bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise testing in patients with variant angina: results, correlation with clinical and angiographic features and prognostic significance.
Authors: Waters D D , Szlachcic J , Bourassa M G , Scholl J M , Théroux P
Published: June 2011

Eighty-two patients with variant angina underwent a treadmill exercise test using 14 ECG leads, and 67 also underwent exercise thallium-201 scans. The test induced ST elevation in 25 patients (30%), ST depression in 21 (26%) and no ST-segment abnormality in 36 (44%). ST elevation during exercise occurred in the same ECG leads as during spontaneous attacks at rest, and was always associated with a large perfusion defect on the exercise thallium scan. In contrast, exercise-induced ST depression often did not occur in the leads that exhibited ST elevation during episodes at rest. The ST-segment response to exercise did not accurately predict coronary anatomy: Coronary stenoses greater than or equal to 70% were present in 14 of 25 patients (56%) with ST elevation, in 13 of 21 (62%) with ST depression and in 14 of 36 (39%) with no ST-segment abnormality (NS). However, the degree of disease activity did correlate with the result of the exercise test: ST elevation occurred during exercise in 11 of 14 patients who had an average of more than two spontaneous attacks per day, in 12 of 24 who had between two attacks per day and two per week, and in only two of 31 who had fewer than two attacks per week (p less than 0.005). St elevation during exercise was reproducible in five of five patients retested during an active phase of their disease, but not in three of three patients who had been angina-free for at least 1 month before the repeat test. Twelve patients wih exercise-induced ST elevation were retested during treatment with calcium antagonist drugs; in 10 of 12, ST elevation did not occur with the second test. During a mean follow-up of 20.3 +/- 14.5 months, death or myocardial infarction occurred in three of the 25 patients with ST elevation during exercise, none of 21 with ST depression and two of 36 with no ST abnormality. We conclude that in variant angina patients, the results of an exercise test correlate well with the degree of disease activity but not with coronary anatomy, and do not define a high-risk subgroup.
Evaluation of a QRS scoring system for estimating myocardial infarct size. I. Specificity and observer agreement.
Authors: Wagner G S , Freye C J , Palmeri S T , Roark S F , Stack N C , Ideker R E , Harrell F E , Selvester R H
Published: June 2011

We evaluated a simplified version of a previously developed QRS scoring system for estimating infarct size using observations of Q- and R-wave durations and R/Q and R/S amplitude ratios in the standard 12-lead ECG. Groups of subjects with a minimal likelihood of having myocardial infarcts and minimal likelihood of having common noninfarction sources of QRS modification were studied to establish the specificity of each of the 37 criteria. Only two criteria required modification to achieve 95% specificity. These 37 criteria form the basis of a 29-point QRS scoring system. A 98% specificity was achieved when a score of more than 2 points was required to identify a myocardial infarct. Fifty patients were studied to determine the intra- and interobserver agreement with this scoring system. Each criterion achieved at least 91% intra- and interobserver agreement. These impressive levels of specificity and observer agreement must be matched by high sensitivity of the scoring system and a good correlation between the point score and infarct size in patients with proven infarcts if the point score is to be useful for detecting and sizing infarcts. Sensitivity and correlation between point score and infarct size are evaluated in later studies in this series. The standard ECG is inexpensive and can be obtained repetitively and noninvasively; its QRS complex may be an important means of estimating the size, presence and location of myocardial infarcts.
Pirmenol, a new antiarrhythmic agent: initial study of efficacy, safety and pharmacokinetics.
Authors: Hammill S C , Shand D G , Routledge P A , Hindman M C , Baker J T , Pritchett E L
Published: June 2011

Pirmenol (CI-845), a new antiarrhythmic drug, was studied for the first time in humans to establish a minimum effective i.v. dose in 10 patients with chronic, stable premature ventricular complexes (PVCs) and to evaluate toxicity and pharmacokinetics. Infusions of 70-150 mg were associated with a 90% or greater reduction in PVCs nine of the 12 times they were administered to six patients. Peak plasma concentrations were 1.0-3.8 micrograms/ml at the end of these infusions. At the same time, small but significant increases in diastolic blood pressure (4 mm Hg) and QTc interval (0.01 second) were seen, but both values were within the normal range. Pirmenol was associated with no change in heart rate, systolic blood pressure, PR interval or QRS duration, renal, hepatic or hematologic function, or symptoms. Blood, plasma and free drug concentrations declined biexponentially after cessation of a 150-mg infusion (n = 4), with a terminal half-life of 7-9.4 hours. The therapeutic response, lack of toxicity, and relatively long half-life indicate that pirmenol is a promising antiarrhythmic agent.
Right ventricular dysplasia: a report of 24 adult cases.
Authors: Marcus F I , Fontaine G H , Guiraudon G , Frank R , Laurenceau J L , Malergue C , Grosgogeat Y
Published: June 2011

Right ventricular dysplasia is characterized by an abnormality in the development of part of the right ventricular musculature. Patients with right ventricular dysplasia may present with ventricular tachycardia, supraventricular arrhythmias, right-heart failure or asymptomatic cardiomegaly. Twenty-two adult patients with right ventricular dysplasia who had recurrent ventricular tachycardia were seen during a 7-year period. The male/female ratio was 2.7:1. The mean age at the time of hospitalization was 39 years. All but one of the patients had ventricular tachycardia of a left bundle branch block configuration. With few exceptions, the T waves were inverted over the right precordial leads. The heart was usually enlarged and the pulmonary vasculature was usually normal. In six patients who had two-dimensional echocardiograms, all showed increased right ventricular diastolic dimensions. All patients had right ventricular angiography; the diagnosis of right ventricular dysplasia was substantiated during surgery in 12 patients and at autopsy in another. Two other patients who did not have arrhythmias had right ventricular dysplasia diagnosed by right- and left-heart angiography. Our unique experience, when combined with a literature review of 34 adult cases, permits a composite clinical profile of this condition in the adult.
Mechanism of early systolic closure of the aortic valve in discrete membranous subaortic stenosis.
Authors: Sabbah H N , Stein P D
Published: June 2011

The mechanism of the apparent early closure of the aortic valve in patients with discrete membranous subaortic stenosis was studied. Discrete membranous subaortic stenosis was simulated in vitro to assess the fluid dynamic characteristics in the region of the aortic valve that may be responsible for the early closure. In the presence of a simulated fixed membranous subaortic obstruction, early systolic closure of the aortic valve was observed on high-speed motion pictures. Opening and early closure of the valve involved only one of the three aortic leaflets. Closure of the open leaflet was associated with the development of a pronounced pressure drop across the open leaflet caused by a large decrease of pressure in the main stream of flow relative to the pressure in the sinus of Valsalva. The pressure decrease in the main stream of flow resulted from a loss of pressure energy caused by an increase in the kinetic energy of the fluid caused by turbulence. Early systolic closure of the aortic valve in discrete membranous subaortic stenosis, therefore, results from the development of a pressure drop across the open leaflet caused by fluid dynamic factors related to the development of turbulent blood flow distal to the subvalvular obstruction.
Prolongation of atrioventricular conduction time by electrical stimulation of the carotid sinus nerves in man.
Authors: Borst C , Karemaker J M , Dunning A J
Published: June 2011

Electrical stimulation of the carotid sinus nerves was applied during diagnostic catheterization of two patients who had coronary artery disease. The immediate reflex prolongation of the atrioventricular (AV) interval was due to prolongation of the AH interval only and was roughly parallel to the reflex RR interval prolongation evoked without atrial pacing. After cholinergic block, the reduced prolongation of both the RR interval and the AV interval caused by reflex inhibition of sympathetic tone followed a time course similar to the arterial pressure decrease. This is the first demonstration in man of the parallel baroreflex effects on the sinoatrial node and the AV node.
The pathologic correlates of the electrocardiogram: complete left bundle branch block.
Authors: Havelda C J , Sohi G S , Flowers N C , Horan L G
Published: June 2011

To assess whether gross pathologic differences exist between hearts with left bundle branch block (LBBB) and left-axis deviation (LAXD) and those with LBBB and a normal frontal plane axis, we examined 70 hearts with LBBB in a series of 1410 sequential dissections (5%). Thirty-two hearts had LAXD and 34 had normal axes on the correlative ECG. Left ventricular enlargement occurred frequently (93%). No significant differences were found in age distribution, left ventricular weight, coronary anatomy or infarct location. Quantitative analysis revealed larger inferoposterolateral and apical infarcts in hearts with LBBB and LAXD (p less than 0.01). The accuracy of various electrocardiographic signs of left ventricular enlargement and myocardial infarction in the presence of LBBB was assessed. Voltage criteria and QRS duration poorly define anatomic chamber enlargement. Anterior infarction is suggested by a q or pathological Q wave in lead I, a q wave in leads I, V5 and V6, or notched S waves in V3 or V4. Pathologic q waves or ST shifts in the inferior leads have high diagnostic specificity but low sensitivity for inferior infarction.
Survival of patients with a strongly positive exercise electrocardiogram.
Authors: Dagenais G R , Rouleau J R , Christen A , Fabia J
Published: June 2011

To assess the prognosis of patients with a strongly positive exercise ECG, the 5-year cumulative survival rate was computed for 220 medically treated patients. Of these patients, 107 had coronary angiograms (group A) and 113 did not (group B). All had horizontal or downsloping ST depression greater than or equal to 2 mm during a multistage Bruce protocol treadmill exercise test. In group A, the overall 5-year survival rate was 74 +/- 5%. Survival decreased with decreasing duration of exercise: All patients who achieved stage IV (541 seconds or more) survived, whereas the survival rate was 86 +/- 6% when the patients terminated their exercise during stage III (361 - 540 seconds), 73 +/- 7% when during stage II (181 - 360 seconds) and only 52 +/- 13% when during stage I (180 seconds or less). The mortality was associated with more severe coronary artery disease, and sudden death was the main cause of death. Patients in group B had a longer mean exercise duration than those in group A and, as expected, a higher survival rate (91 +/- 3%, p less than 0.01), which also varied according to the exercise duration. Among patients with a strongly positive exercise ECG, the duration of exercise identifies subsets that have different survival rates.
Effects of intravenous prostacyclin in variant angina.
Authors: Chierchia S , Patrono C , Crea F , Ciabattoni G , De Caterina R , Cinotti G A , Distante A , Maseri A
Published: June 2011

A lack in prostacyclin (PGI2) production due to atherosclerosis may play a role in the pathophysiology of some of the clinical manifestations of ischemic heart disease and in particular, of coronary vasospasm. We therefore evaluated the effects of i.v. PGI2 in nine patients with variant angina and six normal volunteers. In normal subjects, PGI2 (2.5, 5, 10 and 20 micrograms/kg/min) had significant antiplatelet effects, caused a dose-dependent decrease in both systolic and diastolic arterial pressure and a decrease in pulmonary resistance. Heart rate increased in a dose-dependent manner, but no consistent effects on myocardial contractility (evaluated by ultrasound) were observed. Side effects were negligible and readily reversible. Although producing obvious antiplatelet and vasodilatory effects, PGI2 did not affect the number, severity and duration of spontaneous ischemic episodes due to coronary vasospasm in five patients and ergonovine-induced spasm in three. However, the number of ischemic episodes was consistently reduced in one patient during four consecutive periods of PGI2 infusion alternated with placebo. a severe, prolonged ischemic episode with ST elevation and pain was consistently observed in this patient every time PGI2 was discontinued. In the appropriate environment, PGI2 can be administered safely to patients with ischemic heart disease. Occasionally, PGI2 may result in a complete disappearance of ischemic episodes due to coronary vasospasm, but usually it is ineffective. These conflicting results could be related to different etiologies of coronary spasm.
Left ventricular function in trained and untrained healthy subjects.
Authors: Bar-Shlomo B Z , Druck M N , Morch J E , Jablonsky G , Hilton J D , Feiglin D H , McLaughlin P R
Published: June 2011

Left ventricular function was compared in 18 normal sedentary controls (mean age 28 years, range 22 - 34 years) and nine endurance-trained athletes (mean age 19 years, range 15 - 25 years) at rest and during supine bicycle exercise. Gated radionuclide angiocardiograms were performed at rest and at each level of graded maximal supine bicycle exercise. Heart rate, blood pressure, left ventricular ejection fraction and the relative changes in left ventricular end-diastolic and end-systolic volumes were assessed. Athletes attained a much greater work load than controls (mean 22.1 kpm/kg body weight vs 13 kpm/Kg body weight). Both groups achieved similar increased in heart rate, blood pressure and ejection fractions. In the controls, the mean end-diastolic volume increased to 124% of that at rest (p less than 0.02) during exercise and the mean end-systolic volume decreased to 81% of the rest level (p less than 0.02). In contrast, the mean end-diastolic volume did not significantly change during exercise in the athletes, and the mean end-systolic volume decreased to 64% of rest (p less than 0.05). Thus, although trained and untrained healthy subjects had similar increases in the left ventricular ejection fraction during exercise, different mechanisms were used to achieve these increases. Untrained subjects increased end-diastolic volumes, whereas trained subjects decreased the end-systolic volumes. The ability of athletes to exercise without increasing preload may be an effect of training amd might have important implications in reducing myocardial oxygen demand during exercise.
Effect of coronary blood flow on thallium-201 uptake and washout.
Authors: Nishiyama H , Adolph R J , Gabel M , Lukes S J , Franklin D , Williams C C
Published: June 2011

Myocardial uptake and washout of thallium-201 (201TI) were studied in an experimental dog model in which regional blood flow to the posterior wall was varied by transient 2-minute occlusion of the circumflex coronary artery to produce transient ischemia and reactive hyperemia. Thallium-201 myocardial activity in a region of interest was determined continuously after i.v. administration by a gamma camera and computer program. Activity in the posterior wall was compared with that in the anterior wall in the same dog and the posterior wall of control dogs. Thallium-201 uptake was directly related to blood flow. With reactive hyperemia, there was a rapid and absolute increase in uptake followed by rapid washout; with ischemia, there was slow and decreased uptake followed by a slow washout. The calculated myocardial activity during washout in both ischemic and hyperemic areas approached values in control dogs long after blood flow had returned to baseline levels. Significant differences in washout slopes were found between the three groups of dogs (-0.156%/min in control dogs, -0.244%/min after reactive hyperemia, and -0.076%/min after transient ischemia, with half-washout times of 5.3 hours, 3.4 hours and 11.0 hours, respectively). These data suggest that both the initial decrease in activity in the ischemic area and the initial excess in the hyperemic area are corrected by different washout rates of ischemic and hyperemic cells during redistribution.
Quantitative analysis of segmental wall motion throughout systole and diastole in the normal human left ventricle.
Authors: Klausner S C , Blair T J , Bulawa W F , Jeppson G M , Jensen R L , Clayton P D
Published: June 2011

We traced left ventricular contours, frame-by-frame throughout systole and diastole, of normal sinus beats from 30 degrees right anterior oblique ventriculograms from 32 normal patients. We separated both systole and diastole into 19 equal time intervals each and calculated regional lengths (R), normalized by both end-diastole length and relative time interval (T) in systole and diastole and diastole, for the middle inferior wall, distal inferior wall, apex, distal anterior wall, middle anterior wall, and proximal anterior wall. We also computed the relative velocities of R, delta R/ delta T, over each quarter of systole and diastole. Comparing systole with diastole, we found significant differences between paired values of R at all regions except the distal inferior wall, but these differences were not the same between regions. Between regions, mean R and delta R/ delta T values were significantly different as early as the first quarter of systole. Within a region, there were significant differences between mean R and delta R/ delta T values over intervals as short as one-fourth of systole or diastole. Thus, there is no homogeneity between regions in normal wall motion in both systole and diastole. This normal lack of homogeneity has important clinical implications for identifying abnormal wall motion in individual patients from ventriculographic measurements, and for using the information present in the diastole portion of the ventriculogram to characterize normal segmental function.
Pulsus alternans determined by biventricular simultaneous systolic time intervals.
Authors: Hada Y , Wolfe C , Craige E
Published: June 2011

This investigation was performed to determine the presence of unilateral or bilateral pulsus alternans in the systemic and pulmonary circulations in heart failure and to estimate the prevalence of pulsus alternans in congestive cardiomyopathy. The subjects were 36 adult patients in heart failure due to a variety of cardiopulmonary diseases. We measured left- and right-sided systolic time intervals from simultaneous dual echocardiograms of both semilunar valves. The alternans was left-sided in seven patients, right-sided in one patient and bilateral in six patients. Pulsus alternans was induced by ventricular premature complexes (VPCs), except in one patient with bilateral and persistent alternans. For a VPC to precipitate alternans, the early beat itself must be associated with an abbreviated ejection time. Echophonocardiographic records of 100 patients with congestive cardiomyopathy were reviewed for evidence of pulsus alternans. We found persistent alternans in 10 patients and VPC-induced alternans in seven patients. We could not measure any difference in severity of disease in patients with pulsus alternans compared with those without.
Termination of ventricular tachycardia by carotid sinus massage.
Authors: Hess D S , Hanlon T , Scheinman M , Budge R , Desai J
Published: June 2011

Intracardiac electrophysiologic studies were performed in two patients who had recurrent sustained ventricular tachycardia. In both, the tachycardia was repeatedly terminated by carotid massage. In one patient, intracardiac electrophysiologic studies revealed ventricular tachycardia with 2:1 retrograde ventriculoatrial (VA) block. Carotid massage resulted in alternate Wenckebach retrograde VA conduction terminated by ventricular echo beats. When ventricular echo beats occurred at a coupling interval of 340 - 400 msec, the tachycardia was terminated. Similarly, induced atrial depolarizations (during ventricular tachycardia) produced ventricular capture and terminated the tachycardia when the resultant ventricular coupling interval was 330 - 395 msec. In the second patient, progressively premature atrial or ventricular depolarizations did not terminate the tachycardia. carotid massage had no consistent effect on retrograde VA conduction during ventricular tachycardia, but usually resulted in gradual increases in the tachycardia cycle length (50 - 100 msec) before abrupt termination of the tachycardia. This is the first report documenting termination of ventricular tachycardia by carotid massage alone (i.e., without prior drug intervention); hence, tachycardia termination by simple carotid sinus massage does not prove a supraventricular origin. The mechanism of tachycardia termination was due to ventricular echo beats from retrograde atrioventricular nodal reentry in one patient and to direct vagal effects on either the ventricular muscle or the ventricular specialized conduction system in the other.
Radionuclide measurement of left ventricular volume: comparison of geometric and counts-based methods.
Authors: Massie B M , Kramer B L , Gertz E W , Henderson S G
Published: June 2011

Radionuclide measurements of left ventricular volume were determined in 20 patients by geometric and nongeometric, counts-based techniques using data from first-pass and equilibrium blood pool scintigraphy. Two geometric analytic approaches were used: directly measured long and short axes and the area-length method. Each approach was applied to the single-plane right anterior oblique images obtained by the first-pass technique and to biplane data, using the right anterior oblique first-pass and left anterior oblique blood pool data together. For the nongeometric determinations, background-corrected left ventricular counts were related to blood counts. This ratio was converted to volume by means of a linear regression relationship with angiographic volumes. All methods yielded high correlation coefficients (r greater than or equal to 0.93), but the standard errors of the estimates for the geometric techniques were high, and therefore the 95% confidence limits were wide. The use of biplane data improved the correlations, but area-length analysis of digitized data was no better than direct measurement of short axes from the analog images. The counts-based, nongeometric method provided the highest correlation and lowest standard error. These findings indicate that nongeometric left ventricular volume measurements using equilibrium blood pool scintigrams are the most accurate radionuclide technique. This approach also permits multiple determinations with a single dose of radiotracer.
Characterization of nontransmural myocardial infarction by positron-emission tomography.
Authors: Geltman E M , Biello D , Welch M J , Ter-Pogossian M M , Roberts R , Sobel B E
Published: June 2011

The present study was performed to determine whether positron emission tomography (PET) performed after i.v. 11C-palmitate permits detection and characterization of nontransmural myocardial infarction. PET was performed after the i.v. injection of 11C-palmitate in 10 normal subjects, 24 patients with initial nontransmural myocardial infarction (defined electrocardiographically), and 22 patients with transmural infarction. Depressed accumulation of 11C-palmitate was detected with sagittal, coronal and transverse reconstructions, and quantified based on 14 contiguous transaxial reconstructions. Defects with homogeneously intense depression of accumulation of tracer were detected in all 22 patients with transmural infarction (100%). Abnormalities of the distribution of 11C-palmitate in the myocardium were detected in 23 patients with nontransmural infarction (96%). Thallium scintigrams were abnormal in only 11 of 18 patients with nontransmural infarction (61%). Tomographically estimated infarct size was greater among patients with transmural infarction (50.4 +/- 7.8 PET-g-Eq/m2 [+/- SEM SEM]) compared with those with nontransmural infarction (19 +/- 4 PET-g-Eq, p less than 0.01). Residual accumulation of 11C-palmitate within regions of infarction was more intensely depressed among patients with transmural compared to nontransmural infarction (33 +/- 1 vs 39 +/- 1% maximal myocardial radioactivity, p less than 0.01). Thus, PET and metabolic imaging with 11C-palmitate is a sensitive means of detecting, quantifying and characterizing nontransmural and transmural myocardial infarction.
Estimation of acute myocardial infarct size in man by serum CK-MB measurements.
Authors: Grande P , Hansen B F , Christiansen C , Naestoft J
Published: June 2011

This study was performed to determine the relationship between myocardial infarct size estimated by serum CK-MB methods and the extent of irreversible injury in acute myocardial infarction. In 321 consecutive patients, infarct size was estimated by different mathematical models, and in 22 patients who died in hospital, the extent of myocardial necrosis was determined by autopsy. We also investigated the depletion of CK-MB in infarcted tissue, the recovery of CK-MB in the plasma volume, and the estimation of CK-MB from plasma. Myocardial CK-MB depletion was relatively greater in the larger infarcts, whereas the recovery of enzyme in plasma was independent of the infarct size. Correction of serum CK-MB for changes in plasma volume improved the estimate significantly (p less than 0.05). The correlation between the measured infarct size (g) and the estimated infarct size (units per liter and gram-equivalents) was highly significant (r = 0.85--0.89, SEE = 23--27%, p less than 0.001). Thus, a semiquantitative expression of the extent of myocardial necrosis can be determined in vivo.
Termination of ventricular tachycardia with ventricular stimulation: salutary effect of increased current strength.
Authors: Waxman H L , Cain M E , Greenspan A M , Josephson M E
Published: June 2011

The effect of increased stimulus current strength on the right ventricular effective refractory period during sustained ventricular tachycardia and on the ability of single premature right ventricular stimuli to terminate ventricular tachycardia was evaluated. Studies were performed during 53 episodes of sustained ventricular tachycardia in 25 patients. Forty-four of 53 episodes were slowed by pharmacologic therapy. Current intensities of twice diastolic threshold, 5 mA and 10 mA were used. Increasing current from twice diastolic threshold (1.52 +/- 0.66 mA) to 5 mA (32 episodes) shortened the mean ventricular effective refractory period from 213 +/- 50 to 188 +/- 43 msec (p less than 0.001); and from twice diastolic threshold (1.53 +/- 0.60 mA) to 10 mA (42 episodes), from 206 +/- 55 to 176 +/- 50 msec (p less than 0.001). There was a direct correlation between cycle length of ventricular tachycardia and the ventricular effective refractory period measured at twice diastolic threshold (r = 0.77, p less than 0.001). However, the cycle length of ventricular tachycardia and the amount of shortening of ventricular effective refractory period as current was increased were not significantly correlated (r = 0.40). Eleven episodes of ventricular tachycardia (21%) that could not be terminated by ventricular stimulation at twice diastolic threshold were terminated when increased current strength was used. The ability to terminate ventricular tachycardia was associated with a decrease in ventricular effective refractory period and long tachycardia cycle length. The mean cycle length of the 11 episodes terminated was 455 +/- 50 msec, compared with 381 +/- 63 msec in the 42 episodes not terminated at increased current.
Spasm of a normal or minimally narrowed coronary artery in the presence of severe fixed stenoses of the remaining vessels: clinical and angiographic observations.
Authors: Mercurio P , Kronzon I , Winer H
Published: June 2011

Four patients with medically refractory unstable angina are presented. Each patient had ST-segment abnormalities during some episode of pain. Three patients had at least one episode of documented ST-segment elevation with their spontaneously occurring chest pain. One had recurrent ventricular tachycardia. Two patients had prior myocardial infarction. Angiography demonstrated localized left ventricular akinesis and a severe fixed stenosis in the coronary artery supplying the abnormal segment. There were severe, fixed lesions in two coronary arteries in two patients and in one vessel in two patients. After i.v. ergonovine maleate, coronary artery spasm was documented in a normal or minimally diseased coronary artery in each patient. In two patients, ergonovine-induced spasm not only occluded the vessel, but also markedly decreased retrograde filling of a vessel with severe, fixed narrowing. Each patient's characteristic symptoms appeared with the ergonovine-induced spasm. Thus, ergonovine maleate can provoke spasm of a normal coronary artery, even in the presence of severe fixed stenoses of the remaining vessels. This observation may have an important role in the diagnosis and clinical management of patients with chest pain.
Electrophysiologic effects of disopyramide phosphate in patients with Wolff-Parkinson-White syndrome.
Authors: Kerr C R , Prystowsky E N , Smith W M , Cook L , Gallagher J J
Published: June 2011

We evaluated the electrophysiologic effects of disopyramide phosphate in 12 patients with the Wolff-Parkinson-White syndrome. Electrophysiologic studies were performed during a control period and after administering i.v. disopyramide (four bolus doses of 9.5 mg/kg over 40 minutes superimposed on a continuous infusion at 1.0 mg/kg/hour). All patients were then restudied after 3 days on oral medication in doses of 800-1200 mg/day. In all patients we tried to induce reciprocating tachycardia and atrial fibrillation. The cycle length during reciprocating tachycardia was not changed by i.v. disopyramide, but increased after oral disopyramide, from 331 +/- 53 (+/- SD) to 370 +/- 68 msec (p less than 0.01). This increase occurred predominantly as a result of prolongation of retrograde conduction time in the accessory pathway. Despite prolonging cycle length during reciprocating tachycardia, disopyramide did not prevent its induction. The shortest and mean RR intervals during atrial fibrillation were used to assess antegrade refractoriness of the accessory pathway. Intravenous disopyramide prolonged the shortest RR from 169 +/- 18 to 226 +/- 24 msec (p less than 0.0001) and the mean RR from 255 +/- 58 to 329 +/- 62 msec (p less than 0.005). Oral disopyramide prolonged the shortest RR interval from 169 +/- 18 to 248 +/- 36 msec (p less than 0.0001) and the mean RR from 255 +/- 58 to 360 +/- 93 msec (p less than 0.001). After oral disopyramide, the episodes of atrial fibrillation were shorter and self-terminating. No acute hemodynamic side effects were observed, but five patients developed gastrointestinal or anticholinergic side effects on oral disopyramide. Seven patients elected to have surgical interruption of their accessory pathways and five have been successfully treated with oral disopyramide for 14-33 months. Disopyramide appears to have beneficial electrophysiologic effects in patients with Wolff-Parkinson-White syndrome. Prolongation of refractoriness in the accessory pathway markedly slows the ventricular response during atrial fibrillation and therefore prevents the development of life-threatening arrhythmias.
Influence of physical exercise on coronary collateral blood flow in chronic experimental two-vessel occlusion.
Authors: Schaper W
Published: June 2011

In 45 approximately 1-year-old purebred German shepherd dogs, the left circumflex and the right coronary arteries were chronically occluded by implantation of slowly swelling ameroid constrictors. Before the operation, 27 dogs were trained on a treadmill until they could run 8 mph on a 22% incline for 1 hour, 5 days per week. Two weeks after the operation, exercise was gradually resumed and continued for 4 weeks, until the preoperative fitness level had been regained. Preoperative exercise training lasted 1-3 months; postoperative training lasted 100 +/- 22 days (mean +/- SD). After the dogs had trained with two chronically occluded coronary arteries, collateral and coronary blood flows were measured with tracer microspheres at maximal coronary vasodilation (adenosine infusion) in an isolated, blood-perfused Langendorff preparation at perfusion pressures of 40, 60, 80, 100, 120 and 140 mm Hg. Eighteen nonexercising dogs that also had two-vessel coronary occlusion served as controls. Nine controls and nine exercising dogs were paired littermates. Exercise of relatively high intensity (heart rates greater than 200 beats/min) before and after occlusion had no effect on coronary collaterals. Collateral conductance in trained and untrained dogs reached only slightly less than 40% of that of the replaced coronary artery. This result agrees well with earlier results in a group of nonexercising dogs with chronic two-vessel occlusion studied in an identical way. Two-vessel occlusion was associated with a 25% mortality rate. All dogs died instantaneously without warning symptoms of ventricular fibrillation. Exercise had no influence on mortality.
The effect of moderate physical exercise on the plasma lipoprotein subfractions of male survivors of myocardial infarction.
Authors: Ballantyne F C , Clark R S , Simpson H S , Ballantyne D
Published: June 2011

The effect of regular, moderate exercise on the lipoprotein subfractions of male survivors of myocardial infarction was studied. Nineteen men were randomly allocated to an incremental exercise program and 23 to a control group. Both groups were studied for 6 months. No change occurred in any lipoprotein class in the control group. In the trained group, total triglyceride and low-density lipoprotein (LDL) cholesterol concentrations decreased significantly (0.01 greater than p greater than 0.001 and 0.05 greater than p greater than 0.01, respectively) and high-density lipoprotein (HDL) cholesterol and apolipoprotein A-1 rose (both p less than 0.001). The concentration of the HDL2 subfraction increased with training (0.01 greater than p greater than 0.001) and HDL2 did not change. No relationship was found between changes in lipoproteins and treadmill exercise test performance. Thus, in survivors of myocardial infarction, exercise may alter plasma lipoprotein values beneficially.
Long-term effects of a blood pressure survey on patient treatment in a community.
Authors: Grimm R H , Luepker R V , Taylor H , Blackburn H
Published: June 2011

The influence of a systematic survey and follow-up of blood pressure in a population sample was assessed by a subsequent survey performed an average of 40 months later. A subsample of 764 men, originally ages 35-57 years, was randomly selected for telephone follow-up, while blood pressure was remeasured in 133 (17% of the subsample). These were drawn from 6779 men who had a diastolic blood pressure (DBP) greater than or equal to 90 mm Hg, the average of the second two measurements of three at the initial survey. Ninety percent of the men in the telephone survey reported they had visited their physician or medical-care source. Of these visits, 70% were for consideration of blood pressure, and in 36% this visit was directly attributed to the screen. At follow-up, 52.8% were taking antihypertensive medication and in 61% of this group the medication was started after the initial screen. Follow-up revealed DBP reduced by 8.7% in the group not treated with antihypertensive agents either before or after the initial survey, by 13.4% in the group on treatment before the survey and by 17.7% in the group started on therapy after the survey. Although lack of a suitable comparison group is a limitation, these findings in a population-based cohort strongly suggest that systematic blood pressure screening, combined with effective immediate referral, may be associated with an important effect on blood pressure control in the community.
Pulmonary regurgitation studied with the ultrasonic pulsed Doppler technique.
Authors: Miyatake K , Okamoto M , Kinoshita N , Matsuhisa M , Nagata S , Beppu S , Park Y , Sakakibara H , Nimura Y
Published: June 2011

Sixty patients with pulmonary regurgitation were studied by the pulsed Doppler technique combined with two-dimensional and M-mode echocardiography. Patients with pulmonary regurgitation had abnormal Doppler signals just below the pulmonic valve in the right ventricular outflow tract in diastole on the two-dimensional image. These signals were considered to indicate the regurgitant flow. There are two patterns of pulmonary regurgitant Doppler signals. In pulmonary hypertension, the maximal component of instantaneous flow velocity is sustained at about the same signal strength throughout diastole, but when the pulmonary arterial pressure is normal, the velocity slows down gradually from early diastole to end-diastole. Pulmonary regurgitation was detected by phonocardiography in about half the patients. In the remaining half, pulmonary regurgitant murmur could not be differentiated from aortic regurgitant murmur or was masked by coexistent aortic regurgitation or patent ductus arteriosus, whereas the Doppler technique indicated pulmonary regurgitation.
Regression of myocardial hypertrophy: electrocardiographic-echocardiographic correlations after aortic valve replacement in patients with chronic aortic regurgitation.
Authors: Carroll J D , Gaasch W H , Naimi S , Levine H J
Published: June 2011

Serial electrocardiographic and echocardiographic left ventricular (LV) studies were performed in 21 patients before and after aortic valve replacement (AVR) for chronic aortic regurgitation. Changes in voltage (SV1 + RV5-6) after AVR were assessed and evaluated relative to changes in LV mass. Muscle cross-sectional area (CSA) derived from echocardiographic dimension and wall thickness data was used as an index of LV muscle mass (LV hypertrophy greater than 10 cm2/m2). In 15 patients, voltage was reduced after AVR: Seven had normal voltage (48 +/- 17 mm to 25 +/- 6 mm, p less than 0.005) and eight still had increased voltage (61 +/- 17 mm to 40 +/- 4 mm, p less than 0.01). Patients with normal voltage had complete regression of hypertrophy by echocardiography (CSA decreased from 13 +/- 3 cm2/m2 to 9 +/- 1 cm2/m2, p less than 0.025), while those who had persistently increased voltage had incomplete regression (15 +/- 2 cm2/m2, p less than 0.001). Reduction in voltage generally occurred in the first 6 months after AVR. Three patients with unchanged voltage had evidence of paraprosthetic regurgitation and minimal change in CSA. Three other patients with voltage had evidence of paraprosthetic regurgitation and minimal change in CSA. Three other patients with persistent LV enlargement without paraprosthetic regurgitation had a severe intraventricular conduction delay. Data from 59 electrocardiographic-echocardiographic studies before and after AVR revealed a strong correlation (r = 0.81) between voltage and muscle CSA. After surgical correction of chronic aortic regurgitation, regression of LV hypertrophy can be assessed by serial electrocardiographic studies. These ECG data identify patients with complete, incomplete or no regression of LV hypertrophy.
Rest and exercise hemodynamics after the Fontan procedure.
Authors: Shachar G B , Fuhrman B P , Wang Y , Lucas R V , Lock J E
Published: June 2011

Sixteen consecutive patients (12 with tricuspid atresia) underwent a Fontan procedure, with no operative deaths. There were three late deaths. Eleven of the survivors were electively catheterized 4-25 months postoperatively. Rest and exercise hemodynamics were measured in five patients, and resting hemodynamics alone were measured in three. All exercised patients were New York Heart Association class I Cardiac index was low at rest (2.3 +/- 0.61/min/m2) and during exercise (4.9 +/- 1.11/min/m2) due to a low stroke index both at rest (28 ml) and exercise (35 ml). Accordingly, mixed venous oxygen saturations were decreased (66% at rest and 31% during exercise). These values are significantly lower than those at rest and during exercise from 23 control patients of similar age and size. Heart rates, pulmonary vascular resistances, and left ventricular filling pressures appeared normal both at rest and during exercise. High right atrial pressure at rest (15 mm Hg) was associated with minimal conduit gradient (2 mm Hg). However, exercise increased the mean conduit gradient to 8 mm Hg, demonstrating significant functional conduit obstruction. As expected, the cardiovascular response to exercise is abnormal after the Fontan procedure, even in asymptomatic patients. This abnormal response may be exacerbated by conduit obstruction, and conduit obstruction may not be apparent during resting studies.
Assessment of right ventricular function during supine bicycle exercise after Mustard's operation.
Authors: Benson L N , Bonet J , McLaughlin P , Olley P M , Feiglin D , Druck M , Trusler G , Rowe R D , Morch J
Published: June 2011

Right ventricular (RV) performance during supine bicycle exercise was evaluated by gated equilibrium nuclear angiography in 19 clinically well children with d-transposition of the great arteries (d-TGA), 6.4 +/- 2.7 years after Mustard's operation. Comparisons were made between rest and peak exercise. The mean resting ejection fraction was 44 +/- 12% (range 30-75%) and was unchanged at peak exercise. Eight children had a normal ejection fraction response, whereas 11 children had either no increase or a decrease in ejection fraction. Relative end-diastolic volumes decreased from resting values in all patients who had an abnormal ejection fraction response. Among patients whose ejection fraction increased, the end-diastolic volume increased in three, decreased in four and was unchanged in one at peak exercise. Heart rate increased 84% (range 52-135%) and systolic blood pressure increased 16% (range 0-28%) at peak exercise. There was no correlation between exercise response and age at surgery or interval since surgery. These data indicate that clinically well children after Mustard's procedure may have abnormal right ventricular function under stress, raising concerns about the ability of the right ventricle to function as the systemic ventricle.
Employment patterns in males before and after myocardial revascularization surgery. A study of 2229 consecutive male patients followed for as long as 10 years.
Authors: Johnson W D , Kayser K L , Pedraza P M , Shore R T
Published: June 2011

Loss of productivity is a major concern among patients with heart disease. To assess the effect of surgery on this factor, we surveyed every living male patient of the surgeon authors operated on from January 1968 through March 1978 (96% follow-up) and compared their pre- and postoperative work status with the U.S. population as reported by the U.S. Bureau of Labor Statistics (USBLS). Comparisons were made on an age-for-age basis and adjustments were made for changes in national employment patterns from 1968-1978. Preoperatively, our younger patients had a 10% lower employment rate than the U.S. male population at large according to the USBLS. Postoperatively, many returned to work, but an equal number who worked preoperatively did not postoperatively. The ability to work full time with little or no limitation increased 20% after operation. The main reason for not working was physical disability, with doctor's advice a distance second. Older patients showed a trend of accelerated retirement after surgery. A few returned to work, but many more retired. The ability to work full-time without limitation increased 4%. Thirty percent of all older subjects cited a desire to relax as their main reason for not working. Compared with the early years of surgery, patients in later years were older and did not show as much preoperative disability. There was some evidence of a deterioration of the effects of surgery. Patients with severely impaired left ventricular function fared worse both pre- and postoperatively, but the improvement was the same as for patients with normal or moderately impaired left ventricular function.
The interval ejection fraction: a cineangiographic and radionuclide study.
Authors: Kemper A J , Bianco J A , Shulman R M , Folland E D , Parisi A F , Tow D E
Published: June 2011

To evaluate the clinical usefulness of the first-third ejection fraction (1/3 EF) for detecting patients with coronary artery disease (CAD), resting contrast ventriculography and first-pass radionuclide angiography with a high-count-rate, multicrystal camera system were performed in 47 subjects: 22 normal controls (group 1) and 25 patients with clinically stable angina pectoris and severe CAD (mean 2.3 vessels) without (group 2, n = 12) and with (group 3, n = 13) resting wall motion abnormalities. By contrast angiography, only group 3 had depressed global EF or 1/3 EF compared with control (global EF: group 1,0.71 +/- 0.09; group 2, 0.67 +/- 0.09 [NS]; group 3,049 +/- 0.05 [p less than 0.01 vs groups 1 and 2]; 1/3 EF: group 1,0.29% +/- 0.06;' group 2, 0.28 +/- 0.05 [NS]; group 3,0.22 +/- 0.05 [p less than 0.02 vs groups 1 and 2]). Whereas 11 of 25 CAD patients had global EF outside the normal range, only two of 25 had depressed 1/3 EF. Both had left ventricular asynergy and a depressed global EF. Studies performed using first-pass radionuclide angiography revealed similar results i.e., only four of 25 CAD patients, all with left ventricular asynergy and depressed global EF, had depressed 1/3 EF values. A wide range of 1/3 EF values was found in normal subjects by both techniques. Thus, the ejection fraction during the first third of systole at rest is of limited value for detecting patients with CAD.
Reduced suppressor cell activity in congestive cardiomyopathy and in myocarditis.
Authors: Eckstein R , Mempel W , Bolte H D
Published: June 2011

We studied suppressor cell function in 10 patients who had congestive cardiomyopathy, 13 patients who had myocarditis and 98 healthy controls. Myocardial biopsy, coronary arteriography and left ventricular angiography were used to define and differentiate congestive cardiomyopathy and myocarditis. The suppressor component of the immune response was assessed by examining the in vitro responses of peripheral blood lymphoid (PBL) cells under standard conditions. Briefly, PBL cells were incubated with concanavalin A to stimulate suppressor activity. Induced activity was measured by the ability of PBL cells to inhibit 3H-thymidine uptake of nonstimulated autologous cells when subsequently presented with allogenic or mitogenic stimuli.