bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of perioperative myocardial damage after coronary artery bypass graft surgery.
Authors: Righetti A , Crawford M H , O'Rourke R A , Hardarson T , Schelbert H , Daily P O , DeLuca M , Ashburn W , Ross J
Published: June 2012

In order to evaluate methods for detecting peri-operative myocardial damage we studied 41 patients before and serially following coronary artery bypass graft surgery utilizing the 12-lead ECG, serum MB-CPK measurements, and 99mTc pyrophosphate myocardial scans. Six of the 41 patients (15%) developed persistent new Q waves after surgery. Six other patients demonstrated ischemic ST-T wave changes that persisted for 48 hours or more. Mean total MB-CPK released was highest for the group with new Q waves [1598+/-545 (SE) I.U./L-hr] as compared to the group with ischemic ST-T wave changes 708+/-65 I.U./L-hr) or the group with no ECG changes (262+/-47 I.U./L-hr). Ten patients (24%) has positive postoperative pyrophosphate scans consistent with myocardial infarction. The three techniques were compared in these 41 patients utilizing 465 I.U./L.-hr as the upper limit of normal MB-CPK released after uncomplicated coronary bypass surgery (no ECG changes, negative scan). Five patients with ischemic ECG changes had a positive scan and high MB-CPK; six patients with no ECG changes had high MB-CPK but a negative scan; and one patient with high MB-CPK and new Q wave had a negative scan. We conclude 1) new Q waves on ECG underestimate the incidence of myocardial damage after coronary artery surgery; 2) MB-CPK alone overestimates the incidence of infarction; and 3) a combination of the three techniques is the best means for detecting myocardial damage after coronary artery bypass graft surgery.
The effects of tolbutamide on the myocardium in experimental diabetes.
Authors: Wu C F , Haider B , Ahmed S S , Oldewurtel H A , Lyons M M , Regan T J
Published: June 2012

The effects of chronic tolbutamide treatment were examined in a diabetic animal model in which abnormal myocardial function and composition have previously been demonstrated. Eight diabetic dogs were given tolbutamide 250 mg/day orally and compared with seven untreated diabetics, five healthy dogs receiving tolbutamide, and eight normal controls. After one year, resting hemodynamic studies in the intact anesthetized state showed that treated diabetic dogs had a significantly higher left ventricular end-diastolic pressure of 12.1+/-1.3 mm Hg associated with normal end-diastolic volume, compared to 6.1+/-0.8 mm Hg in untreated diabetics (P less than 0.01) and 6.3+/-0.5 in normals. Stroke work and ejection fraction were similar to normals. Acute volume expansion revealed a larger rise of left ventricular end-diastolic pressure in treated and untreated diabetics than normals, without a significant stroke volume response in treated diabetics. Enhanced stiffness of myocardium appeared to be related to interstitial accumulation of periodic acid-Schiff staining material, further intensified in treated diabetics by triglyceride accumulation observed on electron microscopy and by chemical analysis. Thus treatment of diabetes with tolbutamide, despite improved glucose tolerance, effected further reduction of left ventricular function and altered morphology of myocardium.
Total anomalous pulmonary venous connection and severe pulmonic stenosis in a 52-year-old man.
Authors: Pastore J O , Akins C W , Zir L M , Buckley M J , Dinsmore R E
Published: June 2012

Total anomalous pulmonary venous connection (TAPVC) is a rare cardiac congenital abnormality which usually results in death in infancy or early childhood. We describe a 52-year-old man with TAPVC and severe calcific pulmonic stenosis. Both diagnoses were suspected clinically and from the chest X-ray. Cardiac catheterization was confirmatory, and the patient underwent surgery. His initial postoperative course has been unremarkable. The hemodynamic factors relevant to long survival and relative freedom from symptoms in TAPVC are considered based on findings in this patient.
Sudden death during ambulatory monitoring. Clinical and electrocardiographic correlations. Report of a case.
Authors: Gradman A H , Bell P A , DeBusk R F
Published: June 2012

A man with known coronary heart disease underwent treadmill exercise testing to determine his functional capacity. The test was negative for ischemia. Ventricular ectopic activity was noted at rest and in the recovery period. On the same day, while viewing a sporting event at home, the patient died suddenly. An ambulatory electrocardiographic recording documented ventricular fibrillations as the terminal mechanism. Ventricular ectopic activity and heart rate increased in the two hours prior to death, and ischemic ST-segment depression was noted at the time of the terminal arrhythmia. It is postulated that myocardial ischemia and catecholamine response lowered the threshold to ventricular fibrillation, thus facilitating the emergence of the fatal arrhythmia.
Quantification of the normal Frank and McFee-Parungao orthogonal electrocardiogram at ages two to ten years.
Authors: Kan J S , Liebman J , Lee M H , Whitney A
Published: June 2012

A quantification of the Frank and McFee-Parungao orthogonal electrocardiogram of 175 normal children, ages 2-10 years is presented. There are significant differences in age groups 2-5 and 6-10. The QRS voltages of the younger group demonstrate 1) greater Z anterior, 2) greater initial X right, 3) greater terminal X right, 4) smaller Y inferior, and 5) the T vector is oriented more posteriorly. There are significant differences between the two lead systems. 1) Frank spatial voltages are 70% of those of McFee. 2) Frank X left is 70% of McFee, but terminal X right is 75% and initial X right is 60% of McFee. 3) Frank Y inferior is 78% of McFee, but initial Y superior is 83% and terminal Y superior 61% of McFee. 4) Frank Z anterior is 64% and Frank Z posterior is 70% of McFee. 5) In terms of ratios the Frank is relatively less inferior, about equally posterior and more terminally right. 6) The T vector is more posterior in Frank than McFee.
Sampling rates required for digital recording of intracellular and extracellular cardiac potentials.
Authors: Barr R C , Spach M S
Published: June 2012

Electrocardiograms and cardiac electrograms now frequently are measured for both clinical and experimental purposes by direct digital sampling, with no recording of the signal in analog form. This study examined the question of what sampling rates were required to measure accurately the continuous waveforms from the digital samples. Body surface waveforms and intracellular and extracellular waveforms measured directly from cardiac tissues were evaluated. Cardiac measurements included waveforms from the atrium, ventricle, atrioventricular transmission system and individual Purkinje strands. Sampling rates as high as 15,000 samples/sec were required to record accurately extracellular waveforms of the ventricular conduction system. Decreasing sampling rates were required as the recording site shifted through the ventricle to the body surface, where sampling rates as high as 1500 samples/sec were necessary.
Hypertrophic cardiomyopathy. Evaluation by gated cardiac blood pool scanning.
Authors: Pohost G M , Vignola P A , McKusick K E , Block P C , Myers G S , Walker H J , Copen D L , Dinsmore R E
Published: June 2012

The gated radionuclide cardiac blood pool scan (GCS) can be used to visualize the entire profile of the interventricular septum and left ventricular contraction. Twenty-two patients with hypertrophic cardiomyopathy, nine with valvular aortic stenosis and six normals, underwent echocardiography and GCS. All patients with hypertrophic cardiomyopathy had asymmetric septal hypertrophy and 14 of 22 had resting systolic anterior motion of the anterior leaflet of the mitral valve on echocardiogram. In eight patients with aortic stenosis with adequate echocardiograms, two had asymmetric septal hypertrophy and none had systolic anterior motion. The GCS demonstrated disproportionate upper septal thickening in 11; septal flattening in 16; cavity obliteration in 17; and a filling defect in the region of the left ventricular outflow tract in 16 of the 22 patients with hypertrophic cardiomyopathy. In the nine patients with valvular aortic stenosis, two demonstrated septal flattening, two cavity obliteration, two an outflow tract defect, and none disproportionate upper septal thickening. Both patients with cavity obliteration demonstrated asymmetric septal hypertrophy on echocardiogram. One normal control patient had septal flattening. Thus the gated cardiac blood pool scan provides an atraumatic technique for the evaluation of patients with hypertrophic cardiomyopathy which complements the echocardiogram.
Effects of cycle length on atrial vulnerability.
Authors: Wyndham C R , Amat-y-Leon F , Wu D , Denes P , Dhingra R , Simpson R , Rosen K M
Published: June 2012

The effect of cycle length on atrial vulnerability was studied in 14 patients manifesting reproducible repetitive atrial firing during atrial extra-stimulus (A2) testing. Repetitive atrial firing was defined as the occurrence of two or more premature atrial responses with return cycle (A2-A3) of 250 msec or less and subsequent mean cycle length of 300 msec or less, following A2. The zone of repetitive atrial firing could be defined in terms of its longest and shortest A1-A2 coupling intervals. Each patient was tested at a long cycle length (CL1) (mean 884 msec) and a short cycle length (CL2) (mean 557 msec). CL1 was sinus rhythm and CL2, an atrial paced rhythm. Repetitive atrial firing occurred in two patients at CL1 and in all patients at CL2. Of the former two patients (group 2), the zone of repetitive atrial firing was markedly widened in one at CL2 due to a shortening of atrial functional refractory period (FRP) at CL2. In the other, zone of repetitive atrial firing could not be totally defined due to induction of sustained atrial flutter preventing definition of atrial FRP. The occurrence of repetitive atrial firing at only CL2 in 12 patients (group 1) reflected: 1) a shortening of atrial FRP from 294 +/- 11 msec at CL1 to 242 +/- 10 msec at CL2 (mean +/- SEM; P less than 0.01), allowing delivery of A2 at shorter coupling intervals (9); 2) the new occurrence of repetitive atrial firing at A1-A2 coupling intervals achievable at both cycle lengths (1); or 3) both effects (2). In conclusion, decrease of cycle length potentiated atrial vulnerability. This demonstration implies that atrial pacing could potentiate occurrence of paroxysmal atrial fibrillation or flutter.
Origin of body surface QRS and T wave potentials from epicardial potential distributions in the intact chimpanzee.
Authors: Spach M S , Barr R C , Lanning C F , Tucek P C
Published: June 2012

Epicardial and body surface QRS-T wave potential distributions were measured during normal and ectopic sequences in intact chimpanzees. Epicardial potential distributions were used because they provide a comprehensive picture of total cardiac electrical activity for relating heart and body surface events during both ventricular activation and repolarization. When the epicardial potential gradients existed over a distance greater than that to the recording points on the body surface, e.g., as occurred during the overlap of terminal ventricular activation and early repolarization, the epicardial events were mirrored well on the anterior chest surface. However, when the recording points were at a distance greater than that over which the epicardial potential gradients existed, the details of the epicardial events disappeared and their effect was to produce distinct changes in the low-level potentials over broad distant areas. The major manifestations on the body surface of selective epicardial events frequently were changes in the distant low-level potential areas while there was no change in the pattern near the maximum or minimum. The ST-T wave body surface distributions were as useful as the QRS patterns for localizing the ventricular ectopic foci presented. A direct experimental basis is provided for explaining T wave notches which occurred during normal and ectopic beats and resembled U waves. It should be possible to achieve as precise an understanding of ST-T waves on the basis of epicardial potential distributions as has thus far been achieved for QRS on the basis of isochrones.
The effects of heart rate, myocardial ischemia and vagal stimulation on the threshold for ventricular fibrillation.
Authors: James R G , Arnold J M , Allen J D , Pantridge J F , Shanks R G
Published: June 2012

The minimum current required to cause ventricular fibrillation was determined by electrical stimulation of the normal or ischemic canine left ventricle. The threshold for ventricular fibrillation in the normal heart decreased when the heart rate was rapid. Strong vagal stimulation did not affect the ventricular fibrillation threshold when the heart rate was fixed. The fall in the ventricular fibrillation threshold in the presence of acute myocardial ischemia was greater and more prolonged when the heart rate was rapid. These findings indicate the importance of the immediate correction of tachycardia in patients suffering from acute myocardial infarction.
Six year review of the results of freehand aortic valve replacement using an antibiotic sterilized homograft valve.
Authors: Barratt-Boyes B G , Roche A H , Whitlock R M
Published: June 2012

The long-term behavior of an antibiotic-treated homograft aortic valve inserted in a freehand fashion was assessed in 121 patients operated upon for aortic valve disease and followed from four to six and one-half years. There were seven hospital deaths (5.7%) and 30 late deaths, only one of which was related to the homograft valve. The six year survival was 69% (77% for single valve and 52% for multiple valve surgery). At six years 9% had important homograft aortic valve incompetence (HAVI) and most of these required reoperation. Important HAVI occurred in only 5% of patients with an aortic root diameter less than 24 mm and in 38% of those with a markedly dilated or distorted proximal aorta (P less than 0.01). The freehand aortic homograft was considered superior to prosthetic devices because of the absence of chronic anticoagulation, thromboembolism, sudden death from valve failure and significant obstruction in a small aortic root. With slightly restricted patient selection the valve failure rate is expected to fall to less than 1% per year.
Superiority of dobutamine over dopamine for augmentation of cardiac output in patients with chronic low output cardiac failure.
Authors: Loeb H S , Bredakis J , Gunner R M
Published: June 2012

Dobutamine is a newly developed catecholamine reported to have minimal direct vascular effects relative to its inotropic activity and to have less chronotropic and arrhythmogenic properties than other catecholamines used in the treatment of low output states. In this study, the acute hemodynamic effects of dobutamine were compared to those of dopamine in 13 patients with chronic low output cardiac failure. At dosages adjusted to achieve similar increments in cardiac output, dobutamine reduced left ventricular filling pressure (LVEP) from 24 +/- 2 mm Hg (SEM) to 17+/- 2 mm Hg, while dopamine increased LVEP to 30 +/- 3 mm Hg and in six patients caused arterial O2 saturation to fall below 90%. This poor response to dopamine was probably the result of its vasoconstrictive effects and illustrates the potential advantages of using a cardioselective agent such as dobutamine when the desired goal of therapy is to improve ventricular function by direct inotropic stimulation.
XXII. Intractable paroxysmal tachycardias which proved fatal in type A Wolff-Parkinson-White syndrome.
Authors: Brechenmacher C , Coumel P , Fauchier J-P  , Cachera J-P  , James T N
Published: June 2012

Paroxysmal tachycardias proved fatal in a middle-aged man with type A Wolff-Parkinson-White syndrome. Efforts to control his arrhythmias included a surgical incision into the left atrium, based on discovery of early left ventricular activation during epicardial mapping. The incision did not alter any electrocardiographic or clinical feature; at later necropsy examination it was found that the incision had not cut a nearby left atrioventricular (A-V) connection. Serial section study of the entire A-V rings and septal junction of this heart also demonstrated a second unusual A-V connection, between the atrial septum and the region of the His bundle. This latter connection was anatomically eccentric to the normal organization of this region and may have caused an alteration in the local electrophysiological behavior. The left lateral A-V connection may have been of no electrophysiological significance since it was composed of ordinary working myocardial cells. These and other possible correlations are discussed in the context of the clinical features, numerous electrophysiological observations, and the meticulously determined anatomical findings.
Complete heart block in a case of idiopathic hypertrophic subaortic stenosis: noninvasive correlates with the timing of atrial systole.
Authors: Spilkin S , Mitha A S , Matisonn R E , Chesler E
Published: June 2012

A young man with IHSS who developed complete heart block was successfully treated with a permanent pacemaker. Echocardiography and other noninvasive techniques showed marked cycle-to-cycle variation in the evidence of subvalvular obstruction which decreased markedly when atrial systole preceded the ensuing paced complex by an appropriate interval. Because cycle length and therefore afterload were constant, it is concluded that diminished obstruction resulted from augmented ventricular end-diastolic volume produced by atrial contraction. The mitral valve echocardiogram showed unusual movements in diastole dependent upon the timing of atrial systole. Early reopening of the leaflets was a direct result of atrial contraction when the P waves were appropriately timed in presystole, whereas late reopening was passive and a result of ventricular filling in mid-diastole. Variations in intensity of the first heart sound correlated with the position of the mitral valve leaflets at the onset of ventricular systole.
The effect of "ischemic" blood on transmembrane potentials of normal porcine ventricular myocardium.
Authors: Downar E , Janse M J , Durrer D
Published: June 2012

"Ischemic" blood was obtained in pigs from a local coronary vein on release of coronary artery occlusion. The effects of this blood on transmembrane potentials of muscle strips taken from the same heart were compared with control blood. Whereas action potentials remained stable in control blood, ischemic blood collected after more than 15 minutes of coronary occlusion produced shortening of action potential duration, reduction of resting potential, upstroke velocity and amplitude, then postrepolarization refractoriness and finally unresponsiveness. Ischemic blood collected after shorter periods of coronary occlusion produced only mild effects (shortening of action potential and postrepolarization refractoriness). These effects of ischemic blood could not be attributed to increased potassium concentration even in combination with acidosis, hypoxia and hypoglycemia. It appears that during ischemia unidentified factors are released which have potent depressant effects on the excitability of even normal myocardium.
Reproducibility of thallium-201 myocardial imaging.
Authors: McLaughlin P R , Martin R P , Doherty P , Daspit S , Goris M , Haskell W , Lewis S , Kriss J P , Harrison D C
Published: June 2012

Seventy-six thallium-201 myocardial perfusion studies were performed on twenty-five patients to assess their reproducibility and the effect ofvarying the level of exercise on the results of imaging. Each patient had a thallium-201 study at rest. Fourteen patients had studies on two occasions at maximum exercise, and twelve patients had studies both at light and at maximum exercise. Of 70 segments in the 14 patients assessed on each of two maximum exercise tests, 64 (91%) were reproducible. Only 53% (16/30) of the ischemic defects present at maximum exercise were seen in the light exercise study in the 12 patients assessed at two levels of exercise. Correlation of perfusion defects with arteriographically proven significant coronary stenosis was good for the left anterior descending and right coronary arteries, but not as good for circumflex artery disease. Thallium-201 myocardial imaging at maximum exercise is reproducible within acceptable limits, but careful attention to exercise technique is essential for valid comparative studies.
Distance correction for precordial electrocardiographic voltage in estimating left ventricular mass: an echocardiographic study.
Authors: Horton J D , Sherber H S , Lakatta E G
Published: June 2012

This study was undertaken to assess both the relation between echocardiographic measurement of left ventricular (LV) mass and commonly used electrocardiographic criteria for LV hypertrophy and the effect of the distance from the center of LV mass to the anterior chest wall on precordial voltage. Echocardiograms and standard 12-lead electrocardiograms were obtained on 100 persons, ages 3 to 79. The correlation coefficients of echocardiographically determined LV mass with ECG precordial voltage (SV1 + RV5 or V6), the Estes point score system, and a VL4 wave voltage were .686, .721, and .531, respectively. Extrapolating from the dipole nature of the heart, the precrodial voltage was multiplied by the square of the chest wall to mid-LV distance to correct for the loss of energy across the distance from LV to recording electrode. Utilizing this correction, a much improved precordial voltage estimation of LV mass (r = .846) was obtained. We conclude that the distance of the center of LV mass from the chest wall influences the amplitude of recorded precordial voltage and that correction for this influence improved the correlation of precordial voltage with LV mass.
Hemodynamic effects of dobutamine in patients following open heart surgery.
Authors: Sakamoto T , Yamada T
Published: June 2012

Dobutamine, a new synthetic inotropic agent, was administered by intravenous infusion to 22 patients following open heart surgery. The dosage of dobutamine started from 2 mug/kg/min and was increased stepwise to 4, 6, and 8 mug/kg/min. Cardiac index increased from 2.54 +/- 0.13 to 3.11 +/- 0.19 and 3.50 +/- 0.22 L/min/m2 with 4 and 8 mug/kg/min, respectively. Heart rate increased from 87.6 +/- 2.9 to 96.4 +/- 2.3 and 108.9 +/- 3.2 beats/min with 4 and 8 mug/kg/min, respectively. Systolic and mean aortic pressure and systolic pulmonary arterial pressure were elevated from 126.0 +/- 3.8 to 144.6 +/- 6.0 mm Hg, from 91.8 +/- 2.7 to 96.2 +/- 3.2 mm Hg, and from 33.4 +/- 2.3 to 37.1 +/- 2.5 mm Hg with 8 mug/kg/min, while other pressures were unchanged. Mean left atrial pressure fell significantly from 15.9 +/- 0.6 to 14.8 +/- 0.7 mm Hg. Stroke volume index, stroke work index, and left ventricular work also increased. Premature ventricular beats were observed in only one patient during dobutamine infusion, but no other side effect was observed. We conclude that dobutamine is a potent inotropic agent which increases cardiac output without causing significant tachycardia or arrhythmias, and is useful for the treatment of patients following open heart surgery.
The effect of jejunoileal bypass on the pharmacokinetics of digoxin in man.
Authors: Marcus F I , Quinn E J , Horton H , Jacobs S , Pippin S , Stafford M , Zukoski C
Published: June 2012

Seven subjects who underwent jejunoileal bypass surgery for massive obesity participated in a study to examine the relative bioavailability of digoxin before and one to two months after surgery. They were given a loading dose of 1 mg digoxin in divided oral doses followed by oral maintenance doses of 0.5 mg daily. There were no significant differences in the area under the serum concentration time curve, steady state serum levels or 24 hour steady state excretion of digoxin before and after surgery. We conclude that the bioavailability of digoxin from the Lanoxin tablets employed is not impaired in these patients, although urinary d-xylose and 24 hour fecal fat excretion indicated moderate to severe malabsorption after surgery.
Experience with bretylium tosylate by a hospital cardiac arrest team.
Authors: Holder D A , Sniderman A D , Fraser G , Fallen E L
Published: June 2012

The effect of bretylium tosylate (BT) was determined in 27 consecutive cases of resistant ventricular fibrillation (VF) encountered by a hospital cardiac arrest team. The VF was sustained and completely resistant to multiple injections of lidocaine, sequential DC shocks at 400 watt-sec and one or a combination of intravenous propranolol, diphenylhydantoin or procainamide. Following 30 min of sustained cardiac massage, BT (5 mg/kg i.v.) was administered. In 20 patients, VF was terminated within 9-12 min after DC shock. Eight of these patients failed to recover while 12 (44%) of all patients resuscitated survived to be discharged from hospital. Eleven out of 20 (55%) of all patients who had a cardiac arrest outside the CCU were survivors; only one out of seven in the CCU were successfully resuscitated. While receiving maintanance BT post-resuscitation (5 mg/kg i.m. q 8-12 hrs x 48 hrs), half the patients developed hypotension and three required vasopressors and/or fluid replacement. The data indicate that BT is a useful agent in patients with sustained VF refractory to repeated lidocaine injections, some other antiarrhythmic agents, and multiple DC shocks.
Fluoroscope-generated electromagnetic interference in an external demand pacemaker: report of a case.
Authors: Leeds C J , Akhtar M , Damato A N
Published: June 2012

Electromagnetic interference presented as inhibition and resetting of the demand circuitry of a ventricular-inhibited temporary external pacemaker in a 70-year-old man undergoing surgical implantation of a permanent bipolar pacemaker generator and lead. The arrhythmia was found to be due to oversensing of waveforms modulated to simulate myocardial potentials emitted by a faulty fluoroscopy unit used in the vicinity of external temporary transvenous pacing equipment. The documentation of this disruption of pacemaker rhythm reinforces the need for continuous monitoring of patients treated with external demand pacemakers and for the careful maintenance of all electrical equipment.
Characteristics of sinoatrial conduction in patients with coronary artery disease.
Authors: Jordan J , Yamaguchi I , Mandel W J
Published: June 2012

Electrophysiologic studies were performed in 32 patients with angiographically documented coronary artery disease (CAD). Group I was composed of ten patients (31%) with severe stenosis (greater than or equal to 75%) proximal to the origin of the sinus node artery (SNA); group II was composed of five patients (16%) with moderate (50--75%) proximal stenosis; and group III was composed of 17 patients (53%) with insignificant (0--50%) proximal stenosis. The mean sinoatrial conduction time (SACT) for group I was 119 +/- 18 msec; group II was 84+/- 16 msec; and group III was 72 +/- 5 msec. The SACT was significantly longer in group I than in group III (P less than 0.005). In conclusion 1) in patients with CAD, SACT greater than 72 +/- 5 msec is abnormal; 2) the results suggest a pathogenetic role of CAD in the development of sinus node dysfunction; 3) the SACT is a more sensitive indicator of subtle sinus node dysfunction in CAD patients than is heart rate, sinus node response to artrial extrastimuli, or sinus node recovery time; and 4) the ability to diagnose sinus node dysfunction in its early stages and recognition that coronary artery disease is an etiologic factor may allow for the elucidation of the natural history of the sick sinus syndrome.
The nature and clinical features of myocardial infarction with normal coronary arteriogram.
Authors: Rosenblatt A , Selzer A
Published: June 2012

Six new cases of acute myocardial infarction with normal coronary arteriogram are presented and supplemented by 19 collected cases (group I). These are compared with 16 cases of myocardial infarction caused by occlusive coronary artery disease in a comparable population (group ii). The following significant differences between the two groups are established: patients in group I were younger (27.5 years vs 33.7 years, P less than 0.005); at least one risk factor was present in all patients in group II, but in only 40% of group I (P less than 0.0001). effort angina preceded the attack in ten patients of group II, but in none of group I (P less than 0.0001). The attack was unheralded in 24 of the 25 patients in group I, but was preceded by prodromes in 11 of 16 in group II (P less than 0.0001). Attacks of pain following myocardial infarction occurred in five patients of group 2 and II of group II) (P less than 0.001). Results are discussed in the light of the nature of myocardial infarction in group I. No support is found for the coronary spasm theory. The most likely mechanism for development of myocardial infarction in group I is thought to be a thromboembolic "accident." This accident is not necessarily related to atherosclerotic coronary disease and is presumed to be benign in nature.
Intracardiac pressure-sound correlates of echographic aortic valve closure.
Authors: Hirschfeld S , Liebman J , Borkat G , Bormuth C
Published: June 2012

Echographic aortic valve closure was compared to the dicrotic notch of the aortic pressure and intracardiac A2 to define the exact temporal relationship of the echographic, pressure, and sound parameters of aortic valve closure. Sixteen children, ages 3--20 years, were evaluated by simultaneous aortic valve echograms, micromanometric aortic root pressure tracings, and intracardiac phonocardiograms recorded at paper speeds of 200 mm/sec. Our observations demonstrated that echographic coaptation of the aortic valve leaflets coincides with the trough of the aortic pressure incisura and the onset of A2. The data suggest that A2 is a result of valve closure.
Suprasternal notch echocardiography. Assessment of its clinical utility in pediatric cardiology.
Authors: Allen H D , Goldberg S J , Sahn D J , Ovitt T W , Goldberg B B
Published: June 2012

Echocardiographic suprasternal relationships of the transverse aortic arch (TAA), right pulmonary artery (RPA) and left atrium (Y' LAD) were validated and angiographic-echocardiographic measurement correlations were made for each structure. Normal values were determined with respect to body surface area. In normals, regardless of age or body size, mean dimensional TAA/RPA ratio was 1.2:1 and Y' LAD equaled the anterior-posterior, or Z axis, left atrial dimension (Z LAD)- TAA/RPA ratio was increased in aortic stenosis and tetralogy of Fallot and was decreased in ventricular septal defect, atrial septal defect and pulmonary stenosis. Ratio did not correlate with lesions severity as assessed by cardiac catheterization except in pulmonary stenosis. Discrepant Y' LAD values (usually increased Y' LAD and decreased Z LAD) occurred in children with various forms of heart disease. Some had sternal compression but others had normal chests. Children with pectus excavatum showed similar compression. These findings underscore the need for incorporation of a suprasternal examination into the standard echocardiographic examination of children.
Phonoangiography by autocorrelation.
Authors: Rosen R M , Parthasarathy S P , Turner A F , Blankenhorn D H , Roschke E J
Published: June 2012

Phonoangiography, as a noninvasive quantitative analysis of arterial bruits, was conducted just prior to standard invasive radiographic angiography in 135 patients. Sound records from 162 carotid arteries were analyzed with a new processing technique employing a high speed analog acoustic analyzer, the autocorrelator. In 18 arteries with carotid stenosis, a correlation coefficient of 0.87 resulted between phonoangiographic diameter predictions and radiographic diameter estimates. Bruit analysis identified two patients with patent lumen diameters, but tortuous carotid vessels. One hundred thirty-three carotid arteries had no bruits that could be analyzed, but angiograms showed no extracranial stenosis. Four arteries from which bruits could not be analyzed were found to be totally occluded. Carotid phonoangiography appears applicable in approximately one of seven patients now requiring angiography of head and neck vessels. When applicable, phonoangiography is significantly correlated with angiographic findings.
Early and late results of surgical repair of truncus arteriosus.
Authors: Marcelletti C , McGoon D C , Danielson G K , Wallace R B , Mair D D
Published: June 2012

Ninety-two patients had corrective operation for truncus arteriosus between 1967 and 1975. During the first 30 days after surgery, 23 patients died. No significant differences appear between early mortality and sex, type of truncus, variations in pulmonary arterial anatomy, truncal valve regurgitation, associated anomalies, previous operation, or duration of extracorporeal circulation. Greater risk is probably encountered with the higher but still operable levels of pulmonary resistance. Reoperation has been required in three patients. Fifty-nine percent of survivors are symptom-free, with all but two of the remainder (38%) being in NYHA functional class II. The late result is suggestively less satisfactory in patients with significant preoperative truncal valve regurgitation. Some late complications related to deterioration of the earlier aortic homograft conduit may be avoided by use of a porcine valve Dacron conduit. The current operative mortality of 9%, and the well-being of 97% of surviving patients suggest the continued advisability of recommending operation for appropriate patients.
Myocardial metabolism in cyanotic congenital heart disease studied by arteriovenous differences of lactate, phosphate, and potassium at rest and during atrial pacing.
Authors: Friedli B , Haenni B , Moret P , Opie L H
Published: June 2012

To study myocardial metabolism in chronic hypoxia due to cyanotic congenital heart disease, coronary arteriovenous differences of lactate (L), pyruvate (P), inorganic phosphate (Pi) and potassium (K) were measured in 14 cyanotic patients and seven controls, at rest and during atrial pacing. At rest, there was no difference in any parameter between cyanotic and noncyanotic patients. During atrial pacing (150-175/min) for 10 min, a moderate drop in L-extraction occurred in the control patients with some increase in L/P ratio in coronary venous blood. Cyanotic patients fell into two groups: in nine (group I), the arterial oxygen saturation (SaO2) dropped with pacing. Their L-extraction fell sharply, from 28.1 +/- 3.12 to --2.8 5.51 and L production occurred in five. There was a significance increase in coronary venous L/P ratio. Five cyanotic patients (group II) showed no drop in SaO2 with pacing, and L extraction as well as L/P ratio remained stable. Uptake of Pi was noted in all patients at rest, during pacing this disappeared in controls and group I cyanotics but not in group II. No K changes were seen in any patient. Thus, myocardial metabolism is normal at rest in patients with cyanotic CHD; during atrial pacing, a shift toward anaerobic metabolism occurs if SaO2 drops; cyanotic patients whose SaO2 remains stable appear to withstand pacing better than controls.
Comparative effects of physical training and diet in normalizing serum lipids in men with Type IV hyperlipoproteinemia.
Authors: Lampman R M , Santinga J T , Hodge M F , Block W D , Flora J D , Bassett D R
Published: June 2012

The effect of milk physical training (PT) (group A), Type IV hyperlipoproteinemia (HLP) diet (group B), and PT plus Type IV HLP diet on serum lipids (group C) in 46 men with Type IV HLP was studied. Significant reductions in mean triglyceride (TG) levels from 163, 229, 196, to 136, 145, 116 mg/100 ml serum were found for groups A, B, and C, respectively. Following six weeks of intervention, cholesterol levels also dropped for all groups with the greatest reductions occurring in groups B and C. Minimal weight losses were found for all groups while groups A and C displayed significant reductions in body fatness, but both of these changes appeared independent of lipid reductions. It was concluded that either mild PT or HLP diet or both are effective means of lowering TG levels in Type IV HLP individuals. Furthermore, it appears that patients need to participate regularly in formal programs in order to maintain adherence to these interventions.
Thallium 201 imaging and gated cardiac blood pool scans in patients with ischemic and idiopathic congestive cardiomyopathy. A clinical and pathologic study.
Authors: Bulkley B H , Hutchins G M , Bailey I , Strauss H W , Pitt B
Published: June 2012

In ischemic cardiomyopathy (CM) fibrosis replaces large segments of myocardium, but in idiopathic congestive CM the myocardium contains only small foci of fibrosis or is morphologically normal. As coronary disease and myocardial infarction may be clinically silent, it is not always possible to distinguish ischemic from idiopathic congestive CM during life without cardiac catheterization. To determine whether noninvasive methods, thallium 201 myocardial (Tl) imaging and technetium 99m gated cardiac blood pool scans (GCBPS), could separate the entities, we evaluated radioisotope images of the heart in 13 patients with ischemic, and eight patients with idiopathic congestive CM, and 14 patients with normal hearts. Diagnosis was setablished by cardiac catherterization and/or autopsy in each of the 35 patients. The 14 normals could be readily distinguished from CM, and ischemic could be distinguished from idiopathic dilated CM in 20 of 21 patients. All patients with myocardiopathy showed hypokinetic and dilated left ventricles, but right ventricular dilatation was evident mainly in those with idiopathic CM. Tl images in the ischemic type had defects of greater than 40% of image circumference which corresponded to segmental wall motion abnormalities on GCBPS, whereas those with the idiopathic congestive form were homogeneous or had defects of less than 20% of image circumference. Autopsy studies in 7 of 35 patients correlated Tl defects of greater than 20% of circumference with transmural myocardial fibrosis.
HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study.
Authors: Castelli W P , Doyle J T , Gordon T , Hames C G , Hjortland M C , Hulley S B , Kagan A , Zukel W J
Published: June 2012

The relation between coronary heart disease (CHD) prevalence and fasting lipid levels was assessed by a case-control study in five populations with a total of 6859 men and women of black, Japanese and white ancestry drawn from subjects aged 40 years and older from populations in Albany, Framingham, Evans County, Honolulu and San Francisco. In each major study group mean levels of high density lipoprotein (HDL) cholesterol were lower in persons with CHD than in those without the disease. The average difference was small -- typically 3-4 mg/dl -- but statistically significant. It was found in most age-race-sex specific groups. The inverse HDL cholesterol-CHD association was not appreciably diminished when adjusted for levels of low density lipoprotein (LDL) cholesterol and triglyceride. LDL, totoal cholesterol and triglycerides were directly related to CHD prevalence; surprisingly, these findings were less uniformly present in the various study groups than the inverse HDL cholesterol-CHD association.
Left ventricular and coronary angiographic anatomy. Relationship to ventricular irritability in the late hospital phase of acute myocardial infarction.
Authors: Schulze R A , Humphries J O , Griffith L S , Ducci H , Achuff S , Baird M G , Mellits E D , Pitt B
Published: June 2012

Late hospital phase ventricular arrhythmias in acute myocardial infarction (MI) have been associated with a high incidence of sudden death following hospital discharge. Thirty-eight patients were studied 10-24 days following onset of symptoms of MI. Each patient had a 24-hour ambulatory ECG tape recording and left ventricular and coronary angiography performed. Patients with complicated ventricular arrhythmias (multiform, coupled, R on T VPCs or ventricular tachycardia), when compared to those with uncomplicated ventricular arrhythmias (unifocal or no VPCs), had a greater number of proximally narrowed major coronary arteries (P less than 0.001), a higher coronary "score" (P less than 0.001), a greater incidence of previous myocardial infarction (P less than 0.005), a greater percentage of abnormal left ventricular segments 86% vs 69% (P less than 0.001) and lower ejection fractions. These data suggest that late hospital phase survivors of MI with complicated ventricular arrhythmias have more extensive coronary artery disease with greater left ventricular dysfunction than survivors with uncomplicated ventricular arrhythmias. This more extensive disease may result in increased areas of ischemic myocardium and may help explain the refractoriness of these arrhythmias to pharmacologic therapy.
Quantitative assessment of ventricular performance in unstable ischemic heart disease by dextran function curves.
Authors: Raphael L D , Mantle J A , Moraski R E , Rogers W J , Russell R O , Rackley C E
Published: June 2012

The ability to quantitate the amount of permanent left ventricular dysfunction in patients with unstable ischemic heart disease would have important clinical value. Left ventricular function curves were constructed in sixteen patients with acute myocardial infarctions and five patients with unstable angina pectoris syndrome at an average of 56 hours (+/- 8) after the onset of symptoms. Fifty ml increments of low molecular weight dextran were rapidly infused into the right antrium during constant monitoring of the pulmonary artery end-diastolic pressure (PAEDP) via a Swan-Ganz thermodilution catheter. An average of 400 ml (range 200-800) was infused to produce a significant change in the PAEDP (range 3-13 mm Hg). The cardiac index was measured before and after the dextran infusion. The slope of the left ventricular function curve was calculated by dividing the change in the cardiac index by the change in the PAEDP. The sixteen patients with acute myocardial infarction underwent left heart catheterization and left ventricular biplane angiography an average of six months later. The five patients with unstable angina pectoris were studied within one month. The slope value of the left ventricular function curve was compared angiographic ejection fraction by linear regression analysis and the correlation coefficient was 0.80. These data demonstrate 1) the slope of the left ventricular function curve in patients with acute myocardial infarction or unstable angina correlates well with the angiographically calculated ejection fraction; 2) as early as two days post myocardial infarction, the residual impairment of left ventricular function can be estimated.
The assessment of mitral stenosis and prosthetic mitral valve obstruction, using the posterior aortic wall echocardiogram.
Authors: Strunk B L , London E J , Fitzgerald J , Popp R L , Barry W H
Published: June 2012

The echocardiographic motion of the aortic root reflects, in part, left atrial filling and emptying. Patients with mitral valve obstruction were studied to determine whether clinically important alterations in patterns of left atrial emptying would alter motion of the posterior aortic wall. Patients with mitral stenosis had a characteristic pattern of slowing of left atrial emptying in early diastole, with loss of the conduit phase in mid-diastole. The atrial emptying index, defined as the fraction of passive posterior aortic wall motion occurring in the first third of diastole, was significantly related to the mitral valve area index (r = 0.86), and thus provides a noninvasive quantitation of the degree of mitral stenosis. Determination of the atrial emptying index also proved useful in the evaluation of patients with prosthetic mitral valve obstruction and in documenting improvement in left atrial emptying after mitral valve surgery.
Decreased frequency of exercise-induced ventricular ectopic activity in the second of two consecutive treadmill tests.
Authors: Sheps D S , Ernst J C , Briese F R , Lopez L V , Conde C A , Castellanos A , Myerburg R J
Published: June 2012

Two exercise tests were performed with an intervening rest period of 45 minutes in a group of 13 subjects with previously identified exercise-induced ventricular arrhythmias and no resting arrhythmias. Both normal subjects and patients with heart disease were included in the group. The level of stresss was equal in both tests as judged by similar rate-pressure products at peak exercise. There was a significant decrease (P less than 0.05) in the number of VPCs induced by exercise during and after the second test. When the number of VPCs on test I and test II in the same patients were compared, a regression line fitted the data well (r = 0.92). Analysis of the recovery periods revealed significant (P less than 0.01) decreases in systolic blood pressure at one and three minutes post exercise, comparing the second to the first test. The underlying mechanism may be decreased myocardial oxygen demand during the second test as the lowered rate-pressure products during recovery (P less than 0.01) reflect. The results of this study indicate that tests of effectiveness of an antiarrhythmic drug should not be based solely on a decrease in the amount of severity of ventricular irritability between two successive exercise tests, one immediately before and the other following administration of the drug.
Coronary spasm, variant angina, and recurrent myocardial infarctions.
Authors: Johnson A D , Detwiler J H
Published: June 2012

A 24-year-old male student had three myocardial infarctions, one prior to and two following the angiographic documentation of normal coronary arteries. A spontaneous episode of variant angina prompted repeat coronary angiography, during which intravenous ergonovine caused spasm of the left anterior descending coronary artery, transient ST-segment elevation, and ischemic chest pain; the previously normal right coronary artery was found to be occluded proximally. This constellation of clinical and angiographic findings suggests that coronary spasm can cause acute myocardial infarction as well as variant angina.
Surgical management of life-threatening ventricular arrhythmias in patients with coronary artery disease.
Authors: Ricks W B , Winkle R A , Shumway N E , Harrison D C
Published: June 2012

Twenty-one patients with coronary artery disease and severe, symptomatic ventricular arrhythmias underwent cardiac surgery after failure of medical managememt. All had coronary artery disease and either localized areas of severe hypokinesis (three patients), or ventricular aneurysms (18 patients) documented angiographically prior to surgery. Operation within one month after acute infarction resulted in an 80% in-hospital mortality, whereas operation more than one month postinfarction showed a 20% mortality. Operative treatment that included myocardial resection had a significantly lower mortality (P less than 0.05) than that which did not. With an average of 36.5 months of follow-up, 13 of the 21 patients were long-term survivors, despite the persistence of ventricular arrhythmias. Surgical treatment which includes myocardial resection and occurs more than one month after infarction should be considered in patients with symptomatic ventricular arrhythmias and severe, well-localized left ventricular wall motion abnormalities.