Biomedical subjects

H R Andersen

Publications and source records attributed to H R Andersen.

At least 55 records · Page 3Linked to original sources

PubMed1997

Long-term follow-up of patients from a randomised trial of atrial versus ventricular pacing for sick-sinus syndrome.

BACKGROUND: In a previous study of 225 patients with sick-sinus syndrome randomised to either single-chamber atrial pacing (n=110) or single-chamber ventricular pacing (n=115), we found that after a mean follow-up of 3.3 years, atrial pacing was associated with significantly less atrial fibrillation and thromboembolism whereas there was no significant difference in mortality and heart failure between the two groups. We aimed to find out whether this beneficial effect of atrial pacing is maintained during extended follow-up of up to 8 years. METHODS: Follow-up visits for all patients were at 3 months, 12 months, then once a year at which patients had a physical examination, ECG recording, and pacemaker check-up. Endpoints were mortality, cardiovascular death, atrial fibrillation, thromboembolic events, heart failure, and atrioventricular block. Data was analysed on Dec 31, 1996. FINDINGS: At long-term follow-up, 39 patients from the atrial group had died versus 57 from the ventricular group (relative risk 0.66 [95% CI 0.44-0.99]; p=0.045). 19 patients from the atrial group and 39 patients from the ventricular group died from a cardiovascular cause (0.47 [0.27-0.82]; p=0.0065). The cumulative incidences of atrial fibrillation and chronic atrial fibrillation were also significantly lower in the atrial group than in the ventricular group (0.54 [0.33-0.89], p=0.012 and 0.35 [0.16-0.76], p=0.004, respectively). Thromboembolic events occurred in 13 patients in the atrial group and 26 in the ventricular group (0.47 [0.24-0.92], p=0.023). Heart failure was less severe in the atrial group than in the ventricular group (p<0.05). In multivariate analysis, atrial pacing was significantly associated with freedom from thromboembolic events (0.47 [0.24-0.92], p=0.028) and survival from cardiovascular death (0.52 [0.30-0.91], p=0.022), but no longer with overall survival (0.71 [0.46-1.08], p=0.11) or chronic atrial fibrillation (0.45 [0.20-1.05], p=0.063). Atrioventricular block occurred in four patients in the atrial group (0.6% annual risk). INTERPRETATION: The beneficial effect of atrial pacing found in our previous study is enhanced substantially over time. Patients with sick-sinus syndrome should be treated with an atrial rather than ventricular-pacing system because after long-term follow-up, atrial pacing is associated with a significantly higher survival, less atrial fibrillation, fewer thromboembolic complications, less heart failure, and a low-risk of atrioventricular block.

Aged↗

PubMed1997

Ischemia and reperfusion of the porcine myocardium: effect on collagen.

We studied the effect of acute myocardial infarction and late reperfusion on myocardial collagen in a closed chest porcine model, to investigate if any collagen degradation could be detected in blood samples and myocardium. Sixteen 60-80 kg pigs were used with six animals serving as controls and 10 submitted to ischemia-reperfusion. In the ischemia-reperfusion group the left anterior descending coronary artery was occluded for 6 h by inflation of a percutaneous transluminal coronary angioplasty balloon followed by reperfusion for 3 h. Blood samples were taken from the aorta and the coronary sinus and analyzed for creatine kinase and collagen degradation products, i.e. the N-terminal propeptide of procollagen type III (PIIINP) and C-terminal pyridinoline cross-linked telopeptide of collagen type I (ICTP). Myocardial tissue samples were analyzed for content of hydroxyproline, collagen volume fraction and amount of extractable PIIINP/dry weight. Transmission electron microscopy of biopsies was performed to evaluate myocytes and collagen structure outside and within the infarct zone. Creatine kinase showed a statistically significant increase during ischemia and reperfusion but we found no evidence of release of collagen degradation products either during ischemia or reperfusion compared with control. Myocardial content of hydroxyproline, collagen volume fraction and extractable PIIINP/dry weight did not differ between groups. Transmission electron microscopy of biopsies from the infarct zone showed myocyte damage but no visible evidence of collagen degradation when photos were evaluated blindly. In this porcine model of acute myocardial infarction and late reperfusion no release of collagen degradation products from the myocardium or any decrease in or damage to myocardial collagen was detected.

Analysis of Variance↗

PubMed1997

Antioxidative enzyme activities in human erythrocytes.

Reliable and standardized methods are necessary to determine the expression of antioxidative enzymes and their role in maintaining health. In addition, the variability of the enzyme activities within the general population caused by age, gender, and life-style factors must be described. This study describes methodological conditions that are suitable for analyzing copper-zinc superoxide dismutase (CuZn-SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and glutathione reductase (GR) in human erythrocytes with a high degree of reproducibility. Intervals for the enzyme activities have been established in a randomly selected population of 220 individuals between 20 and 89 years of age. An age-related decrease was observed in CuZn-SOD and GR activities, whereas no age-related changes were demonstrated for GSH-Px and CAT. The GSH-Px activity was positively associated with the intake of dietary supplements and negatively correlated with tobacco consumption. These factors probably account for the fact that women tended to have higher GSH-Px activity.

Adult↗

PubMed1997

Plasma malondialdehyde as biomarker for oxidative stress: reference interval and effects of life-style factors.

Malondialdehyde (MDA) is one of the most frequently used indicators of lipid peroxidation. To generate reliable reference intervals for plasma malondialdehyde (P-MDA), a reference sample group was established in Funen, Denmark. The group consisted of 213 individuals (107 men, 106 women), ages 20-79 years. P-MDA was measured in EDTA-treated plasma after derivatization by thiobarbituric acid (TBA) and separation on HPLC. UV detection was performed at 532 nm. A reference interval was calculated as recommended by IFCC with REFVAL 3.42. The estimated reference limits (0.025 and 0.975 fractals) for the group were 0.36 and 1.24 mumol/L. The data were analyzed for gender- and age-related differences. Analysis of variance showed no interaction between gender and age, but separate analyses showed an independent effect of gender (P = 0.03), but not of age (P = 0.11). Daily smokers had a slightly higher average concentration of P-MDA than nonsmokers (P = 0.05), and P-MDA correlated with daily exposure to cigarette smoke (r = 0.162; P = 0.03). A positive correlation was also demonstrated between P-MDA and weekly alcohol consumption (r = 0.153; P = 0.03). Within-subject and day-to-day variations of P-MDA indicated that the potential of P-MDA as a biomarker for individuals is questionable. However, on a group basis, the present data support that P-MDA may be a potential biomarker for oxidative stress.

Adult↗

PubMed1996

Remodeling rather than neointimal formation explains luminal narrowing after deep vessel wall injury: insights from a porcine coronary (re)stenosis model.

BACKGROUND: Oversized balloon dilatation of normal porcine coronary arteries usually heals without stenosis formation. METHODS AND RESULTS: With the purpose of developing a stenotic model and examining the mechanisms of luminal narrowing after angioplasty, we produced a circumferential deep vessel wall injury by inflating and withdrawing an oversized chain-encircled angioplasty balloon in the left anterior descending coronary artery (LAD) of 20 pigs. Three pigs died and did not complete the study. In 8 pigs (group 1), serial coronary arteriography was performed. The lumen diameter (mean+/-SD) before dilation was 3.4 +/- .4 mm; after dilation, 4.2 +/- 0.6 mm; and at follow-ups 2 and 4 weeks later, 1.6 +/- 0.4 mm (P<.0001). In 9 pigs (group 2) examined postmortem 3 weeks after dilatation, histology revealed that the injury was deep (out to adventitia) in all arteries and completely circumferential (360 degrees) in all but two arteries. Adventitia was markedly thickened as a result of neoadventitial formation. Injury correlated strongly with neointimal formation (middle LAD, r=.71, P=.00001, but neither injury nor neointima correlated with lumen size (r=.14, P=.46 and r=.34, P=.07, respectively); ie, neointimal formation did not explain late luminal narrowing. Lumen size, however, did correlate strongly with vessel size (r=.74, P=000005). The late loss in lumen diameter observed angiographically in group 1 substantially exceeded that caused by neointimal formation seen by histology in group 2. CONCLUSIONS: The chain-encircled angioplasty balloon produced a circumferential deep vessel wall injury that healed by luminal narrowing. In this porcine model, arterial remodeling was more important than neointimal formation in late luminal narrowing.

Angioplasty, Balloon↗

PubMed1996

[Sick sinus syndrome. Pacemaker with atrial versus ventricular stimulation].

In patients with sick sinus syndrome, single chamber atrial pacing has been reported in retrospective studies to be associated with lower frequencies of atrial fibrillation, thromboembolism, heart failure, and mortality than ventricular pacing. We did a prospective randomised trial in 225 consecutive patients (142 women, 83 men; mean age 76 years) with the sick sinus syndrome, randomised to atrial (n = 110) or ventricular (n = 115) pacing and followed for up to five years (mean 40 [SD 18] months). During follow-up, the frequency of atrial fibrillation was higher in the ventricular group. Thromboembolic events (stroke or peripheral arterial embolus) occurred in 20 patients in the ventricular group and in six patients in the atrial group (p = 0.008). Twenty five patients died in the ventricular group compared with 21 in the atrial group (p = 0.74). The number of cases of heart failure did not differ between the two groups. Atrioventricular block occurred in two patients in the atrial group. It is concluded that patients with sick sinus syndrome should be treated with atrial pacing rather than ventricular pacing because atrial pacing is associated with lower frequencies of atrial fibrillation, thromboembolic complications, and a low risk of atrioventricular block.

Aged↗

PubMed1996

Variation in risk indicators of cardiovascular disease during the menstrual cycle: an investigation of within-subject variations in glutathione peroxidase, haemostatic variables, lipids and lipoproteins in healthy young women.

Variations in erythrocyte glutathione peroxidase activity, serum concentrations of lipids and lipoproteins and in blood coagulation and fibrinolysis during the menstrual cycle were studied in healthy young women. Blood samples were drawn twice a week for 9 weeks. A group of males was used for estimation of the influence on the results of factors which were not related to the menstrual cycle. Variations during the menstrual cycle were demonstrated in several of the factors analysed. The activity of glutathione peroxidase was lowest at ovulation. The clotting activity of factor II+ VII+X and the concentration of fibrinogen were lowest during mid-cycle, and the number of platelets increased in the follicular phase (days 5-9). Statistically significant variations in the fibrinolytic factors analysed (tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) were not observed during the menstrual cycle. The serum concentrations of cholesterol and LDL cholesterol were significantly higher at the start of the menstrual cycle (days 3-8) than later in the cycle (days 19-24). The concentration of HDL cholesterol was lowest in the late luteal phase (days 23-28).

Adult↗

PubMed1994

Prospective randomised trial of atrial versus ventricular pacing in sick-sinus syndrome.

In patients with sick-sinus syndrome, single-chamber atrial pacing has been reported, in retrospective studies, to be associated with lower frequencies of atrial fibrillation, thromboembolism, heart failure, and mortality than ventricular pacing; although single-chamber ventricular pacing is most commonly used. We did a prospective randomised trial in 225 consecutive patients (142 women, 83 men; mean age 76 years) with the sick-sinus syndrome, randomised to atrial (n = 110) or ventricular (n = 115) pacing and followed for up to 5 years (mean 40 [SD 18] months). During follow-up, the frequency of atrial fibrillation was higher in the ventricular group, except at the first follow-up at 3 months. Thromboembolic events (stroke or peripheral arterial embolus) occurred in 20 patients in the ventricular group and in 6 patients in the atrial group (p = 0.0083). 25 patients died in the ventricular group compared with 21 in the atrial group (p = 0.74). Heart failure estimated by the New York Heart Association classification and by the daily doses of diuretics did not differ between the two groups. Atrioventricular block occurred in 2 patients in the atrial group. Patients with sick-sinus syndrome should be treated with atrial pacing rather than ventricular pacing because atrial pacing is associated with lower frequencies of atrial fibrillation, thromboembolic complications, and a low risk of atrioventricular block.

Aged↗

PubMed1994

Dofetilide reduces the incidence of ventricular fibrillation during acute myocardial ischaemia. A randomised study in pigs.

OBJECTIVE: The aim was to investigate whether dofetilide, a new selective cardiac potassium channel blocker, would reduce the incidence of ischaemia induced ventricular fibrillation in closed chest pigs. METHODS: A randomised, blinded, and placebo controlled study was performed in 32 closed chest pigs with a body weight of 70-90 kg. The animals were given a dofetilide/placebo bolus of 25 micrograms.kg-1 over a 10 min period followed by a maintenance dose of 12.5 micrograms.kg-1.h-1 for the next 130 min. Electrocardiograms were recorded during sinus rhythm and during atrial pacing, before (t0) and 20 min (t20) after the beginning of drug treatment. Twenty minutes after the start of drug treatment, acute myocardial ischaemia was induced by inflation of a percutaneous transluminal coronary angioplasty (PTCA) balloon placed in the left anterior descending coronary artery proximal to the first diagonal branch. If ventricular fibrillation occurred during the 2 h ischaemia period the balloon was deflated and defibrillation attempted by dc shocks (360 joules) up to a maximum of 10 shocks. RESULTS: Basal characteristics for the dofetilide group (n = 16) and the placebo group (n = 16) were similar: body weight 76.1(SD 5.4) kg v 75.4(4.4) kg; heart weight 296(29) g v 302(43) g; and heart rate (RR interval) 854(261) ms v 800(307) ms. During atrial pacing 100 beats.min-1 the paced QT interval (QTp) measured at t0 in the dofetilide group and the placebo group were similar, at 335(36) ms v 330(31) ms, respectively. During drug treatment (t20) the QTp interval increased to 412(38) ms in the dofetilide group (p < 0.001) whereas a much smaller increase to 341(32) ms was observed in the placebo group (p < 0.05). The heart rate and ST elevation in the two groups were similar during coronary artery occlusion. During the 2 h ischaemic period, ventricular fibrillation occurred in 6/16 (38%) of the dofetilide treated pigs, and in 13/16 (81%) of the placebo treated pigs (p < 0.01). Defibrillation was successful in 5/6 (83%) and 6/13 (46%) of the animals, respectively (p = 0.3). CONCLUSIONS: Dofetilide significantly reduces the incidence of ischaemia induced ventricular fibrillation in closed chest pigs.

Animals↗

PubMed1994

Dose and time relations in Hg(++)-induced tubular necrosis and regeneration.

Mercuric chloride is a well-known human and animal nephrotoxicant. Previous studies have demonstrated an inverse relationship between dose size and relative whole-body retention of mercury after oral administration of mercuric chloride to mice. The present study indicates that this inverse relationship is caused by a dose-related induction of kidney damage leading to increasing leakage of mercury through the kidneys. Histopathologic investigation revealed extensive necrosis of the proximal tubules in kidneys from mice exposed to 100 mumole HgCl2/kg or higher doses. Moreover, maximum renal damage occurred between days 2 and 3 after administration. The renal damage was followed by regeneration, which was observed between days 3 and 7 at increasing dose levels up to 100 mumole HgCl2/kg. The amount of glutathione and the glutathione peroxidase activity in kidney decreased with increasing doses of mercuric chloride. The reduced glutathione peroxidase activity was due to a reduction in selenium-dependent glutathione peroxidase activity. The level of lipid peroxidation was not changed by increasing doses of mercuric chloride, and hence was not a primary toxic mechanism in acute nephrotoxicity induced by mercuric chloride.

Animals↗

PubMed1993

Preserved oxidative activity and chemotaxis of circulating neutrophils in patients with acute myocardial infarction.

The neutrophil granulocyte seems to be intimately involved in the destructive processes leading to myocardial damage observed in ischaemic/reperfusion injuries. The process may cause stress to the peripheral circulating neutrophils leading to exhaustion and decreased function. We conducted a study in which the function of peripheral neutrophil granulocytes was measured in 21 patients with an acute myocardial infarction 0-24 and 48-72 h after the onset of symptoms. Ten patients received thrombolytic treatment (streptokinase). Neutrophil function was judged by superoxide generating capacity and chemotactic ability. Compared to healthy controls neutrophil function was found to be preserved in patients with myocardial infarction. Furthermore, streptokinase treatment of the patients did not modulate neutrophil function. In-vitro studies demonstrated that low concentrations of streptokinase (12-300 U.ml-1) or recombinant plasminogen activator (0.12 micrograms.ml(-1)-3.0 micrograms.ml-1) did not influence neutrophil superoxide generation. However, at higher concentrations (100-10,000 U.ml-1 and 10-100 micrograms.ml-1 respectively) both thrombolytics induced a significant increase in phorbol myristate acetate-stimulated superoxide generation. Neither of the thrombolytics influenced neutrophil chemotaxis in vitro. It is concluded that neither myocardial infarction nor streptokinase treatment decrease superoxide generating capacity or chemotactic ability of circulating neutrophils.

Adult↗

PubMed1993

Effects of dietary alpha-tocopherol and beta-carotene on lipid peroxidation induced by methyl mercuric chloride in mice.

Exposure of male CBA mice to methyl mercuric chloride, CH3HgCl, (10-40 mg/l in drinking water) for 2 weeks resulted in dose-related Hg deposition and enhanced lipid peroxidation in liver, kidney and brain. Mice were fed well-defined semisynthetic diets containing different levels of alpha-tocopherol (10, 100 or 1000 mg/kg) or beta-carotene (1000, 10,000 or 100,000 IU/kg) for four weeks, two groups on each diet. The concentrations of alpha-tocopherol and beta-carotene used corresponded to deficient, normal and high levels. During the last two weeks, one group on each diet was given 40 mg CH3HgCl/l of drinking water. High dietary alpha-tocopherol protected against CH3HgCl induced hepatic lipid peroxidation, whereas the alpha-tocopherol deficient diet further enhanced CH3HgCl induced hepatic lipid peroxidation. Similar, though statistically non-significant effects occurred in the kidneys, alpha-Tocopherol did not protect against CH3HgCl induced lipid peroxidation in the brain. Excess dietary beta-carotene further enhanced CH3HgCl induced lipid peroxidation in liver, kidney and brain. CH3HgCl significantly decreased the activity of total glutathione peroxidase (T-GSH-Px) and Se-dependent glutathione peroxidase (Se-GSH-Px) in the kidneys in all dietary groups. High dietary alpha-tocopherol enhanced the activity of Se-GSH-Px in liver and kidney compared to the activity in mice fed the normal level of alpha-tocopherol. This occurred in mice exposed to CH3-HgCl as well as in unexposed mice, and the difference between CH3HgCl exposed and unexposed mice was not diminished. High dietary alpha-tocopherol increased the activity of both Se-GSH-Px and T-GSH-Px in the brain of CH3HgCl-exposed mice. The dietary level of beta-carotene did not affect the activity of the two enzymes in the organs investigated.

Animals↗

PubMed1993

Catheter-implanted prosthetic heart valves. Transluminal catheter implantation of a new expandable artificial heart valve in the descending thoracic aorta in isolated vessels and closed chest pigs.

A new expandable artificial heart valve was developed for implantation by a transluminal catheter technique without using thoracotomy or extracorporeal circulation. The aim of this study was to implant the valve in isolated vessels of the descending thoracic aorta as well as in closed chest pigs, and furthermore to study the prosthesis' mechanical stability and the valve function. The artificial valve was made by mounting a porcine aortic valve on an expandable stent. Before implantation, the stent-valve was compressed on a deflated balloon catheter and mounted inside an introducer sheath. After intravascular introduction to the descending thoracic aorta the stent-valve was discharged from the sheath. Implantation was performed by balloon inflation which expanded the stent-valve to a diameter exceeding the internal vessel's diameter. After balloon deflation the stent-valve maintained an expanded configuration ensuring a stable fixation against the vessel wall. In vitro implantations were performed in 36 isolated descending thoracic aorta specimens obtained from 80 kg pigs. Mechanical stability was evaluated by applying a downing load to the prosthesis. No displacement occurred at loads < or = 1 kg when a large balloon (31 mm) was used for implantation. Transvalvular pressure differences between 11-47 mmHg (median) were obtained at antegrade flowrates between 5-8 l/min. Furthermore, only moderate leakage flows were measured during retrograde perfusion. In vivo implantations were performed in six 80 kg pigs. Implantation was safe and easy, and angiograph and haemodynamic evaluations revealed essentially no stenosis or regurgitation. No complications in migration, perforation, hemorrhage or thrombosis were observed. This study indicates a good mechanical stability and valve function of the new expandable artificial valves.

Animals↗

PubMed1992

Transluminal implantation of artificial heart valves. Description of a new expandable aortic valve and initial results with implantation by catheter technique in closed chest pigs.

A new artificial aortic valve prosthesis was developed for implantation by the transluminal catheter technique without thoracotomy or extracorporal circulation. The new heart valve was prepared by mounting a porcine aortic valve into an expandable stent. Before implantation, the stent-valve was mounted on a balloon catheter and compressed around the deflated balloon. The stent-valve mounted balloon catheter was then advanced retrogradely to the ascending aorta or the aortic root in anaesthetized pigs. Implantation was performed by balloon inflation which expanded the stent-valve to a diameter exceeding the internal diameter of the vessel--thus ensuring a stable fixation against the vessel wall. A total of nine implantations were performed in seven 70 kg closed chest pigs. Sub- and supracoronary implantation was performed in two and three pigs, respectively, while implantation in both positions was done in two. Angiographic and haemodynamic evaluation after implantation revealed no significant stenosis (less than or equal to 16 mmHg) in any of the nine valves and trivial regurgitation in only two. Complications were associated with restriction of the coronary blood flow in three animals. This preliminary study indicates that artificial aortic valves can be implanted in closed chest animals by transluminal catheter technique.

Animals↗

PubMed1992

Nonpharmacologic treatment of supraventricular and ventricular tachyarrhythmias. A review of 249 consecutive patients.

Incapacitating or life-threatening tachyarrhythmias were treated nonpharmacologically in 249 patients from 1982 to 1991. Among 92 patients surgically treated for supraventricular tachycardia the cure rate was 93% and the complication rate 12%. Radiofrequency catheter ablation gave an equal cure rate in 51 patients, but with no major complications or mortality. Direct-current catheter ablation of the His bundle was successful in 96% of 27 patients with drug-refractory atrial fibrillation or other supraventricular tachyarrhythmias. Among 64 patients undergoing surgery for ventricular tachycardia/ventricular fibrillation, the perioperative mortality was 9%, estimated 5-year survival 69% and estimated 5-year freedom from the preoperative arrhythmias 72%. Of 18 patients treated with implantable cardioverter defibrillator, three (18%) died of heart failure during follow-up. Nonpharmacologic treatment of tachyarrhythmias is concluded to be effective and often definitively curative. The safety-risk ratio is improving as new treatment modalities are developed.

Adolescent↗

PubMed1991

Mercuric chloride-induced kidney damage in mice: time course and effect of dose.

The rate of elimination of mercury after a single oral or intraperitoneal administration of HgCl2 to male or female mice has recently been demonstrated to be inversely related to the dose size (Nielsen and Andersen, 1989, 1990). The present study demonstrates dose-related induction of renal tubular damage, followed by regeneration, after oral administration of HgCl2 to female mice. Dose-related increased fractional urinary mercury excretion (expressed as percent of dose) was also demonstrated. At increasing dose of HgCl2, the renal activity of selenium-dependent glutathione peroxidase decreased, and was only 50% of the activity in untreated controls after administration of 200 mumol HgCl2/kg. At higher doses, the renal concentration of glutathione was significantly reduced as well. The degree of tissue damage was inversely related to the fractional deposition of mercury in the kidneys. This study indicates that the reduction in fractional whole-body retention of mercury with increasing dose size previously demonstrated is due to increased urinary mercury excretion during transient renal damage followed by regeneration, as extensive leakage took place before extensive regeneration was noted.

Administration, Oral↗

PubMed1990

[Supraventricular tachycardia treated with percutaneous catheter ablation of the arteriovenous conduction system].

Twelve patients with supraventricular tachycardia refractory to medical management were treated with catheter ablation (fulguration) of the atrioventricular (AV) conduction system followed by pacemaker implantation. All 12 patients had initially 3 degrees AV block. In ten patients it was permanent. One patient had a permanent 1 degree AV block and left bundle branch block. In one patient with initial 3 degrees AV block AV conduction resumed. No major complications were seen. At follow-up, the mean observation period was 15 months (range 3-57 months). All ten patients with permanent 3 degrees AV block were free of arrhythmic symptoms and without any medication. The patient with permanent 1 degree AV block was free of symptoms and arrhythmia, but died 16 months after the ablation. The patient with relapse of the AV conduction continued to have arrhythmic symptoms, but ECG did not confirm arrhythmia. It is concluded that catheter induced 3 degrees AV block is a safe and efficient treatment of patients with supraventricular tachycardia refractory to medical treatment.

Adolescent↗

PubMed1990

ST deviation in right chest leads V3R to V7R during percutaneous transluminal coronary angioplasty.

ST elevation in right chest leads during evolving inferior myocardial infarction indicates right ventricular involvement. Theoretically, such changes may be due to reversible or irreversible myocardial ischemia. Whether similar ST elevations can be recorded in patients with myocardial ischemia without infarction is unknown. To clarify this, right chest leads V3R to V7R were recorded during percutaneous transluminal coronary angioplasty in 43 patients who had a total of 45 arteries dilated. Balloon occlusion of the right coronary artery caused transient ST elevation, whereas closure of the left anterior descending coronary artery or the left circumflex artery was associated with transient ST depression. These findings were 100% discriminative in leads V5R and V6R. Furthermore, ST elevation greater than or equal to 1 mm in one or more of leads V4R to V7R was seen only when the right coronary artery was occluded. Thus transient myocardial ischemia without infarction may cause ST elevation in the right chest leads and ST elevation greater than or equal to 1 mm in one or more leads V4R to V7R is seen exclusively with occlusion of the right coronary artery.

Angina Pectoris↗