19 P waveRepresent the electrical activity of both atria ( atrial depolarization)The depolarization slow within the AV node, there is a brief delay or PAUSE before the depolarization conducted to the ventricles
20 Normal duration <0.12 sec Absent P wave: Atrial fibrillation SA Block AV Rhythm Peak P wave: Atrial hypertrophy
21 PR interval Normally :0.12-0.2sec Prolonged in : heart block. Short in : W-P-W syndrome.
22 QRS Complex Represent the electrical activity of both ventricles. Ventricular depolarization( initiation of the ventricular contraction
23 QRS Complex Q wave R wave: S wave : : Normal QRS duration < 0.12 sec
29 ST - SegmentST segment: the plateau phase of ventricular repolarization.Isoelectric or> or<1mm.If the ST segment elevated or depressed beyond the normal baseline this usually sign of serious pathology. (MI)
30 T- Wave T-wave :represent rapid phase of ventricular repolarization. peaked T wave:early MIhyperkalemiaBlack racesInverted :MI .Ventricular hypertrophy.HypokalemiaDigoxin
31 Q-T interval 0.4 sec in HR 70 Prolonged in : Hypocalcemia hypomagnesemia
32 U wave repolarization of the interventricular septum. low amplitude Prominent: suspect hypokalemia, hypercalcemia or hyperthyroidism
33 J waverepresents the approximate end of depolarization and the beginning of repolarizationcamel-hump sign .Hypothermiahypocalcemia.
34 Low voltage ECGObesityEmphysemaCOPDSevere hypothyroidism
35 Rate Normal heart rate 60-100/ min < 60 called bradycardia >100 called tachycardia
43 AXISAt any point during depolarization and repolarization electrical potential are being propagated in different directions. Most of these cancel each other out and only the net force is recorded. This net is called AXIS or cardiac VECTOR
49 Principles of ECG recording Explain the indication and the procedure for the patient. (assurance )Ask the patient to take off any metals he/she wears.Expose the wanted sites.Cleaning of skin and shaving if necessary.Place the electrodes in the correct positions .Instruct the patient to remain still (should not talk during the test ) and relax their shoulders and legs while the recording takes place (1 min)
51 How to comment on ECG Name.Age ,Date and time. Calibration and Speed of paperRAWIHI :
52 RAWIHI R: rate, regularity,rhythm(sinus or asinus), A: axis. W:waves. I :intervals.H: hypertrophy.I: ischemia
53 Normal Sinus Rhythm Rate = 60-100 beat / minute. The rhythm is regular All intervals are within normal limitsThere is a P for every QRS and a QRS for every P.P : QRS ratio = 1 : 1.The P waves all look the samePresence of P, QRS, T in each cycle.Normal shape, time of waves, segments and intervals
54 Interfering factors Inaccurate placement of the electrodes Electrolyte imbalancesPoor contact between the skin and the electrodesMovement or muscle twitching during the testDrugs that can affect results include digitalis, quinidine, and barbiturates
55 MI Ischemia ( subendocardial or transmural) Injury When myocardial blood supply is abruptly reduced toa region of the heart, a sequence of injurious eventsoccur :Ischemia ( subendocardial or transmural)InjuryNecrosis, and eventual fibrosis (scarring) if the blood supply isn't restored in an appropriate period of time
61 Lateral Precordial Leads I,AVL,V5 – V6lateral of the left ventricleThe left circumflex
62 Inferior border leads II, III and aVF the Inferior wall of the RV Posterior Descending Branch of the RCA.
63 Posterior MI No leads look at the posterior wall. usually associated with inferior and/or lateral wall MI.The changes of posterior myocardial infarction are seen indirectly in the anterior precordial leads. Leads V1 to V3 face the endocardial surface of the posterior wall of the left ventricle. As these leads record from the opposite side of the heart instead of directly over the infarct, the changes of posterior infarction are reversed in these leads. The R waves increase in size, becoming broader and dominant, and are associated with ST depression and upright T waves. This contrasts with the Q waves, ST segment elevation, and T wave inversion seen in acute anterior myocardial infarction.ST depression is considered reciprocal ECG changes in what should be ST elevation for acute posterior wall injury.
64 ECG Leads - Views of the Heart Arterial supplyborderleadRCAanterior Right VentricleV3 & V4LADSeptumV1 & V2LCXLateral Left Ventriclea VL,V5 & V6inferior borderof right ventricleII+III+AVF