Search

Objective: The aim was to investigate QRS vector changes during the first 30 min of coronary occlusion or the early phase of reperfusion with special reference to location and size of myocardium at risk. Methods: 24 h experiments were performed in closed chest anaesthetised pigs. QRS vectors were studied by computerised vectorcardiography via Frank leads. Occlusion of the left anterior descending coronary artery followed by reperfusion was induced in 23 pigs and a sustained occlusion in 20 pigs: left anterior descending coronary artery in seven, right coronary artery in eight, and left circumflex coronary artery in five. Myocardium at risk was measured in postmortem autoradiograms. Eight animals were excluded. Results: Four minutes after occlusion, QRSmcan deviated towards the ischaemic region in 34/35 animals and returned thereafter at varying speeds. In half of the reperfused animals, deviation of QRS vectors towards the ischaemic territory was also observed during the first minutes of reperfusion. A paradoxical increase in QRS vector changes, “reperfusion peak”, was recorded during the initial minutes of reperfusion in 12/19 animals. Maximum spatial QRS vector magnitude increased in all right coronary or left circumflex coronary occlusion animals compared to 6/25 in left anterior descending coronary occlusion animals. QRS vector difference, change in spatial QRS vector angle, and maximum change in QRS azimuth 4 min after occlusion correlated significantly with extent of myocardium at risk. Conclusions: Marked directional and quantitative QRS vector changes, with significant relation to size and location of myocardium at risk, were recorded during the initial minutes of ischaemia. The transient increase in QRS vector changes during the first minutes of reperfusion deserves further exploration as a new indicator of reperfusion. Cardiovascular Research 1993; 27 :327-333

The aim of the present study was primarily to evaluate the haemodynamic effects of the ACE-inhibitor ramipril which is active via its metabolite ramiprilat. Ramipril 1.25, 2.5 and 5 mg and placebo was administered orally to 4 groups of 12 patients with heart failure (NYHA III) in a double-blind randomised, parallel study. Haemodynamics were monitored for 24 h and blood was sampled and urine collected for up to 96 h. In the placebo-treated group the cardiac index (CI) was significantly increased (15.8%) and right atrial pressure decreased (26.6%). Ramipril 1.25 mg had insignificant haemodynamic effects compared to placebo and the 2.5 mg dose had significant effects on some haemodynamic variables. Ramipril 5 mg had pronounced and sustained effects on pulmonary artery pressure, which fell by 43.7%, and pulmonary capillary wedge pressure (PCWP; −59.1%); systemic vascular resistance was also decreased 21%. A significant effect on CI was only seen after 2.5 mg ramipril (+7.4%). The mean maximal degree of ACE inhibition was 73.2, 90.4 and 98.5%, respectively, after the three doses of ramipril. Complete inhibition of ACE-activity was seen at a mean plasma concentration of ramiprilat of 4.7 ng·ml−1. The degree of inhibition declined with a half life of about 75 h. There was a significant relation between the degree of ACE-inhibition and change in PCWP but not with the change in SVR. Ramipril was mainly eliminated in the form of ramiprilat and inactive metabolites.

A method for large specimen cryosectioning is described. Specimens of pig heart ventricles were lightly fixed by microwave irradiation, embedded in 10% gelatin, frozen in hexan chilled with dry ice, and sectioned using an LKB 2250 PMW cryomicrotome. The sections were collected on transparent film and transferred onto glass slides. Standard histological, enzyme- and immuno-histochemical staining techniques were used. The present method allowed cryosectioning with sections of good quality which could be used for enzyme- and immuno-staining. For studies of experimental myocardial infarction, staining for phosphorylase and Periodic Acid Schiff outlined the ischemic area and antibodies against plasma fibronectin and fibrinogen delineated the infarcted myocardium.

A patient with familial amyloid polyneuropathy and congestive heart failure underwent myocardial imaging using technetium-99m pyrophosphate. Planar scintigraphy showed an intense, diffuse biventricular uptake of the radiotracer. Single-photon emission computed tomography demonstrated an unevenly distributed uptake of the isotope. The greatest activity corresponded to regions with marked echocardiographic changes. Emission tomography may aid in assessing the degree and distribution of the infiltrative lesions in cardiac amyloidosis.

We investigated if superoxide dismutase and catalase could reduce myocardial infarct size in an open chest occlusion-reperfusion model. Thirty pigs were used for the experiment. The left anterior descending artery was ligated for 60 min followed by a 5 h reperfusion period. After randomisation and blinding the two enzymes or placebo were injected into the left atrium as a bolus immediately before and at the end of the occlusion and as a continuous infusion over the first hour of the reperfusion period. The total dose for each enzyme was 8 mg/kg bw. Tetrazolium staining was used to determine infarct size. The study code was not broken until all calculations and exclusions had been made. Nine animals died from intractable ventricular fibrillation, most commonly during the occlusion. Another three were excluded for technical reasons. We found that superoxide dismutase and catalase reduced infarct size in relation to myocardium at risk from a mean of 89% to 63% (P less than 0.01). Initial plasma half life for the two enzymes after the bolus infusions were calculated to be 30 min.

With new interventions minimizing ischemic myocardial injury, accurate and reliable techniques for the detection and continuous monitoring of myocardial ischemia are essential. We compared two techniques used for the detection of myocardial ischemia during coronary angioplasty: on-line computerized vectorcardiographic (cVCG) monitoring and the standard electrocardiography (ECG) leads or the complete 12-lead ECG.Thirty patients scheduled for routine angioplasty were included in the study. cVCG was recorded continuously. The electrodes were placed according to the lead system described by Frank and connected to a computerized system for on-line vectorcardiography. A 12-lead ECG was recorded simultaneously. The absolute variable spatial ST vector magnitude (ST-VM) and the relative variable spatial ST change vector magnitude (STC-VM) were calculated and compared with the standard 12-lead ECG for the detection of ischemia.The sum of deviation in ST segment in all 12 standard ECG leads correlated closely with STC-VM, irrespective of which artery was occluded. STC-VM indicated ischemia during the first balloon inflation in 87% of the patients and demonstrated ischemia in more patients than the standard 12-lead ECG. Myocardial ischemia was not demonstrated by ST-VM in five out of 26 patients with ischemia according to STC-VM. In these cases, mainly directional vector changes and fewer changes in magnitude were observed.Compared with 12-lead ECG, on-line cVCG is a more sensitive method of detecting myocardial ischemia during coronary angioplasty and the reading is easier and faster. Our results support STC-VMor = 0.050 mV as the criterion for ischemia during angioplasty; ST-VM should be applied together with STC-VM.

Background There is conflicting and only scant evidence on the effect of gender on long-term survival after a myocardial infarction (MI). Our aim was to analyse sex-specific survival of patients for up to 23 years after a first MI in northern Sweden and to describe time trends. Methods The Northern Sweden MONICA Myocardial Infarction Registry was linked to The Swedish National Cause of Death Registry for a total of 8630 patients, 25 to 64 years of age, 6762 men and 1868 women, with a first MI during 1985-2006. Also deaths before admission to hospital were included. Follow-up ended on August 30, 2008. Results Median follow-up was 7.1 years, maximum 23 years and the study included 70 072 patient-years. During the follow-up 45.3% of the men and 43.7% of the women had died. Median survival for men was 187 months (95% confidence interval (CI) 179-194) and for women 200 months (95% CI 186-214). The hazard ratio (HR) for all cause mortality after adjustment for age group was 1.092 (1.010-1.18, P = 0.025) males compared to females, i.e. 9 percent higher survival in women. After excluding subjects who died before reaching hospital HR declined to 1.017 (95%CI 0.93-1.11, P = 0.7). For any duration of follow-up a higher proportion of women were alive, irrespective of age group. The 5-year survivals were 75.3% and 77.5%, in younger ( Conclusions Age-adjusted survival was higher among women than men after a first MI and has improved markedly and equally in both men and women over a 23-year period. This difference was due to lower risk for women to die before reaching hospital.

The American College of Cardiology and the European Society of Cardiology have recently published new guidelines on the diagnosis of acute myocardial infarction. These guidelines emphasize the importance of biochemical markers for diagnosis, and define standards for the quality of laboratory methods and decision limits. Each laboratory method in clinical routine use should be described in a peer-reviewed medical publication, the coefficient of variation should be10% in a normal reference population, and the decision level for myocardial injury should be set at the 99th percentile. Blood sampling should be individualized with regard to the onset of symptoms. Analysis of a troponin should be the standard method. If these guidelines become generally accepted the diagnostic accuracy of the methods will be improved and important prognostic information will be gained.