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• ECGS read:

  AP spontaneously generated by the heart results from excitation and contraction of muscle fibres throughout MYOCARDIUM
• blood tests:

  full blood count (FBC) - for example , infection , inflammation(raised CRP) , anaemia (low hb)

  thyroid fn test : an underactive or overactive thyroid gland effects production of hormone , thyroxine , abnormal levels linked to altered heart rate

  lipid profile : total cholesterol

  liver function tests

  clotting screen : prothrombin time
• lab tests for cardiac s&s

  biomarkers = measurement of a biomarker of cardiomyocyte injury

  Tests include = cardiac enzymes , myoglobin , CK , brain-type natriuretic peptide (heart failure) , urea and electrolytes

  
• electrocariography includes :

  — 12-lead electrocardiograms

  — stress test

  — holter monitoring

  — event recorders

  -visualises rhythm abnormalties
• P wave

  heartbeat starts with the generation of an electrical signal at the SA node , the hearts natural pacemaker , and that signal subsequently passes to the atrioventricular node.

  
• PR interval:

  time between the start of the P wave and the start of the QRS complex
• QRS Wave complex

  big spike in the middle of the ECG , which reflects the electrical signals leading to ventricular contraction. Its made up of multiple waves.
• ST interval

  time between the end of the QRS complex and the start of the T wave .

  Represents period of zero potential between ventricular deporisation and repolarisation.

  pause between contraction and recovery
• T wave

  hearts electrical activity returning to baseline - ventricular repolarisation. after ventricular repolarisation, muscles of the ventricle relax >

  
• exercise stress testing

  • treadmill test

  ECG , blood pressure and HR

  useful diagnosis

  • coronary artery disease

  • post myocardial infarction risk stratification

  • exercise induced arrythmia

  • nuclear stress test

  — function of heart muscle

  — assess damage to heart muscle following an MI

  — determine extent of coronary stenosis
• Holter monitoring :

  • small , portable monitoring device

  • continuous ECG while patient conducts normal daily activities

  • used for suspected frequent rhythm abnormalties
• chest X-ray

  Size and configuration of heart and great vessels

  routine cardiac investigation
• Echocardiography :

  ultrasound

  • structure , motion , structural , functional changes
• trans-thoracic echocardiogram

  Trans-oesophageal echocardiogram

  USEFUL IN :

  diagnosis and grading of severity of

  — valvular and congenital heart diseases

  — endocarditis

  — heart chamber movement and hypokinesia

  — pericardial effusion
• Coronary artery calcium scoring

  — most useful in those patients with intermediate risk of CVD

  — result will either lower or raise the risk profile

  — provide a change In management

  — potential clinical cardiovascular risk : low , medium ,

  Adv : convenient, noninvasive

  dis : radiation , no intravenous contrast medium , cannot show coronary artery anatomy or pathology
• Angiography :

  Advanced form of magnetic resonance imaging

  • assessment of congenital disease

  • assessment of tumour

  • abnormality of thoracic aorta;

  • assessment of myocardial perfusion and viability

  • evaluation of infiltrative diseases

  • assessment of diseases of pericardium

  • exclusion of anomalous coronary origins

  • quantification of cardiovascular shunts

  • quantification of ventricular function
• Nitrates: 


  • used in angina and CAD : potent vasodilators , lower BP , control ischaemia

  ACTION; enter vascular smooth muscle cells

  systemic hemodynamics

  —> decrease in myocardial oxygen demand

  —> low doses : small amount of arterial dilatation

  —> higher doses : BP falls , reducing wall stress
• Coronary hemodynamics : increase in coronary blood flow

  SIDE EFFECTS :

  headaches , light-headedness
• Coronary hemodynamics :

  — stable angina need supervision and encouragement

  — closely monitor any symptoms of new-onset chest pain particularly during exercise

  — cease activity and rest

  — be seated when GTN spray/oral sublingual nitrates administered
• nitrate preparations :

  isosorbide dinitrate

  angina

  oral tablet , 15-40 m onset , 4-6 hrs duration ,
• cholesterol lowering :

  Actions :

  • blocks enzyme

  • leads to greater clearance of LDL cholesterol

  side effects :

  • nausea , constipation, diarrhoea , myopathy , aches and pains
• cholesterol lowering drug:

  HMG CoA reductase inhibitors

  oral

  indications: adjunct to diet , CAD or high risk
• ANTIPLATELETS:

  • prevent blood clots that may produce emboli

  • prevent cardiac arrest , collapse and death

  Classified :

  • platelet aggregation inhibitors

  • glycoprotein platelet inhibitors

  Side-effects :

  • bleeding propensity

  • peptic ulcer/gastroduodenal haemorrhage

  
• antiplatet agents :

  glycoprotein IIb inhibitors

  IHD , after CABG , NON-Stemi

  administration : IV
• Beta - blockers ( beta - adrenergic blocking agents)

  peripheral : B-adrenoreceptors stimulation - vasodilation

  cardiac : B-adrenoreceptor stimulation - increased heart rate , contractility
• Beta - blockers : action

  reduce blood pressure by BLOCKING the effects of hormone epinephrine (adrenaline)

  • heart beats slower , less force = lower blood pressure
• beta-blockers : clinical context

  limits normal increase in heart rate seen during exercise

  • thus , do not use heart rate as a target for training intensity
• beta -blockers : side effects

  bronchospasm due to stimulation of B2 receptors in airway smooth muscle

  • signs and symptoms : bradycardia , fatigue , lethargy

  • difficulty with ADLS due to slowed or absent normal rapid increase in heart rate that accompanies exertion
• Clinical context:

  • be familiar with effects and side effects

  patients: combination of medications with different mechanisms of action and side effects

  side effects :

  B-blocker side effects

  e.g. bradycardia , fatigue or lethargy
• medications + actions

  
• Angiotensin II = primary vasoactive hormone of renin angiotensin aldosterone system

  Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers

  angiotensin II causes aldosterone stimulation , regulation of salt and water homeostasis

  main difference between ACE inhibitors and ARBs - selective receptor activity

  ACE inhibitors : inhibits the inactivation of bradykinin ( vasodilator)
• medication actions

  
• diuretics :

  
• calcium channel blockers: action

  
  

  
  

  • inhibits calcium ion influx across cell membranes

  • vascular smooth muscle cells ( decreasing systemic vascular resistance). E.g. Amlodipine or cardiac muscle cells e.g. verapamil which dilates main coronary arteries and coronary arterioles , both in normal and ischaemic regions , inhibits coronary artery spasm
• calcium channel blockers :

  Side effects :

  • headache , light headedness , flushing
• calcium channel blockers :

  Helps treat angina , hypertension , some arrhythmias —> medicine works by blocking the uptake of calcium into the cell which causes arteries to dilate
• acute hypertension:

  Clinical context:

  commonly encountered in ICU where patients have low or a fluctuating blood pressure

  administration:

  all are delivered intravenously via a central line or peripheral line

  side effects:

  excessive vasconstriction (peripheral ischaemia) , hypertension , headache , hyperglycaemia
• peripheral receptor stimulation:

  • adrenoreceptor stimulation - vasoconstriction , adrenoreceptor inhibition - vasodilation

  • b-adrenoreceptors stimulation - vasodilation
• Cardiac :

  • B-adrenoreceptor stimulation — increased heart rate , contractility , conduction velocity and relaxation rate

  • human heart has both B1 - B2 adrenoreceptors , with B2 adrenoreceptors higher in atria the in ventricular myocardium
• disorders of blood pressure :

  adequate perfusion of body tissue depends on :

  pumping ability of the heart

  transport of blood to fill the circulatory system

  tissues ability to extract and use oxygen and nutrients.

  
  

  blood pressure ;

  one of most variable but best regulated functions of the body

  approximated by flow (cardiac output) and systemic vascular resistance