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Fifty-nine consecutive patients presenting within 6 hours of the onset of symptoms of an acute myocardial infarction were treated with 150 mg of soluble aspirin orally, and either 70 or 100 mg of alteplase divided into 2 intravenous bolus injections separated by 30 minutes. Dosage regimens were either 20 followed by 50 mg (group A), 50 followed by 20 mg (group B), or 50 followed by 50 mg (group C). Coronary angiography 60 minutes after the first bolus showed infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction score 2 or 3) in 13 of 16 (81%) patients in group A, 12 of 17 (71%) in group B, and 10 of 11 (91%) in group C (overall patency rate at 60 minutes: 35 of 44 [80%] patients; 95% confidence interval 68 to 91%). At 90 minutes, patency rates were 15 of 20 (75%) patients in both groups A and B, and 18 of 19 (95%) in group C (overall patency rate 48 of 59 [81%] patients; 95% confidence interval 72 to 91%). Residual thrombus was identified with the 90-minute angiogram in 7 patients in group A, 5 in group B, and 3 in group C. Although there was no statistically significant difference in patency between the 3 dosage regimens at either 60 or 90 minutes there was a trend toward increased patency and more complete thrombolysis at 90 minutes in group C. No episodes of bradyarrhythmia, hypotension or cerebrovascular bleeding were observed after double bolus therapy. There were 7 episodes (12%) of reocclusion, and 3 deaths (5%) within 1-month follow-up. Double bolus alteplase therapy is a convenient and highly effective method of promoting early coronary artery patency.

Dennis McCord Boyle was appointed consultant cardiologist at the Royal Victoria Hospital, Belfast, in 1965. He made major contributions to the care of patients with rheumatic valve disease and cardiac disease in pregnancy. …

Of consecutive patients seen with first myocardial infarction (88 of whom were treated out-of-hospital by mobile coronary care staff), 139 received 30 units of intravenous anistreplase at a mean of 101 minutes (range 35-180) from onset of symptoms. Thrombolysis in myocardial infarction patency grade 2 or 3 was found in 76/91 (83.5%) patients. At 3-4 months after hospital discharge, the mean global left ventricular ejection fraction and mean infarct-related regional third ejection fraction declined with increasing delay to anistreplase. For the first, second and third hour administrations, global ejection fraction was 54%, 50% and 45% (P = 0.002) and for regional third ejection fractions 49%, 43% and 41% (P = 0.02) respectively. Of the patients, 130 were reviewed at approximately 1 year: reinfarction had occurred in 9, 6 had undergone coronary angioplasty and 1 had coronary arterial bypass grafting performed since discharge. Mean global left ventricular ejection fraction was 52% and mean infarct-related regional third ejection fraction was 51%. Thus, intravenous anistreplase induces high rates of arterial patency. Global and regional third ejection fractions decline with increasing delay in the time of administration of anistreplase. Mortality and morbidity is low in the first year.

GA,Geddes LA,Bourland JD, Korom-pai FL, Rubio PA: The electrical dose for direct ventriculardefibrillation in man. J Thorac Cardiovasc Surg75: 224, 197836. Ewy GA: Subject dependent factors in ventricular defibrilla-tidn. In Current Problems in Cardiology, vol 2 ( 1), edited byHarvey WP. Chicago, Year Book Medical Publishers, 1978,p4737. Ewy GA, Tacker WA Jr: Transchest electrical ventriculardefibrillation. AmHeart J 91: 403, 197638. DiCola VC, Freedman GS, Downing SE, Zaret BL: Myocar-dial uptakeoftechnetium-99mstannous pyrophosphate follow-ing direct current transthoracic countershock. Circulation 54:980, 197639. Lown B, Neuman J, Amarasingham R, Berkovits BV: Com-parison of alternating current with direct current electroshockacross the closed chest. AmJ Cardiol 10: 223, 196240. Peleska B: Cardiacarrhythmias followingcondenserdischargesandtheir dependenceuponstrength ofcurrentandphaseofcar-diac cycle. Circ Res 13: 21, 196341. GoldJH

Objectives . The purpose of this study was to assess the efficacy of 150 mg of aspirin plus 100 mg of alteplase, administered as two intravenous bolus injections of 50 mg each given 30 min apart, and followed by intravenous heparin, on infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3). Background . previous workers have shown in animals that reducing the duration of an infusion of recombinant tissue-type plasminogen activator increases the initial rate of thrombolysis, resulting in high early infarct-related coronary artery patenecy rates. The logical progression of this idea is bolus administration. Methods , Consecutive patients presenting up to 6 h from the onset of symptoms were recruited for the study. Angiography was performed at 60 and 90 min after the first bolus and between 19 to 48 h after study entry. Patients were followed up for 1 month. Results . At 60 min, angiography revealed infarct-related coronary artery patency of TIMI flow grade 3 in 55 (86%) of 64 patients (95% confidence interval [CI] 75% to 93%) and TIMI flow grade 2 or 3 in 58 (91%) of 64 patients (95% CI 81% to 97%). At 90 min, infarct-related artery patency of TIMI flow grade 3 was achieved in 74 (88%) of 84 patients (95% CI 79% to 94%) and TIMI flow grade 2 or 3 in 78 (93%) of 84 patients (95% CI 85% to 97%). Two patients (2.4%) had early angiographic reocclusion whereas 10 (11.9%) had late reinfarction. Bleeding episodes were mostly minor, and there was no cerebrovascular bleeding. Five patients (6.0%) died within 1 month of the acute myocardial infarction. Conclusions . In 84 patients with acute myocardial infarction, administration of 100 mg of double-bolus (2 × 50 mg) alteplase, aspirin and heparin is associated with remarkably high early infarct-related coronary artery patency rates (TIMI flow grade 3) of 86% and 88%, respectively, at 60 and 90 min.

A 65-year-old woman had severe mitral stenosis and trivial mitral regurgitation. There was no obstructive coronary disease. The mitral valve was replaced with a CarpentierEdwards xenograft. When transferred to the recovery ward she was in sinus rhythm and was receiving intravenous dopamine, the dose of which was gradually reduced. The infusion also contained 20 mEq/liter of potassium chloride. The patient's subsequent course is summarized in Figure 1. Erythromycin lactobionate, I g, and cloxacillin sodium, 500 rag, were given by intravenous injection. Within minutes of the injection VT developed, which reverted to sinus rhythm after the intravenous injection of calcium chloride, 5 ml of 10% solution, isoproterenol, 5 #g, and epinephrine, 2.5 ml of a I in 15,000 solution. During the next 24 hours, there were frequent ventricular premature contractions (VPCs ) with episodes of bigeminy and consecutive VPCs despite varying doses of lidocaine and mexiletine. There was sustained VT with hypotension on 3 further occasions, 2 of which immediately followed the administration of intravenous erythromycin and cloxacillin. The serum potassium level was measured several times during this period and was within the normal range on each measurement, the minimum value being 3. 7 mEq/liter. The serum magnesium concentration was 3.19 mg/lO0 ml and serum calcium 9.68 mg/lO0 ml; both values are above the lower limits for our laboratory. Twenty-four hours after the operation, a 12-lead electrocardiogram was recorded (Fig. 2). Compared with the preoperative ECG (Fig. 2a), sinus rhythm was present, the mean QRS axis had moved to the left and a new Q wave was present in lead A VL (Fig. 2b ). Anterior forces were less prominent than before. There was marked prolongation of the QT interval and there was widespread T-wave inversion. VPCs continued to occur frequently (Fig. 2c). Lidocaine and mexiletine treatment were discontinued. Potassium and calcium were given by intravenous injection and isoproterenol was infused in a dose sufficient to maintain the ventricular rate at 90 beats/rain. No further arrhythmias occurred for 6 hours, until the next injection of antibiotics was given. VT recurred and was successfully terminated by direct-current shock. Erythromycin treatment was then

To assess the thrombolytic efficacy and the effect on the systemic fibrinolytic system of recombinant tissue plasminogen activator doses of 20 mg, 50 mg, and 100 mg were compared in a randomised study. Tissue plasminogen activator was infused intravenously over 90 minutes in 50 consecutive patients with acute myocardial infarction of four hours' duration or less; on average the infusion was started 135 minutes (range 20 to 240) after the onset of pain. The affected artery was patent at the end of the 90 minute infusion in 14/17 (82%) of those who received 100 mg, 12/17 (71%) of those who received 50 mg, and 8/16 (50%) of those who received 20 mg. Regardless of dose, reperfusion rates were significantly better for patients treated within two hours of the onset of symptoms (81%) than for those treated in the third and fourth hours (54%). At the end of the infusion serum fibrinogen concentrations fell to 86% of the preinfusion value after 20 mg, 75% after 50 mg, and 63% after 100 mg, and similar dose dependent changes occurred in plasminogen, (alpha 2 anti-plasmin, and fibrinogen and fibrin degradation products. The mean infarct related regional third ejection fraction was 46% for patients with grade 2 or 3 reperfusion and 35% for those with grade 0 or 1. Ventricular fibrillation occurred in six (12%) patients during the infusion of tissue plasminogen activator, but no late ventricular fibrillation occurred. Bleeding was minimal, reocclusion occurred in three patients, and four patients died from cardiac causes. Recombinant tissue plasminogen activator is an effective thrombolytic agent which produces better reperfusion rates after a 50 or 100 mg dose than after a 20 mg dose. The effect on the systemic fibrinolytic system is dose dependent. Successful reperfusion results in improvement of left ventricular function.

A prospective study of the energy required for transthoracic ventricular defibrillation in adults showed that in 42 (81%) out of 52 episodes of ventricular fibrillation shocks of 100 watt-seconds (Ws) of stored energy were successful. Out of 233 episodes, 222 (95%) were converted by 200 W s shocks. Among patients in whom primary ventricular fibrillation occurred within one hour of the onset of acute myocardial infarction, 200 W s shocks were successful in 40 (98%) out of 41 episodes. When low-energy shocks failed, a stored energy of 400 W s invariably succeeded. The need for large and expensive defibrillators that store more than 400 W s and are less readily available is therefore questioned.