Essential Revision Notes for MRCP Third Edition - PasTest

Essential Revision Notes for MRCP• Paradoxical (pulsus paradoxus): an excessivereduction in the pulse with inspiration (drop insystolic BP .10 mmHg) occurs with leftventricular compression, tamponade,constrictive pericarditis or severe asthma asvenous return is compromisedCauses of an absent radial pulse• Dissection of the aorta with subclavianinvolvement• Iatrogenic: post-catheterisation• Peripheral arterial embolus• Takayasu’s arteritis• Trauma1.1.3 Cardiac apexAn absent apical impulseThe apex may be impalpable in the following situations:• Obesity/emphysema• Right pneumonectomy with displacement• Pericardial effusion or constriction• Dextrocardia (palpable on right side of chest)Apex associationsPalpation of the apex beat (reflecting counter-clockwiseventricular movement striking the chest wallduring isovolumic contractions) can detect the followingpathological states:• Heaving: left ventricular hypertrophy (LVH) (andall its causes), sometimes associated withpalpable fourth heart sound• Thrusting/hyperdynamic: high left ventricularvolume (eg in mitral regurgitation, aorticregurgitation, patent ductus arteriosus (PDA),ventricular septal defect)• Tapping: palpable first heart sound in mitralstenosis• Displaced and diffuse/dyskinetic: leftventricular impairment and dilatation (eg dilatedcardiomyopathy, myocardial infarction (MI))• Double impulse: with dyskinesia is due to leftventricular aneurysm; without dyskinesia inhypertrophic cardiomyopathy (HCM)• Pericardial knock: constrictive pericarditis• Parasternal heave: due to right ventricularhypertrophy (eg ASD, pulmonary hypertension,chronic obstructive pulmonary disease (COPD),pulmonary stenosis)• Palpable third heart sound: due to heart failureand severe mitral regurgitation1.1.4 Heart soundsAbnormalities of first heart sounds are given inTable 1.1 and of second heart sounds are given inTable 1.2.Table 1.1. Abnormalities of the first heart sound (S1): closure of mitral and tricuspid valvesLoud Soft Split VariableMobile mitral stenosis Immobile mitral stenosis RBBB Atrial fibrillationHyperdynamic states Hypodynamic states LBBB Complete heart blockTachycardic states Mitral regurgitation VTLeft-to-right shunts Poor ventricular function InspirationShort PR interval Long PR interval Ebstein’s anomalyLBBB, left bundle branch block; RBBB, right bundle branch block; VT, ventricular tachycardia4