Defibrillators, implantable devices that deliver an electric shock to the heart to reestablish normal rhythm, began widespread clinical adoption in 2003.

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In milder cases you can have a small electric shock to get the heartbeat to return to normal, or like British Prime Minister Tony Blair had last year, a procedure called catheter ablation.

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If it detects a severe arrhythmia, the device is designed to shock the heart, causing it to revert to normal rhythm.

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There is a recognition that, with more than 100 days to absorb the shock of the SNP majority, the re-start of politics-as-normal post-summer requires a clearer strategy.

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