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Related Subjects: |Acute Stroke Assessment (ROSIER&NIHSS) |Atrial Fibrillation |Atrial Myxoma |Causes of Stroke |Ischaemic Stroke |Cancer and Stroke |Cardioembolic stroke |CT Basics for Stroke |Endocarditis and Stroke |Haemorrhagic Stroke |Stroke Thrombolysis |Hyperacute Stroke Care

The key is strokes in different parts of the cerebral circulation

Introduction

• This refers to strokes due to emboli arising from the heart.
• Either from the left atrium, left ventricle or valves or via a shunt such as a PFO or ASD.
• Cardioembolic stroke accounts for between 15-30% of all acute ischaemic strokes.
• In-hospital mortality in cardioembolic stroke is high at 25-30%
• Over 20% of strokes in the over 80s are due to AF which are potentially preventable

Causes/Sources of Cardioembolism

• Highest risk
  • Atrial fibrillation risk depending on CHADS-VASC score
  • Recent MI (LV aneurysm/hypokinetic and akinetic ventricular walls)
  • Mechanical heart valve
  • Dilated cardiomyopathy
  • Mitral rheumatic stenosis
• Post Cardiac Surgery E.g. Valve replacement or TAVI or PCI
• Rheumatic heart disease
• Left atrial appendage thrombus
• Atrial Myxoma
• Infective Endocarditis
• Libman sacks endocarditis
• Mitral papillary fibroelastomas
• Atrial septal defects
• Patent foramen ovale and atrial septal aneurysms

Classification

• Cardiac wall and chamber abnormalities
  • Cardiomyopathies
  • Hypokinetic and akinetic ventricular regions after myocardial infarction
  • Atrial septal aneurysms
  • Ventricular aneurysms
  • Atrial myxomas
  • Papillary fibroelastomas
  • Septal defects and patent foramen ovale
• Valve disorders
  • Rheumatic mitral and aortic valve disease
  • Prosthetic valves
  • Bacterial endocarditis
  • Fibrous and fibrinous endocardial lesions
  • Mitral valve prolapse and mitral annulus calcification
• Arrhythmias
  • Atrial fibrillation
  • "Sick-sinus" syndrome.

Clinical

• Embolic strokes tend to be acute and maximal at onset.
• They may be preceded by a cough or sneeze or a Valsalva
• Can suddenly improve due to passage of the clot distally, variability in collaterals and spontaneous reperfusion.
• There is often a large vessel obstruction amenable to thrombolysis and thrombectomy.
• There is a greater risk of haemorrhagic transformation.
• Multiple stereotypical clinical syndromes in the same territory is not cardioembolic source.
• One caveat is that it can be hard to differentiate cardioembolism from embolism from aortic arch plaque

Causes and Frequency

A dense artery may be seen with a large embolic thrombus	Atrial Fibrillation	large STEMI

Structural Cardiac disease and stroke

Various Cardiac structural defects can lead to the formation of intracardiac thrombi and cardioembolism. If suspected the first investigations include a clinical history and a search for any determinants that will give a clue. Cardiac symptoms suggestive of ischaemic heart disease, chest pain, breathlessness and palpitations which could suggest an ischaemic cardiomyopathy. A history of rheumatic fever could suggest valvular disease. A history of excess alcohol might suggest an alcoholic cardiomyopathy. Cardiomyopathy may also be seen with HIV. Examination may reveal heart failure, rashes, AF, sighs of chronic liver disease, nicotine staining, hypertension and murmurs. An ECG, CXR and then Echo will be useful. A troponin may be useful acutely if recent myocardial infarction is suspected. Temperature and stigmata for endocarditis must always be considered. Most embolism is thrombotic but other rare sources of emboli are air, fat, cholesterol, bacteria, tumour cells, and particulate matter from injected drugs should be considered in rare cases.

Clinical

• Sudden onset of an acute arterial syndrome
• Most often MCA, then PCA, ACA or Vertebral/PICA or Basilar
• May be AF on examination. Murmurs, Clubbing (myxoma)
• Signs of endocarditis
• Recent chest pain or breathlessness from an MI

Investigations

• FBC and ESR: elevated ESR with atrial myxomas and endocarditis or malignancy
• ECG: may show recent STEMI with Q waves or persistent ST elevation suggesting ventricular aneurysms. It may also show AF or sick sinus syndrome.
• Detect AF: 24-48 hour Holter monitoring or even 7 day which may be repeated
• Implantable loop recorder : placed subcutaneously. Can be interrogated about recent rhythms
• CXR: may show an enlarged heart
• CT Scan: multiple territory infarcts
• CTA: May be large vessel obstruction seen on CTA from a large thrombus from the heart
• MRI: May show a large vessel stroke or occasionally an embolic shower with multiple pinpoint infarcts seen on DWI/ADC map
• Transthoracic Echo: Assess LV function, valves and myocardium
• Bubble echo: useful to identify right to left shunt causing a paradoxical embolism
• Trans oesophageal echo: Helps to visualise vegetations on valves, PFO, atrial myxoma also aortic arch and ascending aorta, left atrium and left atrial appendages, intra-arterial septum, pulmonary veins
• Transcranial doppler : bubble tests can help identify shunting

Management

• Standard Ischaemic stroke Management. Treat cause.
• Secondary prevention with anticoagulants should be started as per guidelines usually at 1-2 weeks on a case based approach. Caution in endocarditis.

References

• Cardioembolic Stroke: Clinical Features, Specific Cardiac Disorders and Prognosis. Curr Cardiol Rev. 2010 Aug; 6(3): 150–161.
• Cardioembolic Stroke. Circ Res . 2017;120:514-526.
• Leary MC, Caplan LR. Cardioembolic stroke: An update on etiology, diagnosis and management. Ann Indian Acad Neurol 2008;11, Suppl S1:52-63