[Transcatheter Aortic Valve Implantation versus surgical aortic valve replacement in intermediate-risk patients with severe symptomatic aortic stenosis]. / L'étude clinique du mois. PARTNER-2 : TAVI versus chirurgie dans les risques intermédiaires de sténose aortique sévère symptomatique.

Aortic valve stenosis (AS) is the most commonly operated valvular heart disease in developed countries. Aortic valve replacement is the sole effective treatment of symptomatic patients. PARTNER-1 (Placement of AoRtic TraNscathetER Valves) has recently proved the efficacy of percutaneous aortic valve replacement (TAVI : Transcatheter Aortic Valve Implantation) in patients at high surgical risk, or inoperable. In the present article, we report and discuss the results of the PARTNER-2 study in intermediate risk patients. Data from PARTNER-2 confirmed those of PARTNER-1 with a similar rate of combined events (death or disabling stroke) in the TAVI and surgical groups. At 2 years, the Kaplan-Meier event rates were 19.3% in the TAVI group and 21.1% in the surgery group, with a hazard ratio in the TAVI group of 0.89. The non inferiority analysis was validated with a p inferior to 0.001. In the transfemoral-access cohort, TAVI resulted in a lower rate of death or disabling stroke than surgery (p = 0.05), whereas, in the transthoracic access cohort, outcomes were similar in the two groups. Finally, TAVI was associated with lower rates of new onset atrial fibrillation, acute renal failure, and severe bleeding, whereas surgery resulted in fewer major vascular complications and less paravalvular aortic regurgitation.

La sténose aortique est la valvulopathie la plus fréquemment opérée dans les pays industrialisés. Le remplacement valvulaire aortique est le seul traitement efficace dans les formes sévères symptomatiques. L'étude PARTNER-1 (Placement of AoRtic TraNscathetER Valves/Mise en place de valves aortiques transcathéters) a récemment prouvé l'efficacité du remplacement valvulaire aortique par voie percutanée (TAVI: Transcatheter Aortic Valve Implantation) chez les patients à haut risque chirurgical ou inopérables. Dans cet article, nous rapportons et discutons les résultats de l'étude PARTNER-2 réalisée chez les patients à risque intermédiaire. PARTNER-2 confirme les données observées dans PARTNER-1, avec un critère d'évaluation principal [taux d'événements combinés, décès ou accident vasculaire cérébral (AVC) invalidant] similaire dans les deux groupes (TAVI versus chirurgie). A deux ans, l'incidence de ce critère primaire était de 19,3 % dans le groupe TAVI versus 21,1 % dans le groupe chirurgie, soit un risque relatif de 0,89 dans le groupe TAVI. L'analyse de non-infériorité était validée (p inf�rieur a 0,001). Le TAVI par voie transfémorale était associé à un plus faible taux de décès ou d'AVC invalidant que la chirurgie (p = 0,05), tandis que, dans l'approche transthoracique, le pronostic des patients était similaire dans les deux groupes. Finalement, le TAVI était associé à une incidence moindre de fibrillation auriculaire de novo, d'insuffisance rénale aiguë, et d'hémorragies sévères, tandis que l'avantage de la chirurgie se traduisait par moins de fuites paravalvulaires et de complications vasculaires.

[Fibrillation, an epidemic in the elderly?]. / La fibrillation auriculaire: une épidémie du troisième âge?

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. In its non valvular form, it appears as a disorder of the aged. Surprisingly, its incidence and prevalence have constantly been on the rise over the last decades to the extent that some authors nowadays call this phenomenon an "emerging epidemic". The reasons for that proliferation are not entirely elucidated. Obesity, which has simultaneously and similarly increased in frequency, might have played a significant role. AF is frequently pauci-symptomatic in the aged and can easily go unrecognized. Yet, it entails a higher mortality rate, carries a significant risk of thrombo-embolic events, in particular strokes, and may lead to heart failure. We shall briefly review the current epidemiologic aspects of AF and evoke the possible role of obesity. We shall then discuss the therapy of this disorder with a particular attention to the new oral anticoagulants.

[My pet, a safeguard for my health]. / Mon chien, gardien de ma santé?

For some of us, to possess a pet, and particularly a dog, can be the source of great satisfaction. Recently, the opinion has prevailed that pet ownership provides significant beneficial effects in terms of prevention of cardiovascular diseases and could even improve survival after a coronary event. The American Heart Association has recently summoned some experts to express their view on this matter and their group has issued an official statement. We thought it useful to summarize their publication: it is properly cautious and will surely prompt further research; it will also comfort dog owners in their belief that their pet can indeed, in difficult times, be a resourceful helpmate.

[Atherosclerosis: a complex disease]. / L'athérosclérose: une maladie complexe.

Atherosclerosis is a complex disease resulting from an interaction between environmental risk factors (diet, smoking habit, lack of exercise, stress) and a favourable genetic profile. In the recent past, the analysis of the genetic factors involved has considerably progressed. A significant number of genetic variants associated with the various phenotypes of atherosclerosis or its risk factors have been identified. Each, taken individually, only exerts a modest influence, but as a group, they play a significant role, albeit as yet not precisely quantified, in the aetiology of atherosclerosis. The individual response to various therapies prescribed in atherosclerosis can also be significantly influenced by genetic factors. In the next future, genetics and pharmacogenetics will represent major determinants of our approach to the prevention and individualized treatment of atherosclerosis and its complications.

[Cardiovascular prevention: could the polypill reduce the risk of clinical inertia and poor compliance?]. / Prévention cardio-vasculaire: la "polypill", une solution pour vaincre l'inertie clinique et le manque d'observance?

The concept of "polypill" for cardiovascular prevention was introduced in 2003 in a landmark paper of the British Medical Journal. A model based on results provided by evidence-based medicine suggested that a "polypill", that contains a statin, three blood pressure lowering drugs (each at half standard dose), aspirin and folic acid, would result in an 80% reduction in the incidence of coronary and cerebrovascular events, while being associated with a good tolerance profile and offering a favourable cost-effectiveness ratio. The present paper aims at presenting the new advances dealing with this new paradigm in cardiovascular prevention. We will present the progresses of the "polypill" concept since 2003, the results of a first controlled clinical trial, the pharmaceutical feasibility for routine clinical use and the potential pharmaco-economical impacts of such a strategy. The "polypill" may offer a solution to avoid physician's clinical inertia and reduce patients's lack of compliance, two drawbacks in the field of cardiovascular prevention.

[The top ten major advances in heart disease and stroke research in 2008: a compilation of the AHA]. / Les 10 contributions les plus significatives de la littérature cardiologique en 2008: une sélection de l'American Heart Association.

Following the tradition, the AHA has compiled a list of the top 10 major advances in heart disease and stroke research in 2008. As always, the choice was rather eclectic. There were, to start with, a series of papers providing objective data to validate several programs of public health, prevention, or good practice promotion that the AHA has initiated, or encouraged. Then came the results of some recent clinical trials which may prompt a change in clinical habits, or even in international guidelines related to cardio- or cerebro-vascular disease. Finally, the AHA identified new areas of research which, even if they are still in their early development, show significant promise for the future of medicine.

[The top ten major advances in heart disease and stroke research in 2007: a selection of the American Heart Association]. / Les 10 contributions les plus significatives de la littérature cardiologique en 2007: une sélection de l'American Heart Association.

The AHA has released its annual selection of the 10 top major advances in heart disease and stroke research for 2007. This list is very interesting. It contains papers on genetics which present the newly introduced genome-wide association studies of different common diseases, including coronary artery disease. The results of investigations carried out on cardiomyocytes derived from adult mouse spermatogonial stem-cells are mentioned. The value of angioplasty in chronic stable coronary artery disease is reassessed as is the need for mouth to mouth ventilation in resuscitation manoeuvres for cardiac arrest. The effectiveness and safety of drug-eluting stents in routine clinical practice is demonstrated and the merit of bivaluridin for the treatment of patients with a STEMI infarct is described. The improvement in quality of care provided by a statewide system for coronary revascularisation is outlined. Finally, two papers are devoted to epidemiological issues: one demonstrates that a reduced sodium intake lowers not only blood pressure, but also the risk of clinical cardiovascular disease outcomes; the second stresses that hypertension and prehypertension are often undiagnosed in the pediatric population.

[The 2006 American Heart Association selection of the "top ten advances in heart disease and stroke research"]. / Les 10 contributions les plus significatives en littérature cardiologique en 2006: Une Sélection De L'américan Heart Association.

The American Heart Association (AHA) has once again released its "top ten research advances in heart disease and stroke" for the past year. A place of choice is devoted to stroke as well as to pediatric cardiology and to prevention of heart disease in childhood and adolescence. As is the case every year, reading the selected articles is rich of enlightment and the source of a good many thoughts.

[The 2005 AHA selection of the "top ten advances in heart disease and stroke research"]. / Les dix contributions les plus significatives de 2005 en littérature cardiologique: la selection annuelle de l'American Heart Association ("top ten").

The American Heart Association has once again released its "top ten" research advances in heart disease and stroke for the past year. As always, the choice is rather heterogeneous. Besides the quality of the selected contributions, it also reflects some areas of concern which primarily interest the Unites States, or the support that the AHA wishes to bring to some particular research programmes; Reading this list is however always rich of enlightment for anyone working in the field.

Incidence and significance of pericardial effusion in acute myocardial infarction as determined by two-dimensional echocardiography.

To determine the incidence and clinical significance of pericardial effusion after acute myocardial infarction, two-dimensional echocardiography was serially performed in 66 consecutive patients. Pericardial effusion was observed in 17 (26%); the effusion was small in 13 patients, moderate in 3 and large with signs of cardiac tamponade in 1. In this patient, two-dimensional echocardiography strongly suggested myocardial rupture. The observation of pericardial effusion was not associated with age, sex, previous myocardial infarction, atrial fibrillation or treatment with heparin. It was more often a complication of anterior than of inferior acute infarction. Patients with pericardial effusion had higher peak levels of creatine kinase and lactic dehydrogenase and a higher wall motion score index. More patients with pericardial effusion had congestive heart failure or ventricular arrhythmias, developed a ventricular aneurysm or died within 1 year after their infarction. In conclusion, pericardial effusion is frequently visualized by two-dimensional echocardiography after acute myocardial infarction and its presence is associated with an increased occurrence of complications and cardiac death.

Identification of viable myocardium by echocardiography during dobutamine infusion in patients with myocardial infarction after thrombolytic therapy: comparison with positron emission tomography.

To assess the presence of viable myocardium salvaged by coronary artery reperfusion, 17 patients with acute anterior myocardial infarction were studied. Each received intravenous thrombolysis within the first 3 h of symptoms and underwent two-dimensional echocardiography before and during dobutamine infusion (10 micrograms/kg per min) 7 +/- 4 days after admission and positron emission tomography 9 +/- 5 days after admission. Echocardiography and positron emission tomography were again performed 9 +/- 7 months later. Six comparable segments specific for the territory of the left anterior descending artery were selected for comparison of the two techniques. Wall thickening was evaluated by using an echocardiographic score index. Segmental perfusion and glucose uptake were measured and normalized to the peak activity. A ratio of glucose uptake to perfusion was calculated for each segment. Concordant interpretation of the two techniques was found in 79% of affected segments for both acute and follow-up studies. Positron emission tomography revealed the presence of viable myocardium in 11 patients (group 1); perfusion was within normal limits in 5 of these (group 1A). Myocardial thickening improved with dobutamine infusion in these five patients, the echocardiographic score index decreasing from 12 +/- 2 at rest to 7.8 +/- 1.3 during dobutamine infusion (p = 0.003). Functional recovery was demonstrated in all five patients (follow-up score index 7.4 +/- 1.7). Six patients exhibited decreased perfusion but an abnormally high glucose to perfusion ratio (group 1B); their score index improved with dobutamine from 14.8 +/- 2.2 to 12 +/- 2.1 (p = 0.05), but late functional recovery was found in only one of the six patients (mean follow-up score index in group 1B 16 +/- 1.7). In the six remaining patients in whom no viable myocardium was detected with positron emission tomography (group 2), the echocardiographic score index did not change with dobutamine (15 +/- 0.9 to 14.7 +/- 0.8, p = NS) and there was no functional recovery (follow-up score index 15.5 +/- 1.0). Echocardiography during dobutamine infusion is a promising method to unmask viable myocardium in acute myocardial infarction. Early recovery of perfusion in the area at risk is associated with a good functional outcome, whereas a high glucose to perfusion ratio indicates jeopardized myocardium that frequently loses viability.

Relation between contractile reserve and positron emission tomographic patterns of perfusion and glucose utilization in chronic ischemic left ventricular dysfunction: implications for identification of myocardial viability.

OBJECTIVES: This study sought to determine the incidence and extent of dobutamine-induced contractile reserve in myocardial regions characterized by classical and new positron emission tomographic (PET) patterns in patients with chronic ischemic left ventricular dysfunction. BACKGROUND: PET is considered the most accurate method for assessment of myocardial viability, which is traditionally identified by perfusion-metabolism mismatch. METHODS: In 23 patients, segmental wall thickening expressed by four echocardiographic scores at rest and during low dose (5 and 10 microg/kg body weight per min) dobutamine infusion and regional myocardial uptake of potassium-38 and fluorine-18 fluorodeoxyglucose (F-18 FDG) during glucose clamp were compared in 16 corresponding segments. RESULTS: Of a total of 368 segments, data analysis focused on 214 (58%) dyssynergic segments at baseline. Contractile reserve was identified with increasing incidence according to the six following PET patterns: 1) diminished perfusion and moderate reduction of F-18 FDG uptake (3 [11%] of 28 segments); 2) proportional reduction of perfusion and F-18 FDG uptake (10 [23%] of 43 segments); 3) perfusion-metabolism mismatch (19 [46%] of 41 segments); 4) preserved perfusion but moderate reduction of F-18 FDG uptake (13 [46%] of 27 segments); 5) preserved perfusion and F-18 FDG uptake (37 [59%] of 63 segments) compared with our normal database; and 6) normal perfusion but absolute increased F-18 FDG uptake (8 [73%] of 11 segments). In the latter category, only 7 of 24 segments had normal rest function. In dyssynergic segments with F-18 FDG uptake > or = 50% supplied by vessels with > or = 75% stenosis, improvement in contractility during dobutamine correlated with the presence of collateral channels. CONCLUSIONS: Myocardial regions with the traditional mismatch pattern of viability show contractile reserve in slightly < 50%. In segments with moderate reduction of F-18 FDG uptake, the contractile response to dobutamine is linked to the level of rest perfusion. Most segments with preserved perfusion and increased F-18 FDG uptake have impaired rest function, but contractile reserve is still present. These data suggest that in chronic ischemic left ventricular dysfunction, myocardial hibernation is a heterogeneous condition.

Wiktor stent for treatment of chronic total coronary artery occlusions: short- and long-term clinical and angiographic results from a large multicenter experience.

OBJECTIVES: This study reports the first multicenter experience with the Wiktor coil stent for treatment of chronic total coronary artery occlusions (CTOs). BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) of CTO is associated with very high restenosis and reocclusion rates. Coronary stenting has been proposed as a means of improving outcome. However, the Wiktor device for CTOs has never been tested in a large patient sample. METHODS: From January 1993 to December 1996, 89 patients with 91 CTOs underwent Wiktor stent implantation after successful PTCA. The post-stenting regimen consisted of warfarin (Coumadin) plus aspirin in the initial 49 patients (55%) and aspirin plus ticlopidine in 40 patients (45%). RESULTS: Stenting was successful in 87 patients (98%). At 1 month, 6% of patients had subacute stent thrombosis, 3% had a major bleeding event, and 1% had access-site complications. Subacute stent thrombosis showed univariate association with warfarin therapy (p = 0.009). Angiographic follow-up was obtained in 76 (93%) of 82 eligible patients. The restenosis rate was 32%, including 4% reocclusions. By multiple logistic regression analysis, restenosis was independently associated with multiple stents (adjusted odds ratio [OR] 27.67, 95% confidence interval [CI] 4.25 to 79.95, p = 0.0008) and increasing values of occlusion length (adjusted OR 1.23, 95% CI 1.09 to 1.39, p = 0.001). Freedom from death, myocardial infarction or stented vessel revascularization was 87% and 72% at 1 and 3 years, respectively. CONCLUSIONS: Short- and long-term clinical and angiographic outcomes are favorable in patients undergoing Wiktor stent implantation in CTO. Further technical improvement is needed to reduce the restenosis rate in patients with long lesions and multiple stents.

[The "top" of cardiology literature in 2004: an annual selection of the American Heart Association]. / Le "gratin" de la littérature cardiologique en 2004: une sélection annuelle de l'American Heart Association.

The American Heart Association has once again released its top ten research advances in heart disease and stroke for the past year. As always, the selection is assorted. It contains very pointed, at times preliminary, research, as well as major clinical trials; it also reports findings that seem of particular interest for an American audience or come as a support for a special programme proposed by the association. Reading these ten abstracts is, however, invariably rich of enlightenment, and stimulation for everyone.

[Aspirin and cardiovascular prevention: last minute information]. / Aspirine et prévention cardiovasculaire, dernière minute: prise en charge des effets secondaires gastro-duodénaux.

Just a few days after the publication in this journal of a review on aspirin and cardiovascular prevention, a significant article appeared in the international literature; it provides new information and deserves a brief presentation. This paper is concerned with patients who took aspirin to prevent vascular diseases and who presented with ulcer bleeding. After the ulcers had healed and after eradication of Helicobacter pylori had, if necessary, been achieved, 320 patients were randomly assigned to receive either 75 mg of clopidogrel daily or 80 mg of aspirin daily + 20 mg of esomeprazole twice daily. Recurrent ulcer bleeding occurred in 13 of the 161 patients assigned to receive clopidogrel and in 1 of the 159 who received aspirin plus esomeprazole. The cumulative incidence of recurrent bleeding during the 12 months of follow up was 8.6% in the clopidogrel group and 0.7% in the aspirin-esomeprazole group (p = 0.001). These findings do not support a current American recommendation that patients with major gastrointestinal intolerance of aspirin should be given clopidogrel instead.

Myocardial kinetics of potassium-38 in humans and comparison with copper-62-PTSM.

UNLABELLED: The aim of this study was to define the kinetics of 38K and its suitability to evaluate myocardial blood flow at rest and during pharmacological vasodilation in normal subjects. Potassium-38's kinetic characteristics were also compared to those of a 62Cu-pyruvaldehyde bis(n4-methyl-thio-semicarbazone) copper (II) (PTSM) flow tracer. METHODS: Potassium-38 and 62Cu-PTSM were injected at rest and after pharmacological vasodilation in six healthy volunteers. Dynamic PET acquisition was performed over 20 min and myocardial tracer retention calculated. Homogeneity of regional myocardial tracer distribution was also evaluated. RESULTS: High image quality of the heart was observed at rest and after dipyridamole with both tracers. Potassium-38 demonstrated prolonged myocardial retention with minimal lung and liver accumulation. In contrast to 38K, 62Cu-PTSM demonstrated high liver uptake which may hinder observation of the inferior wall of the myocardium. Copper-62-PTSM dipyridamole-to-rest retention ratio was 1.49. CONCLUSIONS: Potassium-38 and 62Cu-PTSM display suitable kinetics for the qualitative evaluation of blood flow and flow reserve in the human heart. Compared to 62Cu-PTSM, potassium-38, which does not show high liver uptake, may more accurately estimate blood flow in the inferior wall of the heart. However, accurate quantification of myocardial blood flow using 38K or 62Cu-PTSM retention appears to be limited to decreasing retention fraction at hyperhemic states.

Histopathologic correlates of left posterior fascicular block.

Thirteen hearts from subjects (10 male, 3 female; mean age 65 years) with left posterior fascicular block were studied. Left posterior fascicular block was associated with right bundle branch block in nine cases and alternated with left anterior fascicular block in three. In nine of the patients, the conduction disorders were observed during an episode of acute myocardial infarction. Of these nine patients, four showed interruptive lesions at the level of the posterior radiation of the left bundle or of the posterior portion of the main left bundle branch. Two were found to have severe alterations scattered throughout the left bundle branch system: One of them had alternating left anterior and left posterior fascicular block; and the other manifested complete heart block in the course of her illness. No interruptive changes of the posterior fibers were found in three cases in which the heart was obtained early after death. All 9 patients had severe coronary artery disease (six had triple vessel disease and three of the six had a left main coronary arterial stenosis or obstruction; two patients had double vessel disease). Among the four patients with chronic left posterior block, three were found to have heavy calcifications of the left side of the cardiac skeleton; the remaining one had diphtheritic myocarditis. All had major alterations of the left-sided conduction system that were consistently maximal at the level of the posterior fibers or posterior portion of the main left bundle branch. In two of these patients scattered lesions were found throughout the left bundle branch fibers; one had alternating left anterior and left posterior fascicular block and the other had complete heart block. In general, the alterations underlying left posterior fascicular block were less widely spread than in left anterior fascicular block; however, they were more severe and more proximally located.

Hemodynamic effects of a new antiarrhythmic agent, flecainide (R-818), in coronary heart disease.

The hemodynamic effects of flecainide acetate, a new class I antiarrhythmic agent, were studied in 10 patients with coronary heart disease. The drug was injected intravenously at a dose of 2 mg/kg over 30 minutes. The mean drug plasma level achieved was 394 ng/ml (range 329 to 470). The heart rate did not change, but a significant increase (p less than 0.001) in P-R (+17%), QRS (+15%), and Q-T (+7%) duration occurred after drug administration. Negative inotropic effects also were observed and consisted of an increase (p less than 0.01) in pulmonary wedge pressure (+27%) and a decrease (p less than 0.01) in stroke index (-10%), left ventricular stroke work index (-12%), and left ventricular ejection rate (-11%). No significant change in mean aortic pressure or systemic and pulmonary vascular resistance occurred. Left ventriculography performed after drug infusion revealed a significant increase (p less than 0.01) in systolic volume (+9%) and a decrease in ejection fraction (-9%) and mean velocity of circumferential fiber shortening (Vcf) (-13%). A progressive and significant decrease of dP/dt was observed during drug infusion, but 15 minutes after the injection, dP/dt had returned to near basal values. Thus, flecainide acetate has slight, but significant negative inotropic effects, particularly conspicuous during drug infusion. The drug should be administered with caution in patients with poorly compensated heart.

Hemodynamic effects of intravenous diltiazem with impaired left ventricular function.

The acute hemodynamic effects of intravenous diltiazem were studied in 8 patients with coronary artery disease, left ventricular (LV) failure (New York Heart Association functional class III), a rest ejection fraction (EF) less than 40% or a cardiac index less than 2.4 liters/min/m2. Hemodynamic measurements and LV angiograms were performed at rest before and after the administration of diltiazem, 0.5 mg/kg, administered at a speed of 5 mg/min. Diltiazem treatment induced a decrease in heart rate from 68 +/- 12 to 55 +/- 9 beats/min (p less than 0.001). Mean aortic pressure decreased from 94 +/- 14 to 81 +/- 15 mmHg (p less than 0.05). Thus, the pressure-rate product significantly decreased under the influence of the drug, from 8,791 +/- 2,465 to 6,342 +/- 1,808 beats mm Hg/min, (p less than 0.001). Diltiazem induced no significant change of LV end-diastolic pressure, pulmonary wedge pressure, cardiac index and LV stroke work index. Systemic vascular resistance decreased (p less than 0.01), whereas pulmonary vascular resistance showed no change. End-systolic volume diminished (p less than 0.02), which accounts for the increase of stroke volume and ejection fraction (p less than 0.001). Disorders of regional contractility were not aggravated by diltiazem, and even improved in individual cases. Thus, intravenous diltiazem may be used safely in patients with heart failure. However, in view of the marked bradycardic effects seen in some cases, heart rate should be carefully monitored.

Quantitative study of left bundle branch fibrosis in left anterior hemiblock: A stereologic approach.

Serial sectioning of the interventricular septum was carried out in 16 hearts, 8 from elderly subjects with no conduction disturbance and 8 from patients with chronic left anterior hemiblock. The histologic slides were studied stereologically, and the relative density of fibrosis was quantitatively assessed by the point counting technique at various levels of the main subdivisions of the left bundle branch system. Statistical analysis revealed the following: (1) Although some fibrosis was found in the control hearts, the density of fibrosis was consistently and significantly greater throughout the conduction system in patients with left anterior hemiblock. (2) In the group with hemiblock, the relative density of fibrosis tended to increase significantly from the posterior ramification to the midseptal fibers and, finally, to the anterior fascicle. (3) Among the eight patients with hemiblock, fibrosis appeared to be evenly distributed throughout the conduction system in four. It was predominantly located in the anterior and midseptal fibers in one patient and showed an increasing severity from the posterior to the midseptal and anterior fibers in the remaining three patients. From this quantitative study, it is concluded that left anterior hemiblock is a reliable sign of left bundle branch disease but that the underlying lesions are more widely distributed than would be from the expected electrocardiographic terminology since they were found predominantly in the anterior ramifications in only half of the studied cases.