Hybrid-trained operators can achieve overall success rates of 90% in real world practice with acceptable MACE. Use of dissection re-entry and investment procedures maintains high success rates in complex lesions. The hybrid approach represents a significant advance in CTO treatment.

IMPORTANCE Microvascular obstruction commonly affects patients with acute ST-segment elevation myocardial infarction (STEMI) and is associated with adverse outcomes. OBJECTIVE To determine whether a therapeutic strategy involving low-dose intracoronary fibrinolytic therapy with alteplase infused early after coronary reperfusion will reduce microvascular obstruction.

SUMMARY The diagnostic and therapeutic potential of intravenous adenosine was studied in 64 patients during 92 episodes of regular sustained tachycardia. In 40 patients who had narrow complex tachycardias (QRS <0-12 s) adenosine (2-5-25 mg) restored sinus rhythm in 25 with junctional tachycardias (46 of 48 episodes) and produced atrioventricular block to reveal atrial or sinus tachycardia in 15. In 24 patients with broad complex tachycardias (QRS > 0 12 s) adenosine terminated the tachycardias in six patients and revealed atrial or sinus arrhythmias in four. The tachycardias persisted in 14 patients despite doses up to 20 mg, but adenosine allowed the diagnosis of ventricular tachycardia with retrograde atrial activation in two patients by producing transient ventriculoatrial dissociation. Diagnosis based on adenosine induced atrioventricular nodal block was correct in all patients with narrow complex tachycardias and in 92% of those with broad complex tachycardias, compared with correct electrocardiographic diagnoses in 90% and 75% respectively. Adenosine gave diagnostic information additional to the electrocardiogram in 25%. The response to adenosine in broad complex tachycardias identified those of supraventricular origin with 90% sensitivity, 93% specificity, and 92% predictive accuracy. Adenosine restored sinus rhythm in all patients with junctional reentrant tachycardias, but in 10 (35%) the arrhythmias recurred within two minutes. Symptomatic side effects (dyspnoea, chest pain, flushing, headache) were reported by 40 (63%) patients and, although transient, were severe in 23 (36%). There were ventricular pauses ofover 2 s in 16% of patients, the longest pause being 6*1 s.Adenosine is ofvalue in the diagnosis and treatment of narrow and broad complex tachycardias, but its use is limited by symptomatic side effects, a tenfold range in minimal effective dosage, occasional action at sites other than the atrioventricular node, and early recurrence of arrhythmia.Adenosine is a naturally occurring, rapidly metabolised compound that produces transient atrioventricular nodal block in humans when injected intravenously.' It can terminate reentrant supraventricular tachycardias that involve the atrioventricular node,' while in tachycardias of atrial origin it may be of diagnostic value, because adenosine induced atrioventricular block slows the ventricular rate and reveals the unaffected atrial arrhythmia.2 Such diagnostic and therapeutic effects of adenosine should be of most value in broad complex Requests for reprints to Dr A C Rankin,

Background-In animal models of circulatory shock and heart failure concentrations of the endogenous opioid peptide # endorphin are raised and opioid recep To allow some clarification of the relation between the duration and severity of myocardial ischaemia and the release of, endorphin we studied two groups of patients. Study 1 Fifty five consecutive patients admitted to the coronary care unit of Glasgow Royal Infirmary with a clinical diagnosis of acute myocardial ischaemia were studied. Myocardial infarction was confirmed by the presence of at least two of the three standard criteria: a compatible history ofchest pain, typical evolving electrocardiographic changes, and an increase in the concentration of creatine kinase to above twice the upper limit of normal. Patients without these features but with evidence of ischaemia were considered to have unstable angina. Daily clinical examinations were performed and when there was evidence of pulmonary congestion radiological confirmation was sought. Cross sectional echocardiography was performed on day three, and where image quality allowed, we calculated the ejection fraction using apical two and four chamber views and a modified Simpson's formula.'5 Serial blood samples were taken from the time of admission to six weeks after discharge. Patients were asked to quantify the intensity of their chest pain on a 100 mm noncalibrated linear visual analogue scale cued with "very mild" and "very severe".