Acute M. I part 2

Streptokinase
(SK) is the usual thrombolytic agent.
Dose: 1.5 million units in 100mL 0.9% saline IVI over 1h.
SE: nausea; vomiting; haemorrhage; stroke (1%); dysrhythmias.
Any hypotension usually responds to slowing down or stopping the infusion.
Also watch for allergic reactions and anaphylaxis (rare).
Do not repeat unless it is within 4d of the first administration.

Alteplase
(rt-PA), followed by heparin, may be indicated if the patient has previously received SK (>4d ago) or reacted to SK.
Accelerated rt-PA has benefit if given within 6h, especially in younger patients with anterior MI.
Reteplase is given as 2 IV boluses 2h apart, and
tenecteplase is given by bolus injection (over 10sec), which in some cases may be an advantage.

Complications
Recurrent ischaemia or failure to reperfuse (usually detected as persisting pain and ST-segment elevation in the immediate aftermath of thrombolysis): analgesia, GTN, B-blocker, consider re-thrombolysis or angioplasty.
Stroke.
Pericarditis: analgesics, try to avoid NSAIDs.
Cardiogenic shock: see p788 and heart failure: see p786.
Right ventricular infarction
Confirm by demonstrating ST elevation in RV3/4, and/or echo. NB: RV4 means that V4 is placed in the right 5th intercostal space in the midclavicular line.
Treat hypotension and oliguria with fluids.
Avoid nitrates and diuretics.
Intensive monitoring and inotropes may be useful in some patients.