Adverse effect of warfarin in acute myocardial infarction: increased left ventricular thrombus formation in patients not treated with high-dose heparin

In a prospective non-randomized study, 229 patients with a verified first acute anterior myocardial infarction (AAMI) underwent echocardiography before discharge in order to study left ventricular (LV) thrombus formation. Antithrombotic therapy was given according to the routine of each centre. Patients receiving high-dose heparin had few LV thrombi, irrespective of warfarin therapy (6/32 vs 3/25, P ns). In patients not given heparin, however, a significantly higher prevalence of LV thrombi was found in a subgroup of patients treated with warfarin as compared to those who did not receive warfarin (8/13 vs 17/68, P 0.02). A similar, but non-significant difference was observed in patients given low-dose heparin (42% vs 27%, P ns). Within the non-heparin and low-dose heparin groups, age, infarct size, occurrence of Q-wave infarction, congestive heart failure and LV wall motion impairment did not differ between those treated or not treated with warfarin. In conclusion, high-dose heparin seems effective in the prevention of LV thrombosis irrespective of warfarin therapy after AAMI. The start of warfarin therapy in patients not receiving heparin was, however, associated with an increased prevalence of LV thrombosis.

Left ventricular thrombosis and arterial embolism in acute anterior myocardial infarction

To study left ventricular thrombus (LVT) formation and arterial embolism (AE), 106 consecutive patients with a first acute anterior myocardial infarction (AAMI) underwent two-dimensional echocardiography before discharge. Repeated assessments for detection of AE were performed. Patients were non-randomly allocated to either no heparin, low-dose heparin or high-dose heparin. LVT was found in 25 (26.9%) of 93 patients with technically satisfactory echocardiograms. Left ventricular (LV) wall motion impairment (P = 0.0017) and treatment with either heparin or low-dose heparin (P = 0.0019) were independent predictors of LVT formation. AE, all strokes, occurred in 10 patients (9.4%) and was strongly associated with high age (P = 0.0013). In conclusion, LVT and AE are frequent complications to AAMI. LV wall motion impairment predisposes for LVT and low-dose heparin seems not to prevent these complications.

Safety of high doses of low molecular weight heparin (Fragmin) in acute myocardial infarction. A dose-finding study

We postulated that low molecular weight heparin (LMWH) in doses producing plasma levels in the range of 0.6-1.0 anti-Xa U/ml may reduce the incidence of left ventricular thrombi (LVT) secondary to acute anterior wall myocardial infarction (AAMI). In an open, dose-finding study, 72 patients with acute myocardial infarction (AMI) were treated with Fragmin (KABI) 240-360 anti-Xa U/kg/24h subcutaneously for 6-10 days. 300 anti-Xa U/kg/24h given as 2 or 3 injections resulted in a mean plasma concentration of about 0.8 anti-a U/ml. There were 3 minor haemorrhages, all in a subgroup of 22 patients also being treated with 0.3 g aspirin orally per day after 1.5 mill. U streptokinase intravenously on admission. In the 38 patients with AAMI receiving 300 anti-Xa U/kg/24h there were only 3 LVT during the period of treatment (8%). In conclusion, 300 anti-Xa U Fragmin/kg/24h s.c to patients with AMI appears safe, but minor haemorrhage may occur in patients receiving aspirin concomitantly. Although these data are limited, the low incidence of LVT in patients with AAMI suggests efficacy of this dose of Fragmin to prevent LVT.

[Ventricular tachyarrhythmias. Etiology, diagnosis and treatment, based upon a group of patients]

Sustained ventricular tachycardia and ventricular fibrillation are found to be the main causes of sudden cardiac death in out-of-hospital patients. Most of these patients do have serious organic heart disease, hence the arrhythmia must be regarded as a dangerous symptom. Of 44 consecutive patients referred for further investigation of either of these arrhythmias, organic heart disease was found in 43 (98%). Coronary heart disease and cardiomyopathy were the two most common illnesses found. Surgical treatment was efficient in cases of arrhythmias induced by myocardial ischaemia, and even patients with marked reduction in their left ventricular performance tolerated surgery well. As for the medically treated patients, the recurrence rate appeared to be lowest among those who received class-III-antiarrhythmic drugs.

Self-terminating idiopathic ventricular fibrillation presenting as syncope: a 40-year follow-up report

Out-of-hospital ventricular tachyarrhythmia has a high mortality. Most patients sustaining this type of arrhythmia have an organic heart disease. In this case report we present a patient with recurrent ventricular fibrillation with the clinical appearance of syncope, where no relevant organic heart disease could be found at autopsy performed 40 years later.