Right ventricle infarction Dr. P Kruger 2004

General Pathophysiology RCA supply and occlusion Clinical Special examinations Treatment Conclusions Examples

General RVI mostly associated with inferior MI, seldom isolated RVI 30-50% of Inferior MI 10-15% haemodynamic unstable Higher morbidity and mortality than inferior MI Mortality 25-30% - Inferior mi + RVI = 31% - Inferior mi – RVI = 6% Spectrum of disease: Asymptomatic mild RV dysfunction to cardiogenic shock

Pathophysiology RV is a thin walled chamber that function at low O2 demands. RV is a low-volume pressure pump, its contractility is highly dependent on diastolic pressure. It’s perfused throughout the cardiac cycle in both systole and diastole Its ability to extract O2 is increased during haemodynamic stress Collateral blood supply ( esp. anterior wall of RV) All of these factors make the RV less susceptible to infarction than the LV

Right coronary artery Posterior descending branch - Inferior and posterior wall of RV Marginal branches - Lateral wall of RV Conus branch - Anterior wall ( also supplied by L descending artery, moderator branch)

Right coronary artery occlusion Mostly ateriosclerotic occlusion of proximal RCA Direct correlation between anatomic site of RCA occlusion and extent of RVI. More proximal occlusion causes a larger RVI Proximal to RV occlusion of RCA causes:  RV free wall injury  compromises blood supply to SA node, atrium and AV node  sinus brady, atrial infarction, AF, AV block.

Clinical Classic triad of : 1. Raised JVP 2. Clear lung fields 3. Hypotension

Special investigations CXRBLOODSECG Inferior MI - ST elevation in II, III, aVF - With/without abnormal Q waves Right-sided ECG - ST elevation in lead V  R - ST  disappear after 10 hours of onset of pain - ST  more than 1mm/ 0,1mV

LeadsSensitivity (%) Specificity (%) VV 2892 VRVR 6997 VRVR 9395

Lead V4R

Treatment General measurements Recognition Reperfusion Volume loading Inotropic support Rate and rhythm control Complications

RVI should be considered in patients with sensitivity to preload- reducing agents such as diuretics, nitrates, morphine All patients with Inferior MI considered as RVI until proven otherwise