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ECG lead-wire interchanges involving the right leg (RL) are not always detected. These RL lead-wire interchanges cannot be simulated in the same way as other lead-wire interchanges making database collection a necessity for algorithm development. Adult 12-lead ECGs from a single teaching hospital taken between January 2008 and July 2012 were reviewed for lead-wire interchanges by an expert electrocardiographer. Lead-wire interchanges were confirmed by comparison of serial ECGs. Positive interchanges included left arm / right leg (flat lead III, n=134) and right arm / right leg (flat lead II, n=139). A RL lead-wire interchange algorithm was developed by bootstrap aggregation of decision trees with 5-fold cross validation. Test results were summed over the 5-fold cross validation on the partitions not used for training. ECG features included maximum and minimum QRS and T-wave voltages for ECG leads I, II and III. The Haisty algorithm for RA-RL interchange was tested for comparison. Algorithm performance was quantified by sensitivity (SE), specificity (SP) and estimated positive predictive value (PPV) based on SE, SP and realistic prevalence. For a prevalence of 0.2%, performance in SE, SP and PPV was: Haisty, 94, 99.4, 24; tree RA-RL: 84, 99.9, 57; tree LA-RL: 87, 99.9, and 57%. Even though SP was high for all three algorithms, the estimated PPVs were modest due to the low prevalence. Conclusion: Lead-wire interchanges involving the right leg wire can be detected with good sensitivity and high specificity. The higher specificity of the tree based algorithms results in more than twice the PPV of the Haisty algorithm.

This statement provides a concise list of diagnostic terms for ECG interpretation that can be shared by students, teachers, and readers of electrocardiography. This effort was motivated by the existence of multiple automated diagnostic code sets containing imprecise and overlapping terms. An intended outcome of this statement list is greater uniformity of ECG diagnosis and a resultant improvement in patient care. The lexicon includes primary diagnostic statements, secondary diagnostic statements, modifiers, and statements for the comparison of ECGs. This diagnostic lexicon should be reviewed and updated periodically.

This statement provides a concise list of diagnostic terms for ECG interpretation that can be shared by students, teachers, and readers of electrocardiography. This effort was motivated by the existence of multiple automated diagnostic code sets containing imprecise and overlapping terms. An intended outcome of this statement list is greater uniformity of ECG diagnosis and a resultant improvement in patient care. The lexicon includes primary diagnostic statements, secondary diagnostic statements, modifiers, and statements for the comparison of ECGs. This diagnostic lexicon should be reviewed and updated periodically.

This statement examines the relation of the resting ECG to its technology. Its purpose is to foster understanding of how the modern ECG is derived and displayed and to establish standards that will improve the accuracy and usefulness of the ECG in practice. Derivation of representative waveforms and measurements based on global intervals are described. Special emphasis is placed on digital signal acquisition and computer-based signal processing, which provide automated measurements that lead to computer-generated diagnostic statements. Lead placement, recording methods, and waveform presentation are reviewed. Throughout the statement, recommendations for ECG standards are placed in context of the clinical implications of evolving ECG technology.

In the 1920s and 1930s, when pericardiectomy first became an established therapy for constrictive pericarditis, surgeons recognized the condition in which pericardial effusion coexists with a visceral constrictive pericarditis (or constrictive epicarditis) (see Figure). In 1971, clinical and hemodynamic features were described that allowed the diagnosis to be made before an operation or autopsy had been performed. Since that time, individual cases have been reported nearly every year. Many of these cases, including at least one reported in the Case Records of the Massachusetts General Hospital,1 occurred in the United States. Others have been reported in at least 26 countries . . .

The detection and assessment of cardiac chamber hypertrophy has long been an important objective of clinical electrocardiography. Its importance has increased in recent years with the recognition that hypertrophy can be reversed with therapy, and that by doing so, adverse clinical outcomes can be

This statement provides a concise list of diagnostic terms for ECG interpretation that can be shared by students, teachers, and readers of electrocardiography. This effort was motivated by the existence of multiple automated diagnostic code sets containing imprecise and overlapping terms. An intended outcome of this statement list is greater uniformity of ECG diagnosis and a resultant improvement in patient care. The lexicon includes primary diagnostic statements, secondary diagnostic statements, modifiers, and statements for the comparison of ECGs. This diagnostic lexicon should be reviewed and updated periodically.

This statement examines the relation of the resting ECG to its technology. Its purpose is to foster understanding of how the modern ECG is derived and displayed and to establish standards that will improve the accuracy and usefulness of the ECG in practice. Derivation of representative waveforms and measurements based on global intervals are described. Special emphasis is placed on digital signal acquisition and computer-based signal processing, which provide automated measurements that lead to computer-generated diagnostic statements. Lead placement, recording methods, and waveform presentation are reviewed. Throughout the statement, recommendations for ECG standards are placed in context of the clinical implications of evolving ECG technology.

This statement provides a concise list of diagnostic terms for ECG interpretation that can be shared by students, teachers, and readers of electrocardiography. This effort was motivated by the existence of multiple automated diagnostic code sets containing imprecise and overlapping terms. An intended outcome of this statement list is greater uniformity of ECG diagnosis and a resultant improvement in patient care. The lexicon includes primary diagnostic statements, secondary diagnostic statements, modifiers, and statements for the comparison of ECGs. This diagnostic lexicon should be reviewed and updated periodically.

This statement examines the relation of the resting ECG to its technology. Its purpose is to foster understanding of how the modern ECG is derived and displayed and to establish standards that will improve the accuracy and usefulness of the ECG in practice. Derivation of representative waveforms and measurements based on global intervals are described. Special emphasis is placed on digital signal acquisition and computer-based signal processing, which provide automated measurements that lead to computer-generated diagnostic statements. Lead placement, recording methods, and waveform presentation are reviewed. Throughout the statement, recommendations for ECG standards are placed in context of the clinical implications of evolving ECG technology.

QT-interval measurements have clinical importance for the electrocardiographic recognition of congenital and acquired heart disease and as markers of arrhythmogenic risk during drug therapy, but software algorithms for the automated measurement of electrocardiographic durations differ among manufacturers and evolve within manufacturers. To compare automated QT-interval measurements, simultaneous paired electrocardiograms were obtained in 218 subjects using digital recorders from the 2 major manufacturers of electrocardiographs used in the United States and analyzed by 2 currently used versions of each manufacturer's software. The 4 automated QT and QTc durations were examined by repeated-measures analysis of variance with post hoc testing. Significantly larger automated QT-interval measurements were found with the most recent software of each manufacturer (12- to 24-ms mean differences from earlier algorithms). Systematic differences in QT measurements between manufacturers were significant for the earlier algorithms (11-ms mean difference) but not for the most recent software (1.3-ms mean difference). Similar relations were found for the rate-corrected QTc, with large mean differences between earlier and later algorithms (15 to 26 ms). Although there was a

(1996). An Irregularly Irregular Cardiac Rhythm in a Man with a Pacemaker. Hospital Practice: Vol. 31, No. 9, pp. 29-30.

(1995). Bigeminal Rhythm and Cardiac Failure in Rheumatic Heart Disease. Hospital Practice: Vol. 30, No. 2, pp. 37-38.

I appreciate Dr Spodick's interesting comments. The areas of disagreement may be rather small, especially regarding the issues of low voltage and myocardial ischemia. These mechanisms continue to be debated in the absence of methods for definitive proof. I hold out on the issue of paradoxical pulse. By definition, pericardial effusion is present in effusive-constrictive pericarditis. However, there are patients with constrictive pericarditis, usually of subacute nature, with no pericardial effusion in whom paradoxical pulse is a prominent feature. 1 I have termed this the elastic form of pericardial constriction. Echocardiograms sometimes report effusion in such cases, whereas surgical exploration reveals none; the thickened edematous pericardium may represent organization of a previously existing effusion. I also hold out a little on arrhythmias. Could the common arrhythmias after cardiac surgery result from pericarditis? Indeed, a sterile postoperative pericarditis is now used as an experimental model of atrial flutter. 2 I am

Dr Fye's book began as a history of the American College of Cardiology. It was commissioned by that organization in 1990 upon the 40th anniversary of its founding. The idea was expanded into that of a broader survey of the origin and development of the profession of cardiology in the United States. Fye sees the discipline of cardiology as achieving definition during the period 1900 to 1920. He categorizes the physicians driving this development as physiologists, practitioners, academics, and public health enthusiasts. The introduction of the electrocardiograph stands out as a dominant factor in defining and promoting the new specialty. The first electrocardiograph in the United States was installed at Mount Sinai Hospital in New York City in 1909. By 1925, 450 Cambridge instruments were in place in the country, more than one third in physicians' offices. This development could be taken as the beginning of the use of technology

In this slender volume Dr Hurst distills his thoughts from a long career about medical teaching and learning. The bench in his title refers to the legendary bench of Mark Hopkins, which, in a log cabin with a student on one end and a teacher on the other, was said in 1871 to contain the essence of what is needed for the educational process. Hurst's central formulation is the idea of the true teacher, who has the ability to stimulate students to learn. The true teacher contrasts with the ordinary teacher, who may be considered as essentially an announcer of facts. "True teachers understand the teaching-learning process, which includes facts, then thinking, and then usage, and encourage their students to appreciate the joy and importance of learning." "Hurst thinks there is a gene, as it were, for true teaching..." Hurst divides medical teaching into the lecture method and the Socratic

Despite the growing popularity of performance tests, scores on such measures have rarely been interpreted from a criterionreferenced perspective. This paper describes a test of skill in reading electrocardiographs (ECGs). Using generalizability theory, the errors of measurement and standard setting were estimated both alone and together from a criterionreferenced perspective. Performance on this test was also compared with a measure of the quality of training plus the multiplechoice questions and patient-management problems used in a medical certifying examination. Generalizabilityanalysesproduced positive results for the standard setting procedure and the ECGs, both separately and together. The preliminary validity evidence for scores was encouraging. The criterion-referenced ECGs ranked groups of examinees as expected based on prior education and examination experience. The criterion-referenced ECGs also had modest correlations with traditional measures of physician competence.

Ninety-five consecutive patients with constrictive pericarditis that was documented at the time of surgery during 1970 to 1985 were reviewed. The etiologies included idiopathic (42%), postradiotherapy (31%), post-cardiac surgery (11%), postinfective (6%), connective tissue disease-related (4%), neoplastic (3%) uremic (2%), and sarcoidosis (1%). Post-cardiac surgery etiology was seen only after 1980, but constituted 29% of cases during 1980–1985. Postradiotherapy etiology occurred with equal incidence in 1980–1985 and in 1970–1980, but the interval from radiotherapy to presentation with constrictive pericarditis was longer in the more recent period (11 vs 4.75 years). Effusive constrictive pericarditis occurred in 24% overall with similar prevalence in all of the etiologic groups except the postsurgical cases, which were caused by noneffusive fibrous constrictive pericarditis in all instances. Operative mortality was 12% overall: It was lower in the idiopathic group (8%) and higher in the postradiotherapy group (21%). Thus (1) postradiotherapy constrictive pericarditis continues to occur despite technical changes aimed at reducing its likelihood, but recent cases have a longer latent period: and (2) postsurgical constrictive pericarditis has emerged as an important etiology.

This article discusses a thesis regarding the pathophysiology of constrictive pericarditis. The thesis is that there are two forms of constriction, one being elastic and the other more analogous to a rigid shell. The two forms of constriction are considered to cause different patterns of the diagnostic signs of constriction. The elastic form is similar to cardiac tamponade, and is associated with prominent paradoxical pulse and systolic descent in the venous pressure waveform. The rigid shell type has less prominent paradoxical pulse and a more conspicuous diastolic descent in the venous pressure waveform, often associated with an early diastolic sound (pericardial knock). Recognition of these two types of constriction may be helpful in clinical diagnosis and in understanding the pathophysiology of pericardial disease.

The long-term results of aortic valve replacement with the fresh aortic homograft, performed in 114 patients at Stanford University Medical Center from 1967 to 1971, were evaluated. There were 10 operative deaths (8.8 per cent), only 3 (5 per cent) in the period from 1968 to 1971. There were 6 late deaths in the first year (5.8 per cent) and 8 in later years (1.5 per cent per year); 12 late deaths were due to cardicc causes, 6 of them to valve dysfunction. The homograft was replaced later with a prosthetic valve or heterograft in 22 patients (3.2 per cent per year): for regurgitation in 20 and for calcific stenosis in only one. Infective endocarditis occurred in 5 cases, accounting for one operative death, 2 late deaths, and 2 reoperations with survival. Systemic thromboembolism occurred in 6 patients, 3 with mitral valve disease, one with atrial fibrillation, and one with infective endocarditis; none was a proved instance of embolism from bland thrombus on the aortic homograft valve. Of 53 patients followed for 5 years or more with the homograft intact, 47 have minimal or no disability, despite aortic diastolic murmurs in many. We conclude that long-term results are good in the majority of patients, with aortic regurgitation requiring reoperation being the leading complication. These results may serve as a basis for comparison of more recently introduced methods of aortic valve replacement.

The echophonocardiographic diagnoses of valvular and paravalvular insufficiency, calcific stenosis, and thrombolic occlusion of the stent-mounted aortic homograft or heterograft in the mitral position are described. Paravalvular and valvular insufficiency were associated with apical systolic murmurs which decreased in intensity after amyl nitrite inhalation and with echocardiograms which showed initial diastolic slopes of the stents in excess of the normal range (1.9 to 3.3 cm. per second). In clinically improved and stable patients, amyl nitrite inhalation resulted in increased intensity of the commonly heard systolic ejection type murmur at the left sternal border and echocardiographic evidence of further narrowing of the outflow tract measured between the interventricular septum and the anterior portion of the stent. Calcific homograft stenosis was associated with a decreased diastolic stent slope (0.4 cm. per second) and increased echo density from the tissue leaflets. Thrombus formation on the sewing ring caused fatal inflow occlusion in 2 patients. The condition was characterized by an echocardiogram showing decreased ratio of internal-to-external stent diameter, 0.47 (normal range 0.56 to 0.74), decreased diastolic stent slope, and decreased leaflet excursion.

That high doses of x irradiation can damage the heart and pericardium is common knowledge among radiotherapists and radiobiologists. A small number of case reports have described cardiac lesions following radiotherapy of thoracic cancer; the prevailing feeling, however, is that such complications are rare and relatively unimportant (1). The purpose of this report is to review 25 cases in which significant heart disease followed radiation therapy to the chest for a variety of malignant tumors. Study of this unique series of patients from a single institution has provided data on the relative frequency of the various clinical features encountered and their correlation with the radiation technics and doses used, as well as estimates of the incidence of this group of complications in an irradiated population. The importance of recognizing cardiac complications and differentiating them from the manifestations of advancing neoplasm is emphasized. A previous report (2) described in detail the clinical findings, ...

Twenty-seven patients with mitral valve disease and pulmonary arterial systolic pressure greater than 100 mm Hg were evaluated. Twenty-five patients have been subjected to mitral valve surgery, consisting of open valvotomy in 6 and mitral valve replacement in 19, with an operative mortality of zero and 16 percent, respectively. Postoperative hemodynamic studies were obtained in 15 of the 19 late survivors, an average of 29 months after operation. Average pulmonary arterial systolic pressure decreased from 115 preoperatively to 50 mm Hg postoperatively; pulmonary vascular resistance decreased from 1,153 to 305 dynes sec cm−5, and cardiac index rose from 1.9 to 2.5 liters/min per m2. Patients with normal left atrial pressure and normal sinus rhythm postoperatively experienced the greatest hemodynamic and clinical improvement. This study indicates that even extreme degrees of pulmonary hypertension and increased pulmonary vascular resistance due to mitral valve disease regress markedly if surgery adequately decompresses the left atrium.

The influence of amyl nitrite inhalation on the ejection time, corrected for heart rate, was examined in 18 patients with hypertrophic subaortic stenosis and 34 with a variety of other cardiac diseases (control group). The corrected ejection time increased by 0.04 sec. or more in 11 of 18 patients (61 per cent) with hypertrophic stenosis after amyl nitrite; in the control group the corrected ejection time generally decreased, remained constant, or increased by less than 0.04 sec. The augmented degree of outflow obstruction produced by amyl nitrite probably accounts for the prolongation in corrected ejection time in hypertrophic subaortic stenosis. The change in ejection time after amyl nitrite inhalation may be conveniently studied during phonocardiography or right heart catheterization and employed as a simple screening test for hypertrophic subaortic stenosis. Thus, it is useful in determining the indications for left heart catheterization or angiocardiography in patients suspected of having this disease.

In 4 patients with muscular subaortic stenosis the left ventricular outflow tract obstruction was completely reversible from beat to beat with varying cardiac cycle length, being absent in beats following normal or short diastolic periods and present in moderate or severe form in beats following longer diastolic periods. The varying cycle length was due to atrial fibrillation in 2 cases and to ventricular extrasystoles in 2 cases. In 1 patient with atrial fibrillation, a critical cycle length and left ventricular systolic pressure could be demonstrated above which severe outflow tract obstruction was consistently present. The appearance and disappearance of outflow tract obstruction was associated with marked variation in the intensity of the aortic systolic ejection murmur and with marked changes in the arterial pulse contour. These observations suggest a specific abnormality of the outflow tract in patients with muscular subaortic stenosis, since patients with simple diffuse hypertrophy of the left ventricle do not show such phenomena. Disproportionate hypertrophy of the ventricular septum is the most likely abnormality. In 1 case, systemic hypertension appeared to cause the myocardial hypertrophy. The variability of obstruction might be due to changes in contractile force which occur with varying degrees of diastolic filling and varying aortic diastolic pressure in atrial fibrillation. It could also be due to variations in contractile force which occur as a result of varying cycle length alone, the augmentation following longer cycles in atrial fibrillation being similar to post-extrasystolic augmentation as simulated by paired electrical stimulation.

A. Importance. Electrocardiography is the most commonly used diagnostic test in cardiology. Properly interpreted, it contributes significantly to the diagnosis and management of patients with cardiac disorders. Importantly, it is the only practical method of recording arrhythmias and similarly it is the first procedure obtained in patients with chest pain. These two conditions account for the majority of cardiac catastrophes. B. Goal of training. Although every physician should have some basic knowledge of electrocardiography and the general internist should have a more advanced knowledge, the subspecialist in cardiology should be familiar with nearly all clinically encountered patterns and arrhythmias. He or she should understand their clinical implications and, equally important, their sensitivity and specificity. The trainee should have sufficient basic knowledge to understand the physiologic mechanisms for arrhythmias and electrocardiographic waveforms rather than simply recognize patterns. Recognizing and understanding the basis for the items included in the appendix of this task force report are minimal requirements for each trainee. C. Training. The essence of training is to interpret a large volume of electrocardiograms and to review the interpretations with an experienced faculty. The suggested minimal number of electrocardiograms is 3,500/36 months. This can be accomplished by one or more training periods assigned specifically for interpretation of electrocardiograms. The experience should include clinical correlation in patients in intensive care units, emergency rooms and pacemaker clinics. The electrocardiogram should be integrated with the clinical problem. Formal courses in electrocardiography and correlative conferences in electrocardiography are desirable. D. In-training evaluation. Skills in electrocardiography and interpretation of electrophysiologic studies should be reviewed and it is essential that the trainee be familiar with interpretation of electrophysiologic studies and the indications for such studies. Similarly, he or she should be familiar with the principles of intracardiac electrophysiologic studies, thei~ indications, contraindications, sensitivity and specificity. He or she should be evaluated on an ongoing basis by the responsible faculty. An in-training examination

The relationships between aortic stenosis, coronary artery disease, angina pectoris, and myocardial infarction were examined in 173 patients with isolated calcific aortic stenosis who had coronary arteriography as well as cardiac catheterization. All were over age 40 and had definite cardiac symptoms; 156 later had aortic valve replacement. Coronary lesions narrowing the lumen by 50% or more were present in 37% of patients aged 40 to 59 and 68% of those aged 60 to 82. Coronary disease was present in 64% of patients with angina pectoris and 33% of those without angina. Angina which occurred only in association with dyspnea on exertion was associated with coronary disease in 45% of instances, whereas angina which also occurred on exertion without any dyspnea or which occurred with emotional stress, after meals, during sleep, or at rest unprovoked was associated with coronary disease in 80% of instances. Patients with coronary disease without any chest pain or with atypical pain considered nonanginal were men, usually over age 60, with congestive heart failure as the predominant symptom. Electrocardiograms showing transmural inferior or anterolateral infarction nearly always indicated coronary disease, while QS patterns in Leads V1-2 occurred frequently with normal coronary arteries. Serum cholesterol was elevated in 23% of those with coronary disease and 8% of those without. A group of patients with moderate aortic stenosis could be identified, with aortic valve areas of 0.55 to 0.80 cm. per square meter, in whom coronary disease was the sole or chief cause of symptoms. The operative mortality rate with aortic valve replacement was 9.6% in those with coronary disease and 1.4% in those without significant coronary disease. Coronary disease is frequently present in patients with calcific aortic stenosis, particularly in those over 60, those with angina, and those with symptoms despite only moderate aortic stenosis. The type of anginal syndrome, the ECG evidence of transmural infarction, and the coronary risk factors provide additional clues for clinical diagnosis.

A standardized objective examination was developed by the Cardiovascular Subspecialty Board of the American Board of Internal Medicine to assess competence in the interpretation of electrocardiograms (ECGs). The questions consisted of 12 lead ECGs with lead II and V1 rhythm strips, accompanied by brief clinical statements. Examinees chose their answers from a comprehensive list of 129 choices; the list was the same for each question. The score from the ECG examination was combined with scores from the other sections of the examination to derive a single score for the Cardiovascular Board examination using a norm-referenced method for determining the passing score. An additional trial was conducted to study the feasibility of testing for a minimal level of competence; the trial used a subset of "core" ECGs and a criterion-referenced scoring method based on a consensus of members of the Cardiovascular Board on the level of performance that should be expected of certified cardiologists. Fifty examinees (2.7%) failed the core ECG examination. If examinees had been required to pass both the core ECG examination and the remainder of the examination, 164 examinees (9%) would have changed their pass-fail status on the overall examination. The examination appeared to be a valid test for a minimal level of skill in this area of cardiology. The minimal level of competence was met by a large majority but not all of the examinees.