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