Instrumental methods of examinationof cardiovascular system

Prof. S.M. Andreychyn

Electrocardiography

• Is a method of graphic

recording of electric currents

generated in the working heart.

Conducting system

Bipolar limb leads

• I bipolar limb leads – right arm (R+) – left leg (Y-).

• II bipolar limb leads – right arm (R+) – left leg (G-).

• III bipolar limb leads – left arm (Y+) – left leg (G-).

• Ground (black electrode on the right leg)

Bipolar limb leads

Ground

Unipolar limb leads

• aVR – the active electrode, is placed successively on the right arm.

• aVL – the active electrode, is placed successively on the left arm.

• aVF - the active electrode, is placed successively on the left leg.

Unipolar limb leads

Bipolar and Unipolar limb leads

Chest leads

• V1 – right sternal border, the 4th intercostal space.

• V2 – left sternal border, the 4th interspace.

• V3 – left parasternal line, between the 4th and 5th interspace.

• V4 – left midclavicular line, the 5th interspace.

• V5 – left anterior axillary line, the 5th interspace.

• V6 – left midaxillary line, the 5th interspace.

Chest leads

Normal ECG

Normal ECG

The scheme of ECG interpretation

• 1. Is heart rrhythm sinus or ectopic, regular or irregular.

• 2. Heart rate = 60/R-R (when paper speed is 50 mm/sec R-R=N×0,02).

• 3. Amplitude of ECG voltage (amplitude of R in standard leads ≥5 mm or their summation in I,II and III leads ≥15 mm.

• 4. Electrical axis deviation.

• 5. Assessment of all components of ECG.

Normal ECG

Interval P-Q Segment S-TSegment P-Q

Interval Q-T

Interval R-R

ECG interpretation

ECG interpretation

Determination of inner deviation of atriums and ventricles

ECG in standard limb leads

ECG unipolar limb leads

Chest leads in norm

Causes of electrical axis deviation

• causes of right axis deviation• normal finding in children and tall thin adults • right ventricular hypertrophy • chronic lung disease even without pulmonary hypertension • anterolateral myocardial infarction • left posterior hemiblock • pulmonary embolus • Wolff-Parkinson-White syndrome - left sided accessory pathway • atrial septal defect • ventricular septal defect • causes of left axis deviation• left anterior hemiblock • Q waves of inferior myocardial infarction • artificial cardiac pacing • emphysema • hyperkalaemia • Wolff-Parkinson-White syndrome - right sided accessory pathway • tricuspid atresia • ostium primum ASD • injection of contrast into left coronary artery

Electrical axis

Hypertrophies of heart chambers

• Right atrial hypertrophy:

• - high acute P in III, AVF, V1

• Left atrial hypertrophy:

• - broad biphasic P in I, AVL, V5-V6

• Right ventricular hypertrophy:

• - high R in III, AVF, V1

• Discordant displacement of ST segment opposite to the lagest wave in QRS complex

• Left ventricular hypertrophy:

• - high R in I, AVL, V5-V6

• Discordant displacement of ST segment opposite to the lagest wave in QRS complex

• Broad QRS (more than 0,1 sec)

Right atrial hypertrophy

Left atrial hypertrophy

Hyperthrophy of the left ventricle

Hyperthrophy of the right ventricle

Hyperthrophy of the right ventricle

Disorders of heart rrhythm:• I. Disorders of excitation (arrhythmias):• 1. Sinus arrhythmia

• sinus tachycardia,• sinus bradycardia• sinus arrhythmia

• 2. Ectopic arrhythmias:• extrasystole (sinus, atrial, atrioventricular, ventricular)• Paroxismal tachycardia (atrial, ventricular).

• II. Disorders of heart conduction: • sinus, atrial,atrioventricular and ventricular blocks,• III. Combined disorders of excitation and conduction:• flutter (atrial and ventricular)• fibrillation (atrial and ventricular)

SINUS ARRHYTHMIA

• Sinus arrhythmia is a cyclic increase in normal heart rate with inspiration and decrease with expiration. It results from reflex changes in vagal influence on the normal pacemaker and disappears with breath-holding or increase of heart rate due to any cause. The arrhythmia has no significance except in older persons, when it may be associated with coronary artery disease.

SINUS ARRHYTHMIA

SINUS TACHYCARDIA

• Sinus tachycardia is a heart rate faster than

90 beats/min that is caused by rapid impulse formation by the normal pacemaker secondary to fever, exercise, emotion, anemia, shock, thyrotoxicosis, or drug effect. The rate may reach 180/min in young persons but rarely exceeds 160/min.

• In quick heart rate the patient feels palpitation.

SINUS BRADYCARDIA• Sinus bradycardia is a heart rate slower than 60/min due to

increased vagal influence on the normal pacemaker. The rate increases after exercise or administration of atropine. Slight degrees have no significance, especially in youth, unless there is underlying heart disease, especially coronary heart disease or acute myocardial infarction.

• Elderly patients may develop weakness, confusion, or even syncope with slow heart rates. Arrhythmia disappears to use ephedrine or atropine in some patients to speed the heart rate. Rarely, artificial pacemakers are necсessary.

• а-normal sinus rrhythm • б- sinus tachycardia• в- sinus bradycardia• г- sinus arrhythmia

• The most common mechanisms of ectopic arrhythmia are:• 1) reentry mechanism. The depolarization wave front proceeds

antegradely through the fiber whose conduction is slowed and returns retrogradely in a nearly fiber that had unidirectional antegrade block.When this returning echo reaches the site of its origin, it may then reexcite the fiber, which is now no longer refractory.

• Alternative mechanisms are:• 2) abnormal automaticity,• 3) triggered activity (more rarely).• Repetitive reentry may result paroxysmal tachycardia, if the atrial

premature beat is appropriately timed. Similarly, a single atrial premature beat may terminate atrial tachycardia by making the reentry pathway refractory. Recent evidence indicates that about one-third of patients have aberrant pathways to the ventricles.

Ectopic arrhythmias

• I. Extrasystole

• - atrial

• - atrioventricular

• - ventricular.

• II. Paroxismal tachycardia

• - atrial

• - ventricular.

ATRIAL PREMATURE BEATS(Atrial Extrasystoles)

• Atrial premature beats occur when an ectopic focus in the atria fires off before the next expected impulse from the sinus node. Ventricular systole occurs prematurely, and the compensatory pause following this is only slightly longer than the normal interval between beats. P wave is byphasic.

• ECG signs: 1) premature appearance of cardiac complex of ECG,

• 2) non-complete compensatory pause,

• 3) P wave is biphasic or negative,

• 4) P is always recorded before QRS.

Atrial extrasystole

Atrial extrasystoly

Atrial bigeminy

ATRIO-VENTRICULAR PREMATURE BEATS(AV extrasystoles)

• ECG signs:

• 1) premature appearance of cardiac

complex on ECG,

• 2) non-complete compensatory pause,

• 3) Depending on the location of focus

of excitation P wave occurs before

or after QRS complex or can be

superimposed on the last one.

Ventricular Extrasystoles

• Main features:• premature appearance of heart complex;• P wave is abcent;• QRS complex is disfigured depending on the location of pathological focus (right or

left His bundlebranch) and broadened;• Discordant displacement of ST segment opposite to the largest wave in the QRS

complex;• complete compensatory pause.

• а- extrasystole from the left ventricle

• б- extrasystole from the right ventricle

Ventricular extrasystole

Ventricular bigeminy and quadrigeminy

Dangerous extrasystoles by Lawn

Paroxismal tachycardia

• This is a sudden acceleration of the cardiac rhythm• ECG signs:• 1) Acceleration of heart rate more than 150 per min;• 2) The same shape of all cardiac complexes;• 3) Sudden start and stop;• 4) Equal R-R intervals.

PAROXYSMAL ATRIAL TACHYCARDIA

• It occurs more often in young patients with normal hearts. Attacks begin and end abruptly and usually last several hours. The heart rate may be 140-240/min(usually 170-220/min) and is perfectly regular, therate will not vary more than 1-2 beats per minute.Exercise, change of position, breath-holding, carotid sinus massage, or induced gagging or vomiting either has no effect or promptly abolishes the attack. Patient sare asymptomatic except for awareness of rapid heart action unless there is underlying heart disease, especially mitral stenosis and coronary heart disease. Inprolonged attacks with rapid rates, dyspnea or tight-ness in the chest may be felt as palpitation, discomfort in heart region, dizziness.

• а- atrial paroxismal tachycardia• б- atrioventricular (nodal) tachycardia with premature excitation of

ventricles• в- atrioventricular (nodal) tachycardia with simultaneous excitation

of ventricles and atriums

Atrial PT

Ventricular paroxismal tachycardia

• Ventricular PT

ATRIAL FIBRILLATION

• Atrial fibrillation is the commonest chronic arrhythmia. It occurs most frequently in rheumatic heart disease, especially mitral stenosis, and arteriosclerotic heart disease. It is the only common arrhythmia in which the ventricular rate is rapid and the rhythm irregular. An ectopic atrial pacemaker fires 400-600 times per minute.

Atrial fibrillation

ATRIAL FLUTTER

• Atrial flutter is uncommon and usually occurs inpatients with rheumatic or coronary heart disease, cor pulmonale, or atrial septal defect or as a result of quinidine effect on atrial fibrillation. Ectopic impulse formation occurs at rates of 250-350, with transmission of every second, third, or fourth impulse through the atrioventricular node to the ventricles. The ventricular rate is usually one-half the atrial rate (2:1conduction), or 150/min. Carotid sinus massage causes sudden slowing or standstill, with rapid return of the rate to the original level on release of pressure.When the ventricular rate is 75 (4:1 block), exercise may cause sudden doubling of the rate to 150 (2:1block). The first heart sound varies slightly in intensity from beat to beat (but not when the patient is in aconstant 2:1 flutter).

Atrial flutter

Ventricular flutter and fibrillation

Ventricular fibrillation

• а- ventricular flutter

• б- ventricular fibrillation

Disorders of heart conduction:

• Atrial block

• Atrioventricular block:• I degree

• II degree (Mobitz I, II and III)

• III degree

Hiss bundlebranch block (right, left).

Atrial block

• ECG signs: broad P wave

Intraatrial block

AV block

• I degree: Prolongation of PQ• II degree: Prolongation of PQ and periodical missing of QRS,• - Mobitz I: Venkebach’s periods (gradual PQ

prolongation) • - Mobitz II: PQ il longer but equal in all complexes,

periodical missing of QRS• Mobitz III: long PQ, many missed QRS (more P waves on

ECG than QRS complexes but P is recorded before QRS)• III degree or complete AV block: more P waves on ECG than

QRS complexes and P is recorded independently of QRS

AV block I degree

• Permanent prologation of PQ more than 0,20с• а- atrial form• б- nodal form• в- distal (trifascicular) form

I degree AV block

II degree AV block

III degree AV block

Left bundle branch block (LBBB)

Left HBBB

Right HBBB

LBBB

Right bundle branch block (RBBB)

Holter ECG monitoring

Heart sonohraphy (B-mode)

B- and M-mode ultrasound of a heart

X-ray of a heart. Aortic heart configuration

Mitral heart configuration