Paediatric Cardiology for General Paediatricians Dr Varsha Atul Shah
Essentials in looking at an ECGRhythm (sinus….nonsinus)Rate, Atrial and ventricular rates.QRS axis, T axis, QRS-T angleIntervals: PR. QRS, and QTP wave amplitude and durationQRS amplitude and R/S ratioQ waveSt- Segment and T wave abnormalities
ECG tips How do you determine Sinus rhythm? What is T axis? What is QRS/T angle?
Rhythm P before every QRS P axis (0-90). P inverted in aVR
P wave axis The location of the P-wave axis determines the origin of an atrial-derived rhythm: • 0 to 90 degrees = a high right (normal sinus rhythm) • 90 to 180 degrees = a high left • 180 to 270 degrees = a low left • 270 to 0 degrees = a low right
T wave In most leads, the T wave is positive. A negative T wave is normal in lead aVR. Lead V1 may have a positive, negative, or biphasic T wave. In addition It is not uncommon to have an isolated negative T wave in lead III, aVL, or aVF.
Inverted (or negative) T waves can be a sign of Coronary ischemia Left ventricular hypertrophy
T axis Determined by the same methods as QRS 0 to + 90 is normal T Axis out side the normal quadrant could suggest conditions with Myocardial dysfunction.
QRS-T Angle Formed by the QRS axis and the T axis QRS-T angle >60 degrees is unusual but if > 90 degrees, it is abnormal. Abnormally wide angle, with T axis outside the normal quadrant is seen in - severe ventricular hypertrophy with starin - Ventricular conduction disturbances - Myocardial dysfunction of a metabolic or ischemic nature.
Do not forget, nothing replaces good traditional clinical examination and detailed history teaching 1.asx
Syncope How often related to the heart? What are the related cardiac conditions? How do we approach it?
Definition Syncope is a transient loss of consciousness and muscle tone. Near syncope: premonitory signs and symptoms of imminent syncope occur; dizziness with or without blackout, pallor, diaphoresis, thready pulse and low BP
Cause Brain function depends on Oxygen and glucose. Circulatory, metabolic, or neuropsychiatric causes. Adults syncope mostly cardiac. Children’s mostly benign.
Causes of Syncope in Children Extra cardiac causes Vasovagal Orthostatic Failure of systemic venous return Cerebrovascular occlusive disease Hyperventilation Breath holding
1- Vasovagal Syncope Neurocardiogenic Common Syncope Predrome for few seconds; dizziness, light-headedness, pallor, palpitation, nausea, hyperventilation then Loss of consciousness and muscle tone Falls without injury Lasts about a minute, awake gradually
Vasovagal Syncope Anxiety Fright Pain Blood Fasting Hot and humid conditions Crowded places Prolonged motionless standing
Vasovagal Syncope Pathophysiology Standing posture without movement shifts blood to the lower extremities Decrease venous return, stroke volume, BP Less stretching of vent muscle and mechanoreceptors (mrcpts), decline in neural traffic form mrcpts, decreased arterial pressure, increase sympathetic output with Higher HR, vasoconstriction (higher diastolic pressure)
Vasovagal Syncope Patients Decreased venous return produces large increase in ventricular contraction force Activation of LV mechanoreceptors (normally only responds to stretch) Increase neural traffic mimicking high BP condition
Paradoxical withdrawal of sympathetic activity, vasodilatation, hypotension and bradycardia Reduction of brain perfusion
Diagnoses ECG, Holter, EEG, glucose tolerance test all are normally negative in V V E Tilt test
Cardiac causes of Syncope Structural heart disease Arrhythmia
Why Cardiac ? Syncope at rest Provoked by exercise Chest pain Heart disease FH of sudden death
What Cardiac Obstructive lesions Myocardial dysfunction Arrhythmias
Obstructive lesions AS, PS, HOCM, PHTX Precipitated by exercise, no increase in cardiac output to accommodate increased demand. Examination, CXR, ECG, Echo
Myocardial Dysfunction Ischemia, infarction secondary to CHD, Kawasaki’s.. Myocarditis
Arrhythmia Arrhythmia Lack of output (Fast or slow heart) SVT, VT, SSS, CHB, Abnormal Heart Structure Normal Ebsteins, MS, MR, heart structure CCTGALong QT, WPW Post op, TOF, TGA MVP VT Cmpthy SVT, VT, s brady
Long QT Syncope, seizures, palpitation during exercise or with emotion ECG Ventricular arrhythmias (Tachy) with risk of sudden death
Long QT Defective ion channels CongenitalOver 50 mutations in Acquired 4 sites Drugs, illnesses,Jarvell-lange-nielson Autoimmune Deafness AR Neurological Romano-ward Nutritional no deafness AD Electrolytes Sporadic no FH no Deafness
clinically FH 60% Deafness 5% Presentation with Syncope 26%, seizure 10%, cardiac arrest 9%, presyncope palpitation 6% Symptoms during exercise or emotion Normally symptoms related to ventricular arrhythmias, mostly end of second decade of life.
Syncope in adrenergic arousal, exercise (swimming is a particular trigger) Abrupt noises (Alarm, doorbell, phone..)
Tests ECG with QTc >0.46 seconds Frequently finding abnormal T wave Bradycardia (20%) Exercise test, maximum prolongation after 2 minutes of recovery, ventricular arrhythmia in 30% during exercise Holter monitoring may show longer QTc
Diagnoses Criteria Electrophysiological society - QTc >0.44 with no other causes (0.46 sec) - Positive family history plus unexplained syncope, seizure or cardiac arrest proceeded by trigger such as exercise, emotion
Treatment Discuss with cardiologist Avoid drugs associated with long QT Avoid swimming, competitive sports Beta blockers Demand cardiac pacing (Pacemaker and defib) Left cardiac sympathetic denervation
Prognoses Untreated 75-80% mortality Beta blockers reduce mortality to some extent The adjusted annual mortality rate on treatment is 4.5% (10 year mortality of 50%)
Advise related to CHD If one child has CHD, what are the chances of the second? One parent has CHD, can offspring be affected? What are the chances? See Handouts, statistical list of potential risks