bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical Correction of Anomalous Left Ventricular Pre-excitation: Wolff-Parkinson-White (Type A)
Authors: WALLACE ANDREW G. , SEALY WILL C. , GALLAGHER JOHN J. , SVENSON ROBERT H. , STRAUSS HAROLD C. , KASELL JACK
Published: June 2012

This report describes two patients with the Wolff-Parkinson-White syndrome including episodes of supraventricular tachycardia and atrial fibrillation. Both patients had Type A electrocardiograms. Electrophysiological studies demonstrated pre-excitation and evidence that the site of pre-excitation involved the left ventricle. The effective refractory periods of the accessory pathway during atrioventricular conduction were 240 and 220 msec respectively. Epicardial mapping at the time of surgery showed that anomalous excitation began adjacent to the annulus of the mitral valve near a marginal branch of the left circumflex coronary artery. An incision which separated the atrial muscle from the annulus of the mitral valve at the region of anomalous excitation abolished the delta wave. Epicardial maps after surgery showed normal ventricular activation and follow-up studies have shown normal electrocardiograms and no arrhythmias.
Reduction in the Rate of Diastolic Descent of the Mitral Valve Echogram in Patients with Altered Left Ventricular Diastolic Pressure-Volume Relations
Authors: QUINONES MIGUEL A. , GAASCH WILLIAM H. , WAISSER EFRAIN , ALEXANDER JAMES K.
Published: June 2012

Echocardiographic measurements of the rate of descent of the E wave of the anterior leaflet of the mitral valve during diastole (the mitral valve slope) have been said to correlate with the rate of early left ventricular (LV) filling. Thus, a reduced mitral valve slope in the absence of mitral valve obstruction might be related to impaired LV filling secondary to decreased diastolic compliance. In this study mitral valve slope was compared to several estimates of LV compliance and to the LV end diastolic pressure (EDP) in 32 patients undergoing diagnostic cardiac catheterization: nine normal, 11 coronary artery disease (CAD), seven congestive cardiomyopathy (CC), five left ventricular hypertrophy (LVH). Assuming an exponential relation between pressure (P) and volume (V) at end diastole, and a fixed P intercept at zero V, the following estimates of LV compliance were calculated: (1) the slope of the ln P-V relation (k), which indicates whether a P-V curve is shifted to the left or to the right of normal, (2) an end diastolic distensibility index, (dV/dP) ed, and (3) end diastolic compliance, (dV/VdP) ed.

In every instance of mitral valve slope less than 60 mm/sec an abnormality of the LV P-V relation was found. Of the ten patients with a reduced MVS, four had CAD, one had CC and five had LVH. Correlation was good when mitral valve slope was related to k (
r
= –0.72,
P
< 0.001) and to the end diastolic distensibility index (
r
= 0.59,
P
< 0.001); but poor (
P
= NS) when compared to end diastolic compliance or to LVEDP. Thus a reduced mitral valve slope, in the absence of mitral valve obstruction, suggests an alteration in the diastolic properties of the left ventricle.
Reproduction of Maximal Exercise Performance in Patients with Angina Pectoris Despite Ouabain Treatment
Authors: NIEDERBERGER MANFRED , BRUCE ROBERT A. , FREDERICK RICHARD , KUSUMI FUSAKO , MARRIOTT ARTHUR
Published: June 2012

Eight patients with a diagnosis of atherosclerotic heart disease and a history of typical angina pectoris, uncomplicated by cardiac dilatation or heart failure, were studied by means of standardized, symptom-limited treadmill exercise test. Repeatability of such testing was determined during two control tests 1-1.5 hours apart. From two to six days later, the same patients performed two treadmill tests after pulmonary and brachial arterial catheterization. The study design allowed evaluation of the effects of 0.005 mg/kg of ouabain at rest-both supine and standing-and during submaximal and maximal exercise.

Measurements were made of oxygen uptake, arterial-mixed venous oxygen difference, heart rate, systemic arterial pressures and pulmonary arterial mean pressure. The ratio of mean systemic to mean pulmonary arterial pressure relative to cardiac output indicated that acute left ventricular dysfunction limited aerobic work. Treatment with ouabain did not significantly change performance or capacity and angina was not alleviated.
Graded Exercise Stress Tests in Angiographically Documented Coronary Artery Disease
Authors: BARTEL ALAN G. , BEHAR VICTOR S. , PETER ROBERT H. , ORGAIN EDWARD S. , KONG YIHONG
Published: June 2012

Graded exercise stress tests performed on 650 consecutive patients with proven or suspected coronary disease undergoing evaluation by cardiac catheterization were correlated with clinical, hemodynamic, and angiographic findings. Among 451 patients with significant coronary stenosis, 332 (74%) had interpretable stress tests and 65% of these were positive (sensitivity). The rate of "false positives" was 8%.

The clinical syndrome of typical angina identified significant coronary disease in 89% of the patients, and 58% of that group had a positive exercise test defined by objective electrocardiographic criteria.

Patients were not eliminated from this study because of recent digitalis ingestion. Although a higher frequency of uninterpretable exercise tests was found in this group (40%), the test results reflected more severe coronary disease. None of the patients with "false positive" tests were taking digitalis. It is concluded that recent digitalis ingestion should not be considered a contraindication for exercise stress testing.

Among the patients with interpretable exercise tests, the angiographic severity of coronary artery disease correlates strongly with the frequency of positive tests (40%, 66%, and 76%, with 70% or greater occlusion of one, two or three vessels respectively). Left main coronary stenosis of 70% or greater was associated with more severe ST segment changes, inability to achieve target heart rate during stress, and a lower maximum heart rate during exercise. The angiographic occurrence of collateral vessels was related to the extent of coronary disease and was associated with a higher percentage of positive exercise tests; no protective effect of collateral circulation could be demonstrated. Patients with abnormal resting hemodynamics or left ventricular asynergy had no significant difference in the frequency of positive tests after adjustment for the angiographic severity of disease.
The A Wave of the Apexcardiogram and Left Ventricular Diastolic Stiffness
Authors: GIBSON THOMAS C. , MADRY ROBERT , GROSSMAN WILLIAM , MCLAURIN LAMBERT P. , CRAIGE ERNEST
Published: June 2012

This study was made to determine whether the A wave of the apexcardiogram (ACG), a reflection of the late diastolic response of the left ventricle to atrial systole, corresponded in a quantifiable way to left ventricular late diastolic stiffness (LVDS). Using a combined ultrasonic and hemodynamic technique, the slope of the late diastolic left ventricular pressure/diameter relationship (ΔP/ΔD) was calculated in 25 patients and used as a measure of effective LVDS. Most patients had valvular heart disease, all were in sinus rhythm and none had regional abnormalities of contraction. An ACG was recorded in all and the ratio of the size of the A wave to the total amplitude of the ACG wave (A/H) was calculated. When A/H was more than 11%, left ventricular hypertrophy (LVH) and the presence of a fourth heart sound were the rule in the group of patients studied.

Using A/H as an independent variable, correlation coefficients were obtained for ΔP, ΔD, ΔP/ΔD, left ventricular end diastolic pressure (LVEDP), and left ventricular end diastolic volume (LVEDV). Correlation coefficients (
r
) were: ΔP = 0.68; ΔD = –0.05; ΔP/ΔD = 0.87; LVEDP = 0.73; LVEDV = 0.21. It is concluded that A/H corresponds best to LVDS and is a useful noninvasive measurement of this property of the left ventricle.
Electrocardiographic and Cineangiographic Correlations in Assessment of the Location, Nature and Extent of Abnormal Left Ventricular Segmental Contraction in Coronary Artery Disease
Authors: MILLER RICHARD R. , AMSTERDAM EZRA A. , BOGREN HUGO G. , MASSUMI RASHID A. , ZELIS ROBERT , MASON DEAN T.
Published: June 2012

The relationship between the resting electrocardiogram and left ventricular contractile pattern, as documented by angiography, was evaluated in 123 patients with coronary artery disease who underwent left ventriculography. Dyssynergy was present in 73/77 (95%) patients with pathologic Q waves on ECG recordings in contrast to 11/46 ( 24%;
P
< 0.01) without Q waves. The location of Q waves correlated well with the site of abnormal ventricular motion: antero-apical dyssynergy in 40/40 (100%) patients with anterior myocardial infarction (MI) and infero-apical dyssynergy in 25/28 (89%) with inferior MI. Four contraction patterns were defined: 1) normal motion-39 patients (35 without Q waves, four with inferior or posterior Q waves); 2) segmental hypokinesis-37 patients (six without Q, 31 with Q); 3) segmental akinesis-26 patients (four without Q, 22 with Q); and 4) localized dyskinesis-aneurysm in 21 patients (only one without Q, 20 with Q). The presence of ST elevation and T wave inversion (ST↑ - T↓) along with Q waves were associated with dyskinesis or akinesis in 18/19 (95%) patients. The Q wave location reflected the type of dyssynergy: 32/40 (80%) patients with anterior MI had akinesis or dyskinesis, while 18/28 (64%) patients with inferior MI exhibited hypokinesis. Lateral extension of the Q wave in an anterior MI was related to the dyssynergy type (average V lead: 4.9 in dyskinesis and 3.3 in hypokinesis;
P
< 0.05) and extent (dyssynergy area /LV silhouette: 31% with Q to V
3
and 58% to V
5
or V
6
;
P
< 0.05). Dyssynergy area was larger in isolated anterior than inferior MI (42% and 23% of LV perimeter;
P
< 0.05) and largest in the anterior-inferior MI (68%;
P
< 0.05). Dyssynergy was more extensive with Q and ST↑-T↓ than with Q alone (48% and 33% LV perimeter;
P
< 0.05). Thus, specific QRS and ST-T wave alterations, when monitoring coronary disease, accurately predict characteristics of LV dyssynergy: Q identifies its presence and location and Q with ST↑-T↓ estimates its nature and extent.
Coronary Ostial Stenosis
Authors: YATES JAMES D. , KIRSH MARVIN M. , SODEMAN THOMAS M. , WALTON JOSEPH A. , BRYMER JAMES F.
Published: June 2012

Eight patients developing coronary ostial stenosis following Starr-Edwards aortic valve placement are reviewed. Coronary perfusion with a balloon tip perfusion catheter was performed during the intraoperative period on all patients and was considered technically satisfactory. Angina pectoris developed within six months of surgery in seven of eight patients and left main coronary artery occlusive disease was demonstrated in each of these cases. One patient who did not develop angina pectoris had right coronary artery narrowing without intraoperative perfusion of this vessel. All patients were reoperated, five survived, two are free of symptoms. Coronary ostial stenosis is a clinically recognizable complication of aortic valve replacement with potential for surgical correction.
Alterations of Systolic Time Intervals During Pregnancy
Authors: BURG JOHN R. , DODEK ARTHUR , KLOSTER FRANK E. , METCALFE JAMES
Published: June 2012

Systolic time interval measurements were made sequentially throughout pregnancy and during the postpartum period. Recordings were made in the supine and lateral positions. Although the greatest deviations from predicted values were present in the third trimester, changes were evident as early as the first trimester. During the first two trimesters the pre-ejection period (PEP) was significantly shortened. The left ventricular ejection time (LVET) remained normal while the PEP/LVET decreased.

The third trimester was characterized by a markedly shortened LVET, a prolonged PEP, and an increased PEP/LVET, all more apparent in the supine than in the lateral position. These findings are consistent with impaired left ventricular performance and are probably due to decreased left ventricular preload resulting from diminished venous return secondary to inferior vena caval obstruction by the gravid uterus.

In the postpartum period, the PEP/LVET remained elevated in both positions; the PEP was prolonged and the LVET shortened in the lateral posture. It is concluded that alterations in systolic time interval measurements occur normally during the course of uncomplicated pregnancy and persist into the postpartum period. Possible mechanisms are discussed.
Antiarrhythmic Drug Therapy for Sporadic Ventricular Ectopic Arrhythmias
Authors: JELINEK MICHAEL V. , LOHRBAUER LEIF , LOWN BERNARD
Published: June 2012

Exercise stress testing and 24-hour ambulatory monitoring have been employed to evaluate antiarrhythmic drug efficacy in patients with sporadic ventricular ectopic arrhythmias (VEA). Twenty-three patients with often recurring VEA were exercised 123 times and subjected to 66 ambulatory monitoring sessions during control periods and while receiving either procaine amide or quinidine. Two dose schedules were employed; procaine amide, 3.0 and 6.0 g daily and quinidine, 1.2 and 1.8 g daily. Though adequate and even high drug blood levels were reached, an effective antiarrhythmic response was observed in only eight patients receiving procaine amide and in seven of those taking quinidine. These modest successful results were associated with a high incidence of troublesome adverse effects which were noted in 11 patients receiving procaine amide and six of those receiving quinidine. It is concluded that these antiarrhythmic drugs should not be employed in the patient with episodic VEA unless the arrhythmias are symptomatic and are clearly life-threatening.
Pathophysiologic Observations in Prehospital Ventricular Fibrillation and Sudden Cardiac Death
Authors: LIBERTHSON RICHARD R. , NAGEL EUGENE L. , HIRSCHMAN JIM C. , NUSSENFELD SIDNEY R. , BLACKBOURNE BRIAN D. , DAVIS JOSEPH H.
Published: June 2012

In order to better understand the problem of prehospital sudden cardiac death (SCD) two groups of individuals were studied. One group was monitored by rescue squads during attempted rescue. These subjects were defibrillated from prehospital ventricular fibrillation (VF) and hospitalized if they survived or autopsied if they could not be resuscitated. The second group were SCDs which were witnessed and described by observers. Detailed past histories of both groups were collected, and either clinical or autopsy diagnoses were obtained.

On the day of death or VF, one quarter reported new symptoms (primarily chest pain and dyspnea) preceding collapse by more than 30 minutes, one quarter reported symptoms lasting from 1 to 30 minutes, and one half collapsed instantaneously or within 1 minute of acute symptoms. A history of old myocardial infarction (MI) was present in 41% and of angina pectoris in 54%, and 27% reported new or changing symptoms within four weeks.

In defibrillated survivors, "would-be SCDs," electrocardiographic (ECG) changes of acute myocardial infarction (AMI) or ischemia were nearly three times more frequent than changes detected histologically in SCDs, and in the former involved predominantly the anterior wall in contrast to the inferior wall in most autopsied deaths. This disparity implicates acute myocardial lesions, particularly of the anterior wall, in the majority of SCDs.

Acute coronary lesions were found in 58% of SCDs autopsied. Most of these were ruptured plaques although almost one fifth of all autopsied SCDs had thromboses without intimal rupture. Severe chronic multivessel stenosis was present in most subjects, although 15% had only disease of a single vessel and in these, the left anterior descending (LAD) or left main coronary artery were involved in three quarters.

The SCD population may be subgrouped into those with recent MI, those with only myocardial ischemia, and those with no detectable myocardial change. When rescuers were able to monitor prehospital SCDs, VF was found in the majority; however, 28% did have other terminal rhythms.
The Short Cardiac Pre-Ejection Period
Authors: PARISI ALFRED F. , HAMILTON BRUCE P. , THOMAS CHARLES N. , MAZZAFERRI ERNEST L.
Published: June 2012

Systolic time intervals (STI) were determined from simultaneous records of the electrocardiogram, carotid pulse and phonocardiogram in 17 consecutive patients with thyrotoxicosis and sinus rhythm. None of the patients had clinical evidence of congestive heart failure. Intervals measured included electromechanical systole (Q-S
2
), heart sound interval (S
1
-S
2
) and left ventricular ejection time (LVET). From these, the pre-ejection period (PEP), isovolumetric contraction time (ICT) and Q-S
1
intervals were derived. Deviations (ΔSTI) of observed values from expected values (Weissler equations) for the same heart rate were obtained by subtraction. The mean deviation of the thyrotoxic patients ±
sem
from the normal population were ΔQ- S
2
*
= –37.8 ± 4.2; ΔLVET = –4.0 ± 4.1; ΔPEP
*
= –33.8 ± 1.8. The shortening of PEP was due largely to a shortened ICT (ΔICT
*
= –27.2 ± 1.1). In eight patients studied serially during treatment the short PEP returned to the normal range concurrently with serum T
4
measurements. This study indicates that the PEP is a unique noninvasive measurement of biological end organ responsiveness with thyroid dysfunction; a short PEP is characteristic of uncomplicated thyrotoxicosis and serial changes in PEP may be a useful index of therapeutic response.
*
P
< .001.
Prosthetic Aortic Stenosis
Authors: SENINGEN RONALD P. , BULKLEY BERNADINE H. , ROBERTS WILLIAM C.
Published: June 2012

A cause of early death after aortic valve replacement with a caged-ball prosthesis is obstruction to left ventricular outflow because the prosthesis is too large for the aortic root. Of 68 patients dying within two months of aortic valve replacement, death in ten, each of whom had had intractable low cardiac output after operation, was attributed at necropsy to prosthetic aortic stenosis, despite the use of small sized (8A Starr-Edwards) prostheses in seven of them. The diameters of the aorta at the sinotubular junction, determined from the preoperative cineangiograms, in the seven patients with prosthetic stenosis were < 30 mm in all. Poppet clearances, defined as the differences between poppet and aortic root diameters, ranged from 4 to 12 mm (avg. 9). In contrast, the diameters of the aortas at the sinotubular junctions in eight control patients (unobstructed prosthetic aortic valves and early death from other causes) were > 30 in all but one, and the poppet clearances ranged from 12 to 19 mm (avg. 15). Thus, prosthetic aortic stenosis is likely to develop after aortic valve replacement with rigid-framed caged ball valves if the preoperative aortograms disclose aortic diameters at the sinotubular junctions to be < 30 mm. In such patients, either the aorta must be widened for a caged-ball prosthesis or a central flow valve must be used.
Intracardiac Repair in Tetralogy of Fallot
Authors: JOHN STANLEY , SUKUMAR I. P. , CHERIAN G. , GUPTA R. P. , KRISHNASWAMY S. , CHERIAN GEORGE
Published: June 2012

Experience with the first 100 cases with tetralogy of Fallot subjected to intracardiac repair are presented. In this series there was an early hospital mortality of 12 per cent and 6 late deaths occurred. Eighty out of 82 survivors were available for follow-up and 33 of these underwent postoperative catheterization studies. The functional status of the survivors revealed excellent results in 89 per cent, good in 8 per cent, fair in 1 per cent and poor in 2 per cent. This is the largest series reported from India.
Antecedents of Cardiovascular Disease in Six Solomon Islands Societies
Authors: PAGE LOT B. , DAMON ALBERT , MOELLERING ROBERT C.
Published: June 2012

Cardiovascular risk factors have been analyzed as part of a combined ethnographic, anthropometric, and medical study of 1390 adult subjects in defined populations representing six Solomon Islands Societies. The six societies, all at low levels of acculturation, differed in habitat, way of life, and exposure to Western civilization. Criteria for ranking the societies in respect to acculturation were developed based on demographic changes within defined populations, secular increase in adult height, length and intensity of contact with Western cultural influences, religious belief, education, availability of medical care, economy, and diet. The six tribal groups were ranked by these criteria as follows: (1) Nasioi, (2) Nagovisi, (3) Lau, (4) Baegu, (5) Aita, (6) Kwaio. Physical health and nutrition were good in all six groups, and clinical evidence of coronary heart disease and atherosclerosis was absent. Serum cholesterol levels were higher at almost all ages and both sexes in the three more acculturated than in the three less acculturated groups. Serum uric acid levels were lower in the more acculturated than in the less acculturated groups. Among adult males in all groups, systolic blood pressure showed no age-related trend while diastolic blood pressure declined with age in the three less acculturated groups. Among adult females systolic blood pressure increased significantly with age in the three more acculturated groups but showed no age trend in the less acculturated. Weight declined with age in all groups. Analysis of electrocardiograms by the Blackburn method showed striking absence of codable abnormalities in all groups and a lower frequency of most abnormalities associated with coronary disease than in any population previously reported.

The differences in serum cholesterol and uric acid levels, and in intrapopulation trends of blood pressure in relation to age between the more and less acculturated groups were found to correlate best with dietary differences, especially in intake of salt, and of tinned meat and fish. The biologic differences noted may represent the earliest antecedents of cardiovascular disease in these societies.
Cerebrovascular Thrombosis in Patients with Buerger's Disease
Authors: LIPPMANN HEINZ I.
Published: June 2012

Nine cases of cerebrovascular thromboangiitis obliterans were observed among 1700 cases of peripheral thromboangiitis obliterans. These, with 30 acceptable cases from the literature, are analyzed. Smoking appears to activate the disease, which is characterized by, recurrences and remissions of focal cortical signs due to thrombosis of cerebral arteries and cortical granular atrophy. Of my patients, one died. Eight have been followed for 35 to 3 years, and with one exception all are ambulatory. Cessation of smoking is necessary. No other effective treatment is known.
Heart Failure and Pulmonary Edema Produced By Certain Neurologic Stimuli
Authors: PAINE ROBERT , SMITH JOHN R. , BUTCHER HARVEY R. , HOWARD FRANK A.
Published: June 2012

Experimental evidence has indicated that the genesis of acute pulmonary edema due to insufficiency of the left ventricular myocardium is dependent upon pulmonary engorgement and rapid filtration of fluid from the capillaries. It has been possible to demonstrate that significant elevation of arterial blood pressure from noxious stimulation of the central nervous system may be poorly tolerated when the myocardium has been previously damaged, so that acute left ventricular failure has occurred. The resulting massive pulmonary edema clearly followed the hemodynamic changes of severe congestion.
The Specific Treatment of Syphilitic Aortitis
Authors: KAMPMEIER R. H. , MORGAN HUGH J.
Published: June 2012

Penicillin has made the specific treatment of cardiovascular syphilis easy to give and easy to take and has all but abolished dangerous treatment reactions. Just as the curative therapy of acute syphilis with penicillin is simple and feasible, so is the prophylactic treatment of cardiovascular syphilis in individuals with latent syphilis and uncomplicated syphilitic aortitis simple and feasible. In spite of the fact that the effectiveness of such treatment has not been conclusively established, the prospects seem bright that the incidence of cardiovascular syphilis will decrease sharply in the immediate future.

Cardiovascular syphilis may be treated, with or without preliminary bismuth and iodide "preparation," by the administration of 4.8 to 6 million units of penicillin in a period of 8 to 10 days. Larger doses and longer periods of treatment have been employed. Experience thus far does not indicate that penicillin therapy of established complications of syphilitic aortitis will be any more successful than was therapy of the pre-penicillin era.
Distalward Modification of the Arterial Pulse Wave in Children with Congenital Aortic Stenosis
Authors: HAWKER RICHARD E. , SEARA CARLOS A. , KROVETZ L. JEROME
Published: June 2012

In 38 children with congenital aortic stenosis (32 valvar, three subvalvar, and three supravalvar: 28 preoperative, ten postoperative), the left ventricular pressure, left ventricular-to-aortic pressure difference and aortic valve area were compared with several components of the central and peripheral arterial pulse waves. In 23 patients, a catheter-tip manometer was used, and in 15, pressure was measured with a regular manometer system and corrected for artifact by resynthesis of pulse waves after harmonic analysis. The severity of the anomaly was not reflected in the central or peripheral pulse pressure, the first derivative of these pressures, mean aortic pressure, pulse wave velocity, or peripheral amplification of pulse waves or of their individual harmonics.

While in adults with aortic stenosis, the various pulse wave characteristics correlate with severity, the change in the pulse wave as it travels down the aorta in children is so modified by vascular factors as to be worthless in assessing the severity of the obstruction.
Complete His-Purkinje Block Produced by Carotid Sinus Massage
Authors: JONAS ERNESTO A. , KOSOWSKY BERNARD D. , RAMASWAMY KRISHNASWAMY
Published: June 2012

A case of complete heart block (CHB), localized in the His-Purkinje system, induced by carotid sinus massage (CSM) is presented. A 63-year-old male with right bundle branch block and left anterior hemiblock was evaluated for recurrent syncope. Right or left CSM produced brief periods of CHB with presyncopal symptoms. His bundle (HB) studies during normal sinus rhythm revealed normal conduction times (A-H interval = 80 msec; H-V interval = 48 msec). Carotid sinus massage produced progressive slowing of the sinus rate, and complete heart block below the HB occurred whenever the sinus rate fell below 42 beats/min. During atrial pacing at 70 beats/min, CSM produced 2:1 block above the HB with an effective rate to the HB of 35 and complete block below the HB. Atrial pacing at rates above 93 beats/min resulted in 2:1 block below the HB. Administration of intravenous atropine produced an apparent junctional tachycardia with 2:1 block below the HB. Thus, complete heart block related to both bradyCardia (phase 4) and tachycardia (phase 3) was demonstrated. The complete heart block induced by CSM was thought to be secondary to bradycardia-induced left posterior fascicular or intra-His block. However, the possibility of a direct vagal effect on ventricular conduction could not be ruled out.
Pacing the Human Cardiac Conduction System During Open-heart Surgery
Authors: KUPERSMITH JOEL , KRONGRAD EHUD , BOWMAN FREDERICK O. , MALM JAMES R. , WALDO ALBERT L.
Published: June 2012

Specialized fiber electrograms were recorded from selected sites along the His bundle and bundle branches during open-heart surgery in 26 patients. The heart was then paced from the same recording sites. Stimuli applied to the proximal His bundle recording site always resulted in His bundle pacing, which was characterized by a stimulus artifact-to-QRS interval which equaled or very nearly equaled the previously recorded His bundle electrogram-to-QRS interval, and no change in QRS duration or waveform from that recorded with a conducted atrial beat. When stimuli were applied to distal His bundle recording sites, the response was variable: in some instances, ventricular pacing occurred; in other instances, His bundle pacing occurred; and in still other instances, ventricular pacing occurred when high stimulus amplitudes were applied, while His bundle pacing occurred when the stimulus amplitudes were reduced below a range of 0.5-3.5 ma. Stimuli applied to the right or left bundle branch recording sites always resulted in ventricular pacing. Therefore, when stimuli are applied to specialized fiber recording sites and His bundle pacing results, it is certain that the site of origin of the previously recorded specialized fiber electrogram is the His bundle, but when ventricular pacing results, the site of origin of the previously recorded specialized fiber electrogram could be the distal His bundle or the bundle branches.
Echocardiographic Evaluation of Pulmonary Hypertension
Authors: NANDA NAVIN C. , GRAMIAK RAYMOND , ROBINSON TREVOR I. , SHAH PRAVIN M.
Published: June 2012

Echocardiographic studies of the pulmonary valve were obtained in 63 adults. Patients with normal pulmonary artery pressure (22 cases) showed an oblique position of the valve images in diastole, slow valve opening slopes (≤ 300 mm/sec), sizable (> 2 mm) posterior displacement of the cusp echoes with atrial systole (`a' dip), and a relatively short right ventricular pre-ejection period. In contrast, pulmonary valves in pulmonary hypertension (mean pressure > 20 mm Hg, 41 cases) appeared straight in diastole with rapid opening slopes (> 350 mm/sec) and prolonged pre-ejection periods (
P
< 0.001). In patients maintaining sinus rhythm (25 cases), mild to moderate pulmonary hypertension (mean pressure ≤ 40 mm Hg) was indicated by small `a' dips (≤ 2 mm), while absence of `a' dips denoted more severe pulmonary hypertension (mean pressure > 40 mm Hg) when uncomplicated by severe right heart failure. In the latter instance rapid valve opening slopes were associated with large `a' dips. Echocardiography appears to be of value in the assessment of pulmonary hypertension.
Effects of Chronic Heart Failure on the Inotropic Response of the Right Ventricle of the Conscious Dog to a Cardiac Glycoside and to Tachycardia
Authors: VATNER STEPHEN F. , BRAUNWALD EUGENE
Published: June 2012

The effects of ouabain, 20 µg/kg, and elevation of cardiac rate from 90 to 240 beats/min (BQwditch phenomenon) were examined on right ventricular (RV) segment length (SL), pressure (P), velocity of shortening (V), dP/dt, and dP/dt/P in conscious dogs before and after chronic right heart failure was induced by tricuspid avulsion and pulmonary stenosis, or by pulmonary stenosis alone. Chronic pulmonary stenosis and tricuspid regurgitation increased RV systolic P from 25 ± 3 to 59 ± 7 mm Hg, end-diastolic P from 3 ± 1 to 16 ± 2 mm Hg and reduced dP/dt/P from 48 ± 6 to 24 ± 4 sec
–1
and V from 26 ± 3 to 15 ± 3 mm/sec. Both ouabain and tachycardia exerted relatively minor inotropic effects in normal, healthy, conscious dogs; dP/dt/P and V rose by 18 ± 2 and 17 ± 2% with ouabain, and by 15 ± 3 and 16 ± 3% with tachycardia. When the tachycardia-induced reductions in end-diastolic SL were prevented by saline infusion, the increases in dP/dt/P and V were 19 ± 3% and 21 ± 3%. After chronic heart failure had been induced, the positive inotropic increases, with ouabain and tachycardia expressed on an absolute or relative basis, were significantly greater than had occurred in the dogs prior to heart failure; dP/dt/P and V rose by 47 ± 5 and 48 ± 6% with ouabain and by 41 ± 4% and 51 ± 3% with tachycardia. Thus, cardiac glycosides and the Bowditch phenomenon exert relatively minor positive inotropic responses in the nonfailing heart of the conscious dog when compared with the responses to these stimuli in the failing heart.
Oxygen Consumption in Infants and Children during Cardiac Catheterization under Different Sedation Regimens
Authors: FIXLER DAVID E. , CARRELL TED , BROWNE RICHARD , WILLIS KATHRYN , MILLER WILLIAM W.
Published: June 2012

We measured oxygen consumption in 426 infants and children during cardiac catheterization using an open circuit, flow-through technique. Since this method does not require the cooperation of the patient, determinations were readily made in 170 infants. The purpose of this study was to determine those factors which significantly influence oxygen consumption and to determine the potential errors incurred in using predictive equations for estimating oxygen consumption. The type of sedation or anesthesia given was found to be one of the most important variables influencing oxygen consumption; therefore patients were classified into five anesthetic groups. Stepwise regression analysis revealed that each group had a distinctive set of hemodynamic or physical factors which significantly affected oxygen consumption; hence each group required a different predictive equation. Body size in terms of surface area or weight was the only significant variable common to all five patient groups. Using the predictive equations the estimated values differed from measured values by more than 20 percent in approximately one-fifth of the cases. These data indicate that frequently oxygen consumption cannot be accurately estimated from predictive equations. Therefore if blood flow is to be accurately determined by the Fick method in infants and children, oxygen consumption should be measured during the catheterization procedure.
Isolated Aortic Stenosis in the Neonate
Authors: LAKIER JEFFREY B. , LEWIS ALAN B. , HEYMANN MICHAEL A. , STANGER PAUL , HOFFMAN JULIEN I. E. , RUDOLPH ABRAHAM M.
Published: June 2012

We have reviewed the clinical and catheterization data and pathologic findings in ten infants under one month of age with isolated severe aortic valve stenosis. All presented with evidence of progressive cardiac failure and diminished cardiac output. A hyperdynamic right ventricular impulse was present in nine infants who were subsequently shown to have a left-to-right atrial shunt, through a stretched patent foramen ovale. Calculated aortic valve area ranged from 0.12 cm
2
/m
2
to 0.29 cm
2
/m
2
. Three patients died prior to surgical intervention because of low cardiac output and refractory metabolic acidosis. Aortic valvotomy was attempted in the remaining seven. Five died intraoperatively or in the immediate postoperative period and one other died six months after surgery. Necropsy was obtained in all nine patients who died.

We believe that, in this group, the clinical course reflects fetal and postnatal hemodynamics. We have discussed the probable hemodynamic factors which occur and have related them to the morphological development of aortic stenosis in these infants. The poor prognosis of these patients probably results from a combination of factors which include left ventricular outflow obstruction, often associated with a small aortic annulus, a markedly thickened left ventricle, and left ventricular malfunction secondary to subendocardial ischemia and/or endocardial fibroelastosis.
Coronary Arteriography in Long-Term Human Cardiac Transplantation Survivors
Authors: SILVERMAN JAMES F. , LIPTON MARTIN J. , GRAHAM ANTHONY , HARRIS STEVE , WEXLER LEWIS
Published: June 2012

Coronary arterial lesions in survivors of cardiac transplantation result from accelerated coronary atherosclerosis. Clinical recognition of this event is difficult but essential for long-term management and prognostication. Coronary arteriography was performed on 30 occasions in a group of 16 patients 1-4 years after cardiac transplantation. Fifteen patients had normal coronary arteries at one year. Of 10 patients studied at two years, seven showed no change but three others revealed significant coronary arterial lesions which correlated well with clinical signs of coronary artery disease. These three patients subsequently died, two due to coronary artery disease, one due to infection. Three patients have remained normal at three years and one patient is normal at four years as evidenced on yearly coronary arteriograms. A postmortem examination of the patients who died with coronary artery disease confirmed the extent of the luminal narrowing due to atheromatous plaques superimposed on intimal lesions. Coronary arteriography has proven to be a safe, reliable method for assessing the coronary circulation of long-term cardiac transplant survivors.
Hemodynamic Effects of Orally Administered Isosorbide Dinitrate in Patients with Congestive Heart Failure
Authors: FRANCIOSA JOSEPH A. , MIKULIC ESTEBAN , COHN JAY N. , JOSE ERNESTO , FABIE ANASTACIA
Published: June 2012

The efficacy of orally administered isosorbide dinitrate (IS) has been questioned. Recently vasodilators have been shown to lower left ventricular filling pressure (LVFP) and raise cardiac output in heart failure. In the present study oral IS was evaluated in 12 patients with high LVFP due to heart failure. After right heart catheterization, patients with LVFP > 14 mm Hg were randomized double-blind to receive either 20 mg IS or placebo (P). Supine heart rate (HR), arterial pressure (BP), and LVFP were monitored for five hours. After this the alternate drug (P or IS) was given, followed by five more hours of monitoring. In the 12 patients after receiving IS, LVFP reached a peak reduction of 6.7 mm Hg (-26%,
P
< 0.005) at 30 min. Significant reduction persisted for 4.5 hours. Blood pressure fell concomitantly with the LVFP. At 60 min HR was unchanged, systolic BP was reduced by 8.9 mm Hg (P < 0.025) and diastolic BP by 6.3 mm Hg (
P
< 0.005). In the ten patients receiving P, control values were not significantly different from those given IS, and after receiving P, HR, BP, and LVFP failed to change significantly over the next five hours. Thus, oral IS produces a sustained reduction in LVFP and therefore merits further evaluation as chronic therapy for left ventricular failure.
Echocardiographic Patterns of Pulmonic Valve Motion with Pulmonary Hypertension
Authors: WEYMAN ARTHUR E. , DILLON JAMES C. , FEIGENBAUM HARVEY , CHANG SONIA
Published: June 2012

Echocardiographic tracings of the pulmonic valve were examined in two groups of patients. The first group contained 24 normal patients. The second group consisted of 32 patients with pulmonary hypertension (mean pulmonary artery pressure ≥20 mm Hg). Parameters considered included presence or absence and depth of the "a" wave, amplitude of valve opening (b-c separation), diastolic (e-f) slope, and presence or absence of mid-systolic closure or fluttering of the pulmonic leaflet. An "a" wave was present in all 24 normal subjects. The "a" wave varied with respiration and the maximum "a" wave depth (A Max) averaged 3.7 ± 1.2 mm (mean ±
sd
, range 2-7 mm). A Max was ≥2 mm in all 24 normal patients. In 19 of 24 patients with pulmonary hypertension and sinus rhythm no "a" wave was present. In the other five patients small "a" waves (≤2 mm) occurred. In four of these five patients, right heart failure was present. The diastolic (e-f) slope averaged 36.9 ± 25.4 mm/sec (range 6-115 mm/sec) in normals. With pulmonary hypertension, this slope was significantly less than normal (average 5.2 ± 8.9 mm/sec, range –9 to +30 mm/sec,
P
< .001). In six patients with pulmonary hypertension a negative e-f slope was seen; this never occurred in normals. Mid-systolic closure or notching of the systolic (c-d) segment occurred in 18 of 20 subjects with pulmonary hypertension in whom the leaflet was clearly recorded in mid-systole. This finding was not observed in normals. Likewise, mid-systolic fluttering was present in 22 of 24 patients with pulmonary hypertension. There was no difference in amplitude of leaflet opening between the two groups.
Further Observations on the Etiology of the Right Bundle Branch Block Pattern Following Right Ventriculotomy
Authors: KRONGRAD EHUD , HEFLER STEPHEN E. , BOWMAN FREDERICK O. , MALM JAMES R. , HOFFMAN BRIAN F.
Published: June 2012

Fifteen patients with various congenital heart defects were studied during open heart surgery in order to establish the precise mechanism by which a right ventriculotomy causes a right bundle branch block (RBBB) pattern on the scalar electrocardiogram (ECG). All required a right ventriculotomy for the correction of their defects. In each, the right ventriculotomy was carried out in steps, with incisions (3 to 7) of approximately 1 cm in length. Six simultaneous scalar ECG leads were recorded prior to the first incision and following each incision. The QRS duration was then measured and related to the length of the ventriculotomy.

Following the right ventriculotomy, 12 of the 15 patients developed an RBBB pattern; the remaining three did not. In all cases, the total increase in QRS duration occurred during one specific incision of the right ventricular free wall and was not related to the total length of the ventriculotomy or to the sequence of the incisions. The site at which incision of the right ventricle caused the RBBB pattern was located at between 40 to 73% of the distance between the pulmonary artery annulus and the inferior border of the heart in nine patients; in three patients the site was higher on the right ventricular free wall.

Our results explain why some patients who had a right ventriculotomy during open heart surgery do not develop an RBBB pattern on the scalar ECG. Also, since no relation was found between the length of the incision and the QRS duration, our results suggest that the ventriculotomy-induced RBBB pattern is unlikely to be due to disruption of a continuous Purkinje network but is probably due to disruption of a distal branch or branches of the right bundle.
Left Ventricular Ejection Time by Densitometry in Patients at Rest and During Exercise, Atrial Pacing and Atrial Fibrillation
Authors: CHIRIFE RAUL , FOERSTER JAMES M. , BING OSCAR H. L.
Published: June 2012

A comparison of left ventricular ejection time (LVET) measured directly from the central aortic pressure tracing (CAPT) and a densitogram recording was carried out in 39 patients during diagnostic cardiac catheterization. The correlation coefficient between the LVET derived from the CAPT and densitogram of 32 patients while at rest was 0.974 with a standard deviation from regression (
sdr
) of 6.2 msec. Sequential LVETs were analyzed in two patients during atrial pacing, three patients during exercise and three patients with atrial fibrillation. Correlation coefficients were 0.981, 0.951 and 0.974 with
sdrs
of 5.3, 6.2 and 6.7 msec respectively. Assuming LVET from the CAPT to be error free, the over-all error of estimating LVET by densitogram was less than 5% for over 95% of the measurements. The largest mean difference between CAPT and densitogram derived LVETs was present during atrial pacing and corresponds to an error of less than 2% of the average LVET for the group. We conclude that densitometry is a practical and reliable noninvasive method for LVET measurements in a variety of physiological and pathological conditions.
The Clinical Pharmacology of Lidocaine as an Antiarrhythymic Drug
Authors: COLLINSWORTH KEN A. , KALMAN SUMNER M. , HARRISON DONALD C.
Published: June 2012

This article reviews current knowledge about lidocaine, with reference to its chemistry, metabolism, electrophysiology, hemodynamic effects, antiarrhythmic uses, pharmacokinetics, and side effects. The critical importance of blood levels and their relation to lidocaine's antiarrhythmic and toxic effects is noted, with special emphasis given to patients with compromised clearance due to heart failure. On the basis of this information, we present our current approach to the clinical use of lidocaine in the treatment of ventricular arrhythmias, with particular reference to patients with acute myocardial infarction.
Improvement in left ventricular wall motion following nitroglycerin.
Authors: McAnulty J H , Hattenhauer M T , Rösch J , Kloster F E , Rahimtoola S H
Published: June 2012

Coronary artery disease patients frequently have left ventricular wall motion abnormalities. Though nitroglycerin is commonly used in ischemic heart disease, its effects on wall motion abnormalities is unknown. In this study we have evaluated the effects of nitroglycerin on wall motion abnormalities and on ejection fraction in 25 patients. Sixteen had coronary artery disease (greater than 70% luminal narrowing). Six had no evidence of heart disease and three had congestive cardiomyopathies with normal coronary arteries. Left ventricular angiography was performed prior to and six minutes after administration of 0.4 mg of sublingual nitroglycerin. Twelve of the 16 coronary artery disease patients had wall motion abnormalities, and in seven of these, segmental wall motion improved after nitroglycerin. In five, all motion did not change. The initial heart rate, left ventricular systolic and end-diastolic pressure, and left ventricular end-diastolic volumes were not different for those whose wall motion improved versus those whose did not. The increase in the former and fall in the latter three hemodynamic parameters were significant (P less than 0.01) and similar for the two groups. In those whose wall motion abnormalities improved after nitroglycerin, ejection fraction (mean plus or minus se) increased significantly (P less than 0.05), from 0.47 plus or minus 0.025 to 0.62 plus or minus 0.046. In those without improvement, the ejection fraction went from 0.55 plus or minus 0.056 to 0.58 plus or minus 0.051 (NS). Three patients with congestive cardiomyopathy showed no improvement in ventricular wall motion or ejection fraction after nitroglycerin. Left ventricular wall motion abnormalities and ejection fraction improved in some coronary artery disease patients following nitroglycerin. The mechanism for this is unknown; however, ventriculography before and after nitroglycerin may be of potential usefulness for identifying areas of reversible wall motion abnormalities.
The echocardiogram of the anterior leaflet of the mitral valve. Correlation with hemodynamic and cineroentgenographic studies in dogs.
Authors: Pohost G M , Dinsmore R E , Rubenstein J J , O'Keefe D D , Grantham R N , Scully H E , Beierholm E A , Frederiksen J W , Weisfeldt M L , Daggett W M
Published: June 2012

The echocardiogram of the anterior leaflet of the mitral valve (ECHO) was compared to hemodynamic and cineroentgenographic data to evaluate its accuracy in timing mitral valve (MV) opening and closure, and to validate it as an indicator of MV motion. The ECHO, high speed cineroentgenography at 250 frames/sec, and/or measurement of intracardiac pressures allowed accurate timing of the events of MV motion in dogs on right heart bypass. The intersection of left ventricular and left atrial pressures in early diastole preceded the onset of rapid anterior motion of ECHO (D' point) by 17 to 33 plus or minus 7.6 msec; r equals 0.98. The onset of left ventricular systole occurred before the termination of final rapid posterior motion of the ECHO in end diastole (Co point) by 25 plus or minus 10 msec; r equals 0.96. Radiopaque clips were attached to the free edges of both leaflets of the MV. Cineroentgenographically determined plots of clip distance from the ultrasound transducer were morphologically similar to the simultaneously recorded ECHO. A delay of 23 plus or minus 3 (0 to 40) msec was observed in the ECHO peaks of diastolic anterior excursion compared to clip motion. Contrast medium advances beyond the free edges of MV leaflets mixing with left ventricular blood 43 plus or minus 3 msec after initial separation. These cineroentgenographic studies elucidate nonuniformity of leaflet motion responsible for ECHO delays. Thus, ECHO D' and Co correlate well with hemodynamic indicators of MV opening and closure. However, ECHO motion, although qualitatively similar, is unpredictably delayed compared to cineroentgenography of clips on the MV free edge. Since the ECHO correlates well with hemodynamic indices of MV opening and closure, this noninvasive technique can be used as a reference in the timing of intracardiac events and in the determination of systolic and diastolic time intervals.