familial hypercholesterolemia

- type IIA hyperlipidemia
- autosomal codominant disorder characterised by elevated plasma levels of LDL-C with normal triglyceride, tendon xanthomas and premature coronary atherosclerosis
- homozygous FH occurs in approximately 1 in 1 million persons worldwide, whereas heterozygous FH occurs in 1 in 500 persons
- most homozygous FH present in childhood with cutaneous xanthomas on hand, wrist, elbows, knees, heels, or buttocks. Total cholesterol levels are usually >500mg/dL and devastating complication of homozygous FH is accelerated atherosclerosis
- treatment for FH is LDL apheresis (homozygous) and statin in combination with cholesterol absorption inhibitor
- family history is usually positive for premature atherosclerotic cardiovascular disease

Dextrocardia

ECG findings of dextrocardia
- right axis deviation
- positive QRS complex in aVR
- lead I : global negativity (inversion of all complexes)
- absent R wave progression in chest leads (dominant S wave throughout)

Atrial fibrillation

- Should look for AF in patient who presents with dyspnea, palpitation, syncope/dizziness, chest discomfort, stroke/TIA
- In patient with permanent AF who need treatment for rate control, beta blocker or rate-limiting CCB should be preffer initial monotherapy, digoxin is considered in predominantly sedentary patient
- In patient with persistent AF considered for pharmacological cardioversion, Class Ic drug (flecainide or propafenone) should be drug of choice in the absence of structural heart disease and amiodarone in the presence of structural heart disease
- rate control strategy should be the preferred initial option in persistent AF patient with
  ~ age over 65
  ~ coronary heart disease
  ~ with contraindication to antiarrhythmic drug
  ~ unsuitable for cardioversion
  ~ without congestive heart failure
- rhythm control strategy should be the preferred initial option in persistent AF patient with
  ~ younger patient
  ~ symptomatic
  ~ presenting for first time with lone AF
  ~ those with AF secondary to a treated/corrected precipitant
  ~ with congestive heart failure
- patient should be maintained on therapeutic anticoagulation with warfarin to keep INR between 2.0-3.0 for minimum of 3 weeks before cardioversion and 4 weeks after cardioversion





Reference: NICE clinical guideline 36 Atrial fibrillation

Carotid sinus hypersensitivity (CSH)

- exaggerated response to carotid sinus stimulation
- diagnosis is made after ischemic heart disease and rhythm disturbance is excluded
- CSH may be predominantly cardioinhibitory (resulting in bradycardia), vasodepressor (resulting in hypotension) or mixture of both
- presents with recurrent dizziness, near syncope, syncope, unexplained falls (drop attacks), symptoms produced when wearing tight-fitting collar clothes or when taking carotid pulse
- cardioinhibitory CSH is managed with insertion of dual-chamber pacemaker and vasodilatory CSH is managed with support stocking, fludrocortisone and midodrine (alpha-1 agonist)

Peripartum cardiomyopathy

- develops during the last trimester or within first 6 months after pregnancy
- between 1:3000 and 1:15,000 deliveries
- risk factors are increased maternal age, increased parity, twin pregnancy, malnutrition, tocolytics, and pre-eclampsia
- cause is unknown
- management is supportive with sodium restriction, digoxin, diuretics and vasodilators (eg:hydralazine)
- increased incidence of thrombosis and common to anticoagulate patient with heparin
- risk of recurrence in future pregnancy is 40%
- prognosis is reasonable with recovery of ventricular function in up to 50% patients

Wellens syndrome

- a.k.a LAD coronary T wave syndrome
- criteria: characteristic T wave changes (deep inversion of T wave segment in precordial leads, generally leads V1 to V4) , history of anginal chest pain, normal or minimally elevated cardiac enzymes level, ECG without Q wave, without significant ST elevation, normal precordial R wave progression
- this syndrome represent preinfarction stage of coronary artery disease that often progress to devastating anterior wall infarction
- the characteristic pattern classically presents only during chest pain free period and is important to notice since it is a sign if LAD disease

VT versus SVT

Features that favour VT are
- QRS > 140 ms
- cannon a waves on JVP (suggest AV dissociation)
- fusion and/or capture beats
- concordance of QRS complexes in chest leads
- dissociated p waves
- history of ischemic heart disease
- RBBB with left axis deviation
- HR >170bpm

2 algorithms are proposed for prediction of VT versus SVT

i) Brugada
- absence of RS complexes in precordial leads
- RS duration of more than 100ms in any precordial leads
- ventriculoatrial dissociation in any of 12 leads
- certain QRS morphologies, such as QR or QS in V6

ii) Vereckei
- presence of an initial R wave in aVR
- width of an inital r or q wave > 40ms in aVR
- notching on the initial downstroke of a predominantly negative QRS complexes in aVR
- ventricular activation-velocity ratio (Vi/Vt) less than or equal to 1

Carotid artery stenosis

- carotid artery disease accounts for 20% of stroke and TIAs

- 7.5% risk of stroke and death within 30days of endarterectomy

- there is no benefit to treat completely occluded vessel

Management

- Symptomatic patient < 50% stenosis : optimal medical therapy without revascularisation

- Asymptomatic patient < 60% stenosis : optimal medical therapy without revascularisation

- Symptomatic patient >= 50% stenosis : carotid endarterectomy with optimal medical therapy

- Asymptomatic patient >= 60% stenosis with low operative risk : carotid endarterectomy with optimal medical therapy

- Symptomatic patient >=50% stenosis with high operative risk : carotid stenting

- carotid artery stenting is inappropriate for asymptomatic patient with carotid artery stenosis. Possible exception may include patients with acceptable medical risk who present with severe carotid artery stenosis (>= 80%) with high anatomic risk for carotid endarterectomy but with compelling anatomy for stenting

Source: Clinical practice guideline for society of vascular surgery (J Vasc Surg 2008;48:480-6)

   

Pacemaker syndrome

- due to AV dyssynchrony
- presents with symptoms of reduced cardiac output (dizziness, syncope, dyspnea, fatigue, weakness, palpitation)
- classically occurs in conjuction with single chamber ventricular pacing
- signs: elevated JVP, cannon A wave, pulmonary edema
- ECG: retrograde P wave
- for ventricularly paced patients, addition of an atrial lead and institution of AV synchronous pacing usually resolves symptoms

Atrial septal defect

- accounts for 10-15% of all congenital cardiac anomalies
- more common in women than men (2:1)
- 2 types: ostium secundum (75%) and ostium primum
- complications rarely occur in childhood, but prolonged shunting leads to pulmonary hypertension, atrial fibrillation, Eisenmenger syndrome, but not risk of endocarditis
- sign: pulmonary flow murmur, splitting of second heart sound
- ECG: RBBB & RAD (secundum) ; RBBB & LAD (primum)
- association: Holt Oram syndrome (ASD with triphalangeal thumb and radial abnormalities); Lutembacher syndrome (ASD and MS)
- treatment: ASD closure before age of 10 years old
- Uncorrected, 70% develop symptoms by age of 40

Atrial myxoma

- most common primary cardiac tumor
- most cases are sporadic. 10% are familial (autosomal dominant)
- majority are solitary, usually develop in left atrium (75-85%) and are polypoid, gelatinous structures attached by a pedicle to atrial septum
- may obstruct mitral valve and can send showers of emboli
- constitutional symptoms in a third of cases
- signs: loud first heart sound, tumor 'plop' (loud third heart sound produced as pedunculated tumor comes to an abrupt halt), mid diastolic murmur and signs due to embolism
- raised ESR
- rarely, associated with adrenal hyperplasia, Leydig cell tumor and Carney complex

Marfan's syndrome

- autosomal dominant
- mutation in fibrillin gene (FBN-1) on chromosome 15 (15 alphabates in Marfan's syndrome)
- abnormal fibrillin-1 interfere with normal microfibril formation, results in defects in ligament of lens, as well as abnormalities in structural integrity of aortic wall, lens zonules, ligaments, lung airways and spinal dura
- clinical features: tall stature, ectopia lentis, MVP, aortic root dilatation, aortic dissection, scoliosis, high arched palate, pectus excavatum, upward and temporal lens dislocation (downward in homocystinuria)
- treatment: beta-blocker (slow rate of dilatation of aortic root), lifestyle alteration, yearly echocardiogram

Echocardiography

M-mode
- details changing motion of structures along the ultrasound beam with time
- assess LV wall and cavity dimensions, pericardial thickness


2-dimensional echo
- assessment of ventricular volumes and ejection fraction; delineation of specific anatomy of cardiac structures including valves


Pulse doppler echocardiography
- assess diastolic function and dysfunction by assessing transmitral flow velocities, differentiate between constrictive and restrictive cardiomyopathy

Continuous wave doppler
- assess transvalvular pressure gradients, to estimate severity of stenotic lesions (which causes increased velocities)

Color doppler
- assess severity of valvular regurgitations

Brugada syndrome

- first described in 1992
- more common in young male adults in South East Asia
- autosomal dominant
- approximately 20% of cases, the underlying cause is genetic defect in SCN5A gene, which encodes sodium channel controlling the depolarisation phase of cardiac action potential
- manifests with syncope and cardiac arrest, typically occurs in 3rd or 4th decade of life, usually at rest or during sleep
- ECG: ST elevation in leads V1 to V3 and RBBB (present spontaneously or provoked by ajmaline or flecainide)
- treatment: ICD

congenital long QT syndrome

- 2 major syndromes
  Jervell and Lange-Nielsen syndrome (associated with deafness) - autosomal recessive
  Romano Ward syndrome - autosomal dominant
- mutations in cardiac potassium and sodium channel genes
- 3 major subtypes
   LQT1: provoked by exercise (LQT1 most common) - slow delayed rectifier potassium channel mutation
   LQT2: provoked by emotion and acoustic stimuli (eg: door bell or telephone ring)
   LQT3: at rest or when asleep
- presents with syncope and palpitations or sudden death
- management : beta blocker (reduce adrenergic demand and reduce sympathetic activation from left stellate ganglion). Avoid drugs that prolong QT interval

Familial hypercholesterolemia

- autosomal dominant (mutation on short arm of chromosome 19)
- heterozygote 1:500; homozygote 1:1 million
- mutations in LDL receptor or Apo B
- tendon xanthomata is hallmark of the disease
- elevated LDL, with normal Tg
- premature cardiovascular disease
- treatment: statins

J wave

- most characteristic of moderate to severe hypothermia
- best seen in left chest leads and are described as a dome or hump in the terminal portion of QRS complex
- size of J wave correlated with degree of hypothermia

Mitral valve prolapse (MVP)

- posterior bulging of leaflets of mitral valve in systole
- occurs in 5% of population, usually female with narrow AP chest diameter
- presents with chest pain, palpitation or fatigue
- association: Marfan's syndrome, ASD, pseudoxanthoma elasticum, Ehler's Danlos syndrome, WPW syndrome, HCM, SLE, autoimmune thyroid disease
- mid to late systolic click and murmur (squatting increase click, standing increase murmur)
- myxomatous degeneration and redundant valve tissue due to deposition of acid mucopolysaccharide material
- sequelae (less than 1% per year): embolic phenomena, rupture of mitral valve chordae, risk of endocarditis, prolonged QT, sudden death
- treat with beta blocker if there is symptoms of dysautonomia (eg: palpitation, chest pain)

Sick sinus syndrome

- a.k.a tachy-brady syndrome
- fibrosis or fatty infiltration of sinus node, AV node, bundles of His or its branches
- characterised by periods of sinus bradycardia, sinus arrest, a combination of sinoatrial or atrioventricular conduction defect and supraventricular tachycardia
- presents with light-headedness, palpitation, syncope or stroke.
- treatment: permanent dual chamber pacemaker (single chamber pacing is associated with pacemaker syndrome)
- if patient is on beta blocker, reduce to dose slowly instead of stopping completely to avoid rebound tachycardia

Palmar crease xanthoma

- pathognomonic of type III hyperlipidemia (Broad beta disease / remnant hyperlipidemia / familial dysbetalipoproteinemia) - autosomal recessive
- caused by deficiency of apoliproprotein E (ligand for chylomicron)
- characterised by increased LDL, triglyceride and cholesterol, decreased HDL
- have elevation of IDL, a VLDL remnant
- diagnosed by lipoprotein electrophoresis or genotyping of apoprotein E
- also presents with tuboeruptive xanthoma