elevation). note those leads where T wave inversion occurs, then identify which coronary vessel is narrowed (next page). inversion • Isolated (non-infarction) ischemia may also be located; NOTE: Always obtain patient’s previous ECG’s for comparison! 4/8/2012 12:56 AM Infarction

PowerPoint Presentation:

Infarction Location & Coronary Vessel Involvement Coronary Artery Anatomy Right Coronary Artery Left Coronary Artery circumflex Anterior descending Infarction Location/Coronary Vessel Involvement C Posterior • large R with ST depression in V 1 & V 2 • mirror test or reversed transillumination test (Right Coronary Artery) Lateral Q’s in lateral leads I and AVL (Circumflex Coronary Artery) Inferior (diaphragmatic) Q’s in inferior leads II, III, and AVF ( R. or L. Coronary Artery) Anterior Q’s in V 1 , V 2 , V 3 , and V 4 ( Anterior Descending Coronary Artery) 4/8/2012 12:56 AM Right Ventricular Infarction

Infarct Location:

Infarct Location On ECG the QRS complex represents ventricular contraction. The Q wave is the first downward wave of the QRS complex, and it is followed by an upward R wave, however the Q wave is often absent on ECG . Necrosis (death) of an area of the heart muscle produces a Q wave on ECG . The Q wave makes the diagnosis of infarction . If there are Q waves in lead I and lead AVL, there is a lateral infarction. Inferior ("diaphragmatic") infarction is diagnosed by the presence of Q waves in II, III, and AVF. Q waves in chest leads V1, V2, V3, or V4 signify an anterior infarction. It is common practice to determine the general location of an infarction, but with a little anatomical knowledge of the heart's coronary blood supply*, we can make a far more sophisticated diagnosis. A lateral infarction is caused by an occlusion of the Circumflex branch of the Left Coronary Artery. An anterior infarction is due to an occlusion of the Anterior Descending branch of the Left Coronary Artery. The base of the left ventricle receives its blood supply from branches of either the Right or the Left Coronary Artery, depending on which artery is "dominant .“ “ Septal / Anterior Infarct.“  4/8/2012 12:56 AM

PowerPoint Presentation:

Other Clinically Significant Aspects Pulmonary Embolism • S1Q3T3 – wide S in I, large Q and inverted T in III • Acute Right BBB (transient, often incomplete) • R.A.D. and rightward rotation (horizontal plane ) • Inverted T waves V1 ➞ V4 and ST depression in II Artificial Pacemakers Modern artificial pacemakers have sensing capabilities and also provide a regular pacing stimulus. This electrical stimulus records on ECG as a tiny vertical spike that appears just before the “captured” cardiac response . • are “triggered” (activated) when the patient’s own rhythm ceases or slows markedly. sinus rhythm ceases pacemaker spikes • are “inhibited” (cease pacing) if the patient’s own rhythm resumes at a reasonable rate. PVC stops pacemaker, but… • will “reset” pacing (at same rate) to synchronize with a premature beat. ▼ ▼ ▼ ✕ Pacemaker Impulse ▲ (delivery modes) pacemaker resumes in step with premature beat. ▲ ▲ Ventricular Pacemaker ( electrode in Right Ventricle) (Asynchronous) Epicardial Pacemaker Ventricular impulse not linked to atrial activity. Atrial pacemaker Atrial Synchronous Pacemaker P wave sensed, then after a brief delay, ventricular impulse is delivered. Dual Chamber (AV sequential) Pacemaker External Non-invasive Pacemaker 4/8/2012 12:56 AM

PowerPoint Presentation:

Electrolytes Potassium wide, flat P peaked T no P Increased K + (hyperkalemia ) wide QRS QRS widens moderate ve extreme prominent U wave Decreased K + ( hypokalemia ) flat T moderate U wa extreme ++ Calcium Hyper Ca ++ Hypo Ca short QT prolonged QT Digitalis ECG appearance with digitalis (“digitalis effect”) •Remember Salvador Dali . • T waves depressed or inverted . • QT interval shortened . Digitalis Excess C (blocks) • SA Block • P.A.T. with Block • AV Blocks • AV Dissociation Digitalis Toxicity (irritable foci firing rapidly) • Atrial Fibrillation • Junctional or Ventricular Tachycardia • multiple P.V.C.’s • Ventricular Fibrillation Quinidine Effects Quinidine wide, notched P wide QRS U • ECG appearance with quinidine ST long QT interval • Excess quinidine or other medications that block potassium channels ( or even low serum potassium) may initiate Torsades de Pointes Other Clinically Significant Aspects 4/8/2012 12:56 AM Digitalis causes a gradual down-sloping of the ST segment, to give it the appearance of Salvador Dali's moustache. Type of VT known as “twisting of the points.” Usually seen in those with prolonged QT intervals

PowerPoint Presentation:

Other Clinically Significant Aspects Hypothyroidism- Myxedema May exactly simulate the pattern of acute/old myocardial infarction . Fortunately most of the patients of myxedema are diagnosed clinically, even before the hormonal assay may reveal raised TSH. Low or inverted T waves associated with generalized low voltage of the QRS complexes or prolonged QT interval, Sinus bradycardia . Hyperthyroidism Common manifestations are a) Arrhythmias : Sinus tachycardia, Atrial extrasystoles , PAT, PAFlutter , PAFibrillation , Idionodal tachycardia & Paroxysmal AV nodal tachycardia. Note that ventricular rhythms are not usually associated with hyperthyroidism but may occur when there is associated cardiac decompesation . b) Other : Shortened P-R like WPW, Shortened Q-T, Prominent ‘U’ waves 4/8/2012 12:56 AM


Say “300, 150, 100” …“75, 60, 50” • but for bradycardia: 1. RATE rate = cycles/6 sec. strip ✕ 10 2. RHYTHM Identify the basic rhythm, then scan tracing for prematurity , pauses, irregularity, and abnormal waves . • Check for: P before each QRS. QRS after each P . • Check: PR intervals (for AV Blocks ). QRS interval (for BBB). • If Axis Deviation, rule out Hemiblock . 3. AXIS • QRS above or below baseline for Axis Quadrant (for Normal vs. R. or L. Axis Deviation). For Axis in degrees, find isoelectric QRS in a limb lead of Axis Quadrant using the “Axis in Degrees” chart . • Axis rotation in the horizontal plane: (chest leads) find “transitional” (isoelectric) QRS . 4. HYPERTROPHY Check V 1 { P wave for atrial hypertrophy . R wave for Right Ventricular Hypertrophy . S wave depth in V 1 … + R wave height in V 5 for Left Ventricular Hypertrophy. 5. INFARCTION Scan all leads for : • Q waves • Inverted T waves • ST segment elevation or depression Find the location of the pathology (in the Left ventricle ), and then identify the occluded coronary artery . Summary 4/8/2012 12:56 AM

Important Precautions:

Important Precautions Must be Performed & Interpreted by the treating physician Correct Lead placement and good contact Proper earth connection, avoid other gadgets Deep inspiration record of III,aVF Compare serial ECGs if available Relate the changes to Age, Sex, Clinical history Consider the co-morbidities that may effect ECG Make a xerox copy of the record for future use Interpret systematically to avoid errors 4/8/2012 12:56 AM

Be’ware of Normal ECG:

Be’ware of Normal ECG Normal Resting ECG – cannot exclude disease Ischemia may be covert – supply / demand equation Changes of MI take some time to develop in ECG Mild Ventricular hypertrophy - not detectable in ECG Some of the ECG abnormalities are non specific Single ECG cannot give progress – Need serial ECGs ECG changes may not co-relate with Angio results Paroxysmal event may be missed in single ECG 4/8/2012 12:56 AM

Life Preserving Syndromes:

Life Preserving Syndromes Regardless of our expertise and level of education, we should look for the following - easily identified - electrocardiographic signs of impending (life-threatening!) problems, even in apparently healthy persons. The atria contract, pumping blood into the ventricles just before ventricular contraction. The electrical current ("depolarization") that causes atrial contraction is conducted very slowly to the ventricles to allow time for blood to fill the ventricles. The AV Node, the only electrical connection between the atria and the ventricles, conducts the depolarization impulse (from the contracting atria to the ventricles) very slowly. This provides a brief pause for ventricular filling after atrial contraction. On ECG, the P wave (representing atrial contraction) is normally followed by a short span of level baseline (pause) before the QRS complex (ventricular contraction). 4/8/2012 12:56 AM

Wolff-Parkinson-White Syndrome [WPW]:

Wolff-Parkinson-White Syndrome [WPW] In some people, an anomalous conduction pathway, the "Kent bundle," connects the atria and the ventricles, short-circuiting the AV Node. The anomalous conduction pathway allows rapid conduction to the ventricles without the normal delay. This produces Wolff Parkinson White (WPW) syndrome, which is characterized by conduction of the atrial depolarization current to the ventricles immediately after atrial contraction On the ECG of patients with WPW syndrome, the usual short span of baseline following the P wave is replaced by a curving "delta wave," representing too-early stimulation ("pre-excitation") of a portion of the ventricles. This is easy to detect in most leads as a gentle upward curve that connects the P wave and the QRS complex. Pre-excitation of the ventricles, per se, is not serious, but it may lead to rapid ventricular rhythms that are dangerous, particularly in elderly persons or those with heart conditions. WPW is easily treatable; the Kent bundle can be ablated (destroyed) using a radio frequency intra-cardiac catheter. Therefore, early detection of delta waves on ECG can allow these patients to enjoy a normal life span. 4/8/2012 12:56 AM

Brugada Syndrome:

Brugada Syndrome Brugada syndrome is a recognized cause of sudden death in apparently healthy individuals. It is responsible for about one-half of sudden deaths in young persons without structural heart disease, therefore early detection is critical. This familial condition is due to malfunctioning sodium (Na+) channels in the heart cells. Although the deadly arrhythmias (abnormal rhythms) that victims experience cannot be prevented, they can be successfully treated with an Implantable Cardioverter -Defibrillator (ICD), which corrects the arrhythmia immediately upon its occurrence. But persons with this syndrome must be identified in order to provide this life-saving treatment. In Brugada syndrome , the QRS is widened and has two upward peaks in (chest) leads V1 and V2, and the ST segment is elevated. The ST segment begins at the second peak of the widened QRS then slopes gradually downward. In Brugada syndrome , lead V3 also has a wide QRS and ST elevation that is stereotypical for this condition. All medical personnel who frequently observe cardiac monitors or ECG strips should make a mental note of this ECG pattern . If we keep a mental reference of the ECG morphology of Brugada syndrome in leads V1, V2, and V3, perhaps we can prevent an untimely death, since lead MCL1, which is a variation of leads V1 and V2, is the most common lead used for cardiac monitoring. 4/8/2012 12:56 AM On the standard ECG, there is usually a short segment of level baseline ("ST segment") immediately following the (normally narrow) QRS complex. The ST segment is normally level with the baseline in all ECG leads .

Wellen’s Syndrome:

Wellen’s Syndrome Rarely are we warned of an impending myocardial infarction long before it occurs. However, in patients with Wellens syndrome, stenosis (narrowing) of the Anterior Descending (the most important) branch of the Left Coronary Artery is revealed on ECG in patients with negligible or even absent symptoms. Therefore it is important that all medical personnel be ever-vigilant for the tell-a-tale signs of this important syndrome. On normal ECG's the T wave (which follows the ST segment) is usually upright or somewhat flattened in leads V2 and V3. However, in the ECG of some patients with stenosis of the Anterior Descending coronary artery, the T waves are markedly inverted (upside down) long before symptoms are present. For those patients with Wellens syndrome , this easily detected ECG sign is life-saving only if the person observing the ECG are savvy enough to recognize this important problem. Be that person ! Stenosis of the Anterior Descending coronary artery is very treatable, and it is important that treatment be initiated before the artery is totally occluded causing myocardial infarction... even death. Using a special expandable catheter placed in the stenosed artery, the narrowed area can be dilated by a cardiologist using a procedure known as "angioplasty .“ 4/8/2012 12:56 AM Currently, most angioplasty procedures employ the implantation of a metal mesh tube known a "stent" inside the artery, to keep it open and prevent re-stenosis of this vital artery. Intervention using angioplasty with stenting can indeed be life saving, but our recognition of Wellens syndrome is the critical link.

Long-QT Syndromes:

Long-QT Syndromes There is a group of familial syndromes collectively known as Long QT syndrome . There are at least six different forms of Long QT syndrome thought to be caused by dysfunctional ion channels; they all can produce dangerous or deadly ventricular arrhythmias. Early treatment with proper medications should be instituted as soon as this syndrome is detected, ideally during childhood. There are, however, perhaps many thousands of people with undetected Long QT syndrome who require treatment . Although the heart rate varies somewhat (in response to physiological needs), the QT interval (measured on ECG from the beginning of the QRS to the end of the T wave) always remains less than one-half of the cardiac cycle . With Long QT syndrome the QT interval is longer than one-half the length of the cardiac cycle (usually measured from R wave to R wave). A quick glance at any lead will reveal the lengthened QT interval. Lengthening of the QT interval can be caused by a variety of medications that block ion channels (usually K+ channels). Certain types of cardiac pathology or metabolic conditions can also lengthen the QT, but in general, lengthening of the QT interval, regardless of the etiology , predisposes the patient to Torsades de Pointes , and other dangerous arrhythmias. Don't overlook it! 4/8/2012 12:56 AM


THANKS ! 4/8/2012 12:56 AM

Q-T Interval & QTc:

Q-T Interval & QTc Definition : Time interval between beginning of QRS complex to the end of T wave. measurement of the refractory period or the time during which the myocardium would not respond to a second impulse; measured from the beginning of the QRS complex to the end of the T wave Best leads to measure the QT are V2 or V3 Q-T interval should be roughly less than half the preceding R-R interval Tip: Instead of calculating the QTc , a quick way to estimate if the QT interval long is to use the following rule: A QT > half of the RR interval is probably long. It is longer with slower rates and shorter with faster rates Normally: At normal HR: QT ≤ 11mm (0.44 sec) QT interval varies based on heart rate Abnormalities : Prolonged QT interval: hypocalcemia and congenital long QT syndrome. Short QT interval: hypercalcemia . The duration of the QT interval is proportionate to the heart rate. The faster the heart beats, the faster the ventricles repolarize so the shorter the QT interval. Therefore what is a “normal” QT varies with the heart rate. For each heart rate you need to calculate an adjusted QT interval, called the “corrected QT” ( QTc ): The Q-T interval can be corrected for heart rate using Basset's formula: Normal QTc interval = 0.39 ± 0.04 sec A prolonged QT can be very dangerous. It may predispose an individual to a type of ventricular tachycardia called Torsades de Pointes. Causes include drugs, electrolyte abnormalities, CNS disease, post-MI, and congenital heart disease. 4/8/2012 12:56 AM

Sick Sinus Syndrome :

Sick Sinus Syndrome SSS: The function of sinus node was degenerated. SSS encompasses both disordered SA node automaticity and SA conduction. Causes: CAD, SAN degeneration, myopathy, connective tissue disease, metabolic disease, tumor, trauma and congenital disease. With marked sinus bradycardia, sinus arrest, sinus exit block or junctional escape rhythms Bradycardia-tachycardia syndrome ECG Recognition: Sinus bradycardia, ≤40 bpm; Sinus arrest > 3s Type II SAB Non-sinus tachyarrhythmia ( SVT, AF or Af). SNRT > 1530ms, SNRTc > 525ms Instinct heart rate < 80bmp Therapy: Treat the etiology Treat with drugs: anti-bradycardia agents, the effect of drug therapy is not good. Artificial cardiac pacing.

Sick Sinus Syndrome:

Sick Sinus Syndrome Sinoatrial block (note the pause is twice the P-P interval) Sinus arrest with pause of 4.4 s before generation and conduction of a junctional escape beat Severe sinus bradycardia 4/8/2012 12:56 AM

Bifascicular/ Trifascicular Blocks:

Bifascicular / Trifascicular Blocks RBBB with either left anterior or left posterior fascicular block Diagnostic criteria 1.Prolongation of the QRS duration to 0.12 second or longer 2.RSR’ pattern in lead V1,with the R’ being broad and slurred 3.Wide,slurred S wave in leads I,V5 and V6 4.Left axis or right axis deviation Trifascicular The combination of RBBB, LAFB and long PR interval Implies that conduction is delayed in the third fascicle 4/8/2012 12:56 AM Bifascicular

Cardiac Pacemakers:

Cardiac Pacemakers Indications For Implantation of Permanent Pacing in Acquired AV Blocks 1.Third-degree AV block, Bradycardia with symptoms Asystole e.Neuromuscular diseases with AV block ( Myotonic muscular dystrophy ) 2.Second-degree AV block with symptomatic bradycardia 4/8/2012 12:56 AM

Cardiac Pacemakers:

Cardiac Pacemakers Definition Delivers artificial stimulus to heart Causes depolarization and contraction Uses Bradyarrhythmias Asystole Tachyarrhythmias (overdrive pacing) Types Fixed Fires at constant rate Can discharge on T-wave Very rare Demand Senses patient’s rhythm Fires only if no activity sensed after preset interval (escape interval) Transcutaneous vs Transvenous vs Implanted Demand Pacemaker Types Ventricular Fires ventricles Atrial Fires atria Atria fire ventricles Requires intact AV conduction Demand Pacemaker Types Atrial Synchronous Senses atria Fires ventricles AV Sequential Two electrodes Fires atria/ventricles in sequence Problems Failure to capture No response to pacemaker artifact Bradycardia may result Cause: high “threshold” Management Increase amps on temporary pacemaker Treat as symptomatic bradycardia Failure to sense Spike follows QRS within escape interval May cause R-on-T phenomenon Management Increase sensitivity Attempt to override permanent pacer with temporary Be prepared to manage VF 4/8/2012 12:56 AM

Implanted Defibrillators:

Implanted Defibrillators AICD Automated Implanted Cardio-Defibrillator Uses Tachyarrhythmias Malignant arrhythmias VT VF Programmed at insertion to deliver predetermined therapies with a set order and number of therapies including: pacing overdrive pacing cardioversion with increasing energies defibrillation with increasing energies standby mode Effect of standby mode on Paramedic treatments Potential Complications Fails to deliver therapies as intended worst complication requires Paramedic intervention Delivers therapies when NOT appropriate broken or malfunctioning lead parameters for delivery are not specific enough Continues to deliver shocks parameters for delivery are not specific enough and device senses a reset may be shut off (not standby mode) with donut-magnet 4/8/2012 12:56 AM

ECG Monitoring:

ECG Monitoring Einthoven’s Triangle The positioning for leads I, II, and III were first given by Einthoven. Form the basis of Einthoven’s triangle. Each lead “looks” from a different perspective Can determine the direction of electrical impulses Upright electrical recording indicates electricity flowing towards the + electrode positive deflection 4/8/2012 12:56 AM 1901 - Dr. William Einthoven invented the ECG machine

PowerPoint Presentation:

Unipolar Leads 1 positive electrode 1 negative “reference point” calculated by using summation of 2 negative leads Augmented Limb Leads aVR, aVF, aVL vertical plane Precordial or Chest Leads V1-V6 horizontal plane 4/8/2012 12:56 AM

PowerPoint Presentation:

Bipolar Leads 1 positive and 1 negative electrode RA always negative LL always positive Traditional limb leads are examples of these Lead I Lead II Lead III Provide a view from a vertical plane 4/8/2012 12:56 AM

authorStream Live Help