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E C G to continue…. Interval changes assessment. PR (PQ) interval. Normally .12 s - .20 s (that is 3 – 5 mm of horizontal distance) Shorter (e.g.) in preexcitation syndromes Longer (e.g.) in AV block of first degree Dependent of the frequency For 60 beats / s is around 0.45 s.
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PR (PQ) interval • Normally .12 s - .20 s • (that is 3 – 5 mm of horizontal distance) • Shorter (e.g.) in preexcitation syndromes • Longer (e.g.) in AV block of first degree • Dependent of the frequency • For 60 beats / s is around 0.45 s QT interval
Preexcitation syndromes Accessory signal pathway Orientation of QRS complex vector depends on the direction of propagation of the signal Sy Wolff-Parkinson-White has “delta” wave Sy Lown-Ganong-Levin (without “delta” wave) Risk of supraventricular paroxysmal tachycardia
Reentry tachyarrythmias Reentry in Wolff-Parkinson-White’s Syndrome Accessorypathway Ectopic atrial extrasystole tachycardia wave Short PR
AV block 1-st degree: Long PR inteval 2-nd degree type one type two 3-rd degree: No connection between atria and ventriculi
AV block of 2-nd degree Wenkebach’s periods (Mobitz II)
Short PR interval preexcitation sy, sympathetic act., hypoK, AV nodal rhythms from the beginning of it Long PRinterval AV block1-stdegree parasympathetic act., hyperK, IHD, medicaments(e.g. beta blockers) Short QT intervalDigitalis, hyperCa (hyperK – tallpointing T wave) Long QT hypertension, after MI hypoCa, (hypoK– U wave), Congenital (risk of sudden death) Other causes of interval changes
Sokolow’s index: R in (V5 or V6) + S inV1 > 35mm Attention young slim individuals (heart as a voltage source is closer to the chest leads – bigger voltage on the leads without hypertrophy) QRS – left ventricular overload Left heart hypertrophy physiological
QRS – right ventricular overload Vertical electrical axis (> 100°) in V1: R >= 7mm or qR (volume overload) in avR: r > 4 mm in V6: R smaller/equal S(volume overload) Physiological Pressure overload Physiological Volume overload
QRS - right BBB • Causes: Dilatation and/or overload of right heart, MI, sometimes“physiological” • QRS > 0,11 s • If complete, then R’(r’) wave is bigger then R(r ) in V1 • Repolarization changes
QRS – left BBB • Causes: IHD, hypertension, cardiomyopathy, valvular disease, unknown • QRS >0,11s (with complete block) • Discordant T! and discordant dinivelization of ST
QRS – Q wave myocardial infarction • In the Q-wave MI, there is necrosis throughout the cardiac wall, while in the non-Q wave, necrosis affects the endocardial zone only. • Pathological Q-wave Appears in the first 0,04 s of QRS Appears in the leads where there should be no Q or overlays the normal R (r) (e.g. in V1 to V5) – absence of the R-wave Deeper then 2mm (6mm in III) Q > 0,25 R for I, II, avL, (avF) Q > 0,15 R forV1 to V6
QRS – Q wave MI • There is no Q-wave in the beginning, but so-called “Pardee’s”wave (elevation of ST+ negative T) • We imagine the (left) heart as pyramid to describe the MI location. • Anterior • Septal (right) • Lateral (left) • Inferior (down side at the apex)and it’s posterior extension (close to the base of the pyramid)