bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison between apexcardiographic and angiographic indexes of left ventricular performance in patients with aortic incompetence.
Authors: Manolas J , Krayenbuehl H P
Published: June 2012

Left ventricular (LV) apexcardiogram (ACG) and its first derivative (dA/dt) was obtained in 104 normal subjects and 34 patients with chronic aortic incompetence (AI). In the patients with AI the ACG was recorded simultaneously with LV pressure (tipmanometer). The systolic upstroke time (SUT), the time to peak dA/dt (t-dA/dt) and the a wave percentage amplitude (a/H) of the ACG was measured. In normal subjects SUT averaged 99 +/- 17 (SD) msec. In 17 patients with AI and normal ejection fraction (EF) (group 1) SUT was within normal limits; in 17 patients with AI and decreased EF (group 2) it was prolonged (142 +/- 19 msec) (P less than 0.001). The SUT was closely correlated with EF (r = 0.85) and less with contractile indexes derived from pressure curves. The indexes t-dA/dt and a/H were not significantly different in groups 1 and 2; they were weakly correlated only with the time to peak rate of LV pressure rise (r = +0.56) and the LV end-diastolic pressure (r = +0.59), respectively. These results demonstrate the superiority of SUT over the other apexcardiographic parameters. The measure provides another means of noninvasive assessment of the LV performance in patients with AI.
Noninvasive study of early diastole in mitral stenosis.
Authors: Toutouzas P , Velimezis A , Castellanos S , Avgoustakis D
Published: June 2012

Cardiac events of early diastole were studied in 50 normal subjects and 46 patients with mitral stenosis (MS) by simultaneous recordings of the mitral valve echogram (MVE), phonocardiogram, and apexcardiogram (ACG). Left ventricular isovolumic relaxation time (IRT), measured between A2 and onset of the MVE opening motion, had almost the same values in normals 54 +/- 7 msec, and MS 51 +/- 16 msec. The interval between A2 and the ACG "O" point was approximately double that of IRT: 99 +/- 11 msec in normal subjects, 109 +/- 20 msec in MS. The normal MVE opening motion had a velocity 293 +/- 76 mm/sec and duration 45 +/- 6 msec, values significantly different (P less than 0.001) from 536 +/- 271 mm/sec, 23 +/- 7.5 msec found in MS patients. In atrial fibrillation the length of the cardiac cycle did not affect A2-O interval or mitral valve opening movement duration; however cycle length was clearly related to isovolumic relaxation time. This resulted in a variation in the interval between completion of the mitral valve opening (opening snap) and O point. This interval was longer after a short diastole and vice versa.
Thallium-201 scintigraphy in unstable angina pectoris.
Authors: Wackers F J , Lie K I , Liem K L , Sokole E B , Samson G , van der Schoot J B , Durrer D
Published: June 2012

Thallium-201 scintigraphy was performed during the pain free period in 98 patients with unstable angina. Scintiscans were positive in 39 patients, questionable in 27 patients and normal in 32 patients. Eighty-one patients responded favorably to treatment (group I). Seventeen patients had complicated courses (group II) and despite maximal treatment with propranolol either developed infarction (six patients) or continued to have angina necessitating coronary surgery (11 patients). In group I during the pain free period 26 of 81 patients had positive thallium-201 scans, whereas 20 patients had an abnormal ECG at that time; during angina 18 patients had transient ECG changes. In group II during the pain free period 13 of 17 patients had positive scans, whereas two patients had abnormal ECG at that time; during angina 12 patients showed transient ECG changes. The sensitivity to recognize group II was 76% for thallium-201 scintigraphy, 11% for ECG during the pain free period; 70% for ECG during angina; 94% for the combination of either positive scans or abnormal ECG. Thus, 1) positive thallium-201 scans occur in patients with unstable angina, 2) positive scans can be obtained during the pain free period, 3) thallium-201 scans are more frequently positive in patients with complicated course.
Coronary sinus reflux. A source of error in the measurement of thermodilution coronary sinus flow.
Authors: Mathey D G , Chatterjee K , Tyberg J V , Lekven J , Brundage B , Parmley W W
Published: June 2012

In seven patients thermodilution coronary sinus flow (TD-CSF) was higher (164 +/- 21 ml/min) during ventricular pacing than during atrial pacing (119 +/- 21 ml/min, P less than 0.005) at identical heart rate, without an increase in the determinants of myocardial oxygen consumption. To assess the possibility of right atrial admixture in coronary sinus blood during ventricular pacing we compared electromagnetic coronary arterial blood flow (CBF) with TD-CSF in nine dogs during interventions that increased right atrial pressure. During ventricular pacing, rapid atrial pacing, pulmonary artery constriction and increased intrathoracic pressure, right atrial pressure increased and electromagnetic CBF was significantly less (41-166%) than TD-CSF. Marked reflux from the right atrium to the coronary sinus was also demonstrated by bolus injection of cold saline into the right atrium and continuous infusion of contrast material into coronary sinus. Caution needs to be exercised in interpreting TD-CSF in the presence of changing right atrial pressure.
Calcific deposits in stenotic mitral valves. Extent and relation to age, sex, degree of stenosis, cardiac rhythm, previous commissurotomy and left atrial body thrombus from study of 164 operatively-excised valves.
Authors: Lachman A S , Roberts W C
Published: June 2012

The presence or absence and the extent of calcific deposits in excised stenotic mitral valves was determined by radiographs of the excised valve in 164 patients aged 26 to 72 years. The extent of the mitral calcific deposits was determined by the percent of the valvular circumference containing the deposits = grade 0 (14 patients); grade I = less than 25% (43 patients); grade II = 25-50% (34 patients); grade III = 51-75% (39 patients); and grade IV = greater than 75% (34 patients). The amount of calcific deposits in the stenotic mitral valves correlated with sex and with the mean diastolic pressure gradient across the mitral valve (P less than 0.05), but it did not correlate with the patient's age, cardiac rhythm, pulmonary arterial or pulmonary arterial wedge pressure, previous mitral commissurotomy, presence of thrombus in the body of left atrium or the presence of disease of one or more other cardiac valves.
De subitaneis mortibus. XXIX. Randomly distributed focal myocardial lesions causing destruction in the His bundle or a narrow-origin left bundle branch.
Authors: James T N , Schlant R C , Marshall T K
Published: June 2012

Most focally destructive lesions of the heart (e.g., myocarditis) have an essentially random distribution. Any mechanical significance of such diseases depends primarily on there being a very large number of foci. However, single even very small lesions can have profound electrophysiological significance if appropriately located within the cardiac conduction system. Two cases of sudden unexpected death are here reported which had destructive lesions involving the His bundle and a narrow-origin left bundle branch. Not much is known of the electrical or mechanical effects of acute left branch block which is due to complete anatomical transection of that structure in the human heart, and some possible consequences (including sudden unexpected death) are considered. Myocarditis or any other focally destructive disease in the heart may be of little functional importance if it is not widespread, unless some of the lesions happen to damage any of several small but crucially important sites in the cardiac conduction system. Studies to determine the presence or absence of this precise type of damage should be done especially in cases of sudden unexpected death.
Absent tricuspid valve with aortic atresia in mixed levocardia (atria situs solitus, L-loop). A hitherto undescribed entity.
Authors: Brenner J I , Bharati S , Winn W C , Lev M
Published: June 2012

Clinical, angiographic and pathologic features are described in a 36-hour-old male infant with mixed (discordant) levocardia, aortic valve atresia, absent tricuspid (left atrioventricular) valve and resultant massive cardiomegaly. This is the first reported case of this type of complex in a heart with discordant chambers. A possible embryologic explanation is offered for the concomitant presence of semilunar valve atresia and absence of the tricuspid valve.
Long-term tocainide therapy for ventricular arrhythmias.
Authors: Winkle R A , Meffin P J , Harrison D C
Published: June 2012

Long-term tocainide therapy has been evaluated in 17 patients with ventricular arrhythmias. Ventricular tachycardia and/or fibrillation was recurrent and sustained in nine patients, and symptomatic but unsustained in three others. Five patients had frequent but only mildly symptomatic ventricular irritability. In all patients, arrhythmias could not be managed with quinidine, procainamide or propranolol. Tocainide doses ranged from 300 to 700 mg every 8 hours (mean steady-state plasma concentrations ranged from 5.75 to 12.18 microgram/ml). Tocainide therapy was unsuccessful in eight patients; three died during therapy and five had no antiarrhythmic response. The data suggest that evaluation of long-term drug efficacy, using the criterion of reduction of asymptomatic arrhythmias, is best documented by multiple sequential ambulatory electrocardiographic recordings, both on and off the drug. Tocainide controlled arrhythmias in nine patients (53%), with criteria of success being continued reduction of ectopic beats and/or control of symptomatic recurrences. Seven patients remain on therapy. Side effects generally have been minor and well-tolerated.
Anomalous origin of left coronary artery from the pulmonary artery with ventricular septal defect.
Authors: Pinsky W W , Gillette P C , Duff D F , Wanderman N , Morriss J H , Mullins C E , McNamara D G
Published: June 2012

Only two cases have been reported previously of the association of ventricular septal defect (VSD) with anomalous origin of the left coronary artery (ALCA) arising from the pulmonary artery. The purpose of this paper is to present two additional cases, to describe the pathophysiology, and to emphasize how the clinical course of this combination of defects differs from that of isolated ALCA. Patients with both of these anomalies present in infancy with manifestations only of a large left-right ventricular shunt and pulmonary hypertension. Initially the ALCA is well perfused from the high pressure in the pulmonary artery. In these instances in which the pulmonary artery pressure subsequently decreased because of spontaneous reduction in size of the VSD, the left coronary arterial system became less well perfused. Because of this decreased perfusion in association with the left ventricular myocardial stress initially caused by volume overload, myocardial ischemia and ultimately infarction occurred. Early identification and repair of the anatomic abnormality could prevent irreversible myocardial damage.
Epicardial mapping in the Wolff-Parkinson-White syndrome.
Authors: Gallagher J J , Kasell J , Sealy W C , Pritchett E L , Wallace A G
Published: June 2012

Epicardial mapping provides a method for defining antegrade and retrograde sites of pre-excitation. It is best undertaken only after a careful, detailed preoperative electrophysiological study has been performed. The potential pitfalls of the technique are many and technical expertise must be constantly available to maintain a functioning system. For these reasons, it is not likely to lend itself to widespread application. The same techniques can be applied to localization of the site of origin of atrial or ventricular dysrhythmias, localization of myocardial ischemia and infarction, as well as to differentiate between epicardial delays due to conduction delay and those caused by intramural myocardial delay.
The anatomical substrates of wolff-parkinson-white syndrome. A clinicopathologic correlation in seven patients.
Authors: Becker A E , Anderson R H , Durrer D , Wellens H J
Published: June 2012

Clinicopathological correlations were made on the hearts from seven patients known to have exhibited electrocardiographic evidence of the Wolff-Parkinson-White syndrome. In each case, clinical and pathological investigations were conducted independently, neither group of investigators having knowledge of the other's results. In all seven hearts, the entire atrioventricular junctions were serially sectioned. Accessory atrioventricular connections were predicted in all seven cases following electrocardiographic investigation. Connections were identified histopathologically in four hearts in the predicted site. In another case two connections were identified, one being considered responsible for the pre-excitation. In the sixth case a right lateral connection was anticipated, but only accessory nodo-ventricular fibers were identified following histopathologic studies. In the final case, a posterior septal connection was predicted but the entire septum had fibrosed following previous operation. These findings are discussed in the light of the investigative techniques used, the theories of pre-excitation and the embryogenetic mechanisms producing accessory atrioventricular connections.
Depressant effect of digoxin on atrioventricular conduction in man.
Authors: Ricci D R , Orlick A E , Reitz B A , Mason J W , Stinson E B , Harrison D C
Published: June 2012

We examined the effect of chronically administered digoxin on atrioventricular (A-V) conduction in nine cardiac transplant recipients. We assessed A-V conduction by measuring the duration from the pacing stimulus to the onset of the QRS complex (S'R interval) and by determining the occurrence of Wenckebach periodicity during rapid atrial pacing. We made measurements during a control period and during a period of digoxin administration of up to 37 days. During the digoxin period, the cycle length at which Wenckebach block occurred was prolonged by 14% of the control value and the S'R interval was significantly prolonged at paced rates of 110 beats per minute and faster. After digoxin was discontinued, the Wenckebach periodicity and S'R interval returned to control values. Atropine and propranolol did not alter digoxin's effect on A-V conduction. We conclude that digoxin exerts a direct (or non-neurally mediated) depressant effect upon A-V conduction in man, although the stress of tachycardia is necessary to demonstrate the effect.
An ultrasound system for combined cardiac imaging and Doppler blood flow measurement in man.
Authors: Griffith J M , Henry W L
Published: June 2012

An ultrasound instrument has been developed that combines a real-time cross-sectional imaging system and a spectrum analyzer-based Doppler velocimeter. This combination allows the Doppler sample volume to be superimposed on the cross-sectional image of the heart so that the sample volume can be located accurately. The same 2.2 MHz transducer utilized for cross-sectional imaging is stopped mechanically and quickly switched to transmit and receive the Doppler ultrasound signal. Preliminary experience in 20 young and adult normal subjects indicates that it is possible to place the Doppler sample volume in the proximal main pulmonary artery at a point where the sound beam and blood flow stream are parallel. Measurement of the distance from transducer to the sample volume and the peak blood flow velocities in the main pulmonary artery of normal subjects indicates that these quantities are within the measurement capabilities of the system. The ultimate goal of this device is to make measurements of volume blood flow in man noninvasively.
Transcutaneous doppler jugular venous flow velocity recording.
Authors: Sivaciyan V , Ranganathan N
Published: June 2012

Transcutaneous bidirectional Doppler jugular venous flow velocity patterns were classified and correlated in 82 patients with right heart hemodynamics. The normal forward flow pattern was biphasic with systolic flow (Sf) greater than the diastolic flow (Df). With rare exceptions, flow patterns of Sf = Df, Sf is less than Df and Df alone indicated abnormal right heart hemodynamics. Abnormal flow patterns (Sf = Df and Sf is less than Df) seen in post cardiac surgery states, and in some rare patients with severe mitral regurgitation despite normal right-sided pressures, were probably secondary to postoperative change in right atrial compliance in the former and to a Bernheim effect in the latter. The most common cause of retrograde systolic flow in the absence of atrioventricular dissociation was tricuspid regurgitation. Persistent retrograde end-diastolic flow with normal forward flow was associated with high right atrial "a" wave pressures, indicating significant decrease in right ventricular compliance with a vigorous atrial contraction. The study clearly established that the jugular venous flow velocity pattern truly reflected derangements in the right heart hemodynamics, irrespective of the underlying etiology. The applicability to bedside evaluation of the jugular venous pulse and the right heart hemodynamics is emphasized.
Assessment of the pulmonary vascular bed by echocardiographic right ventricular systolic time intervals.
Authors: Riggs T , Hirschfeld S , Borkat G , Knoke J , Liebman J
Published: June 2012

Echocardiography was used to measure right ventricular systolic time intervals (RVSTI) in 85 normal children (group I) and in 229 patients undergoing cardiac catheterization (group II). Corrected right ventricular pre-ejection period (RPEPC) and right ventricular ejection time (RVETc) (based on regression analysis of group I) and RPEP/RVET were each correlated with pulmonary artery (PA) diastolic and mean pressures and pulmonary vascular resistance (PVR). The best correlation (0.83) was between a second degree polynomial of the RPEP/RVET and PA diastolic pressure. The RPEP/RVET allowed prediction of PA diastolic pressure within 10 mm Hg in 85% of the patients. The utility of RPEP/RVET was confirmed in sequential data of 22 patients, in whom alteration in RPEP/RVET accurately reflected the changing PA diastolic pressure. The RPEP/RVET could not be used to assess PA pressure in six patients with congestive cardiomyopathy nor in 18 patients with complete right bundle branch block (CRBBB).
The prognostic spectrum of left main stenosis.
Authors: Conley M J , Ely R L , Kisslo J , Lee K L , McNeer J F , Rosati R A
Published: June 2012

Three-year survival for 163 consecutive medically treated patients with 50% or greater left main stenosis was 50%. Survival was significantly higher for patients with 50 to 70% left main stenosis (one and three-year survivals of 91% and 66%) than for patients with 70% or greater left main stenosis (one and three-year survivals of 72% and 41%). In fact, left main lesions of less than 70% were not associated with the increased risk usually attributed to patients with left main stenosis. A number of noninvasive and catheterization characteristics were significant predictors of survival for patients with 70% or greater left main stenosis. Noninvasive descriptors defined a low risk subgroup (one and three-year survivals of 97% and 74%) and a high risk subgroup (one- and three-year survivals of 59% and 25%). These observations have important implications both in assessing therapeutic interventions and in managing individual patients.
Right ventricular ejection fraction in patients with acute anterior and inferior myocardial infarction assessed by radionuclide angiography.
Authors: Tobinick E , Schelbert H R , Henning H , LeWinter M , Taylor A , Ashburn W L , Karliner J S
Published: June 2012

We measured right and left ventricular ejection fracttion (EF) from high frequency time-activity curves obtained during the initial passage of an intravenous bolus of 99mTc (Sn) pyrophosphate. In 22 normal controls right ventricular EF averaged 0.52 +/- 0.04 (SD). In 24 acute anterior or lateral infarction patients right ventricular EF was normal (0.56 +/- 0.10), while left ventricular EF was reduced (0.45 +/- 0.10, P less than 0.001 vs controls). In 19 acute inferior infarction patients left ventricular EF also was depressed (0.51 +/- 0.09, P less than 0.001 vs controls). Among 7 of 19 inferior infarction patients with right ventricular by scintigraphy, right ventricular EF was reduced (0.39 +/- 0.05; P less than 0.001 vs normals; P less than 0.01 vs inferior infarction patients without right ventricular involvement). In the latter group right ventricular EF averaged 0.51 +/- 0.10 (NS vs normals). We conclude 1) a single injection of 99mTc (Sn) pyrophosphate can identify right and left ventricular dysfunction and infarct location in acute myocardial infarction, 2) right ventricular EF is well-preserved except when inferior infarction involves the right ventricle.
Reduction of enzyme levels by propranolol after acute myocardial infarction.
Authors: Peter T , Norris R M , Clarke E D , Heng M K , Singh B N , Williams B , Howell D R , Ambler P K
Published: June 2012

The effect of propranolol (0.1 mg/kg intravenously followed by 320 mg given over 27 hour orally) on serum levels of creatine kinase enzyme was studied in a randomized trial involving 95 patients seen within 12 hours of onset of symptoms of uncomplicated myocardial infarction. In 15 patients who were treated with propranolol within 4 hours of onset, and who eventually developed pathological Q waves, peak measured enzyme levels were 27% (P less than 0.0125) lower than in 19 control patients who were also seen within 4 hours of the onset but had no specific treatment. Total calculated enzyme appearance was also lower in the treated patients (reduced 25%, P less than 0.05) as was the calculated rate of the appearance (33%, P less than 0.005). No significant difference was found for treated compared with control patients entering the trial more than 4 hours after the onset of chest pain. This evidence suggests that propranolol may reduce the size of uncomplicated infarctions if it is given intravenously within 4 hours of the onset.
The posterior left atrial echocardiogram of mitral regurgitation.
Authors: Patton R , Dragatakis L , Marpole D , Sniderman A
Published: June 2012

The motion of the posterior wall of the normal left atrium has not been studied systematically. The superoposterior portion of the left atrium is adynamic throughout the cardiac cycle, whereas the inferoposterior portion is displaced posteriorly with left atrial filling during ventricular systole. In the present study, the left atrial diameter (LAD), the left atrial systolic motion (LASM) and the left atrial systolic velocity (LASV), were determined in the following groups of patients: 34 normals; eight patients with either coronary artery disease or aortic stenosis; six patients with aortic insufficiency; and three patients with ventricular septal defect. The results obtained were compared to 15 patients with angiographically documented mitral regurgitation. In the last group, the LAD (4.2 +/- .19 cm) and LASV (12.3 +/- 1.23 cm) and LASM (1.2 +/- 0.4 cm) were significantly greater reflecting the early accentuated filling of the left atrium induced by mitral regurgitation. As well, the product of these three parameters was greater in the mitral regurgitation group (63.2 +/- 7.34 cm3/sec) than in the other groups and patients with mild to moderate regurgitation had a significantly lower value than those with moderate to severe regurgitation (45.7 +/- 4.1 vs 78.5 +/- 10.9, P less than 0.02). The left atrial echocardiogram, therefore, is an aid in the diagnosis of mitral regurgitation and provides a rough index of the severity of the lesion.
Short-term intramuscular therapy with procaine penicillin plus streptomycin for infective endocarditis due to viridans streptococci.
Authors: Wilson W R , Geraci J E , Wilkowske C J , Washington J A
Published: June 2012

Thirty-three patients with viridans streptococcal infective endocarditis were treated for two weeks with intramuscular procaine pencillin, 1.2 million units every 6 hours, plus streptomycin, 500 mg intramuscularly every 12 hours. Nine patients (27%) had infections with relatively penicillin-resistant microorganisms (MIC greater than 0.1 microgram/ml or MBC greater than or equal 3.12 microgram/ml). Follow-up ranged from 2 months to 3.5 years. There were no relapses; Mild vestibular toxicity developed in one patient. One patient died two months after completion of antimicrobial therapy from sudden onset of severe congestive heart failure; Seven patients required cardiac valve replacement after completion of antimicrobial therapy. None died. We believe that this therapeutic regimen is effective antimicrobial therapy for infective endocarditis caused by viridans streptococci, irrespective of in vitro microbiologic data.
Pressor response to saralasin (1-sar-8-ala-angiotensin II) bolus injection in hypertensive patients.
Authors: Waks U A , Maxwell M H , Marks L , Zawada E T , Kaufman J J
Published: June 2012

A 10 mg bolus of the angiotensin blocker saralasin was injected 113 times in 68 subjects with essential or renovascular hypertension. Ninety percent of injections caused a transient increase in blood pressure, which correlated with plasma renin activity (PRA) (r = -0.54); Mean increase at 2 minutes was 21/13.4 mm Hg (P less than 0.001) and was independent of pre-injection control blood pressure, with a rapid decrease to or below control values thereafter. Thirty-seven subjects were studied on successive days before and after furosemide-induced sodium depletion (152 +/- 26 mEq [SE] sodium loss). In the low renin group, sodium depletion did not change PRA or the magnitude of the pressor response to saralasin, but significantly decreased control MAP by 13 mm Hg (P less than 0.01). In normal and high renin patients, MAP was unchanged after diuresis, but PRA increased significantly and the pressor response was attenuated. The net effect of sodium depletion was to reduce the pressor response to saralasin in all renin subgroups by 9 to 12 mm Hg. Saralasin bolus injection, unlike infusion, saturates available vascular receptors only briefly, eliminating prolonged pressor responses.
Clinical, angiographic, and hemodynamic assessment of late results after Mustard operation.
Authors: Hagler D J , Ritter D G , Mair D D , Davis G D , McGoon D C
Published: June 2012

Since 1974, late results of the Mustard procedure for correcting complete transposition of the great arteries have been evaluated by cardiac catheterization, electrocardiography, roentgenography, history, and physical examination of 48 Mayo Clinic patients. Of these, 15 were studied 1 month to 2 years postoperatively because of clinical deterioration. The other 33 had been asymptomatic but were asked to return for hemodynamic reevaluation one-half to 11 years postoperatively. Of the asymptomatic group, 19 underwent exercise electrocardiography prior to catheterization and eight performed supine exercise during catheterization. Cardiac catheterization proved the most effective mode of study. Significant cardiovascular abnormalities (caval obstruction, residual pulmonary stenosis, etc.) were found in 35 of the 47 patients--including 20 of the 33 who were asymptomatic. Eight of the symptomatic group and three of the others have died since this restudy. These poor results warrant renewed effort to devise better methods for correcting complete transposition,
De subitaneis mortibus. XXX. Observations on the pathophysiology of the long QT syndromes with special reference to the neuropathology of the heart.
Authors: James T N , Froggatt P , Atkinson W J , Lurie P R , McNamara D G , Miller W W , Schloss G T , Carroll J F , North R L
Published: June 2012

Eight patients (different families) with syncopal attacks and a long QT interval in the ECG died suddenly. Five heard normally and three were born deaf. At postmortem examination of all eight hearts the single consistent abnormality was focal neuritis and neural degeneration within the sinus node, A-V node, His bundle and ventricular myocardium. Although the etiology of this intracardiac neural disease is uncertain, a chronic viral infection or some noninfectious degenerative process are among the plausible causes discussed. If intracardiac neuritis and neural degeneration prove to be a prevalent finding among other victims dying from the long QT syndromes, further consideration should be given to whether there is any genuine hereditary component in the pathogenesis. Because of the asymmetrical and focal distribution of the cardioneural lesions, the response to present forms of medical or surgical treatment of the lung QT syndromes may vary from benefit to harm. Until more is known of the true etiology of the neural disease, treatment will probably remain empirical in nature and should be conducted with cautious clinical observation.
Reentrant ventricular arrhythmias in the late myocardial infarction period. 6. Effect of the autonomic system.
Authors: El-Sherif N
Published: June 2012

The effect of the autonomic system on conduction disorders in the infarction zone (IZ) and related reentrant ventricular arrhythmias (RVA) in the late myocardial infarction period in the dog was studied utilizing averaged recordings of the reentrant pathways from the epicardial surface of the IZ. Vagal (V) stimulation was found to have no significant direct electrophysiologic effect while sympathetic (S) stimulation resulted in a direct slight improvement of conduction in the IZ. However, because of the marked rate-dependency of conduction in the IZ, the effects of both V and S stimulation were modified through changes in the heart rate. The bradycardia produced by V stimulation resulted in improvement of conduction in the IZ and disappearance of RVA, while the tachycardia induced by S stimulation resulted in worsening of conduction in the IZ and the occurrence of RVA. Thus, in spite of its slight enhancing effect on conduction in the IZ, the propensity of S stimulation to induce RVA was primarily due to its tachycardiac effect.
Stroke volume calculated from the mitral valve echogram in patients with and without ventricular dyssynergy.
Authors: Rasmussen S , Corya B C , Feigenbaum H , Black M J , Lovelace D E , Phillips J F , Noble R J , Knoebel S B
Published: June 2012

A formula was derived for calculating mitral valve stroke volume (MVSV) using the rate of mitral valve (MV) opening (DE slope on the MV echogram), the vertical disease between the mitral leaflet echoes early in diastole (EE), the electrocardiographic PR interval and heart rate. The formula was tested prospectively on 80 consecutive patients from whom 95 simultaneous MV echograms and either thermodilution (45) or Fick (50) cardiac outputs were obtained. Sixteen patients were normal; 54 had coronary artery disease; three had cardiomyopathy; and seven had nonrheumatic mitral regurgitation (MR). Linear regression for stroke volume was r = 0.90, SEE +/- 6, and for cardiac output r = 0.83, SEE +/- 0.5 liter for the 73 patients without MR. The presence or absence of ventricular dyssynergy did not alter statistical findings. MVSV consistently overestimated forward stroke volume for the seven patients with MR. This study shows that the MV echogram provides an accurate, widely applicable method for calculating MVSV.
Physician and patient exposure during cardiac catheterization.
Authors: Rueter F G
Published: June 2012

A survey of the literature was conducted to establish the anticipated ranges of exposure to both physicians and patients during cardiac catheterization. A brief explanation of a technic for using time-lapse photography and a computer model for exposure calculation is presented. The thermoluminescent dosimeter (TLD) results used as controls for exposure values calculated by the developed technique are presented in detail. Physician eye exposures of approximately 20 mR per cardiac catheterization procedure were measured, which would suggest a limit of five procedures per week for physicians. The average patient skin entrance exposure of 28 R is high, as is the 12 mR gonadal exposure; however, they are accepted because of the possible benefits of the procedure.
Takayasu's disease in twin sisters. Possible genetic factors.
Authors: Numano F , Isohisa I , Kishi U , Arita M , Maezawa H
Published: June 2012

Takayasu's disease is well-known for its characteristic clinical features and its elusive etiology. Recently, we encountered twin Japanese sisters, both of whom were diagnosed as having Takayasu's disease. The parents, two sisters, and one brother are healthy. Family history revealed the parents are first cousins. Analyses of serveral blood types and HLA typing were performed on all members of the family, and it was confirmed that these twins are monozygotic. Moreover, HLA typing analyses revealed that one haplotype found in the father was passed only to these twins. The history of consanguinity of the parents, the occurrence in twins, and the results of HLA typing suggest a genetic factor in the etiology of Takayasu's disease.
Multiple coronary arterioventricular fistulae.
Authors: Rose A G
Published: June 2012

A 62-year-old man who died suddenly was found at autopsy to have multiple coronary arteriosystemic fistulae involving all three major coronary arteries and both ventricles. This is the second such case reported and the first with biventricular involvement and autopsy findings. A congenital bicuspid valve was also present. Numerous small blood vessels opened onto the endocardial surface of both ventricles and there were microscopic foci of persistent embryonic spongy myocardium.
Noninvasive recording of His-Purkinje activity in man by ORS-triggered signal averaging.
Authors: Wajszczuk W J , Stopczyk M J , Moskowitz M S , Zochowski R J , Bauld T , Dabos P L , Rubenfire M
Published: June 2012

Mobile instrumentation and a clinically applicable method have been developed for external His bundle recording. High gain signal amplification (10)(5) filtering (30--300 HZ) and averaging (128 or 256 consecutive cycles) are used. Acquisition of signals arising in the P-R interval is triggered by the patient's QRS signal at the end of that interval. The precordial bipolar electrodiogram is digitized at 5k HZ with 8 bit resolution and transferred to a 1,024 word, 18 bit signal averager. The averaged signal is then displayed on an oscilloscope and photographed. Good correlations were obtained between direct intracardiac and precordial recordings in experimental animals and in humans. Noise level after averaging was below 0.3 microV, and there was good elimination of asynchronous atrial and ectopic ventricular activity. With averaging of 128 or 256 consecutive cycles, the signal attenuation after propagation to the chest wall was in the range 1:2000 to 1:4000 in comparison with the directly recorded His bundle activity deflections. The noninvasive method may be of value in follow-up of acute and chronic disturbances of atrioventricular conduction, as well as in studies of effects of pharmacologic interventions.
Hemodynamic and metabolic response after abrupt uithdrawal of long-term propranolol.
Authors: Myers J H , Horwitz L D
Published: June 2012

Because the mechanism of adverse reactions to abrupt withdrawal of propranolol in patients with coronary disease is an enigma, we studied the effect of cessation of propranolol on beta receptor reactivity to catecholamine stimulation. Heart rate and maximum rate of rise of left ventricular pressur (dP/dt max) during isoproterenol infusions and plasma free fatty acids (FFAs) after epinephrine infusions were measured in six conscious dogs before, during and after four weeks of oral propranolol (40 mg p.o. q8h). Rises in heart rate, dP/dt max and FFAs were blocked during propanolol administration. Twenty-four hours after withdrawal from propranolol, heart rate and dP/dt max responses remained significantly attenuated, although FFA responses were at premedication levels. The 72-hour, 96-hour and one week postmedication responses did not differ from premedication values. Thus, partial beta blockade of the heart was still present at 24 hours and no evidence of heightened beta receptor sensitivity was detected on repeated study one week after withdrawal from a long-term, high dose propranolol regimen.
Pressure-flow characteristics of the coronary collateral circulation during cardiopulmonary bypass. Effects of ventricualr fibrillation.
Authors: Kleinman L H , Wechsler A S
Published: June 2012

Even though ventricular fibrillation is used frequently during cardiopulmonary bypass (CPB), the effects of fibrillation on myocardial regions supplied by collateral vessels have not been determined. To study these effects, nine dogs with left ventricles (ameroid model) consisting of a region of myocardium supplied by collateral vessels (CR) and a region supplied by normal coronary arteries (NR) were subjected to normothermic CPB at two perfusion pressures. In both the empty beating heart (EBH) and empty fibrillating heart (EFH) regional myocardial flow was determined by tracer microspheres. Retrograde coronary pressure was measured via cannulation of the circumflex artery distal to the ameroid induced occlusion. When perfusion pressure was maintained at 80 mm Hg, retrograde coronary pressure was similar in the EBH (46 +/- 4 mm Hg) and in the EFH (48 +/- 3 mm Hg). During fibrillation subendocardial flow in the CR was unchanged, while flow in the NR increased (P less than 0.02). In addition, the endo/epi was greater in the NR than in the CR (P less than 0.01), a difference which did not exist in the EBH. The flow response to fibrillation in the CR could be produced in the NR by reducing the perfusion pressure to 50 mm Hg. These data suggest that during CPB, fibrillation exaggerates existing subendocardial perfusion deficits in collateral regions and the impaired flow response appears to be related to a low regional intravascular pressure.
Effect of potassium cardioplegia on myocardial ischemia and post arrest ventricular function.
Authors: Schaff H V , Dombroff R , Flaherty J T , Bulkley B H , Hutchins G M , Goldman R A , Gott V L
Published: June 2012

To assess the effects of moderate potassium cardioplegia (37 mEq/l KCl) on the severity of myocardial ischemia during arrest and on post arrest ventricular function, 32 isolated, isovolumic feline hearts were studied before, during and 1 hour after ischemic arrest. Normothermia (37 degrees C) was maintained in the remaining 16 hearts, eight without KCl and eight with KCl. Hypothermia (27 degrees C) was maintained in the remaining 16 hearts, eight with KCl and eight without KCl. Myocardial oxygen (PmO2) and carbon dioxide tensions (PmCO2) were measured by mass spectrometry. Maximum developed intraventricular pressure (max DP) and max dP/dt were used as indices of performance. Compared with normothermic or hypothermic arrest alone, the addition of potassium cardioplegia resulted in a significant reduction in the peak PmCO2 measured during the arrest period. Hypothermia alone resulted in morphologic evidence of improved myocardial preservation and a significant reduction in peak PmCO2 compared with normothermia. Post arrest ventricular function was best with the combination of hypothermic arrest and potassium cardioplegia (max DP = 96 +/- 6% of control and max dP/dt = 99 +/- 5% of control). These data suggest that the beneficial effects of postassium cardioplegia and 27 degrees hypothermia are additive, and that reduction in myocardial ischemia as evidenced by a reduction in peak PmCO2 correlated with improvement in ventricular performance in the post arrest period and with preservation of myocardial structure.
Surgery using cardiopulmonary bypass in the elderly.
Authors: Stephenson L W , MacVaugh H , Edmunds L H
Published: June 2012

This study included 89 patients, 70-82 years (mean 72.8 years), who had procedures using cardiopulmonary bypass since 1955. Twenty-six patients had elective aortic valve replacement (AVR), with two hospital deaths. One patient who underwent emergency AVR for bacterial endocarditis died of septic shock. Ten patients had AVR and coronary artery bypass surgery (CABG), with one hospital death (10%). Fourteen patients had mitral valve replacement (MVR), with eight hospital deaths (57%). Two died of left ventricular rupture after leaving the operating room, and the remainder died of low cardiac output. Twenty-five patients had CABG with no early deaths. Seven patients had aneurysms of the thoracic aorta, with two early deaths. Six patients had other procedures with one death, making a total of 16 operative deaths in the 89 patients. Eighty-four of the patients (94%) were New York Heart Association (NYHA) Functional Class III or IV for congestive heart failure and/or angina, preoperatively. Of these, 12 were in extremis immediately before surgery, and six survived. There were 10 late deaths. The actuarial survival rates for one, two and five years for all patients were 69% (40 patients), 47% (20 patients) and 21% (seven patients), respectively. At recent follow-up (mean 20 months) 84% of the hospital survivors were symptomatically improved at least one NYHA Functional Class. We conclude that CABG and/or AVR can be performed in elderly patients with a low hospital mortality and with symptomatic improvement. However, MVR in the elderly carries an unusually high mortality (7.3 times greater than patients less than 70, in our experience), and this risk must be weighed when considering MVR in these patients.
Reentry within the His-Purkinje system. Elucidation of reentrant circuit using right bundle branch and His bundle recordings.
Authors: Akhtar M , Gilbert C , Wolf F G , Schmidt D H
Published: June 2012

Routes of impulse propagation during reentry in the His-Purkinje system (Re-HPS) in 13 patients were studied using the right ventricular extra stimulus (V2) method and right bundle branch (RBB) recordings in addition to the conventional His (H) bundle recordings. The H-V and RB-V intervals during sinus rhythm averaged 44.2 and 27.6 msec respectively, with the average antegrade H-RB interval 16.6 msec. All 13 patients demonstrated Re-HPS in the form of V3 showing a left bundle branch block (LBBB) pattern, and two of the 13 patients also manifested V3 with a right bundle branch block (RBBB) pattern. During Re-HPS showing a LBBB pattern, the retrograde activation of the His bundle (H2) in response to V2 occurred via the left bundle branch (LBB), as indicated by inscription of retrograde H2 prior to RB2 in nine of 13 cases (average H2-RB2 = 9.4 msec), and simultaneous incription of retrograde H2 and RB2 in the remaining four. When V3 showed a RBBB pattern the retrograde RB2 preceded H2, suggesting H2 activation via the RBB. These findings suggest that circuit of Re-HPS incorporates both bundle branches and the bundle of His. The H-RB recordings were also useful in distinguishing sustained Re-HPS from atrioventricular nodal reentry when in both instances the QRS complex showed a LBBB pattern.
Dual echocardiographic determination of atrial contraction sequence in atrial flutter and other related atrial arrhythmias.
Authors: Fujii J , Foster J R , Mills P G , Moos S , Craige E
Published: June 2012

We have applied the new technique of dual echocardiography to determine the sequence of atrial contraction as reflected in the simultaneously recorded movements of the tricuspid and mitral valves. The study group included 29 normal subjects and 23 patients with either atrial flutter, coarse atrial fibrillation or atrial tachycardia with block. In normal individuals, right atrial contraction preceded left atrial contraction, with an average interatrial contraction time of 17 +/- 8 msec. In contrast, the atrial contraction sequence was reversed in atrial flutter, with left preceding right atrial contraction and a prolonged interatrial contraction time of 82 +/- 20 msec. In two patients with atrial tachycardia with block, atrial contraction was either simultaneous or left preceded right atrial contraction by a brief interval. The sequence of atrial excitation, as determined by electrode catheter recordings from the right and left atria in one patient with atrial flutter and one patient with normal sinus rhythm, was the same as the contraction sequence. Left atrial pacing reversed both excitation and contraction sequences. After cardioversion of three patients from atrial flutter to normal sinus rhythm, interatrial contraction time was shortened but remained longer than in normal subjects, suggesting an interatrial conduction disturbance in patients with atrial flutter. In coarse atrial fibrillation, the contraction sequence varied. Significant motion of both mitral and tricuspid valves coincident with fibrillary waves occurred frequently, especially when the fibrillary waves were coarse and regular. Dual echocardiography permits the noninvasive determination of the sequence of atrial contraction and excitation, and may be useful in studying the characteristics of atrial arrhythmias.
Diagnosis of ventricular septal defect by pulsed Doppler echocardiography. Sensitivity, specificity and limitations.
Authors: Stevenson J G , Kawabori I , Dooley T , Guntheroth W G
Published: June 2012

The M-mode echocardiographic findings of ventricular septal defect (VSD) are nonspecific. A specific pulsed Doppler echocardiographic (PDE) diagnosis of VSD can be made by following the turbulent VSD jet through the septum. To assess the sensitivity, specificity and limitations of PDE diagnosis of VSD, 105 children undergoing cardiac catheterization were examined by PDE. These children had a variety of cardiac defects, and a PDE diagnosis of VSD was made in 46/51 (90%) who had VSD proven at catheterization. There was one false positive PDE diagnosis of VSD, for a specificity of 98%. Factors influencing the ability to diagnose VSD by PDE include the location of the defect, level of pulmonary vascular resistance and direction of blood flow through the VSD. The presence of additional defects did not interfere with PDE diagnosis of VSD. The PDE detection of additional defects may identify situations where M-mode echocardiographic estimation of dimensions may not be indicative of the size of VSD shunt.
Real-time cross-sectional echocardiographic imaging and measurement of the patent ductus arteriosus in infants and children.
Authors: Sahn D J , Allen H D
Published: June 2012

While echocardiography has been used to noninvasively document indirect effects on the heart of left-to-right shunting through a patent ductus arteriosus, no noninvasive technique has been developed to image the duct itself. In this study, 35 sequential studies were performed on 28 patients with a mechanical sector scanner to image the distal pulmonary artery and its bifurcation by scanning along the axis of the right ventricular outflow tract. Cross-sectional imaging, just superior to the take-off of the right pulmonary artery, provided visualization of the patent ductus as a distal continuation of the pulmonary artery connecting to the descending aorta. Ductal visualization by cross-sectional echo was validated by saline echo contrast observations of right-to-left and left-to-right shunting through the duct in 14 patients, by surgical observations in 11, angiographic observations in 13 and autopsy observations in three. Angiographic size of the ductus arteriosus, whether constricted or widely patent, tortuous or straight, was predicted correctly and echo/angiographic correlations for smallest inner ductal dimension were excellent (r = 0.97). This study provides a method for and validates the direct imaging of the ductus arteriosus and suggests that cross-sectional echocardiography can accurately predict ductal contour and quantitative ductal cross-sectional size noninvasively.