Paediatric Cardiology for General Paediatricians presentationPresentation Transcript
Paediatric Cardiology for General Paediatricians Dr Talal Farha Consultant Paediatrician SpR Regional Teaching Taunton 22 Jan 2008
Essentials in looking at an ECG Rhythm (sinus….nonsinus) Rate, Atrial and ventricular rates. QRS axis, T axis, QRS-T angle Intervals: PR. QRS, and QT P wave amplitude and duration QRS amplitude and R/S ratio Q wave St- Segment and T wave abnormalities
How do you determine Sinus rhythm?
What is T axis?
What is QRS/T angle?
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
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
Left ventricular hypertrophy
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.
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.
Top Tip For ECG
Read more ECGs
Do not forget, nothing replaces good traditional clinical examination and detailed history
How often related to the heart?
What are the related cardiac conditions?
How do we approach it?
Syncope is a transient loss of consciousness and muscle tone.
premonitory signs and symptoms of imminent syncope occur; dizziness with or without blackout, pallor, diaphoresis, thready pulse and low BP
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
Failure of systemic venous return
Cerebrovascular occlusive disease
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
Hot and humid conditions
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
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
ECG, Holter, EEG, glucose tolerance test all are normally negative in V V E
Supine +/- feet up
2- Orthostatic Hypotension
What happen when we stand up?
Absent or inadequate upright position response, Hypotension without increased HR
BP and HR supine and standing up.
BP drop after 5-10 minutes up still by 10-15 mmHG
Positive tilt test without autonomic signs
High salt diet
Slow upright position
Rare form of orthostatic
Rapid bladder decompression associated with degreased total peripheral vascular resistance.
3- Failure of systemic venous return
Increased intrathoracic pressure
Decreased venous tone (drugs; nitroglycerin)
Decreased volume (bleed…)
4- Cerebrovascular occlusive disease
Cardiac causes of Syncope
Structural heart disease
Why Cardiac ?
Syncope at rest
Provoked by exercise
FH of sudden death
AS, PS, HOCM, PHTX
Precipitated by exercise, no increase in cardiac output to accommodate increased demand.
Examination, CXR, ECG, Echo
Ischemia, infarction secondary to CHD, Kawasaki’s..
Arrhythmia Arrhythmia Lack of output (Fast or slow heart) SVT, VT, SSS, CHB, Normal heart structure Long QT, WPW Abnormal Heart Structure Ebstein's, MS, MR, CCTGA Post op, TOF, TGA MVP VT Cmpthy SVT, VT, s brady
Syncope, seizures, palpitation during exercise or with emotion
Ventricular arrhythmias (Tachy) with risk of sudden death
Long QT Defective ion channels Congenital Over 50 mutations in 4 sites Jarvell-lange-nielson Deafness AR Romano-ward no deafness AD Sporadic no FH no Deafness Acquired Drugs, illnesses, Autoimmune Neurological Nutritional Electrolytes