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The association between use of oral contraceptives (OC) and death from myocardial infarction (MI) in young women was investigated in a collaborative case-control study conducted in the five largest metropolitan areas in the US. Potential cases were identified from computer tapes of the National Center for Health Statistics. Controls were selected from among women who died from, or were hospitalized for, acute conditions other than heart disease or from accidents, and were matched to cases on age, geographic area, and year of death. Information on cause of death, personal characteristics, OC use, and the presence of conditions predisposing to MI was obtained from interviews with relatives and abstracts of hospital, clinic and physician records. Odds ratios as approximations to relative risks for fatal MI in relation to OC use, and the associated 95% confidence limits, were calculated overall and for subgroups determined by demographic and health history characteristics. Odds ratios in the total study population were not significantly different from one. However, odds ratios significantly different from one were found when attention was restricted to white subjects without contraindications to OC use, andincluding only those cases whose deaths were attributed to MI with the greatest degree of certainty. Smoking was found to be a significant risk factor for fatal MI.A collaborative case-control study was conducted in the 5 largest metropolitan areas in the United States in order to investigate the association between oral contraceptive (OC) use and death from myocardial infarction (MI) in young women. Potential cases were identified from computer tapes of the National Center for Health Statistics. The controls were selected from among women who died from, or were hospitalized for, acute conditions other than heart disease or from accidents; they were matched to cases on age, geographic area, and year of death. The population of study cases was defined to be all women, age 15-44, who died of an acute MI during the January 1974-June 1975 period. 163 cases were classified as either MI or sudden death (SD). Information regarding cause of death, personal characteristics, OC use, and the presence of conditions predisposing to MI was obtained from interviews with relatives and abstracts of hospital, clinic and physician records. Odds ratios as approximations to relative risks for fatal MI in relation to OC use, and the associated 95% confidence limits, were calculated overall and for subgroups determined by demographic and health history characteristics. Odds ratios in the total study population were not significantly different from 1, but odds ratios significantly different from 1 were found when attention was restricted to white subjects without contraindications to OC use, and including only those cases whose deaths were attributed to MI with the greatest risk of certainty. A signficant risk factor for fatal MI was smoking. The data suggest that use of OCs may increase the risk of death from MI.

An electrocardiographic-angiographic-hemodynamic correlation was conducted in 136 patients undergoing diagnostic coronary angiography. Eighty-four subjects had coronary artery disease (vessel narrowing greater than 50 percent) and were compared to 52 subjects without significant vessel obstruction (narrowing less than 50 percent). Left atrial enlargement occurred more commonly in subjects with significant coronary artery disease (p> 0.001). Patients with abnormal ventricular contrac tility or ventricular aneurysms had a significantly higher incidence of left atrial enlargement than those with normal contractility (p

Atrial pacing was compared with multistage treadmill exercise testing in 50 patients undergoing diagnostic cardiac catheterization to determine the diagnostic sensitivity of atrial pacing. Coronary artery disease was considered significant if luminal narrowing greater than 75 percent was present. Twenty-one subjects (Group I) had no significant coronary artery disease with vessel narrowing of less than 50 percent. Twelve (Group II) had single vessel disease and 17 (Group III) had disease of two or more vessels. The mean maximal heart rate during atrial pacing was 140/min and during exercise testing was 131/min. A positive atrial pacing test result was obtained in 5 percent of patients in Group I, 17 percent of patients in Group II and 24 percent of patients in Group III. A positive multistage treadmill exercise test result was obtained in 10 percent of patients in Group I, 67 percent of patients in Group II and 94 percent of patients in Group III. These differences are statistically significant (P < 0.001). The sensitivity of atrial pacing was 20 percent compared with 83 percent for multistage treadmill exercise testing. The specificity of atrial pacing was 95 percent compared with 90 percent for multistage treadmill exercise testing. Thus, atrial pacing is an insensitive test in the diagnosis of ischemic heart disease and does not improve the diagnostic value of multistage treadmill exercise testing.

The number of diagnostic and therapeutic procedures performed in cardiology continues to grow. These pro cedures are generally considered safe or of minimal risk to the patient. However, it is important to remember that significant complications may occur, and in each patient the risk: benefit ratio must be carefully weighed. In this review, the complications documented in the medical literature resulting from the use of cardiologic interventions and procedures are discussed. A thorough knowledge of these complications and their precipitat ing factors can help minimize the risk to the patient.

The prevalence of cardiac abnormalities in the spectrum of human immunodeficiency virus (HIV) infection is unknown. Sixty consecutive HIV-infected patients were studied using echocardiograms, electrocardiograms (50 patients) and ambulatory electrocardiographic monitoring (43 patients). Group A (25 patients) were seropositive but pre-AIDS, whereas group B (35 patients) had AIDS and included 24 with an active opportunistic infection (group B1) and 11 without it (group B2). Abnormalities were identified in 32 of 60 patients (53%) and were more frequent in group B (23 of 35, 66%) than in group A (9 of 25, 36%, p less than 0.05) but independent of active opportunistic infection (15 of 24, 62%, in group B1 vs 8 of 11, 73%, in group B2). Echocardiographic abnormalities were identified in 21 of 60 patients (35%), including 7 of 25 (28%) in group A vs 14 of 35 (40%) in group B (difference not significant), and 7 of 24 (29%) in group B1 vs 7 of 11 (64%) in group B2 (difference not significant). Those patients with an absolute CD4 lymphocyte count less than or equal to 100/mm3 had a higher prevalence of echocardiographic abnormalities (12 of 22) than those with CD4 counts greater than 100/mm3 (1 of 14, p less than 0.01). Left ventricular dilation or hypokinesis was identified in 14 of 60 patients (23%), including 4 of 25 (16%) in group A and 10 of 35 (29%) in group B. Electrocardiographic abnormalities were seen in 22 of 50 patients (44%) including 5 of 18 (28%) in group A and 17 of 32 (53%) in group B (difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

A simple quantitative diagram for analysis of electrocardiographic tracings suspected of bilateral bundle branch block is presented. It is particularly useful in cases of unequal asynchronous block of the two bundle branches. Four cases in which the diagram was of great help are presented. It is believed that the more widespread use of this diagram will facilitate teaching of the subject of bilateral bundle branch block and unearth many new cases. It is suggested that the diagram be used in cases showing changing QRS complexes, changing P–R intervals and some degree of atrioventricular block or a combination of at least two of these features.

A system is described for remote computer-assisted surveillance of implanted pacemakers from a patient's home. Using an inexpensive, portable, frequency-modulated transmitter, a patient's electrocardiogram is sent over voice-grade telephone lines to any cardiology clinic. The signal can be demodulated and the pacemaker spike plus electrocardiogram recorded on paper for visual review by the physician. The modulated signal is further transmitted to a remote on-line computer system. The computer calculates the spike-spike interval to approximately five millisecond precision, stores pacemaker information and other patient data on disk, and displays calculated results on a cathode ray screen in the cardiology clinic. The cardiologist can immediately review past and present pacemaker function, patient medications, and other pertinent data from the computer terminal. If further medical action is warranted, the patient can be immediately advised.

Simultaneous apex cardiograms and left ventricular pressure pulses were recorded in 20 cardiac patients in various stages of compensation in search of a clinically useful correlation between the external phenomena at the apex and the intracardiac diastolic pressure events. For an understanding of the normal variations, apex cardiograms were recorded in 50 healthy subjects. A useful relation between the amplitude of the diastolic components of the apex cardiogram ( a wave and diastolic filling wave) and the height of left ventricular diastolic pressure has been found. The genesis of apex cardiographic deflections and the possible explanations for the correlation described have been discussed.

Lateral head movements were observed in eight patients with severe right ventricular failure. These motions, easily detectable from a distance, occurred in patients with elevated right atrial “a” waves. These movements appear to be related to a forceful right atrial contraction and reflect a decrease in right ventricular compliance.

1. 1. The time sequence of right atrial and left atrial depolarization as a guide to the origin of ectopic atrial beats was studied in 46 patients with heart disease: in 36 patients after electrical stimulation of known areas of the two atria and in 10 patients with ectopic atrial rhythms. A direct right atrial and a bipolar esophageal lead were recorded simultaneously with one or more limb and chest leads on a photographic recorder. A catheter-pacemaker assembly was used for electrical stimulation of the atria. 2. 2. Right atrial depolarization always preceded the left by an average of 0.04 sec. in all instances of normal sinus rhythm and after stimulation of the right atrium. Conversely, the left atrial component of the P wave occurred before the right by an average of 0.037 sec. when the wall of the left atrium was stimulated. 3. 3. In retrograde P waves ascending through the atrioventricular junction after stimulation of the ventricles, the right and left atria depolarized either simultaneously or in quick sequence, with an interatrial conduction time not exceeding 0.03 sec. 4. 4. Stimulation of the lower regions of the interatrial septum depolarized both atria very rapidly in a manner analogous to activation of the atria by retrograde P waves. 5. 5. It is concluded that the sequence of right and left atrial depolarization is a useful and possibly indispensable measure for determining the origin of the P waves. More refined studies may eliminate the overlapping encountered in the present investigation and render this technic an essential component in the study of atrial electrophysiology.

Pacemaker overdrive is an accepted method for treating drag resistant ventricular tachyarrhythmia. We report a paradoxic response to this mode of therapy in a 47-year-old man without demonstrable organic heart disease and His bundle documented ventricular tachycardia. Normally functioning ventricular demand pacemaker at a pacing rate of 107 per minute caused recurrent episodes of ventricular tachycardia. The latter also occurred with spontaneous acceleration of patient's heart rate, treadmill exercise, emotional stress and atrial pacing. The mechanisms involved are unknown. Propranolol therapy was effective.

Electrophysiologic studies were performed in 16 patients after Mustard's operation for d-transposition of the great vessels. Standard 12 lead electrocardiograms showed the following rhythms: “sinus” (10 patients), junctional (4 patients), atrial flutter (1 patient) and alternating sinus and junctional (1 patient). Overdrive atrial stimulation was used to determine sinus nodal recovery time in the 16 patients. Atrial and atrioventricular (A-V) nodal effective refractory periods were determined in 12 patients utilizing the atrial extrastimulus technique. Twenty-four hour Holter electrocardiographic monitoring was performed in 15 patients. Ten (63 percent) of the 16 patients had abnormal sinus nodal recovery time. The atrial effective refractory period was prolonged in 4 (33 percent) of the 12 patients in whom it was measured. All 12 patients had a normal A-V nodal effective refractory period. Previously undetected arrhythmias were found in all patients when the 24 hour Holter electrocardiogram was compared with the standard electrocardiogram. Atropine shortened the sinus nodal recovery time, atrial effective refractory period and A-V nodal effective refractory period in all patients studied. One patient, whose junctional pacemaker was first to recover after termination of atrial pacing, had conversion to sinus rhythm and normal sinus nodal recovery time after administration of atropine. This study indicates (1) that a diseased sinus node and interrupted atrial pathways are involved in the genesis of arrhythmias after Mustard's operation, and (2) that adequate evaluation of arrhythmias in patients after this operation requires not only the standard electrocardiogram, but also a 24 hour Holter monitor, His bundle electrograms and determination of sinus nodal recovery time and atrial and A-V nodal effective refractory periods.

Summary A method to expedite processing of electrocardiograms (ECGs) is described. The hard-ware configuration utilizes conventional equipment, and the ECG data is stored in magnetic data cards. The electrocardiographer's interpretation is made using a specially developed code of 253 diagnostic statements of 2 to 9 words each. A minicomputer converts the code into full alphanumeric description and 2 characters into English statements. The diagnostic print-out appears in the same page as the reproduction of the original ECG data. This system has significantly reduced the ECG processing time, freed manpower to increase availability of technicians and decreased the size of permanent files.

Twelve patients exhibited electrocardiographic evidence of fascicular block during hyperkalemia. Isolated left posterior hemiblock occurred in four, isolated left anterior hemiblock in two, right bundle branch block with left anterior hemiblock in two, right bundle branch block with left posterior hemiblock in one, left bundle branch block with abnormal left axis deviation in two and advanced atrioventricular block in one. In all seven patients with sinus rhythm the P-R interval shortened after correction of hyperkalemia. Electrophysiologic studies using His bundle recording and atrial pacing in one patient revealed intraatrial conduction delay and marked prolongation of conduction time in the His-Purkinje system. It is concluded that conduction defects in the specialized intraventricular conduction system are common in hyperkalemia and result in electrocardiographic patterns of fascicular block.

Precordial maps have been used for some 15 years to estimate the extent of myocardial injury in patients with acute anterior or lateral wall infarction. Estimates have been based on various QRS- and ST-T-derived parameters, including amplitude sum of ST elevations. Application of the electrodes, commonly 35, is cumbersome and time-consuming with the critically ill. A subset of 5 or 7 selected leads can be applied instead, and the remaining leads calculated from that subset with minimal loss of QRS and ST-T information. Maps were recorded from 100 patients within 72 hours of onset of anterior or lateral infarct. Optimal lead subsets for QRS and ST-T feature extraction were found by the sequential selection method of Lux. Subsets numbering between 2 and 15 leads were derived, with their lead-transform coefficients. Measures to estimate goodness of fit for reconstructed leads included correlations, error-to-signal ratios and root-mean-square errors. These measures were calculated separately over the QRS and ST-T complexes. Reconstructions from a 7-lead subset had a mean 0.92 correlation with ST-T in the original leads and root-mean-square error of only 0.04 mV. Sum of ST elevation differed by only 2% between original leads and reconstructions based on 5 or more leads. To confirm repeatability, lead-transform coefficients were also calculated from a training population of 50 patients and applied to the maps of the other 50.

We evaluated the recently proposed concern that ECG anterior ST segment depression in patients with acute inferior wall myocardial infarction represents an additional area of ischemia and therefore implies worsened prognosis. We studied patients enrolled in the Aspirin Myocardial Infarction Study (AMIS), ages 30 to 69 years, who sustained an inferior myocardial infarction within 6 months from the start of the study. Two hundred nineteen patients who met those criteria were followed for an average of 38.2 months. One hundred ten patients had significant anterior lead ST depression (greater than or equal to 0.1 mV) during their acute inferior infarction and their 3-year mortality rate was 9.1%. One hundred nine patients had no anterior ST abnormality and a mortality rate of 10.1% (p = ns). Only one patient with significant depression had a subsequent anterior wall myocardial infarction. Anterior ST depression correlated closely with the magnitude of inferior ST segment elevation. Since ST depression does not alter long-term mortality but relates to magnitude of ST elevation, it probably represents a reciprocal change.

Twin brothers suffering from severe alveolar hypoventilation secondary to tonsillar hypertrophy are presented. The ventilatory abnormalities were more severe in the child with greater degree of upper airway obstruction. Pulmonary hypertension and right ventricular failure developed only in the latter twin thus confirming a cause-effect relationship between upper airway obstruction and the cardiac complications. The cardiac abnormalities were completely relieved after tonsillectomy, but not after adenoidectomy in the child who had both procedures. The procedure of cardiac catheterization was complicated by considerable respiratory difficulty and cardiac arrest in the twin with larger tonsils. When the right heart catheter was left open to air for a short time, large quantities of air were sucked into the heart causing near fatal air embolism. This danger should be kept in mind when patients with upper airway obstructions are catheterized. There seems to be a definite place for tonsillectomy when the tonsils are sufficiently large to interfere with ventilation.

The study consisted of observations on nine male patients with palpable dicrotic as evidenced by cardiomegaly and the presence of prominent atrial and ventricular diastolic gallop sounds. Most of these patients were diagnosed as having primary myocardial disease. The indirect carotid pulse was characterized by a single systolic wave, a low dicrotic notch, and a large dicrotic wave. The direct brachial arterial pressure pulse had a similar configuration with a shortened ejection time index. The hemodynamic data on these patients was characterized by low cardiac output, low stroke volume, elevated pulmonary arterial wedge pressures, and high total systemic resistance. From these observations we conclude that the presence of a marked dicrotic pulse in afebrile patients at rest may indicate severe functional impairment of the myocardium.

Clinical observations in 6 patients with acutely acquired tricuspid insufficiency are presented. The atrial sound and atypical murmur of tricuspid regurgitation are documented and the origin localized to the right ventricle. The short duration of the murmur was due to the rapid equalization of pressures in the right atrium and ventricle during the latter part of systole. The presence of an atrial sound suggested a powerful right atrial contraction with diminished right ventricular compliance.

Thirty cases of congenital stenosis of the branch pulmonary arteries are presented. This defect occurred as an isolated cardiovascular anomaly in 17 of the 30 patients. Clinically the most significant diagnostic feature was the wide distribution of the murmur, which was seldom louder than grade 3 6 . It is suggested that auscultation at the axillas and the back should be included in the routine evaluation of the cardiovascular system. Data are presented which suggest that comparing the rate of rise of the prestenotic with the poststenotic pressure pulse may differentiate organic from functional pressure gradients. Some pitfalls in the interpretation of the hemodynamic data are discussed.

Electrical alternation of a single electrocardiographic wave is rare and has not been adequately explained. We describe a case of U wave alternans associated with extreme ventricular irritability. Relationship to hypomagnesemia is indicated by rapid response to magnesium therapy. Mechanisms that may be responsible for this phenomenon are discussed.

A systematic study of the complications resulting from temporary transvenous endocardial pacing was conducted. One hundred thirteen patients requiring insertion of 142 temporary transvenous pacemaker catheters were evaluated. On 61 occasions the pacemakers were introduced through the brachial vein, and on 81 the femoral vein approach was utilized. Evidence of pacemaker malfunction, manifested as failure to capture or to sense spontaneous QRS, was encountered in 95 separate episodes or 43 percent of the total instances of insertion. Malfunction occurred in 45.9 percent of catheter pacemakers inserted through the arm vein and 40.7 percent of catheter pacemakers inserted through the femoral vein. Complications from transvenous endocardial pacing consisted primarily of ventricular tachycardia-fibrillation, myocardial perforation, pulmonary emboli, hematoma or abscess at the insertion site. Thirty-two complications were encountered in 24 instances of pacemaker therapy or 16.9 percent of the total. No deaths could be directly attributable to the complications of cardiac pacing. The high incidence of malfunctions detected during constant electrocardiographic surveillance indicate that, although temporary transvenous pacing is a safe technique, the availability of continuous electrocardiographic monitoring must be considered a prerequisite for the extensive use of temporary pacing. No significant difference could be demonstrated in the incidence of malfunction or complications from the two most commonly used sites of pacemaker insertion.

William of Ockham was a 13th century theologian and philosopher who espoused the medieval rule of economy, "plurality should not be assumed without necessity." 1 This maxim has become known as "Ockham's razor." In the practice of medicine this principle has been taught to generations of medical students and house staff in the form of "all clinical signs, symptoms and laboratory abnormalities should be attributable to a single disease process." The physician who postulates more than one pathologic entity to account for a clinical symptom complex is treading on thin ice. Nevertheless, like all rules in medicine, Ockham's razor is not inviolate. Many patients do have more than one acute illness, and recognizing this may present a difficult challenge to the physician's clinical acumen. In patients with multiple problems, a clear-cut relationship between disease processes is often evident, such as with a patient with acute myelogenous leukemia in whom gram-negative