bluuebunny/crossref_metadata_2025 huggingface dataset:
Sinus node recovery time and calculated sinoatrial conduction time in normal subjects and patients with sinus node dysfunction.
Authors: Breithardt G , Seipel L , Loogen F
Published: June 2012

In 61 patients sinus node function was tested by programmed (sinoatrial conduction time, SACT) and overdrive atrial pacing (sinus node recovery time, SRT). In the control group (N = 20), mean sinus cycle length was 773 +/- 140.2 msec, mean absolute SRT 1044 +/- 215.8 msec [corrected SRT (CSRT) 270 +/- 112.5 msec; mean +/- SD] and calculated SACT was 82 +/-19.2 msec. The upper limit of normal SACT was defined as 120 msec. In 41 patients with sinus node dysfunction, mean age (55 +/- 14.7 years), mean spontaneous cycle length during the study (1094 +/- 248.0 msec), the lowest heart rate observed (42 +/- 7.5 beats/min), maximal SRT (2110 +/- 1269.1 msec), maximal CSRT (1016 +/- 1182.8 msec), and calculated SACT (126 +/- 47.3 msec) were significantly longer than in the control group. Abnormalities of sinus node function, as evidenced by the degree of spontaneous bradycardia, SRT and calculated SACT were more frequent in patients with bradycardia-tachycardia syndrome or spontaneous sinoatrial block than in those exhibiting isolated sinus bradycardia. We conclude 1) that in patients with sinus node dysfunction both sinus node automaticity and sinoatrial conduction may be abnormal, and 2) that overdrive and programmed premature atrial stimulation can separate patients with sinus node dysfunction according to their clinical presentation.
Induction of iatrogenic electrocardiographic patterns during electrophysiologic studies.
Authors: Akhtar M , Danato A N , Gilbert-Leeds C J , Batsford W P , Reddy C P , Gomes J A , Calon A H , Dhatt M S
Published: June 2012

Indwelling cardiac catheters by producing local mechanical stimulation or trauma can induce electrocardiographic (ECG) patterns which simulate known electrophysiologic phenomena. Catheter-induced ECG patterns were analyzed in 447 consecutive patients undergoing electrophysiologic studies. Iatrogenic nature of these patterns was suggested by 1) absence prior to placement of catheter; 2) sudden appearance with catheter placement and disappearance with catheter repositioning; 3) reoccurrence with remanipulation of catheters; and 4) simulation (in some cases) by programmed electrical stimulation from the catheter. Common catheter-induced patterns were 1) right bundle branch block (RBBB) lasting less than 24 hours occurred in 19 patients; 2) transient third degree atrioventricular block in His-Purkinje system developed in 3/13 patients with pre-existing left BBB; 3) catheter-induced ventricular pre-excitation which simulated ECG patterns of type B Wolff-Parkinson-White syndrome; 4) fortuitous synchronization of right ventricular excitation from the catheter, and left ventricular excitation from sinus beat resulted in normalization of the QRS complexes in 5/68 patients with pre-existing RBBB; 5) premature beats from the atria, right ventricle, and His bundle, which were common, resulted in complex ECG patterns. These iatrogenic ECG patterns must be identified in order to avoid errors in interpretation.
Comparison of the cardiocirculatory effects of exercise and isoproterenol in children with pulmonary or aortic valve stenosis.
Authors: Truccone N J , Steeg C N , Dell R , Gersony W M
Published: June 2012

Isoproterenol infusion during cardiac catheterization as a simulator of exercise was evaluated with hemodynamic studies in children with pulmonary (15) or aortic (8) valve stenosis. Cardiac function was monitored during rest, mild exercise and isoproterenol infusion. Similar heart rates were maintained in both procedures. Peak pulmonary and aortic valve gradients as well as right and left ventricular dp/dt/p were significantly higher and cardiac index significantly lower with isoproterenol as compared to exercise. Isoproterenol induced a significantly greater decrease in systemic vascular resistance, and systemic blood pressure than did exercise. Left ventricular systolic pressure rose to similar levels and this resulted in substantially higher peak aortic gradients with isoproterenol. A consistent correlation was observed for peak valvular gradients measured during exercise and isoproterenol in both groups of patients. Accordingly, regression equations were obtained allowing reasonably accurate prediction of exercise valvular gradients on the basis of the isoproterenol data.
Technetium-99m stannous pyrophosphate myocardial scintigraphy. Reliability and limitations in assessment of acute myocardial infarction.
Authors: Cowley M J , Mantle J A , Rogers W J , Russel R O , Rackley C E , Logic J R
Published: June 2012

Two hundred-three patients had -echnetium 99m (stannous) pyrophosphate myocardial scintigrams for the evaluation of chest pain and suspected acute myocardial infarction. In addition to routine imaging at 60--90 minutes after injection of the radio-pharmaceutical, the blood pool was imaged immediately in each patient for comparison with routine anterior, left anterior oblique, and left lateral views. Further delayed studies were obtained when residual blood pool activity was identified. Seventy patients had acute myocardial infarction by clinical, electrocardiographic, and enzymatic (CK-MB) criteria. Sixty-five of these 70 patients with acute infarction had positive myocardial scintigrams, with one technically unsatisfactory study. Only four of the 70 patients had negative scintigrams when imaged 18--72 hours after infarction in this study. Technically satisfactory scintigrams were recorded in 125 patients without evidence of infarction. Ninety-six had negative scintigrams at 60--90 minutes, while 19 patients (15%) had precordial activity at 60--90 minutes which was identical in distribution to early blood pool images and cleared with further delay. With these included, the true negative incidence was 92%. Ten of 125 patients had false positive scintigrams; two had recent cardioversion with resultant chest wall damage. The other eight patients had previous infarction 1 1/2 to 72 months earlier and had akinetic segments shown angiographically in the areas of the persistently positive scintigrams. Myocardial scintigraphy correlates well with the presence of other evidence of acute infarction, as well as with the absence of acute infarction when residual blood pool activity is identified. False positive scintigrams can occur following cardioversion and in patients with previous myocardial infarction and resultant ventricular wall motion abnormalities.
Electrocardiographic recognition of sinus node dysfunction in children and young adults.
Authors: Yabek S M , Swensson R E , Jarmakani J M
Published: June 2012

Twenty-four children and young adults with electrocardiographic evidence of sinus node dysfunction (SND) are described. The patients, whose ages ranged from three days to 25 years, were divided into three groups based on the type of SND. Ten patients had persistent and inappropriate sinus bradycardia (group I): twelve patients had episodes of prolonged sinus arrest (group II); and seven patients had repeated episodes of Mobitz type I or II sinoatrial exit block (group III). Eighteeen patients had significant heart disease and in 11 of these the SND followed corrective cardiac surgery. Seven were operations for atrial septal defect and transposition repair. Seven patients with SND were symptomatic, having either syncopal (3) or near syncopal episodes (4). All three with syncope have received permanent demand pacemakers. These data show that sinotrial exit block occurs in many young patients with SND (29% in this series). Its recognition, however, requires careful electrocardiographic analysis in order to differentiate sinus bradycardia and sinus arrhythmia. Although SND most commonly occurs in children with congenital or acquired heart disease, particularly following corrective cardiac surgery, it may occur in the absence of other cardiac abnormalities.
Left precordial isopotential mapping during supine exercise.
Authors: Mirvis D M , Keller F W , Cox J W , Zettergren D G , Dowdie R F , Ideker R E
Published: June 2012

Junctional depression is often observed during physical exercise in overtly normal subjects. To explore its pathogenesis, 15 normal volunteers were studied during supine, bicycle ergometer, submaximal stress tests. Electrocardiograms were simultaneously recorded from 42 electrodes on the left anterior precordium at two minute intervals at rest and during exercise. Data were used to construct isopotential maps throughout the P-QRS-T intervals. At rest, maps throughout the ST segment were dominated by a single maximum along the upper left sternal border. During exercise, all subjects developed junctional depression that was maximal along the lower left sternal border. Exercise maps during the early to mid-ST segment showed an intense minimum along the lower left sternal border that was continuous with terminal QRS forces in both intensity and location. Later in ST, this minimum decreased in strength and was replaced by a maximum located in the same area as that observed at rest. These observations suggest that junctional depression is the result of competition between two effects, one being normal repolarization which is obscured in the early ST segment by the second, possibly representing delayed terminal depolarization forces.
The determinants of atrioventricular nodal re-entrance with premature atrial stimulation in patients with dual A-V nodal pathways.
Authors: Denes P , Wu D , Amat-y-Leon F , Dhingra R , Wyndham C R , Rosen K M
Published: June 2012

In patients with dual atrioventricular (A-V) nodal pathways, atrial extrastimulus testing induces either no echoes, single atrial echoes (Ae), or repetitive re-entrance (repetitive atrial and ventricular beating). We examined the fast and slow pathways properties in 38 patients with dual pathways in order to delineate the determinants of re-entrance. Seventeen patients had no Ae. Of these, six had no V-A conduction and 11, intact V-A conduction. The mean paced ventricular cycle length producing retrograde V-A block (VABCL) in this group (a measure of retrograde fast pathway refractoriness) was 552 +/- 32 msec (mean +/- SEM; 10 pts). In contrast, all 21 patients with Ae had intact V-A conduction with mean VABCL of 382 +/- 21 msec (14 pts) (P less than 0.05). Repetitive re-entrance occurred only when Ae conducted to the ventricles. Seven patients had only single Ae. The mean paced atrial cycle length producing Wenckebach periodicity (CLAWP) in this group (a measure of antegrade slow pathway refractoriness) was 490 +/- 31 msec (5 pts). Fourteen patients had repetitive re-entrance. The mean CLAWP in this group was 399 +/- 18 msec (8 pts) (P less than 0.05). In conclusion, our results suggest that in patients with dual pathway, the occurrence of single or repetitive re-entry is dependent upon measurable slow and fast pathway properties.
Effect on training on myocardial oxygen supply/demand balance.
Authors: Barnard R J , MacAlpin R , Kattus A A , Buckberg G D
Published: June 2012

In five well-trained and five sedentary control subjects potential subendocardial blood supply was estimated from the diastolic pressure time index (DPTI) and myocardial oxygen demands from the tension time index (TII) during a progressive near-maximal treadmill test. DPTI/TTi was used to assess the effects of training on myocardial oxygen supply/demand balance. DPTI/TTI was significantly higher in trained subjects at rest and comparable workloads. At 6.4 km/hr, 18% grade (maximum for the controls), TTI was significantly lower (4300 +/- 76 vs 4495 +/- 99 mm Hg-sec/min) and DPTI significantly higher (2534 +/- 86 vs 2295 +/- 91 mm Hg-sec/min) in the trained subjects; DPTI/TTI was significantly higher (0.59 +/- .02 vs 0.50 vs .03). At near-maximal heart rates both groups achieved the same supply/demand balance (0.50); however, the trained subjects were working at higher workloads. We conclude that endurance conditioning increases work capacity, reduces myocardial O2 demands, increases potential O2 supply and improves the supply/demand balance at any given submaximal workload which reduces the risk of ischemia.
Echocardiographic evaluation of fixed left ventricular outlet obstruction in children. Pre and postoperative outlet obstruction in children.
Authors: Johnson G L , Meyer R A , Schwartz D C , Korfhagen J , Kaplan S
Published: June 2012

Rencently, several investigators have utilized the echographically determined magnitude of relative left ventricular posterior wall hypertrophy as a reflection of normalized systolic wall stress to estimate left ventricular systolic pressure noninvasively. In this study, relative wall thickness determined echographically was compared to peak systolic pressure measured at catheterization in 20 children without obstruction to left ventricular outflow and with normal left ventricular function. From these data a relationship, pressure = 225 X left ventricular systolic wall thickness/left ventricular end-systolic internal dimension, was derived. The relationship was then applied to 57 children with fixed aortic stenosis. Left ventricular pressure estimated echographically compared well with that demonstrated at cardiac catheterization (r = 0.89). Twenty-one patients had further echographic studies following surgical relief of outlet obstruction. Estimated left ventricular pressure fell to normal values within two months following surgery in over half the patients with good surgical relief of obstruction, and was normal at subsequent studies up to 22 months postoperatively in all but one patient with good surgical relief. In patients in whom outlet obstruction was not adequately relieved at surgery, echographically estimated left ventricular pressure remained persistently elevated.
Chronic congestive heart failure after repair of tetralogy of Fallot.
Authors: Rocchini A P , Rosenthal A , Freed M , Castaneda A R , Nadas A S
Published: June 2012

The etiology of chronic congestive heart failure (CHF) after repair of tetralogy of Fallot was determined in 102 patients consecutively catheterized 1 to 12 years postoperatively. Chronic CHF was observed in 36/102 patients. The most prevalent abnormality leading to congestive failure (31/36) was a large residual ventricular septal defect alone or in combination with other lesions. All postoperative patients with pulmonary to systemic flow ratios greater than 2:1 (25/102) had congestive failure and evidence of biventricular dysfunction. Significant tricuspid regurgitation (N = 11) and persistent systemic to pulmonary artery shunts (N = 6) contributed to volume overload and congestive failure in the patients with large residual ventricular septal defect. Isolated severe residual right ventricular outflow tract obstruction was a common cause of chronic CHF. Pulmonary artery hypertension was present in 20/36 patients with CHF. The increased pulmonary pressure was not wholly due to an increased pulmonary flow since 7/20 patients had pulmonary vascular resistance greater than 3 mm Hg/L/min/m2. Our findings indicate that persistent or chronic congestive heart failure in postoperative tetralogy of Fallot patients requires bilateral cardiac catherterization since an identifiable and surgically correctable lesion is nearly always present.
Abnormal left ventricular contraction pattern in the systolic click-late systolic murmur syndrome.
Authors: Mathey D G , Decoodt P R , Allen H N , Swan H J
Published: June 2012

A contraction abnormality of the left ventricle has previously been described in patients with systolic click-late systolic murmur syndrome. To determine if the contraction abnormality is present in the preprolapse period, LV dimensions and the instantaneous velocity of circumferential fiber shortening (VCF) were studied in 18 patients with the mitral valve prolapse and 16 normal subjects using computer analysis of echocardiograms. VCF attained its maximum (max VCF) during the preprolapse period an average of 94 msec before the mid-systolic click. Max VCF was significantly reduced in patients with mitral valve prolapse (2.06 vs 2.55 circ/sec in normal subjects, P less than 0.001). Despite the reduction in max VCF, no difference in the extent and percentage of diameter shortening was found between patients and normal subjects. This discrepancy is explained by a sustained rate of mid-to-late systolic diameter shortening in the presence of mitral valve prolapse as manifested by a typical VCF profile (P less than 0.001) and a longer duration of diameter shortening (353 vs 306 msec in normal subjects, P less than 0.01). The decrease of max VCF in patients with mitral valve prolapse suggests a reduction in LV contractility. Since the abnormality is present in the preprolapse period, it is unrelated to a direct mechanical effect of the prolapse itself. Additional fiber shortening in mid-to-late systole indicates that the sudden displacement of the mitral leaflets may have an unloading effect on the left ventricle.
Efficacy of ambulatory systemic vasodilator therapy with oral prazosin in chronic refractory heart failure. Concomitant relief of pulmonary congestion and elevation of pump output demonstrated by improvements in symptomatology, exercise tolerance, hemodynamics and echocardiography.
Authors: Awan N A , Miller R R , DeMaria A N , Maxwell K S , Neumann A , Mason D T
Published: June 2012

The long-term efficacy of the new oral vasodilator, prazosin (PZ), was evaluated in nine patients with refractory heart failure due to chronic coronary heart disease. Ventricular function was assessed by cardiac catheterization, echocardiography, and treadmill testing; symptomatic evaluation was carried out for two to four months. One hour following 2-7 mg PZ, control left ventricular filling pressure was reduced (32 to 18 mm Hg, P less than 0.001) and cardiac index was elevated (1.95 to 2.89 L/min/m2, P less than 0.001) for a 6-hour period. After two weeks of PZ 2 to 7 mg four times daily, echographic end-diastolic dimension fell (5.7 to 5.4 cm, P less than 0.001) while shortening fraction increased (27.6 to 30.2%, P less than 0.005). Treadmill exercise duration increased from 209 to 317 seconds (P less than 0.001). Symptoms diminished throughout the duration of follow-up (mean 94 days) with improvement in NYHA functional class (3.7 to 2.2, P less than 0.001). Thus, prazosin possesses sustained nitroprusside-like balanced dilator actions on the systemic arterial and venous systems and is effective in the ambulatory management of chronic severe heart failure.
Effects of digitalis on resting and isometric exercise myocardial perfusion in patients with coronary artery disease and left ventricular dysfunction.
Authors: Vogel R , Kirch D , LeFree M , Frischknecht J , Steele P
Published: June 2012

Digitalis has been shown to improve the impaired ventricular function associated with coronary artery disease as well as to increase myocardial oxygen consumption and produce coronary vasoconstriction. To elucidate the net result of these contrasting effects, six patients with coronary artery disease and left ventricular ejection fractions less than 0.50 had 1.0 mCi thallium-201 injected intravenously at rest and during three minutes of 33% of maximal handgrip, off and on 0.25 mg daily maintenance digoxin. Thallium-201 scintigram images were taken 30 minutes later and were computer processed with orthogonal linearly interpolated background subtraction and maximal count density equalization. Processed images were visually graded on a 0, 1, or 2 scale for 18 sectors--nine from the AP projections and nine from the 40 degrees left anterior oblique projections. A score resulting from the summation of the 18 sector grades was made for each study, the maximum score being 36. Off digitalis, patients performing handgrip exercise decreased their scintigram scores from 25.7 +/- 1.5 (mean +/- SEM) to 23.0 +/- 1.0, P less than 0.05. When patients were on maintenance digoxin, scores did not change significantly during handgrip exercise. Post exercise scores were significantly higher on digoxin than off (P less than 0.05), whereas, resting scores were unaffected by digoxin. These data suggest that myocardial perfusion, as measured by thallium-201 uptake, is improved in patients on digitalis who have coronary artery disease and left ventricular dysfunction.
A study of the human heart as a multiple dipole source. IV. Left ventricular hypertrophy in the presence of right bundle branch block.
Authors: Holt J H , Barnard A C , Kramer J O
Published: June 2012

This report concerns the task of electrocardiographic (ECG) diagnosis and quantitation of left ventricular hypertrophy (LVH) in patients with right bundle branch block (RBBB). In 36 patients with RBBB the left ventricular mass (LVM) of each patient was independently known from quantitative biplane angiography. Two ECG techniques, standard 12-lead ECG and multiple dipole electrocardiography (MDECG), were evaluated. In diagnosing LVH, the best performance of the several standard ECG criteria was sensitivity = 29%, specificity = 100%, and that of the MDECG was sensitivity = 94%, specificity = 96%. In quantitating LVH, the standard ECG gave a correlation with LVM of r = 46% and a standard error of estimate of 98 g. The corresponding figures for the MDECG were r = 81% and the root mean square prediction error = 64 g. These results confirm other studies showing that the conventional ECG is of only marginal value in the task of diagnosing LVH in the presence of RBBB. In contrast, the MDECG performs well both in this task and that of quantitating LVH. The results provide further support of the accuracy of the model of the cardiac electrical generator and volume conductor used in the MDECG method.
Re-entrant ventricular arrhythmias in the late myocardial infarction period. 4. Mechanism of action of lidocaine.
Authors: El-Sherif N , Scherlag B J , Lazzara R , Hope R R
Published: June 2012

The effect of lidocaine on re-entrant ventricular arrhythmias (RVA) was studied in dogs 3-7 days following ligation of the anterior descending coronary artery; direct recordings were made of the re-entrant pathway (RP) from the epicardial surface of the infarction zone (IZ). Lidocaine in a therapeutic dose consistently prolonged refractoriness of potentially RP(s) in the IZ and produced a higher degree of conduction block at a constant heart rate. Conduction in the adjacent normal zone was not affected. The impairment of conduction induced by lidocaine in the RP was directly related to its ability to abolish re-entrant ventricular beats and tachycardia. Gradual slowing of conduction in the RP consistently developed before abolition: lengthening of coupling of extrasystolic beats in surface leads and gradual slowing of ventricular tachycardia rate occurred. The termination of re-entry was characteristically associated with complete block in the RP. A "selectivity hypothesis" for the antiarrhythmic action of lidocaine is proposed.
Sinoatrial pacemaker shift following atrial stimulation in man.
Authors: Steinbeck G , Lüderitz B
Published: June 2012

Indirect evidence of a sinoatrial pacemaker shift after programmed atrial stimulation in man is presented. Following electrically induced beats, time intervals and postextrasystolic morphology of atrial electrogram and P waves were scrutinized in 30 catheterization studies. Applying premature atrial stimulation, a decrease of the interval between the last basic atrial depolarization and the stimulus-produced atrial excitation (curtailed cycle) below a critical interval was followed by a sinoatrial pacemaker shift in three cases. This electrophysiologic event consisted of a concomitant change in shape of high right atrial electrogram and an increase of atrial cycle length. Simultaneous alteration of P waves could be detected in 2/3 patients. Assuming that the pacemaker shift indicates the arrival of ectopic activation in the sinus node, capture of the sinus node by the premature beat could be distinguished from failure to capture. Thus, pacemaker shift can be used for estimating sinoatrial conduction time in addition to present methods using measurement of postextrasystolic atrial intervals. The changes described could be seen both before and after atropine administration. Tracings of a pacemaker shift after cessation of rapid atrial pacing are also presented. In summary, we found a sinoatrial pacemaker shift underlying sinus node response to ectopic atrial activation in man, a phenomenon which contributes to our understanding of indirect assessment of sinoatrial conduction time by the premature stimulation technique.
Serial electrocardiograms in hypertensive cardiovascular disease.
Authors: Dunn R A , Zenner R J , Pipberger H V
Published: June 2012

A graphic method for depicting serial changes in electrocardiograms is described and demonstrated for patients being treated in an antihypertension clinic. For these patients, the diagnostic categories, normal, left ventricular hypertrophy, and biventricular hypertrophy, are of primary interest. For each electrocardiogram, 14 measurements are used to compute posterior probabilities for each of the three categories. A triangular grid is used to plot each set of probabilities for an electrocardiogram as one point, which by its position in the triangle can be related to the three categories simultaneously. Points representing successive electrocardiograms can be plotted in the same triangle, giving a pattern of change with time. This pattern of change has been corroborated with associated clinical information on a number of patients. This display, which can be produced quickly and efficiently on a computer graphics terminal, should be considered as a possible tool in evaluating the status of individual hypertensive patients in terms of increase or decrease of ventricular hypertrophy and the efficacy of therapeutic measures.
Echocardiographic and hemodynamic relationships of ejection sounds.
Authors: Mills P G , Brodie B , McLaurin L , Schall S , Craige E
Published: June 2012

The physiologic correlates of ejection sounds have been studied by simultaneous phonocardiograms, echocardiograms and high fidelity pressure tracings. Ejection sounds associated with semilunar valve stenosis or hypertension of the systemic or pulmonary circulation occur at the moment of complete opening of the aortic or pulmonary valve recorded echocardiographically. The start of opening of these valves occurs at the onset of the pressure rise in the corresponding great vessel and completion of valve opening always occurs on the pressure upstroke. The ejection sound in the presence of stenotic valves occurs with checking of the opening motion of the thickened valve cusps. Although the hypertensive ejection sounds also occur at the precise moment of full opening of the valve it remains to be seen whether this relationship is causal or coincidental.
Echocardiography of right ventricular tumors.
Authors: Ports T A , Schiller N B , Strunk B L
Published: June 2012

The clinical and echocardiographic findings of four patients with right ventricular tumors (three myxomas and one metastatic melanoma) are presented. All four patients previously had been evaluated by competent cardiologists, and the diagnosis of a right ventricular tumor was missed. The initial echocardiograms were interpreted as not showing any right ventricular tumor; but on review we found that the correct diagnosis could have been made. The presence of the right ventricular myxomas was confirmed at angiography and surgery. However, the attachment of the stalk of the mycoma could not be determined confidently by angiography alone, and in two of the three cases two-dimensional echocardiography was required to identify correctly the location of the base of the stalk. This paper emphasizes the usefulness and technical difficulties of M-mode and two-dimensional echocardiography in the diagnosis of a right ventricular tumor.
Two-dimensional echocardiographic findings in atrial septal defect.
Authors: Lieppe W , Scallion R , Behar V S , Kisslo J A
Published: June 2012

Two-dimensional echocardiographic findings in a group of 24 patients with atrial septal defects were correlated with findings obtained by cardiac catheterization and M-mode echocardiography. The prevalence of mitral prolapse was 95% by two-dimensional echocardiography and 59% by angiography in patients with secundum and sinus venosus atrial septal defects. The majority of the group with echocardiographic prolapse manifested a distinctive pattern of prolapse, with predominant involvement of the anterior mitral leaflet. Thirty-eight percent of the patients in this series manifested paradoxical septal motion by M-mode and/or two-dimensional echocardiography. In the patients with abnormal septal motion, the net systolic anterior movement of the septum was caused by an exaggerated systolic anterior movement of the main body of the left ventricle. The atrial septal defect could be visualized with confidence by two-dimensional echocardiography only in the two patients with ostium primum atrial septal defects. Cleft anterior mitral leaflets were also clearly demonstrated in these two patients.
New vistas for the study of structural and functional dynamics of the heart, lungs, and circulation by noninvasive numerical tomographic vivisection.
Authors: Wood E H
Published: June 2012

Major segments of the biologic sciences and the practice of medicine are based on study and knowledge of the relationships of anatomic structure to biologic function. Traditionally, this knowledge has been gained by indirect means, inference, or by direct surgical vivisection or postmortem examination. The revolutionary capability of nondestructive, operator interactive, mathematical vivisection provided by synchronous cylindrical scanning tomography to obtain similar information non-invasively and painlessly will provide these data to the internist for individual patients. Furthermore, this information will be in a computerized format which can be subjected to myriad types of objective measurements and display. These developments promise beneficial effects of clinical diagnosis and health care which may approach those associated with the discoveries of the biomedical investigative and clinical diagnostic value of X-rays and cardiac catheterization.
Postextrasystolic compliance of the left ventricle.
Authors: Gaasch W H , Bing O H , Cole J S , Hanley H G
Published: June 2012

The effects of a single premature contraction (PC) on left ventricular diastolic distensibility was studied in man, in the conscious chronically instrumented dog, and in the isolated (isovolumic) blood perfused dog heart. In the isolated dog heart at a constant volume, there was no difference in end-diastolic pressure when control diastolic pressure was compared to that following a PC. In man and conscious dogs, there was no difference between the overall pressure-volume or pressure-length plots when control diastolic data were compared to data from the diastole immediately following a PC (no change in the modulus of chamber stiffness). In the intact circulation of man dog, increased filling during the post PC pause causes the ventricle to operate higher on the steep (stiffer) portion of its pressure-volume or pressure-length curve (decrease in preload-dependent compliance). Thus, although a PC does not alter the modulus of chamber stiffness, a preload-dependent change in compliance may occur during post PC diastole.
Estimation of the probability of exercise-induced ischemia by quantitative ECG analysis.
Authors: Simoons M L , Hugenholtz P G
Published: June 2012

In order to improve the value of exercise tests for the detection of coronary artery disease (CAD) a system for on-line computer processing of the Frank lead exercise ECG was developed. Data were analyzed from 95 patients with CAD and 129 ostensibly healthy men. All subjects had a normal ECG at rest. Visual ECG interpretation during exercise yielded a sensitivity of 50% and a specificity of 95%. A large number of QRS and ST measurements were compared by discriminant function analysis in a group of 86 normal subjects and 52 patients (designated training group). Best results were obtained with a combination of two ST amplitudes from lead X: sensitivity, 85%, specificity, 90%. This was confirmed in a test group of 43 patients and 43 normal subjects. The results of the discriminant function were expressed as the likelihood ratio for an abnormal or normal ST segment at a given heart rate, a figure which provides a quantitative assessment of the degree of exercise-induces ischemia. This is a more realistic approach than classification into normal or abnormal since persons with and without CAD fall along the same continuous spectrum.
Doppler echocardiography. Use of a graphical display system.
Authors: Lorch G , Rubenstein S , Baker D , Dooley T , Dodge H
Published: June 2012

Pulsed Doppler echocardiography (PDE) is a technique for evaluating blood flow characteristics at specific locations within the heart and great vessels. Because this method assesses blood flow rather than cardiac structures, PDE complements the findings of M-mode echocardiography. A new on-line graphical method for displaying pulsed Doppler information provides 1) a printed, permanent record of flow information, 2) precise timing of blood flow events, and 3) information on the direction of flow in the heart and great vessels.
The effect of acute changes in coronary blood flow on left ventricular end-diastolic wall thickness. An echocardiographic study.
Authors: Gaasch W H , Bernard S A
Published: June 2012

The effect of acute alterations in coronary blood flow (CBF) on left ventricular (LV) end-diastolic wall thickness was measured by reflected ultrasound in twelve anesthetized dogs. During five minutes of coronary ligation, wall thickness decreased from a control of 9.0 +/- 0.3 mm to 8.1 +/- 0.3 mm (P less than 0.001); during reperfusion (reactive hyperemia), wall thickness was greater than control (10.2 +/- 0.2 mm at one minute, P less than 0.001). Increased CBF produced by intracoronary nitroglycerin or papaverine resulted in transient increases in wall thickness from 8.9 +/- 0.1 mm to 9.7 +/- 0.2 at one minute (P less than 0.001) and 10.0 +/- 0.6 mm to 11.2 +/- 0.7 mm at one minute (P less than 0.001), respectively. The observed direct relation between CBF and wall thickness suggests a dynamic role for CBF in calculations of LV mass, diastolic wall stress, and myocardial stiffness constants.
The pathology of wear in the Beall model 104 heart valve prosthesis.
Authors: Silver M D , Wilson G J
Published: June 2012

We examined 13 Beall model 104 prostheses recovered at surgery or autopsy 10 to 84 1/2 months after insertion and observed the pattern of prosthesis wear. We defined wear as "mild" when the disc was notched but neither the metal of the struts was exposed not the cloth seat torn. In "moderate" wear the disc was notched, the Teflon coating of the struts was worn away exposing the underlying metal but the cloth of the set was not torn. The cloth seat was torn in "severe" wear, exposing the metal seat and causing a different pattern of disc erosion. In one case this allowed the disc to tilt into the valve lumen and, later, to escape from its cage. Most of the prostheses studied showed "moderate" or "severe" wear. We believe that some degree of wear is inevitable. Clinical signs and symptoms were not specific but a rough correlation existed between the severity of hemolysis, as indicated by serum LDH levels, and the degree of prosthesis wear. When wear was "severe", the results of cardiac catheterization studies usually mirrored the change, but there were a few exceptions. All patients with the Beall model 104 prosthesis may eventually develop "severe" wear, and we recommend regular reassessment with a view toward prosthesis replacement.
Noninvasive detection and quantification of left-to-right shunts in children using oxygen-15 labeled carbon dioxide.
Authors: Tamer D M , Watson D D , Kenny P J , Janowitz W R , Gelband H , Gilson A J
Published: June 2012

A method for the detection and quantification of left-to-right intracardiac shunts is described which utilizes a single breath inhalation of oxygen-15 labeled carbon dioxide (C15O2). The inhaled gas rapidly crosses the alveolar membrane and the oxygen-15 label is exchanged through the carbonate cycle to form oxygen-15 labeled water within the pulmonary capillary blood. Pulmonary indicator clearance curves are measured by external scintillation probes. A simplified method of shunt flow quantification was developed from indicator dilution principles and used for the analysis of the clearance curves. Inhalation studies were performed with 62 children on the day prior to cardiac catheterization. The presence or absence of left-to-right shunt was confirmed by contrast angiography in all cases. Twenty-six children were found to have no shunts by C15O2 inhalation, oximetry or angiography. Of the 36 with shunts, 34 were detected by C15O2. Two of these were designated as equivocal because they were considered to be less than the threshold of definitive detection by C15O2 (having Qp/Qs less than 1.2); 32 were positive and there were two false negatives with small ventricular septal defects. There were no false positives by C15O2. The correlation coefficient between C15O2 and oximetry values of shunt flow for those patients with proven shunts was 0.82.
Coronary revascularization in patients maintained on chronic hemodialysis.
Authors: Crawford F A , Selby J H , Bower J D , Lehan P H
Published: June 2012

Thirty-two thousand patients are presently maintained in chronic dialysis programs. Cardiovascular complications have been shown to be responsible for 50 to 65% of the deaths in such patients. Despite this and the increasingly frequent use of coronary bypsss surgery in the general population, only two patients have previously been reported to have successfully undergone coronary bypass surgery while maintained on chronic hemodialysis. This reports two additional such patients who successfully underwent coronary revascularization without difficulty. Pertinent details of preoperative, intraoperative, and postoperative management are outlined for these patients and the other 13 chronic dialysis patients who have had cardiopulmonary bypass for other reasons. With careful planning, coronary revascularization can be successfully carried out in this group of patients with minimally increased operative risk.
Real-time cross-sectional echocardiographic diagnosis of coarctation of the aorta: a prospective study of echocardiographic-angiographic correlations.
Authors: Sahn D J , Allen H D , McDonald G , Goldberg S J
Published: June 2012

Real-time cross-sectional echocardiographic sector scan examinations were performed from a suprasternal notch location to image aortic anatomy in 15 children (ages 1 day to 21 years) who were subsequently shown at cardiac catheterization to have coarctation of the descending thoracic aorta. The resulting echocardiographic images of the ascending, transverse and descending aorta imaged juxtaductal coarctation in all 15 patients. Echocardiography predicted discrete coarctation of the aorta in eight, isthmic hypoplasia in two, hourglass type coarctation deformities in three and longer segment coarctation in four patients. Catheterization and angiography confirmed all of these anatomic observations. The control group, 100 patients with congenital heart disease but without angiographic coarctations, included four patients with right-sided aortic arch and six patients with dextrocardia. The ascending, transverse and descending aorta were adequately imaged in 94 of these and no descending aortic abnormalities were noted. This study shows the potential utility of cross-sectional echocardiography for the noninvasive precatheterization or preoperative assessment of coarctation of the aorta in children and critically ill newborns.
New criteria to enhance the predictability of coronary artery disease by exercise testing in asymptomatic subjects.
Authors: Lozner E C , Morganroth J
Published: June 2012

Thirty-seven subjects (10 asymptomatic and 27 symptomatic) who had undergone maximal treadmill exercise tests and coronary arteriography were selected to determine whether the predictive value of ST-segment depression as a marker of coronary artery disease (CAD) in asymptomatic subjects could be enhanced. All subjects had greater than or equal to 2 mm ST-segment depression during testing. Three of the ten asymptomatic subjects had significant CAD (predictive accuracy 30%) and all had greater than or equal to 2 mm ST depression in the one-minute recovery tracing. ST-segment depression resolved by one minute in all seven subjects without CAD. All 27 symptomatic subjects had CAD (predictive accuracy 100%) and 26 of 27 had greater than or equal to 1 mm (21/24 greater than or equal to 2 mm) ST depression in the one-minute recovery tracing. The age, maximum heart rate and exercise tolerance did not differ significantly between the symptomatic and asymptomatic subjects. Thus the predictive accuracy for CAD in asymptomatic subjects is not enhanced by increasing the degree of ST depression required for a positive exercise test. The predictive value may be enhanced if ST depression persists for greater than or equal to 2 minutes into recovery. These data suggest that by using new criteria accurate identification of asymptomatic patients with CAD by exercise testing may be practical.
Anomalous pulmonary venous return with intact atrial septum: diagnosis and pathophysiology.
Authors: Alpert J S , Dexter L , Vieweg W V , Haynes F W , Dalen J E
Published: June 2012

Twenty-one patients with partial anomalous pulmonary venous drainage with intact atrial septum have been studied. These include 13 patients not previously reported from our laboratories and eight patients with complete hemodynamics reported by others. Methods for identification of this abnormality and for identification of an intact atrial septum are described, including differential indicator dilution curves, catheter probing of the atrial septum and pulmonary angiography. Blood flow through anomalously draining lobes of the lung is usually higher than through normally drainage lobes attributable to the higher pressure differences across the anomalous lung, right atrial pressure being uniformly lower than left atrial pressure. The pulmonary vascular resistance when "standardized" to the flow of blood normally present in different portions of the lung indicated that no significant differences existed between normally and anomalously draining lobes. Six patients had coexisting rheumatic mitral stenosis and one had congenital mitral stenosis. Its influence on the hemodynamic changes produced by PAPVD is discussed.
Relationship between plasma lipid concentrations and coronary artery disease in 496 patients.
Authors: Gotto A M , Gorry G A , Thompson J R , Cole J S , Trost R , Yeshurun D , DeBakey M E
Published: June 2012

The relationship between fasting plasma cholesterol and triglyceride concentrations and the frequency and extensiveness of coronary artery disease (CAD) was studied in 496 subjects evaluated for chest pain by coronary arteriography at The Methodist Hospital. One hundred six of the patients had no CAD while 390 had 25% or greater stenosis of one or more major vessels. Ninety-one percent had 75% or greater stenosis of at least one major vessel. Mean age for the group with CAD was 55.7 +/- 8.7 and without disease 49.4 +/- 11.6 (P less than 0.01). Both cholesterol and triglyceride concentrations were higher (P less than 0.001) in the group with CAD. Mean cholesterol concentration in males increased from 195 +/- 36 mg/dl in the group without CAD to 219 +/- 41 in the group with three vessel disease and in females from 207 +/- 40 to 252 +/- 42. A progressive increase in triglyceride values was also detected but was less consistent. At the level of 25% and greater obstruction, the partial correlation coefficients between the number of vessels involved and the cholesterol and triglyceride concentrations, respectively, were +0.201 and +0.181.
Methysergide-induced heart disease: a case of multivalvular and myocardial fibrosis.
Authors: Mason J W , Billingham M E , Friedman J P
Published: June 2012

Methysergide (Sansert) is known to cause mitral and aortic valvular fibrosis and dysfunction, but has generally not been known to damage right heart valves or the myocardium, and cardiac fibrosis has not been considered to be a risk if therapy is intermittently interrupted. The woman who is the subject of this case report developed catheterization-proven severe tricuspid and moderate aortic and mitral regurgitation during noncontinuous therapy with methysergide. In addition, right ventricular endomyocardial biopsy revealed extensive endocardial and intramyocardial fibrosis.
Radiographic assessment of leaflet motion of Gore-Tex laminate trileaflet valves and Hancock xenograft in tricuspid position of dogs.
Authors: Imamura E , Kaye M P , Davis G D
Published: June 2012

Six samples of various thicknessess of Gore-Tex compounds were fashioned into trileaflet valves. A radiopaque marker was placed on the center of the free margin of each cusp, and the prostheses were implanted in the tricuspid position of dogs. Two Hancock valves were studied for comparison. Catheterization revealed that the hemodynamic function was normal in all valves tested. High-speed radiography permitted analysis of leaflet movement throughout the cardiac cycle. Of the six Gore-Tex valves, five opened completely. The cusps of these five valves were fabricated from 4, 6, 8, 10, and 12 layers of Gore-Tex film. The remaining valve, which was fabricated from 15 layers of Gore-Tex film, and both porcine xenograft aortic valves did not open completely. We postulate that the laminates of 12 layers or less of Gore-Tex film are suitable for further study to evaluate their potential applicability in trileaflet cardiac valve prostheses.
De subitaneis mortibus. XXVII. Histological abnormalities in the sinus node, atrioventricular node and His bundle associated with coarctation of the aorta.
Authors: James T N , Jackson D A
Published: June 2012

A twenty-year-old carpenter died suddenly and unexpectedly nine years after surgical treatment of coarctation of the aorta. Both before and after surgery he had paroxysmal atrial fibrillation, T wave inversions in the ECG and persisting cardiac hypertrophy. At postmortem examination there was focal fibromuscular dysplasia narrowing the sinus node artery, but other small coronary arteries were normal and there was no focal fibrosis of the ventricular myocardium. Within the sinus node there were several small glomera surrounding branches of the sinus node artery. Pericardial fibrosis was present over much of the heart, including margins of the sinus node. The central fibrous body was thickened, particularly on the left, and the His bundle was smaller than normal in cross section. The His bundle appeared displaced toward the right. The artioventricular (A-V) node was split into an upper and lower half tenuously connected through the central fibrous body which divided it. In its lower half the A-V node was directly continuous with ordinary myocardial cells of the interventricular septum. Possible developmental relationships between these unusual anatomical findings in the conduction system and coarctation of the aorta are discussed. How these findings might relate to the known electrophysiological disturbances and some causes for his sudden death are considered.
Truncus arteriosus communis. Unusual case associated with transposition.
Authors: Angelini P , Verdugo A L , Illera J P , Leachman R D
Published: June 2012

A child with truncus arteriosus communis, characterized by the posterior origin of an individualized pulmonary trunk is presented. This relationship between the great arteries is unusual in truncus arteriosus communis and the spatial orientation resembles that seen in transposition of the great vessels. A brief discussion is proposed about a proper terminology in this type of complex anomaly.