bluuebunny/crossref_metadata_2025 huggingface dataset:
Infarct size estimated from serial serum creatine phosphokinase in relation to left ventricular hemodynamics.
Authors: Bleifeld W , Mathey D , Hanrath P , Buss H , Effert S
Published: June 2012

In 50 patients with proven acute myocardial infarction (AMI), left ventricular hemodynamics (pulmonary end-diastolic pressure [PAEDP]; cardiac index [CI]; stroke volume index [SVI]; and SVI/PAEDP were related to the size of the acute infarct. Acute infarct mass was calculated from serial determinations of serum creatine phosphokinase (CPK) every two hours, using a computer program. In 15 cases postmortem measurement of acute infarct size after staining with Nitro-BT was made and correlated with calculated infarct size. Correlation in this limited number of cases was good with a mean difference of 7 g. Acute infarct mass in 38 survivors was 46 +/- 5 g and was significantly smaller (P less than 0.05) than in the 12 nonsurvivors (76 +/- 12 g.) PAEDP in surviving patients was significantly lower (17 +/- 1 mm Hg) and SVI (36 ml/m2) and SVI/PAEDP (2.4 ml/m2/mm Hg) significantly higher than in the nonsurvivors (PAEDP: 24 mm Hg; SVI: 23 ml/m2; SVI/PAEDP: 0.86 ml/m2/mm Hg) (P less than 0.001 for all differences). Similar significant differences were observed between patients not in shock and those in cardiogenic shock. Although in 39 patients, in whom the infarction was their first, infarct mass was larger (58 +/- 6 g) than in 11 patients with repeat infarctions (37 +/- 8 g), left ventricular hemodynamics were slightly more impaired in reinfarctions (PAEDP: 21 +/- 3 mm Hg; CI:2.60 L/min/m2) than in first infarctions (PAEDP: 18 +/- 1 mm Hg; CI:2.82 L/min/m2). The occurrence of cardiogenic shock was a strong predictor of death; however, the wide scatter of the data for the parameters cardiac index, PAEDP, and acute acute infarct mass precluded their usefulness, when taken individually, in predicting survival. When a relationship between hemodynamics and infarct size was looked for, four constellations of individual patients were identified. These groups were defined by PAEDPs of above or below 18 mm Hg and infarct sizes above or below 65 g. Class A patients (N = 22) had a small infarct (29 +/- 4 g) and good pump function (PAEDP: 13 mm Hg; SVI: 40 ml/m2; SVI/PAEDP: 3.27 ml/m2/mm Hg); prognosis was good for these patients. In class B (N = 13) the infarct was large (96 +/- 8 g) and pump function markedly impaired (PAEDP: 26 mm Hg; SVI: 24 ml/m2; SVI/PAEDP: 0.98 ml/m2/mm Hg); 54% of these patients died. Five patients in class C had, in the presence of a large infarct (84 g), only a slightly elevated PAEDP of 17 mm Hg and an almost normal SVI of 37 ml/m2. In contrast, the ten class D patients had an infarct size (34 g) similar to that in class A, but high PAEDP (23 mm Hg) and moderately reduced SVI (31 ml/m2). In this group a high incidence of reinfarctions (six out of ten) occurred. It is concluded that infarct mass calculated from serial CPK analysis, as a single parameter, cannot be used to predict mortality or development of cardiogenic shock in an individual patient.
Hemodynamic effects of labetalol, an alpha and beta adrenergic blocking agent, in hypertensive subjects.
Authors: Mehta J , Cohn J N
Published: June 2012

Labetalol was administered to six hypertensive subjects in increasing doses for seven days. A decrease in both supine and standing arterial pressure and heart rate was observed with no change in cardiac output and few side effects. Exercise tolerance was unaltered by the drug, but the heart rate and arterial pressure response to exercise were significantly blunted. The infusion rate of isoproterenol required to produce tachycardia was increased sevenfold by 800 mg/day labetalol and tenfold by 1600 mg/day. More than twice the control dose of phenylephrine was required during labetalol therapy to produce a rise in diastolic arterial pressure reflex tachycardia to amyl nitrite-induced hypotension was attenuated. These studies indingina pectoris.
Sustained hemodynamic and antianginal effect of high dose oral isosorbide dinitrate.
Authors: Danahy D T , Burwell D T , Aronow W S , Prakash R
Published: June 2012

Twenty-one patients with documented coronary atherosclerotic heart disease were studied to determine the effect of high dose oral isosorbide dinitrate (ISDN) on heart rate, blood pressure, and exercise time until angina pectoris. Patients were tested in two phases, initially with 0.4 mg of sublingual nitroglycerin and with sublingual placebo, and then with oral ISDN, mean dose 29 mg, and oral placebo. Both phases of the study were conducted in a randomized, double-blind, crossover manner. After ISDN was compared to oral placebo, heart rate increased at 30 to 300 min (P less than 0.01) (peak increase 18 beats/min at 60 min), and systolic blood pressure decreased from 45 to 300 min (P less than 0.005) (peak decrease 18 mm Hg at 60 min). Exercise time at 2 min after sublingual nitroglycerin increased 51% as compared to oral placebo, exercise time increased 54% at 1 hr (P less than 0.005), 37% at 3 hr (P less than 0.01), and 12% at 5 hr (NS). Twelve of 21 patients (57%) improved their exercise time until angina larger than or equal to 25% at 1 hr after oral ISDN. The exercise response to sublingual nitroglycerin was a good predictor of this response to oral ISDN.
The effects of minoxidil on pulmonary and systemic hemodynamics in hypertensive man.
Authors: Klotman P E , Grim C E , Weinberger M H , Judson W E
Published: June 2012

Pulmonary hypertension has been described as a possible complication of the antihypertensive vasodilator, minoxidil. A prospective study was undertaken in seven severely hypertensive patients refractory to multiple drug therapy. Treatment was initiated with fixed doses of hydrochlorothiazide (100 mg/day) and propranolol (160 mg/day) for a control period. Mean systemic arterial pressure, cardiac output, and pulmonary artery pressure were then compared before and after the addition of acute (5 day) and chronic (2 month) therapy with minoxidil. Mean arterial blood pressure decreased from a control value of 135 mm Hg to a value of 104 mm Hg acutely and 108 mm Hg chronically. Significant increases in mean cardiac output occurred with minoxidil therapy (from 4.2 L/min control to 5.4 L/min acutely and 5.1 L/min chronically) despite concomitant propranolol treatment. Mean pulmonary artery pressure did not increase either acutely or chronically. The data suggest that in patients with normal pulmonary hemodynamics prior to treatment, pulmonary hypertension does not develop during two months of minoxidil therapy.
Regional myocardial perfusion in patients with atherosclerotic coronary artery disease, at rest and during angina pectoris induced by tachycardia.
Authors: Maseri A , L'Abbate A , Pesola A , Michelassi C , Marzilli M , De Nes M
Published: June 2012

We studied regional myocardial perfusion by scintigraphic computer-assisted analysis of initial distribution, washout rates, and residual activity of 133Xe injected into the left coronary artery of four patients with normal arteriograms and 14 patients with coronary stenosis. At rest, residual activity in poststenotic regions was always greater than in control regions, but initial washout rates were not slower. During angina, following xenon injections, the amount of indicator distributed to the poststenotic regions was markedly reduced; the increase of the initial washout rates was smaller than in control regions relative to rest, and residual activity was higher. Initial washout rates did not differ as much as from those of normal myocardium because in severe ischemia too little indicator is deposited initially in these regions to produce a change of any magnitude. Indeed, when angina was induced immediately after the xenon injection, poststenotic washout rates became much slower during angina than at rest, a finding that implicates functional factors in impairing poststenotic myocardial perfusion during angina.
The relationship between enzymatic and histologic estimates of the extent of myocardial infarction in conscious dogs with permanent coronary occlusion.
Authors: Roe C R , Cobb F R , Starmer C F
Published: June 2012

Relationships between enzyme estimates (EE) and histologic measurements of infarct size (HIS) were analyzed in 14 conscious dogs with permanent occlusion of the circumflex coronary artery. EE were derived from serial CPK, CPK-MM, CPK-MB, and CPK-BB. Estimates were obtained using methods of Shell et al., Norris et al., and Roberts et al. HIS was determined from multiple histologic sections 5-6 days after infarction. In 14 animals, HIS ranged from 0.1-26.6 grams. Regression analysis demonstrated poor correlation (r2 less than 0.06) between EE by each method and HIS. Using the Shell method and restricting the analysis to HIS of less than 13 grams, improved the correlation (r2 = 0.42). Correlation in this subgroup could be further improved by using CPK-MM and MB data, elimination of animals with high background values, or limiting analysis to the portion of the curve where LDH isoenzymes indicated a cardiac zone. When the analysis was restricted to animals with HIS of less than 13 grams, Norris and Roberts modifications as compared to Shell's method improved correlation with CPK-MB but reduced correlation using CPK and CPK-MM data. In this subgroup, each method overestimated extent of HIS; Shell greater than Norris greater than Roberts. In this study it was not possible to distinguish small from large HIS by serum enzyme measurements.
Multiclinic controlled trial of bethanidine and guanethidine in severe hypertension.
Authors: Ramirez E A , Elson L , Gear A S , Oster J R , Talmers F N , Thomas J R
Published: June 2012

One hundred and eight patients with initial diastolic blood pressure in the range of 100-124 mm Hg while taking hydrochlorothiazide were assigned randomly and double-blind to hydrochlorothiazide plus either bethanidine or guanethidine. The average reduction of the fifth and sixth months' diastolic blood pressure was 18.4 mm Hg for guanethidine and 13.6 mm Hg for bethanidine (P less than 0.01). The distribution of the individual values was such that 68.8% of guanethidine treated patients achieved a diastolic level below 90 mm Hg, compared to only 45.5% of the bethanidine treated group (P less than 0.025). The degree of orthostatic fall in blood pressure was greater with bethanidine than with guanethidine (P less than 0.05). The diurnal variation of blood pressure was slightly greater with bethanidine than with guanethidine. The results significantly favor guanethidine. This study failed to demonstrate that the shorter action of bethanidine confers significantly better control of blood pressure than the longer action of guanethidine.
Echocardiographic observations on the association between mitral valve prolapse and asymmetric septal hypertrophy.
Authors: Chandraratna P A , Tolentino A O , Mutucumarana W , Gomez A L
Published: June 2012

One hundred and ninety consecutive patients with mitral valve prolapse (MVP) were studied by echocardiography. Asymmetric septal hypertrophy (ASH) was noted in 16 patients. Three patients had syncope which was associated with supraventricular arrhythmias. Three others had episodes of presyncope which were not related to rhythm disturbances. One of the patients with MVP and ASH had a family history of idiopathic hypertrophic subaortic stenosis. The septal thickness ranged from 1.6 to 3.1 cm, mean = 2 cm. The posterior wall thickness ranged from 0.7 to 2.1 cm, mean = 1.0 cm. The ratio of the thickness of the interventricular septum to that of the posterior wall ranged from 1.5 to 2.5, mean = 1.9. The percentage of thickening of the septum in systole was reduced in 13 patients. The excursion of the interventricular septum was reduced in three patients. In nine patients the left ventricular end-systolic dimension was below the lower limit of normal. Percentage fractional shortening of the left ventricle was increased in eight patients. Since MVP predisposes to cardiac arrhythmias which are poorly toletated in the setting of ventricular hypertrophy and reduced left ventricular compliance, the recognition of this combination of MVP and ASH is of clinical importance.
Augmentation of serum CPK activity by digitalis in patients with acute myocardial infarction.
Authors: Varonkov Y , Shell W E , Smirnov V , Gukovsky D , Chazov E I
Published: June 2012

The effect of acetyl strophanthanin on the rate of creatine phosphokinase (CPK) efflux was evaluated in 59 predominantly class I and II patients randomly allocated between treated and control. Therapy (0.5 mg) was begun 11-15 hours after the onset of symptoms and repeated four hours later (0.25 mg). Accumulated CPK activity (ACA) was determined from serial serum CPK changes sampled every two hours and compared to predicted CPK activity (PCA) determined from the first seven hours of CPK changes. In the control group, ACA was not significantly different from PCA. Digitalis consistently resulted in an augmentation of CPK efflux into serum which was temporally related to drug administration and resulted in a corresponding increase in ACA (P less than 0.001). Thus acetyl strophanthanin appears to increase apparent CPK activity in serum in class I and II patients.
Evaluation of precordial orthogonal vectorcardiographic lead ST-segment magnitude in the assessment of myocardial ischemic injury.
Authors: Foerster J M , Vera Z , Janzen D A , Foerster S J , Mason D T
Published: June 2012

Relationship has been established between epicardial ST-segment elevation, considered a reliable estimate of ischemic injury in experimental myocardial damage, and ST changes by multiple-lead precordial electrocardiography. However, 35-lead precordial mapping is time-consuming and suitable only for anterior infarctions. An alternate, more rapid method for recording ST segments is an external 3-lead orthogonal vectorcardiographic (VCG) system which also can assess the entire ventricle. Accordingly, validity of VCG ST magnitude was evaluated by direct comparison with changes in epicardial ST magnitude (EST) induced by occlusion of major coronary arteries, reperfusion, and pharmacologic interventions in 15 closed-chest dogs. A total of 404 data points (average 27/dog), 20 epicardial grid and 3 Frank XYZ leds each, demonstrated close correlation (least squares linear regression) between VCG ST and EST changes (r = 0.921 +/- 0.02 SEM). These data document the accuracy of precordial VCG ST in noninvasive assessment of ischemic injury in various areas of myocardium and its practicality for clinical application.
Serial serum creatine phosphokinase MB isoenzyme activity after myocardial infarction. Studies in the baboon and man.
Authors: Yasmineh W G , Pyle R B , Cohn J N , Nicoloff D M , Hanson N Q , Steele B W
Published: June 2012

Serum CPK-MB iosenzyme activity was measured serially after mercury embolization of the left circumflex coronary artery in five baboons and after clinical acute myocardial infarction (AMI) in 20 patients. The calculated amount of enzyme released into the baboons' circulation (CPK-MBR) correlated well (r = 0.991) with the amount of MB isoenzyme depleted from the myocardium (CPK-MBD) when a previously determined decay constant (Kd) was used, but not when Kd was calculated from individual curves or when CPK-MM values were used. In clinical AMI, CPK-MMR averaged 97% (0 to 350%) greater than CPK-MBR, probably because of release of MM isoenzyme from nonmyocardial sources. The mean Kd for CPK-MB in patients (0.0012 min-1) was significantly (P less than 0.01) lower than that obtained in the baboon following bolus injections (0.0018 min-1), probably reflecting delayed myocardial release of enzyme. Therefore, in both experimental and clinical AMI, serial samples for CPK-MB activity, but not total or CPK-MM activity, could provide an accurate index of myocardial enzyme depletion.
Cross-sectional echocardiographic assessment of the severity of aortic stenosis in children.
Authors: Weyman A E , Feigenbaum H , Hurwitz R A , Girod D A , Dillon J C
Published: June 2012

Real-time, cross-sectional echocardiographic studies of the aortic valve were performed in 28 children with congenital valvular aortic stenosis and in 22 normal subjects. The presence of a stenotic valve was indicated by increase in echo production, abnormal motion pattern, and abnormal systolic position of the valve leaflets. Comparison of the maximum aortic cusp separation (MACS) to calculated aortic valve area yielded an r of 0.91. MACS was then expressed as a percentage of aortic root diameter (AOD) to correct for patient size. In normals MACS averaged 72.7% (range 63-92%) of AOD. With mile aortic stenosis MACS averaged 53.1% of AOD (range 42-62%) (P less than 0.001 vs normal). With moderate and severe aortic stenosis MACS averaged 29.9% of AOD (range 20-35%) (P less than 0.001 vs mild AS). Comparing the ratio MACS/AOD to peak systolic gradient yielded an r of 0.88. Further comparing this ratio to calculated aortic valve area yielded an r of 0.80. Cross-sectional echocardiography can detect the presence of aortic stenosis in children and, by comparing the ratio MACS/AOD, can provide information concerning the severity of the stenotic lesion.
Target organ damage in black hypertensives.
Authors: Entwisle G , Apostolides A Y , Hebel J R , Henderson M M
Published: June 2012

A representative sample of black hypertensives has been appraised to determine candidacy for hypertension treatment. A total of 1759 black residents were successfully screened at home. Forty-one percent of the males and 33% of the females had diastolic blood pressures of 95 mm Hg or greater. They were invited for secondary screening along with those hypertensives controlled on therapy. Clinical and laboratory evidence of cardiovascular disease was common among examined patients who were studied to determine their eligibility for therapy based on criteria of elevated blood pressure (greater than 104 mm Hg) at two visits, or evidence of end organ damage at lowere blood pressure levels. Of patients previously aware of their hypertension but not on therapy, 88% of the males and 67% of the females were considered candidates for therapy. Of patients not previously aware of their elevated blood pressure, 72% of the males and 67% of the females were considered candidates.
Relationship between epicardial ST-segment elevation, regional myocardial blood flow, and extent of myocardial infarction in awake dogs.
Authors: Irvin R G , Cobb F R
Published: June 2012

This study was designed to examine the relationship between epicardial ST change (EpST) and regional myocardial blood flow (RMBF) following coronary occlusion and extent of myocardial infarction (MI) in awake dogs. Fifteen min and two hr after coronary occlusion simultaneous measurements of EpST and RMBF were made. Six days later histologic MI and RMBF were determined in transmural myocardial samples from each electrode site. Greatest ST elevation occurred at sites of greatest ischemia and MI. However, 15 min after occlusion 29% of sites with greater than 50% MI and 39% of sites with greater than 50% reduction in RMBF did not demonstrate ST elevation greater than 2 mV. There were poor correlations between EpST and MI (r = 0.59) and RMBF (r = 0.57). Comparable relationships were observed two hr after occlusion. In the present study, there were not close quantitative or qualitative relationships between EpST and MI or RMBF. A good correlation was observed between RMBF at two hr and MI (r = 0.89).
The origin of ventricular arrhythmias 24 hours following experimental anterior septal coronary artery occlusion.
Authors: Spear J F , Michelson E L , Spielman S R , Moore E N
Published: June 2012

The anterior septal coronary artery was acutely ligated in 16 open-chest anesthetized dogs to produce an infarct of the septal myocardium. Twenty-four hours following occlusion complete epicardial mapping and extensive plunge electrode recording techniques were used to localize the sites of origin and patterns of activation of the ventricular tachyarrhythmias that developed during recovery. The earliest electrical activity for 13 individual rhythms was recorded from surviving septal subendocardial Purkinje fibers at the margins of the infarct, in the right or left ventricle, directly underlying the sites of earliest epicardial breakthrough. The sites of origin were verified by demonstrating unchanged activation sequences during pacing through the electrode sites which recorded the earliest activity. None of the arrhythmias arose from the His bundle or bundle branches despite the fact that these tissues course directly through the necrotic septum. The data presented supports the hypothesis that ventricular arrhythmias occuring in the 24-36 hour post acute infarction period may originate in the surviving subendocardial Purkinje system. Our experimental model shows that in cases in which a malignant rhythm arises from a focus, whether it is due to enhanced automaticity or local re-entry, epicardial mapping alone may not identify the source of the arrhythmias. Extensive endocardial mapping may provide a more rational basis for surgical interventions designed to abolish these arrhythmias.
Correlation of coronary arteriograms and left ventriculograms with postmortem studies.
Authors: Hutchins G M , Bulkley B H , Ridolfi R L , Griffith L S , Lohr F T , Piasio M A
Published: June 2012

To assess the accuracy of angiographic determinations of disease of coronary arteries and left ventricular myocardium we compared clinical with postmortem coronary arteriograms and left ventriculograms with myocardial pathology in 28 patients, all of whom died postoperatively and within three months of angiography; 19 had ischemic heart disease, four valvular heart disease, and five both. Comparison of pre and postmortem lumenal occlusion in 315 epicardial coronary segments, excluding those operated upon, showed greater than 50% narrowing discrepancies in 21 (7%). Significant coronary artery lesions were overestimated in six and underestimated in 15. Of the six overestimations, three appeared to be due to coronary spasm; of the 15 underestimations, 12 were due to overlapping images; six discrepancies were unexplained. Comparison of wall motion in 140 ventriculogram segments with myocardial pathology, excluding any post-study or perioperative injury, showed good correlation of reduced motion with 48 (34%) infarcted and 10 (7%) aneurysmal segments. However, 58 (41%) other segments had poor or absent ventriculogram motion, with structurally normal myocardium and patent coronary artery supply; 19 were on infarct margins and 39 in dilated or hypertrophied hearts. Thus, premortem coronary arteriographic occlusions generally indicate atherosclerotic narrowing; but decreased or absent segmental wall motion frequently does not indicate a myocardial lesion. It may be attributable to ischemia in the distribution of a critically narrowed coronary artery or it could be due to abnormal ventricular topography.
An unusual variety of atrioventricular nodal re-entry due to retrograde dual atrioventricular nodal pathways.
Authors: Wu D , Denes P , Amat-Y-Leon F , Wyndham C R , Dhingra R , Rosen K M
Published: June 2012

Three patients with paroxysmal supraventricular tachycardia (PSVT) had discontinuous ventriculo-artrial conduction curves (V1-V2, A1-A2), suggesting dual A-V nodal pathways. Ventricular echoes occurred simultaneously with sudden increase of V-A interval. These echoes were characterized by retrograde P waves occurring in front of QRS, suggesting utilization of a slow pathway for retrograde conduction and a fast pathway for antegrade conduction. In case one, atropine improved retrograde slow pathway and antegrade fast pathway conduction and made A-V nodal re-entry sustained, resulting in PSVT (with retrograde P in front of the QRS). In cases 2 and 3, atropine markedly shortened retrograde fast pathway refractory period and slightly improved antegrade slow pathway conduction. The discontinuous V1-V2, A1-A2 curves and echoes were no longer demonstrable. However, with improvement of retrograde fast pathway and antegrade slow pathway conduction, A-V nodal re-entrant echoes and PSVT were observed, utilizing the slow pathway for antegrade conduction and the fast pathway for retrograde conduction (P simultaneous with QRS).
The application of radionuclide infarct scintigraphy to diagnose perioperative myocardial infarction following revascularization.
Authors: Klausner S C , Botvinick E H , Shames D , Ullyot D J , Fishman N H , Roe B B , Ebert P A , Chatterjee K , Parmley W W
Published: June 2012

To evaluate the application of radionuclide infarct scintigraphy to diagnose myocardial infarction after revascularization, we obtained postoperative technetium 99m pyrophosphate myocardial scintigrams, serial electrocardiograms and CPK-MB isoenzymes in ten control and 51 revascularized patients. All control patients had negative electrocardiograms and scintigrams, but eight had positive isoenzymes. Eight revascularized patients had positive electrocardiograms, images and enzymes and two had positive scintigrams and enzymes with negative electrocardiograms. Thirty-four patients with negative electorcardiograms and scintigrams had positive isoenzymes; in only seven patients were all tests negative. Our data suggest radionuclide infarct scintigraphy is a useful adjunct to the electrocardiogram in diagnosing perioperative infarction. The frequent presence of CPK-MB in postoperative patients without other evidence of infarction suggests that further studies are required to identify all factors responsible for its release.
Correlation of angiographic estimates of myocardial infarct size and accumulated release of creatine kinase MB isoenzyme in man.
Authors: Rogers W J , McDaniel H G , Smith L R , Mantle J A , Russel R O , Rackley C E
Published: June 2012

Accumulated creatine kinase MB isoenzyme release (sigma CK-MB) during acute myocardial infarction was correlated with biplane left ventricular (LV) angiographic estimates of percent abnormally contracting segment (%ACS) and ejection fraction (EF) in 35 patients who underwent diagnostic angiography at a mean of 33 +/- 4 days post myocardial infarction (MI). Of the 35 patients, 18 had no evidence of prior MI and their sigma CK-MB showed good correlation with %ACS (r = 0.84) and with EF (r = - 0.78). An additional two patients with first (inferior) infarct secondary to stenosis of the right coronary artery proximal to the origin of the right ventricular arterial blood supply had disproportionately large sigma CK-MB, suggesting a combination of LV and RV necrosis. In the 15 patients with prior infarct, there was no significant correlation between sigma CK-MB and %ACS or EF. However, in the subgroup of patients with anterior MI, %ACS correlated with sigma CK-MB, both in patients with no prior MI (r = 0.88, N = 12) and in patients with prior MI (r = 0.69, N = 9). These independent angiographic and enzymatic data suggest that enzymatic infarct size estimates utilizing accumulated CK-MB release may be a valid and reliable clinical measure for assessing the extent of LV necrosis in the setting of acute anterior myocardial infarction. However, limitations may exists in certain cases of inferior MI, probably because of concomitant right and left ventricle necrosis.
Hemodynamics and antianginal effects of high dose oral isosorbide dinitrate after chronic use.
Authors: Danahy D T , Aronow W S
Published: June 2012

In a randomized, double-blind, crossover study, 19 patients with angina were exercised 2 min after 0.4 mg sublingual nitroglycerin and after sublingual placebo and before and 1, 3, and 5 hours after oral isosorbide dinitrate (ISDN) and oral placebo. After initial testing, patients took the dose of ISDN they had had during the study (mean dose 29 mg) for a mean period of 5.6 months before retesting using the same protocol. Compared to placebo, exercise time after sublingual nitroglycerin increased 56% (P less than 0.001) initially and 51% (P less than 0.001) at retest. Compared to placebo, exercise time increased 58% (P less than 0.05) initially and 58% (P less than 0.005) at retest 1 hour after ISDN, 38% (P less than 0.05) initially and 27% (P less than 0.005) at retest 3 hours after ISDN, and 13% (NS) initially and 21% (P less than 0.02) at retest five hours after ISDN. The mean exericse times initially and at retest were not significantly different. Hemodynamic changes (decrease in systolic blood pressure and increase in heart rate) at 15 min persisted through 300 min after ISDN during both initial testing and during retesting. However, these changes were significantly less during retesting. We conclude that a partial tolerance to the hemodynamic effects of the drug develops after chronic use of high dose oral ISDN but that the antianginal efficacy of both sublingual nitroglycerin and oral ISDN is unimpaired.
Prognostic value of infranodal conduction time in patients with chronic bundle branch block.
Authors: Scheinman M M , Peters R W , Modin G , Brennan M , Mies C , O'Young J
Published: June 2012

His bundle recordings were obtained in 121 patients with chronic bundle branch block and the patients were followed for a mean period of 18 months. Seventy-nine patients had an infranodal conduction time (H-Q) less than 70 msec while 42 had H-Q greater than or equal to 70 msec. There was no significant difference in mean age, smoking history, diabetes, syncope, dizziness, blood pressure, and serum cholesterol or triglyceride levels between the two groups. There was a significantly greater incidence of progresssion to second degree or third degree atrioventricular block (9/42, 21%), and of severe congestive heart failure (16/42, 38%) in patients with H-Q greater than or equal to 70 compared with those with H-Q less than 70 (1/79, 1.3%; and 13/79, 16%, respectively). The risk of sudden death was significantly greater only in the group with H-Q greater than or equal to 70 and severe congestive heart failure. There was no correlation between the presence of first degree atrioventricular block and/or any particular type of bundle branch block pattern with sudden death and/or progression to second degree or third degree atrioventricular block. Analysis of the surface electrocardiogram is only of limited value in predicting high risk patients with chronic bundle branch block. Electrophysiologic studies are of greatest value in patients with bundle branch block with transient neurologic symptoms in whom no cause for the symptoms is evident.
Cross-sectional echocardiography in the diagnosis of congenital heart disease. Identification of the relation of the ventricles and great arteries.
Authors: Henry W L , Maron B J , Griffith J M
Published: June 2012

Using a mechanical sector-scanner, two-dimensional echocardiograms were obtained from 28 normal subjects, 15 patients with tetralogy of Fallot, 11 patients with complete transposition of the great arteries and six patients with double outlet right ventricle. The image obtained perpendicular to the long axis of the left ventricle at the base of the venticular septum was superimposed on the image obtained perpendicular to the long axis at the origin of the great arteries. In normal subjects, these superimposed images demonstrated that the aorta originated posterior and to the left of the ventricular septum. In patients with tetralogy of Fallot, the aorta was displaced anterior and to the right resulting in the aorta over-riding the ventricular septum. In patients with double outlet right ventricle both great arteries originated anterior to the ventricular septum (i.e., from the right ventricle). In patients with complete transposition, the aorta originated anterior and the pulmonary artery posterior to the ventricular septum. Thus, cross-sectional echocardiography permits noninvasive identification of the relation of the ventricles and great arteries and, therefore, provides important information for the diagnosis of patients with congenital heart disease.
The Erysichthon syndrome. Progression of coronary atherosclerosis and dietary hyperlipidemia.
Authors: Nash D T , Gensini G , Simon H , Arno T , Nash S D
Published: June 2012

One hundred nineteen patients with coronary artery disease confirmed by coronary arteriograms were studied. Cine coronary arteriography confirmed progression of atherosclerosis in 106 (89%) patients (mean age 50.9 yr) and nonprogression in 13 (11%) patients (mean age 50.3 yr). Progression was defined as follows: any increase to 50% stenosis, 50% to 75% narrowing, 75% to 90%, 90% to 99%, 99% to total occlusion. Only one patient of the 106 who progressed (less than 1%) had ideal values for both cholesterol and triglyceride. Three of 13 patients (23%) who did not progress had ideal lipid values (P less than 0.005). Fifty four of 106 patients who progressed had cholesterol levels greater than or equal to 250 mg%; none of 13 patients who did not progress had such levels (P less than 0.005). Thirty-nine of 98 (40%) patients who progressed had hypertension; only one (8%) who did not progress had hypertension (P less than 0.025). Seventy-four of 96 patients who progressed were smokers (77%); two of 13 nonprogression patients smoked (15%) (P less than 0.005).
Termination of ventricular tachycardia by an increase in cardiac vagal drive.
Authors: Waxman M B , Wald R W
Published: June 2012

Out of 12 patients in whom phenylephrine terminated ventricular tachycardia, four were selected for detailed studies of its mechanism of action. Pretreatment with edrophonium (15-20 mg, i.v.) decreased, while atropine (2.4 mg, i.v.) increased by at least a factor of two, the dose of phenylephrine required to break ventricular tachycardia. Carotid sinus massage following pretreatment with edrophonium in unusually high (15-20 mg, i.v.) doses broke ventricular tachycardia in all four patients. The evidence presented supports the assumption that a vagal mechanism caused both instances of termination. These findings significantly alter our interpretation of vagal interventions in the bedside clinical diagnosis of wide QRS complex tachycardias.
Evaluation of left ventricular size and function by echocardiography. Results in normal children.
Authors: Gutgesell H P , Paquet M , Duff D F , McNamara D G
Published: June 2012

Left ventricular (LV) size and function were studied by echocardiography in 145 normal children. The LV end-diastolic diameter (EDD) and its percentage change with systole (%deltaLVD) were measured and mean velocity of circumferential fiber shortening (Vcf) calculated. The LV pre-ejection period (PEP) and ejection time (LVET) were determined from recordings of aortic valve motion. The EDD increased by approximately threefold during childhood and was best correlated with the log of body weight (r = 0.95) and the log of body surface area (r = 0.96). The mean %deltaLVD was 36 +/- 4 (SD), and this index of LV function was independent of age and heart rate. Mean Vef was higher, and the absolute values of PEP and LVET shorter, in younger children with a faster heart rate. The mean ratio of PEP/LVET was 0.31 +/- 0.003, and was relatively independent of age (r = 0.41) and heart rate (r = 0.37). The %deltaLVD and PEP/LVET appear to be particularly useful indices of LV function because they remain constant during the course of childhood.
Individualized values for the disappearance rate parameter (Kd) in the enzymatic estimation of infarct size. A critique.
Authors: Slutsky A S
Published: June 2012

A mathematical model to measure infarct size from serial estimates of CPK has been developed by Shell et al. Norris et al. have recently introduced a modification of this method by calculating an individualized disappearance rate parameter (Kd) from the uniformly monoexponential portion of the CPK vs time curve. This modification is based on the assumption that when CPK is decaying monoexponentially, the amount of CPK appearing in the circulation is zero. This paper presents a mathematical analysis which shows that the method of Norris et al. is theoretically unsound, as the CPK appearance function may be significantly different from zero and yet CPK vs time may still be monoexponential. Their method may lead to erroneous results in the calculation of infarct size.
Sudden death after repair of tetralogy of Fallot. Electrocardiographic and electrophysiologic abnormalities.
Authors: Gillette P C , Yeoman M A , Mullins C E , McNamara D G
Published: June 2012

In order to try to determine the mechanism of sudded death in patients after surgical repair of tetralogy of Fallot, electrocardiographic, intracardiac electrophysiologic, and clinical data of 51 children who had postoperative intracardiac electrophysiologic studies were reviewed. Ninety-four percent had developed right bundle branch block (RBBB) and 16 percent had additional left anterior hemiblock (LAH). Two had had transient complete A-V block (CAVB) and one had permanent CAVB. Six had a first degree A-V block and nine had premature ventricular contractions (PVC). Nine patients were found to have prolonged intra-atrial conduction times, four prolonged A-V nodal conduction, four prolonged His-Purkinje conduction, and five prolonged corrected sinus node recovery times. Patients with first degree A-V block or LAH did not have an increased incidence of abnormalities on electrophysiologic study. No patient with RBBB and LAH developed complete A-V block or died. Three of the nine patients with PVCs died, one of intractable ventricular fibrillation and two suddenly, presumably of dysrhythmia. All three had significant congestive heart failure. Although late complete A-V block occurs and should be watched for, ventricular dysrhythmias in patients with PVCs may be the cause of most sudden deaths after tetralogy repair. We currently are treating all of our postoperative tetralogy patients who have PVCs with quinidine or propranolol.
A new, noninvasive technique for inducing post-extrasystolic potentiation during echocardiography.
Authors: Cohn P F , Angoff G H , Zoll P M , Sloss L J , Markis J E , Graboys T B , Green L H , Braunwald E
Published: June 2012

Left ventricular function was evaluated in 34 patients with the echocardiogram, and an external mechanical cardiac stimulator was used to induce a ventricular premature contraction (VPC) noninvasively. Extent of post-extrasystolic potentiation (PESP) was determined by comparing systolic dimensional shortening and ejection fraction of the sinus beat preceding the VPC to that of the potentiated beat which followed it. Using this technique, a VPC could be introduced into the cardiac cycle of 30 of the 34 patients, six of whom were free of obvious cardiac disease and 24 of whom had valvular, coronary or myopathic heart disease. The only complication observed was mild breast ecchymosis in a female patient. Systolic dimensional shortening and ejection fraction increased from control values by an average of 21% and 17% respectively, with a range of 0-100%. The degree of PESP was very reproducible in repeat studies and when the same patients were subsequently evaluated during a spontaneously occurring or catheter-induced VPC. The technique can safely and reliably induce post-extrasystolic potentiation during echocardiography and is a potentially important adjunct to the noninvasive evaluation of left ventricular function.
The Starr-Edwards model 6000 valve. A fifteen-year follow-up of the first successful mitral prosthesis.
Authors: Macmanus Q , Grunkemeier G , Thomas D , Lambert L E , Starr A
Published: June 2012

The Starr-Edwards model 6000 mitral valve was the first successful mitral prosthesis. A fifteen year follow-up of 110 patients undergoing isolated mitral valve replacement with this prosthesis from 1960 to 1966 is presented. There were 22 (20%) operative and 37 (42%) late deaths at a mean of 8.6 years postoperatively. Preoperative variables leading to late death and thromboembolism are analyzed. Seventeen of 25 operative survivors had improvement in their NYHA Functional Class status and eight other remained unchanged an average of 13.1 years after surgery. There are 5000 patients world-wide currently relying on this prosthesis. Despite a high rate of thromboembolism in the past, elective replacement is not recommended except in selected patients.
Lung hypoplasia in congenital pulmonary valve stenosis.
Authors: De Troyer A , Yernault J C , Englert M
Published: June 2012

The pulmonary function of ten adult patients with congenital pulmonary valvular stenosis was investigated. The patients clearly showed smaller lungs than healthy control subjects of equivalent age and height; lung elastic recoil pressure was normal at any given percentage of measured total lung capacity, indicating that postnatal parenchymal damage is not the cause of the small lungs. The lung diffusing capacity for carbon monoxide was reduced, reflecting the anatomical alterations of the pulmonary vascular bed. Finally, the maximal flow-static recoil curves showed a fixed (not dynamic) reduction of airway dimensions: the critical transmural pressure in the collapsible flow-limiting segment (Ptm') was normal, but the conductance of the S segment was lowered. These abnormalities most likely reflect inadequate development of the lung and suggest that pulmonary blood pressure may be an important determinant of lung growth in the postnatal period.
A study of instruments in preparation for a blood pressure survey of children.
Authors: Webber L S , Voors A W , Foster T A , Berenson G S
Published: June 2012

In preparation for the measurement of blood pressure in children of a total geographic community, several preliminary studies of the validity and reliability of various methods and instruments for indirect blood pressure measurements were performed. These studies included Graeco-Latin Square designs, examination of children in a field setting, and assessments of the replicability of reading automatically recorded blood pressures. Each of the studies was designed to monitor the validity and replicability of instruments, methods, and observers. Controlling for subject, we compute biases due to instrument, method and observer and, where possible, eliminated them in the enusing studies. One automatic instrument, the Physiometrics recorder, was selected and used in conducting epidemiologic studies where it complements the measurements by the mercury sphygmomanometer.
Coronary neovascularity and fistula formation: a sign of mural thrombus.
Authors: Soulen R L , Grollman J H , Paglia D , Kreulen T
Published: June 2012

Fifteen patients have shown neovascularity in the left heart during selective coronary arteriography, with associated fistulous communication to a cardiac chamber in ten. In nine the abnormalities were adjacent to and within ventricular mural thrombi, associated with ventricular aneurysms in seven and congestive cardiomyopathy in two. In six patients with mitral stenosis and atrial fibrillation the angiographic changes related to left atrial thrombi. Histologic study of two atrial thrombi showed revascularization patterns in keeping both with the angiographic findings and with an intermediate stage in the evolution of mural thrombus. Though myxomas can produce a similar appearance, clinical and additional angiographic features should permit differentiation in most instances between this infrequent tumor and the far more common mural thrombus.
Inhibition of bipolar demand pacemaker by diaphragmatic myopotentials.
Authors: Barold S S , Ong L S , Falkoff M D , Heinle R A
Published: June 2012

This report describes inhibition of a normally functioning bipolar demand pulse generator by diaphragmatic myopotentials. Transient pacemaker suppression occurred repeatedly with deep respiration, straining, the Valsalva maneuver, coughing, sneezing and laughing. When the magnet was applied, none of these maneuvers inhibited the pacemaker. Extensive investigations ruled out an intermittent electrode problem such as a wire fracture or insulation break. Sensing of diaphragmatic myopotentials should be considered in the differential diagnosis of unexplained pacemaker pauses.
Neural regulation of renin release: experimental evidence and clinical implications in arterial hypertension.
Authors: Zanchetti A S
Published: June 2012

The assessment of the possible role played by the renin-angiotensin system in maintaining arterial hypertension requires an understanding of the mechanisms regulating renin release from the kidney. In addition to intrarenal mechanisms of control, recent investigation stresses the importance of sympathetic influences on the juxtaglomerular cells both in experimental animals and in man. Studies with beta-adrenergic blocking agents, interfering with sympathetic release of renin, and with peptides interfering with sympathetic release of renin, and with peptides interfering with the generation or action of angiotensin II, suggest that renin may play some pressor role in a number of cases of hypertension: a major one in the small group of patients with high plasma renin, and possibly a minor one in the large population of patients whose renin is stimulated by treatment with diuretics and vasodilators. On the whole, available evidence suggests that renin disturbances in essential hypertension are rarely primary. It is unlikely, therefore, that renin levels alone can suffice as guideline for treatment of hypertension. A more comprehensive approach should be based on a multifaceted profile, including but not limited to renin.
Tetralogy of Fallot: postoperative electrophysiologic studies.
Authors: Neches W H , Park S C , Mathews R A , Lenox C C , Marin-Garcia J , Zuberbuhler J R
Published: June 2012

Electrophysiologic studies performed during postoperative cardiac catheterization in 51 patients following repair of tetralogy of Fallot (TF) were compared with studies performed in a control group of 30 patients. These studies include His bundle electrograms, measurement of atrioventricular (A-V) conduction at progressively increasing atrial pacing rates, and evaluation of sinus node recovery time. More postoperative TF patients (20%) had prolonged H-V intervals compared to the controls (7%). With atrial pacing, no patient in the control group developed second degree A-V block below 160 beats/min, while 23% of the postoperative TF patients developed block below this level. Half of these patients had normal His bundle studies. Stress of the A-V conduction system by atrial pacing may unmask conduction abnormalities not present on the surface electrocardiogram or on His bundle electrogram. Two-thirds of the patients had some form of conduction abnormality on the basis of evaluation of one or more parameters but about half of the patients with a given abnormality had normal findings in other areas. The high incidence of electrophysiologic abnormalities following TF repair may have future prognostic significance. Systematic evaluation of atrioventricular conduction during preoperative and postoperative cardiac catheterization may be of value.