14.02.12 Cardiology revision

Bacteria

    • Strep. pyogenes

      • = GAS

      • => Rheumatic fever

    • Viridans Strep.

      • e.g. S. mutans (dental caries)

      • Unique ability to synthesize dextrans from glucose => fibrin-platelet aggregates at damaged heart valves

      • => Endocarditis

Rheumatic fever

    • Typically 5-15 years

    • Antigenic mimicry => Pancarditis

      • Endo-, Myo-, Peri-

RV Strain Pattern

  • Prominent R waves in V1, aVR

  • ST depression and T wave inversion in the leads corresponding to the right ventricle, i.e:

    • The right precordial leads: V1-3, often extending out to V4

    • The inferior leads: II, III, aVF, often most pronounced in lead III as this is the most rightward-facing lead

Jones Criteria for rheumatic fever

    • Evidence of recent streptococcal infection (eg history of scarlet fever, positive throat swab or rising or increased ASOT >200U/mL or DNase B titre)

    • Plus 2 major criteria, or 1 major and 2 minor criteria

    • Major criteria - SPACE:

      • Subcutaneous nodules

      • (Peri)-Carditis (occurs in 40% of patients)

      • Arthritis

      • Chorea (also known as Sydenham's chorea and 'St Vitus' Dance')

      • Erythema marginatum

    • Minor criteria:

      • Fever

      • Raised ESR, CRP

      • Arthralgia

      • Prolonged PR interval

Digoxin ECG changes

  • Major:

    • Downsloping ST depression with a characteristic “sagging” appearance

      • Flattened, inverted, or biphasic T waves

      • Shortened QT interval

    • Minor:

      • Mild PR interval prolongation of up to 240 ms (due to increased vagal tone)

      • Prominent U waves

    • Peaking of the terminal portion of the T waves

      • J point depression (usually in leads with tall R waves)

    • Exacerbated by hypokalaemia (competition for receptors or something)

    • Can treat with digibind

Aortic stenosis

    • Turbulent flow => Wear

    • Echo criteria:

      • Peak gradient

      • Peak velocity

      • Valve area

    • Symptoms (SAD):

      • Syncope (3 yrs survival)

      • Angina (5 years survival)

      • Dyspnoea (2 years survival)

    • No medical management improves survival

Papillary muscles

  • Five in total:

      • Anterior, posterior, and septal papillary muscles of the right ventricle each attach via chordae tendineae to the tricuspid valve

      • Anterior and posterior papillary muscles of the left ventricle attach via chordae tendineae to the mitral valve

  • In the LV:

    • Anterolateral papillary muscle more frequently receives two blood supplies

      • LAD, LCX

        • Therefore more frequently resistant to coronary ischemia

    • Posteromedial papillary muscle is usually supplied only by the PDA

      • Significantly more susceptible to ischemia

Graham Steell murmur

    • Typically associated with pulmonary regurgitation

    • High pitched early diastolic murmur heard best at the left sternal edge in the second intercostal space with the patient in full inspiration

    • Usually a consequence of pulmonary hypertension

    • Cor pulmonale

    • COPD

    • Secondary to MR

Carcinoid heart disease

  • Common in patients with carcinoid syndrome

    • Up to 50%

  • Characterised by right sided cardiac involvement

    • Caused by plaque-like deposits of fibrous tissue which are thought to be caused by serotonin, via action on the 5HT2b receptor

    • Most commonly seen on valve cusps and leaflets, but can be anywhere in the cardiac chambers

    • Left side of the heart is relatively protected, with the pulmonary circulation filtering out the majority of the serotonin produced by the tumour

  • Echocardiography demonstrates thickening of the tricuspid/pulmonary valve leaflets and sub-valvular apparatus

    • +/- Functional regurgitation and stenosis

Ortner's syndrome

    • Rare cardiovascular syndrome

  • RLN palsy from dilated LA due to MS/Pulmonary HTN/Thoracic aorta aneurysm

Notes

    • Erythema marginatum

    • Pink rings on the trunk and inner surfaces of the limbs

    • Come and go for as long as several months

    • Primarily on extensor surfaces

  • IABP / Nitroprusside can buy time in MR before surgery but do not increase survival

  • HARD to exclude LA thrombus on TOE

  • IV flecainide contraindicated in LV impairment due to negative inotropic effects

  • WPW

    • Whatever you do, don't slow the AV node - e.g. CCBs/Adenosine

    • Propafenone / Flecainide can slow accessory pathway

  • Atrial tachycardia is distinct from sinus tachy - Ectopic atrial pacemaker (often near SA node)

  • Patient with Ca bowel

    • Strep. bovis can invade through bowel wall => Infective endocarditis

  • QTc is measured to the TANGENTIAL END OF THE T WAVE

      • QTc is prolonged if > 440ms in men or > 460ms in women

      • QTc > 500 is associated with increased risk of torsades de pointes

      • QTc is abnormally short if < 350ms

      • A useful rule of thumb is that a normal QT is less than half the preceding RR interval