Electrophysiologic and clinical effects of oral encainide in paroxysmal atrioventricular node reentrant tachycardia.

The electrophysiologic effects of oral encainide (75 to 150 mg daily) were evaluated in 14 patients (6 male and 8 female, aged 49 +/- 9 years) with atrioventricular (AV) node reentrant tachycardia of the slow-fast type. The patients were studied in control conditions and after 2 to 12 days of treatment. Encainide increased the AH interval from 67 +/- 10 to 82 +/- 23 ms (p less than 0.02). Anterograde Wenckebach cycle length was increased in three patients, reduced in four, unchanged in one; it was not measurable in the remaining patients because tachycardia was induced. Retrograde Wenckebach periodicity increased from 307 +/- 71 to 401 +/- 92 ms (p less than 0.005) in all nine patients in whom it was measurable; complete retrograde block was observed in one patient. At the control study, tachycardia was induced in all patients, with a mean cycle length of 341 +/- 50 ms; after encainide, tachycardia was inducible in only 1 patient, with an increase in cycle length from 270 to 320 ms; in the other patients, tachycardia was not inducible because of a lack of retrograde (11 patients) or anterograde (2 patients) conduction. The mean plasma concentrations of encainide and its metabolites O-demethyl-encainide and 3-methoxy-O-demethyl-encainide measured in 13 patients during the repeat study were 161 +/- 304, 128 +/- 100 and 95 +/- 85 ng/ml, respectively; three poor metabolizers who presented a high concentration of the parent compound were observed in this series. All patients were discharged on encainide at a mean daily dose of 112 +/- 39 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

An in vivo study of phosphorus and glucose metabolism in Alzheimer's disease using magnetic resonance spectroscopy and PET.

OBJECTIVES: To study phosphorus and glucose metabolism in whole-brain slices of otherwise healthy patients with dementia of the Alzheimer type (DAT) and healthy controls. DESIGN: We used proton nuclear magnetic resonance imaging phosphorus spectroscopy and positron emission tomography to study in vivo brain phosphorus and glucose metabolism. PATIENTS: Whole-brain slice phosphorus metabolism was studied in nine drug free patients with mild to moderately severe dementia of the Alzheimer type (DAT) and in eight age- and sex-matched healthy controls. Mean ages (+/- SD) of the patients and controls were 60 +/- 10 years and 64 +/- 16 years, respectively. Positron emission tomography was used to study cerebral glucose metabolism in seven of the patients with DAT and seven of the healthy controls. RESULTS: Patients with DAT had significant brain glucose hypometabolism compared with controls, but there was no significant group difference in any phosphorus metabolite concentration or ratio in the same volume of brain tissue. Also, within patients with DAT there was no correlation between any phosphorus metabolite concentration or ratio and either severity of dementia or glucose metabolism. CONCLUSIONS: We suggest glucose metabolism is reduced early in DAT (reflecting decreased basal synaptic functioning) and is unrelated to a rate limitation in glucose delivery, abnormal glucose metabolism, or abnormal coupling between oxidation and phosphorylation. Normal or near-normal levels of phosphorus metabolites are maintained in mild, moderate, and severe DAT. Therefore, altered high-energy phosphate levels are not a consequence of reduced glucose metabolism in DAT, and do not play a major role in the pathophysiology of the disorder, at least in whole-brain sections.

Brain atrophy in hypertension. A volumetric magnetic resonance imaging study.

To determine whether hypertension, the predominant risk factor for stroke and vascular dementia, is associated with brain atrophy, magnetic resonance imaging (MRI) scans were performed to quantify brain volumes and cerebrospinal fluid spaces. Eighteen otherwise healthy, cognitively normal older hypertensive men (mean +/- SD age, 69 +/- 8 years, duration of hypertension 10-35 years) and 17 age-matched healthy, normotensive male control subjects were studied in a cross-sectional design. Axial proton-density image slices were analyzed using region-of-interest and segmentation analyses. The hypertensive subjects had significantly larger mean volumes of the right and left lateral ventricles (p less than 0.05, both absolute volume and volume normalized to intracranial volume) and a significantly smaller normalized mean left hemisphere brain volume (p less than 0.05) with a trend toward significance for a smaller normalized mean right hemisphere volume (p less than 0.09). Four hypertensive subjects and one healthy control subject were found to have severe periventricular hyperintensities on T2-weighted MRI images. When data for these subjects were removed from the analyses, the normalized lateral ventricle volumes remained significantly larger in the hypertensive group. Lateral ventricle enlargement was not related to age or use of diuretics in the hypertensive group nor to duration of hypertension between 10 and 24 years. Our findings suggest that long-standing hypertension results in structural changes in the brain. Longitudinal studies will determine whether MRI-associated changes are progressive and if such changes identify hypertensive subjects at increased risk for clinically apparent brain dysfunction.

Early detection of Alzheimer's disease: a statistical approach using positron emission tomographic data.

Correlational analysis of regional cerebral glucose metabolism (rCMRglc) obtained by high-resolution positron emission tomography (PET) has demonstrated reduced neocortical rCMRglc interactions in mildly/moderately demented patients with probable Alzheimer's disease (AD). Thus, identification of individual differences in patterns of rCMRglc interactions may be important for the early detection of AD, particularly among individuals at greater risk for developing AD (e.g., those with a family history of AD). Recently, a statistical procedure, using multiple regression and discriminant analysis, was developed to assess individual differences in patterns of rCMRglc interdependencies. We applied this new statistical procedure to resting rCMRglc PET data from mildly/moderately demented patients with probable AD and age/sex-matched controls. The aims of the study were to identify a discriminant function that would (a) distinguish patients from controls and (b) identify an AD pattern in an individual at risk for AD with isolated memory impairment whose initial PET scan showed minor abnormalities, but whose second scan showed parietal hypometabolism, coincident with further cognitive decline. Two discriminant functions, reflecting interactions involving regions most involved in reduced correlations in probable AD, correctly classified 87% of the patients and controls, and successfully identified the first scan of the at-risk individual as AD (probability > 0.70). The results suggest that this statistical approach may be useful for the early detection of AD.

Activation of cerebral blood flow during a visuoperceptual task in patients with Alzheimer-type dementia.

Changes in regional cerebral blood flow (rCBF) associated with a face-matching task were examined using positron emission tomography (PET) and H2(15)O in 7 patients with mild-moderate dementia of the Alzheimer type (DAT) and in 8 healthy age-matched controls. rCBF was normalized to whole brain flow and pixel-by-pixel difference images were computed by contrasting flow during a control task to flow during face matching. Both patients and controls showed bilateral rCBF increases in occipitotemporal extrastriate cortex during face matching. The magnitude of these increases was not significantly different between the groups. In addition, the patients showed greater rCBF activation in regions of occipital and frontal cortex. These results show that early in the course of DAT, patients utilize extrastriate cortex to perform a visuoperceptual task, as do control subjects but also show rCBF increases in additional cortical areas. Activation of these additional areas of cortex in the patients may reflect an increased attentional load during face matching due to their reduced cognitive capacity.

The effect of white matter hyperintensity volume on brain structure, cognitive performance, and cerebral metabolism of glucose in 51 healthy adults.

OBJECTIVE: To assess the association of MRI white matter hyperintensities (WMHI) with cognitive performance, cerebral structure, and cerebral metabolism in 51 healthy individuals aged 19 to 91 years without cerebrovascular risk factors. BACKGROUND: Abnormal white matter signals have been associated with brain atrophy, reduced cerebral blood flow, focal neurologic signs, gait disorder, and poorer neuropsychological test performance. Most studies of WMHI, however, include subjects with hypertension or other identifiable causes of cerebrovascular disease that may have an independent effect on brain structure and function. To assess brain changes associated with WMHI independent of cerebrovascular risk factors, we determined WMHI volume, brain volume, cerebral metabolism, and cognitive performance for a group of subjects free of medical illness. Regional cerebral metabolism and cognitive domains were also assessed to evaluate the possible role of frontal lobe dysfunction in subjects with WMHI. DESIGN: Cross-sectional study of 51 very healthy subjects aged 19 to 91 years. METHODS: WMHI, brain, and CSF volumes were determined by MRI segmentation. Neuropsychological tests were employed to assess multiple cognitive domains. Brain metabolism was determined from 18-fluoro-2-deoxy-D-glucose PET. Multivariate relations were tested with stepwise linear regression. Models included the potential confounders of age and education where appropriate. RESULTS: The distribution of WMHI volume was bimodal, with five subjects having WMHI volumes beyond three SDs from the normally distributed population. A WMHI volume of greater than 0.5% of intracranial volume was considered abnormal. Within the multivariate models, WMHI volumes were significantly predictive of increased ventricular volume, reduced brain volume, and reduced cognitive scores. Subjects with greater than 0.5% WMHI volume also had significantly lower frontal lobe metabolism, significantly higher systolic blood pressure, significantly larger ventricular volume, and significantly lower scores on frontal lobe-mediated neuropsychological tests than age-matched controls. CONCLUSION: WMHI volume is associated with structural and functional brain changes even within a group of very healthy individuals. WMHI is associated with poorer frontal lobe cognitive function and, when severe, is accompanied by significantly reduced frontal lobe metabolism. Subjects with large WMHI volumes have significantly higher systolic blood pressure, brain atrophy, reduced cerebral metabolism, and lower scores on tests of frontal lobe function than age-matched controls. Large amounts of WMHI are, therefore, pathologic and may be related to elevated systolic blood pressure even when it is within the normal age-related range.

High-resolution PET studies in Alzheimer's disease.

Forty-seven patients with probable dementia of the Alzheimer type (DAT) and 30 healthy age-matched controls were scanned using [18F]-2-fluoro-2-deoxy-D-glucose on a Scanditronix PC 1024-7B tomograph (inplane resolution = 6 mm, axial resolution = 10 mm). Patients and controls were scanned in the resting state with their eyes patched and ears occluded. The regional cerebral metabolic rates for glucose (rCMRglc) in most major neocortical and subcortical gray matter regions, and certain metabolic ratios (rCMRglc/ calcarine rCMRglc), quantitatively discriminated even the mildly demented patients from healthy controls. The association neocortices showed metabolic abnormalities that were more severe than those in the sensorimotor and calcarine regions. All demented groups showed significant neuropsychological disturbances when compared to healthy controls. These data demonstrated widespread metabolic disturbances, particularly in the association areas, relatively early in Alzheimer's disease, and more profound involvement with disease progression.

Spontaneous remission of variant angina documented by Holter monitoring and ergonovine testing in patients treated with calcium antagonists.

Twenty-four patients with Prinzmetal's variant angina showing a favorable initial response to calcium antagonist treatment were studied to assess the evolution of the disease and the frequency and time course of spontaneous remission. At 3, 6 and 12 months from the acute phase, patients underwent in-hospital control studies, with 48-hour Holter monitoring and ergonovine testing carried out during treatment and after its interruption. During calcium antagonist therapy complete protection from spontaneous attacks was documented in 22 of 24 patients at 3 months, in 19 of 21 at 6 months and in all 21 at 12 months; ergonovine test results were negative in 16 of 23 patients at 3 months, in 16 of 20 at 6 months and in all 20 studied at 12 months. After stopping treatment spontaneous attacks did not reappear in 7 of 24 patients (29%), 14 of 21 (66%) and 16 of 21 (76%) at 3, 6 and 12 months respectively, while the ergonovine test response remained negative in 6 of 21 (28%), 7 of 18 (39%) and 13 of 20 (65%) of the patients controlled at 3, 6 and 12 months. Thus, complete remission of angina documented by both Holter recording and ergonovine testing occurred in 5 of 24 patients (21%) at 3 months, in 7 of 21 (33%) at 6 months and in 12 of 21 (57%) at 12 months. Patients with remission of angina had a shorter duration of symptoms and more often showed normal or not critically diseased coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperventilation and ergonovine tests in Prinzmetal's variant angina pectoris in men.

Hyperventilation and ergonovine tests were carried out in a group of 30 patients with variant angina to assess the sensitivity of the 2 tests and to correlate the response with spontaneous disease activity. Hyperventilation produced a positive response in 83% (25 of 30) and ergonovine in 93% (28 of 30) of the patients. After hyperventilation 22 of 25 showed ST-segment elevation, 2 ST depression and 1 T-wave pseudonormalization; after ergonovine ST-segment elevation developed in 23 patients, ST depression in 4 and T-wave pseudonormalization in 1. In all cases the electrocardiographic changes occurred in the same leads as during the spontaneous attacks. The incidence of chest pain and ventricular arrhythmias was similar during both tests; spontaneous remission of ischemia, however, was more frequent (48 vs 14%) after hyperventilation than after ergonovine. Acute ischemia developed at a mean of 218 +/- 112 seconds after the end of hyperventilation in 19 of 25 positive tests; at that time double product was not significantly different from basal values. The sensitivity of hyperventilation was similar (95 vs 100%) to ergonovine in the patients with greater than or equal to 1 daily attack, while in those with less than 1 daily attack the sensitivity of hyperventilation decreased to 55% compared to 77% with ergonovine. Thus, in variant angina the sensitivity of both tests correlates with disease activity. Hyperventilation is a safe provocative test with a sensitivity similar to ergonovine in patients with active disease; however, in patients with sporadic attacks hyperventilation has a lower sensitivity than ergonovine and therefore a limited diagnostic value.

Treatment of vasospastic angina pectoris at rest with nitroglycerin ointment: a short-term controlled study in the coronary care unit.

The effectiveness of nitroglycerin ointment in vasospastic angina pectoris at rest was evaluated in 10 patients selected for study. The study was performed after a 24 hour control period, and a randomized single-blind crossover experimental design was followed. Two percent nitroglycerin ointment (15 mg) or placebo ointment was administered every 6 hours for a period of 48 hours each; the first treatment period was followed by a second in which each preparation was used for a 24 hour period. All patients were hospitalized in the coronary care unit; an objective evaluation was carried out using a multichannel electrocardiographic recording to assure recognition of the painless ischemic episodes. Coronary angiography showed critical stenosis of one or two vessels in 9 of the 10 patients; spasm was demonstrated in 3. Results of the ergonovine test were positive in nine of nine patients. Nitroglycerin ointment produced a significant reduction in the mean daily number of episodes during the first (12.5 +/- 3.9 versus 0.5 +/- 0.4, p less than 0.02) as well as the second treatment period (10.6 +/- 3.8 versus 0.6 +/- 0.4, p less than 0.02). These results demonstrate that nitroglycerin ointment provides effective, long-lasting protection against angina due to coronary spasm.

Treatment of angina at rest with nifedipine: a short-term controlled study.

The effectiveness of nifedipine in treating angina pectoris at rest was evaluated in 14 patients with frequent ischemic episodes associated with S-T segment elevation or depression. The trial consisted of (1) a 48 hour control period; (2) a placebo period and a period of treatment with nifedipine of 48 hours each; and (3) a second placebo period and a second period of treatment with nifedipine of 24 hours each. The efficacy of treatment was evaluated by continuous electrocardiographic recording to detect painless ischemic episodes. During coronary angiography coronary spasm was demonstrated in five patients. The ergonovine maleate test was positive in seven of eight patients. No statistically significant difference was found in the mean daily number of ischemic episodes between the control period and the first placebo period, or between the control and the second placebo periods. Nifedipine produced a highly significant reduction in the mean daily number of episodes compared with the response to placebo during the first as well as the second period. Nifedipine is effective in angina at rest caused by coronary arterial spasm. The prevention of ischemia may be related to the ability of nifedipine to decrease calcium-dependent coronary muscle tone and to prevent coronary spasm.

Ventricular tachyarrhythmias in Prinzmetal's variant angina: clinical significance and relation to the degree and time course of S-T segment elevation.

Fifty-six patients with active Prinzmetal's variant angina were studied to determine the incidence and clinical significance of ventricular tachyarrhythmias and the correlation between arrhythmias and degree and time course of S-T segment changes during the ischemic attacks. Twenty-nine patients (Group I) had no ventricular arrhythmias in any of the 1,083 recorded episodes, while 27 patients (Group II) developed arrhythmias in 18% of the attacks. No significant differences in clinical, electrocardiographic, angiographic, or hemodynamic findings could be found between the 2 groups. In 23 of the 27 Group II patients, ventricular arrhythmias developed during maximal S-T segment elevation (occlusion arrhythmias), while in 10 they occurred during resolution of S-T segment changes (reperfusion arrhythmias); 6 of the latter patients also had occlusion arrhythmias. Eight of the 23 patients with occlusion arrhythmias and 6 of the 10 with reperfusion arrhythmias had ventricular fibrillation or ventricular tachycardia. Maximal S-T segment elevation was significantly greater (p less than 0.001) in patients with occlusion arrhythmias than in those without arrhythmias. The episodes with reperfusion arrhythmias were significantly longer (p less than 0.001) and showed a significantly greater S-T segment elevation (p less than 0.001) than those without arrhythmias in Group I patients. This study shows that significant ventricular tachyarrhythmias develop during ischemic attacks in about 50% of patients with active variant angina; clinical and angiographic features are not useful in distinguishing patients with arrhythmias from the others. Our findings suggest that in variant angina ventricular arrhythmias may be due to the effects of both coronary artery occlusion and reperfusion; both types of arrhythmias are correlated with the severity of ischemia, as measured by the degree of S-T segment elevation. Reperfusion arrhythmias also appear to be correlated with the duration of ischemia.

Brain metabolic function in older men with chronic essential hypertension.

BACKGROUND AND METHODS. To determine the effects of hypertension on brain function, positron emission tomography (PET) studies using (18F)-2-fluoro-2-deoxy-D-glucose (FDG) were performed on a group of 17 otherwise healthy older hypertensive men (mean age +/- SD = 69 +/- 8 yr) and 25 age- and gender-matched controls. Subjects had medically treated essential hypertension for a minimum of 10 years (range = 10 to 24 yr) with no evidence of end-organ impairment from hypertension by routine clinical screening and by history. All hypertensive and control subjects were determined to be cognitively normal by extensive neuropsychological testing. The hypertensive subjects previously had been reported to have lateral ventricle enlargement and left hemisphere brain atrophy by quantitative MRI. PET data were analyzed using t-tests to look at group differences.

Network analysis of PET-mapped visual pathways in Alzheimer type dementia.

Using path analysis to determine the systems-level neural networks mediating specific tasks from regional cerebral blood flow (rCBF) data obtained by positron emission tomography (PET), we recently found in young subjects strong functional linkages during a face matching task along a right hemisphere ventral network including occipital, temporal, and frontal regions. In this study, PET data obtained during a face matching task from mildly affected patients with dementia of the Alzheimer type (DAT) and healthy matched controls showed that (1) the neural model obtained in young subjects provides a good fit to data from old subjects; (2) although the DAT patients could perform this task with the same accuracy as controls, they did not use the same functional network.

Interregional correlations of resting cerebral glucose metabolism in old and young women.

A correlational analysis of normalized (regional to whole-brain) regional cerebral metabolic rates for glucose obtained in the 'resting' state (eyes covered, ears plugged) using [18F]fluorodeoxyglucose, demonstrated differences between old and young women in patterns of functional associations. Fifteen healthy young (age less than 40 years) and 17 healthy old women (age greater than 64 years) were scanned with a Scanditronix PC1024-7B tomograph. The brain was divided into 65 regions of interest. The old women had fewer and less positive correlations between pairs of metabolic ratios in the frontal and parietal cortices. The results suggest an age-related reduction in frontal and parietal functional interactions in the 'resting' state that is consistent with a prior correlation analysis using a low resolution ECAT II scanner on young and old men. Reduced functional interactions may reflect age-related cognitive changes.

When are arrhythmias and conduction disturbances markers of myocardial ischemia at rest?

Myocardial ischemia, particularly when transmural as in variant angina pectoris, may be associated with ventricular tachycardia, ventricular fibrillation and paroxysmal atrioventricular block (15%). Syncope (7%) and sudden death (3%) due to these malignant arrhythmias are sometimes a unique marker of myocardial ischemia. Two-hundred fifty-four patients (220 males and 34 females), aged 5 +/- 9 years with transmural myocardial ischemia related to coronary artery spasm, were studied. Particular attention was paid to the role of syncopal attacks as unique clinical manifestation of silent ischemia. Patients examined were divided into 3 Groups. Group 1 includes 5/254 (2%) patients with atrial fibrillation during acute ischemia. Group 2 was divided into four subgroups: subgroup A includes 17/254 (7%) patients with syncopal attacks due to malignant arrhythmias (ventricular tachycardia and advanced A-V block); subgroup B, 15/254 (6%) patients with documented malignant arrhythmias, without syncopal attacks; subgroup C, 7/254 (3%) with ventricular fibrillation during acute ischemia and subgroup D, 18/254 (7%) patients with history of syncopal attacks without documented arrhythmias during hospital observation. Group 3 includes 17/254 (7%) patients with left anterior hemiblock in basal condition, 7/254 (3%) patients with left anterior hemiblock and one left posterior hemiblock during acute ischemia and one patient with right bundle branch block during acute ischemia. Syncopal symptoms are present in many of these cases of angina pectoris; paroxysmal A-V block is documented in nearly half of the cases with syncope (65%); ventricular tachycardia is frequently demonstrated during ischemia but leads to syncope in only a few cases; patients with syncope do not present specific clinical features.(ABSTRACT TRUNCATED AT 250 WORDS)

A strategy for improvement in care at the end of life: the VA Faculty Leaders Project.

Given the commitment of the Veterans Health Administration (VA) to excellent, compassionate end-of-life and palliative care and the VA's extensive system of academic affiliations with the nation's medical schools, there may exist an opportunity to accelerate acceptance of state-of-the-art training for improved care for dying patients. Accordingly, the VA has initiated a project to develop strategies for implementation of benchmark curricula for end-of-life and palliative care. With the support of the Robert Wood Johnson Foundation, this initiative has been implemented in 30 internal medicine residency training programs affiliated with the VA nationally.

Dihydroquinidine versus disopyramide: efficacy in patients with chronic stable ventricular ectopy.

Dihydroquinidine (DQ) is contained in substantial amounts in quinidine salts, but its direct antiarrhythmic action has not been studied. The efficacy of oral DQ (300 mg t. i. d.) compared to disopyramide (D) (200 mg t.i.d.) was thus investigated using a double-blind crossover placebo-controlled protocol in 12 patients, aged 13 to 67 years, with chronic stable high frequency premature ventricular beats (PVB), defined as greater than 100 PVB/h during 48-72-h control Holter monitoring. The protocol included three 72-h treatment periods: DQ, D, and placebo at random. On days 2 and 3 of each period a 24-h Holter recording was carried out; drug blood levels were determined at peak (days 2 and 3) and trough time (day 3). No significant difference in the mean PVB/h was found between control (735 +/- 400) and placebo periods (564 +/- 388), or between the two Holter recordings of each period. Compared to placebo both DQ (106 +/- 113, p less than 0.005) and D (240 +/- 263, p less than 0.05) reduced the mean PVB/h, but the decrease was significantly higher with DQ (78 versus 53%, p less than 0.02). Nine patients (75%) on DQ and 5 (42%) on D had a greater than 70% decrease in mean PVB/h; complex PVBs were abolished in 3 of 6 patients on both treatments. On day 3, DQ plasma levels were 1.31 +/- 0.44 (peak) and 0.92 +/- 0.45 (trough) mg/l; D plasma levels were 2.88 +/- 0.64 (peak) and 2.02 +/- 0.31 (trough) mg/l; no significant difference was found between day 2 and day 3 samples.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of surgery in the treatment of post-infarction ventricular tachycardia. A 5 year experience.

The purpose of this report is to present a 5 year experience in electrophysiologically guided surgical treatment of post-infarction ventricular tachycardia (VT) in a consecutive series of 39 patients. In every case the arrhythmia was not responsive to pluripharmacological therapy. The diagnostic steps included preoperative endocardial, intraoperative epi- and endocardial mapping, automatically carried out when possible. Surgical techniques were: classic Guiraudon's encircling endocardial ventriculotomy (EEV), partial EEV, endocardial resection (ER), cryoablation or combined procedures. The hospital mortality was of 4 patients (10%). During the follow-up period (1-68 mo), 4 patients (11%) died of cardiac non-VT related causes. Among the survivors, 90% are in sinus rhythm. The authors consider electrophysiologically guided surgery a safe and reliable method for the treatment of post-infarction VT and suggest more extensive indications. They stress the importance of automatic mapping in pleomorphic and non-sustained VT, and the necessity of tailoring the surgical technique to the characteristics of each case.

[Multiplexed peroperative mapping in unstable rhythm disorders]. / La cartographie per-opératoire multiplexée dans les troubles du rythme instables.

Since the introduction and development of mapping methods in clinical practice, some arrhythmias can now be treated surgically. We studied an automatized method of epicardial mapping necessitating only a single ventricular complex for the definition of epicardial activation; the signal was acquired from 35 monopolar electrodes spread out over the whole of the ventricular epicardium or concentrated in the zone of epicardial break through to localise its site more accurately. The acquisition, elaboration and tracing of these maps were performed with a computer; the activation can be presented as isochrones or isopotentials. The main value of this method of automatic mapping is the possibility of studying irregular arrhythmias whose potentials are difficult to obtain beat manually. This method has already been applied to 21 patients with ventricular tachycardia unresponsive to medical treatment and referred for surgery.