What is definition of HOCM and it's prevalence?
LVH in absence of other loading conditionsPrevalence 0.2% or 1 in 500!
Epidemiology of HOCM?
AD with variable penetranceOffspring of affected = 50%Can be benignCommonest cause of sudden cardiac death <35 yearsCan have angina, signs of pulm congestion (PND, orthopnoea), syncope, and palpitations
What are the clinical examination features of HOCM?
Jerky rapidly rising pulseProminent LV impulseApical systolic murmur that increases with valsalva (related to dynamic obstruction)Fourth heart sound
What are the ECG findings in HOCM?
What are the causative genes of HOCM?
Primarily encode sarcomere or sarcomere related proteins
Cardiac β-myosin heavy chain (β MHC) (45%)
Myosin binding protein C (MyBPC) (35%)
Cardiac troponin T, tropomyosin, cardiac
troponin I, essential and regulatory myosin light c
hain, and more recently, titin and actinin-2 genes
What is the role of genetic testing in HOCM?
Identifies at-risk earlierAvoids unecessary screening of non-carriersCan distinguish between other causes of LVHPick up rate of 50-50%
When does sudden death in HOCM most frequently occur?
Sudden death occurs most commonly in HCM either during or immediately after exercise, although death can also occur at rest
Who should be screened for HOCM and how often?
All first-degree relatives of an affected individual be clinically screened for HCM. As a minimum, this involves a physical examination by a cardiologist, an ECG and a transthoracic echocardiogram.
>31 - every 3-5 years
21-30 - every 2-3 years
11-20 - every 1-1.5 years
When should the physician report someone to the RTA?
The health professional should considerreporting directly to the driver licensing authority in situations where the patient is either:•unable to appreciate the impact of their condition, or•unable to take notice of the health professional’s recommendations due to cognitive impairment, or•continues driving despite appropriate advice and is likely to endanger the public
What are the driving rules for:
Elective PCI - 2 daysMI - 2 weeksCABG - 4 weeksArrest - 6 months
What are the driving rules for:
DVT - 2 weeksCardiogenic syncope - 4 weeksPE - 6 weeks
What is the driving license rule with regard to heart failure?
Sx on moderate exertion = no licence
What are the driving rules for seizures?
First seizure - six months
First treatment - on treatment for six months and compliant, even if they had a seizure within those six months.
Otherwise - 12 months
How long after a stroke can you drive?
4 weeks - 2 if TIASAH - 3 months
How do you differentiate between chronic hypertension and pre-eclampsia?
Chronic hypertension - hypertension before 20 weeks gestation, often diastolic - no or stable proteinuria
(if after 20 weeks gestation and no proteinuria --> gestational hypertension)
What does the a-wave of JVP mean?
'a' wave = atrial contractionlarge if atrial pressure e.g. tricuspid stenosis, pulmonary stenosis, pulmonary hypertensionabsent if in atrial fibrillation
coincides with first heart sound
What is a cannon a-wave?
Cannon 'a' wavescaused by atrial contractions against a closed tricuspid valveare seen in complete heart block, ventricular tachycardia/ectopics, nodal rhythm, single chamber ventricular pacing
What is the v wave of the JVP?
due to passive filling of blood into the atrium against a closed tricuspid valve
giant v waves in tricuspid regurgitation - very reliable sign
What does the S1 of the heart sound refer to? Pathology?
closure of mitral and tricuspid valves
soft if long PR or mitral regurgitation
loud in mitral stenosis
What does the S2 of the heart sound refer to? Pathology?
closure of aortic and pulmonary valves
soft in aortic stenosis
splitting during inspiration is normal
What is the significance of an ASD?
- most likely congenital heart defect to be found in adulthood. They carry a significant mortality, with 50% of patients being dead at 50 years.
DVTs can cross the circulation and embolise to the brain.
What are the features of an ASD?
ejection systolic murmur
fixed splitting of S2
embolism may pass from venous system to left side of heart causing a stroke
How do you calculate stroke volume?
Stroke Volume = End Diastolic Volume– End Systolic Volume
How do you calculate cardiac output?
Cardiac Output = Heart Rate x Stroke Volume
What is VO2 max?
VO2 max (also maximal oxygen consumption, maximal oxygen uptake, peak oxygen uptake or maximal aerobic capacity) is the maximum rate of oxygen consumption as measured during incremental exercise
Why is it useful to measure the mixed venous oxygen concentration?
It can be used as a marker of how well O2 is being delivered to the peripheral tissues by extrapolation (if SvO2 low and patient in multiorgan failure then we can add a inotrope to help increase cardiac output ie. in severe sepsis)
increased O2 delivery (increased FiO2, hyperoxia, hyperbaric oxygen)
decreased O2 demand (hypothermia, anaesthesia, neuromuscular blockade)
high flow states: sepsis, hyperthyroidism, severe liver disease
decreased O2 delivery:
1. decreased Hb (anaemia, haemorrhage, dilution)
2. decreased SaO2 (hypoxaemia)
3. decreased Q (any form of shock, arrhythmia)
increased O2 demand (hyperthermia, shivering, pain, seizures)
How do you calculate venous oxygen content?
Venous Oxygen content = Arterial Oxygen content - Oxygen consumption / Cardiac output.
Therefore, mixed venous O2 content is directly related to arterial oxygen content (therefore related to hemoglobin concentration and partial pressure of Oxygen) and cardiac output (therefore it will increase in cases of low cardiac output) and oxygen consumption which means tissue perfusion (therefore you have increased mixed venous O2 content in shock and in any case of impaired tissue perfusion).
What is Fick's principle?
CO = VO2 (oxygen consumption) / arteriovenous oxygen difference (Ca-Cv)
How do you measure VO2?
VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorber
What happens to the heart in old people?