bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term follow-up of the Hancock bioprosthetic heart valve: a 6-year review.
Authors: Cohen L H , Koster J K , Mee R B , Collins J J
Published: June 2012

Clinical experience with the Hancock porcine bioprosthetic heart valve was reviewed in 467 patients (254 men and 213 women, 18--84 years old, average, 56 years) who received 528 valves from January, 1972, to January, 1978. Associated procedures, including coronary bypass graft, ascending aortic aneurysm, and valvuloplasty were done in 102 of the 467 patients (22%). The overall operative mortality was 25/467 (5.6%), 12/226 (5.3%) for aortic valve replacement (AVR), 11/183 (6%) for mitral valve replacement (MVR), and 2/58 (3.4%) for multiple valve replacement. The first 323 patients with a minimum follow-up of 16 months (16--75 months, average 33 months) were analyzed for survival and thromboemboli. Actuarial survival at 66--75 months was 75.7% for AVR, 79% for MVR, and 75.8% for multiple valve replacement. Emboli per 100 patient-years was 0.55 for AVR (no anticoagulants), 3.9 for MVR, and 4.8 for multiple valve replacement (anticoagulants for atrial fibrillation patients only); emboli occurred only in patients with atrial fibrillation. There were seven of 528 primary dysfunctional valves (1.3%): calcification in two, tissue failure in two, and fibrosis in three. A hemodynamic study of four patients with a 21 mm Hancock Modified Orifice aortic valve prosthesis showed improved orifice areas (greater than 1.3 cm2) over the standard aortic valve. The Hancock porcine xenograft bioprosthetic heart valve has been a durable heart valve in excess of 6 years and has a low associated incidence of thromboemboli in patients off anticoagulants except in those with chronic atrial fibrillation.
Straddling and displaced atrioventricular orifices and valves.
Authors: Bharati S , McAllister H A , Lev M
Published: June 2012

This is an anatomic study of 96 hearts with straddling or displaced atrioventricular (AV) valves and orifices. In the complete form, both the annulus and the peripheral connections of either AV valve straddle a ventricular septal defect (VSD) and connect to both ventricles. In the annular form, only the annulus, and in the peripheral type only the peripheral connections of the valve are found in both ventricles. In displaced AV valve, the entire annulus and periphery of one AV valve are displaced into the opposite chamber. These anomalies are commonly seen in complete transposition with or without ventricular inversion, and in double outlet right or left ventricle. Straddling mitral valve is frequently seen in the Taussig-Bing heart. Any type of VSD may be associated with straddling tricuspid valve; however, they usually are of the AV canal type. Straddling and displaced AV valves should be differentiated from criss-cross hearts in which both AV valves are completely connected to oppositely placed ventricles.
Effect of submaximal exercise on vulnerability to fibrillation in the canine ventricle.
Authors: Dawson A K , Leon A S , Taylor H L
Published: June 2012

The risk of instantaneous death due to ventricular fibrillation was compared in resting and exercised dogs. Three weeks before testing, all dogs had bipolar left ventricular stimulating electrodes implanted and a reversible snare was placed around the anterior descending coronary artery. The dogs were randomly assigned to either an exercise (13 dogs) or a control (12 dogs) group. We measured ventricular fibrillation thresholds (VFTs) in all dogs before and after inducing ischemia by tightening the snare while the dogs stood at rest. The next day, nonischemic and ischemic VFTs were redetermined for control dogs at rest and for the exercise group during a treadmill run. No statistically significant changes were noted within and between groups in nonischemic or in ischemic VFTs at rest. In five exercise dogs, spontaneous ventricular fibrillation occurred during the first 8 minutes of the ischemic run, For the eight other exercise dogs, running increased the mean drop in VFTs during coronary occlusion by 23% (p less than 0.01). These data suggest that moderate dynamic exercise may greatly enhance the risk of ventricular fibrillation and sudden death in the presence of myocardial ischemia. In the absence of ischemia, exercise does not appear to increase vulnerability to ventricular fibrillation.
Evaluation of warning arrhythmias before paroxysmal ventricular tachycardia during acute myocardial infarction in man.
Authors: de Soyza N , Meacham D , Murphy M L , Kane J J , Doherty J E , Bissett J K
Published: June 2012

In order to determine the relationship of paroxysmal ventricular tachycardia (PVT) to any antecedent (premonitory) ventricular arrhythmias during the early phases of acute myocardial infarctions, 24-hour Holter monitoring was begun on 52 male patients an average of 12.6 hours after the onset of prolonged chest pain that was documented as acute infraction. Twenty-four patients had PVT and 28 did not. We analyzed in detail the incidence of frequency of premature ventricular complexes (PVCs), prematurity and pairing during the 10 minutes immediately preceding PVT from a continuous 10-minute rhythm strip. There was no positive correlation between PVT and the number or complexity of PVCs in the 10 minutes immediately before ventricular tachycardia. These findings suggest that there is no consistent pattern or frequency of ventricular arrhythmia that could be identified as premonitory for PVT during the immediate pre-PVT period, even during the acute phase of myocardial infarction in man.
Platelet suppressant therapy in patients with prosthetic cardiac valves. Relationship of clinical effectiveness to alteration of platelet survival time.
Authors: Steele P , Rainwater J , Vogel R
Published: June 2012

Platelet survival time (SURV) has correlated with thromboembolism in patients with prosthetic cardiac valves. Sulfinpyrazone increases SURV. SURV (autologous labeling with 51Chromium) was measured in 126 patients who had aortic or mitral valve replacement. These patients were followed prospectively. Ninety-four with shortened SURV received sulfinpyrazone; 32 with normal SURV were not treated with platelet suppressants. Eighty-seven patients were anticoagulated with warfarin--67 with shortened SURV and 20 with normal SURV. Eleven patients have had thromboembolism, and all had shortened SURV (2.4 +/- 0.08 days; average half-time +/- SEM; normal 3.7 +/- 0.03 days; n = 26) none had an increase of SURV with sulfinpyrazone (2.3 +/- 0.09 days). Of 83 patients with shortened SURV who did not have embolism, sulfinpyrazone increased SURV in 59 (71%) 2.6 +/- 0.05 to 2.9 +/- 0.06 days). Of 35 patients with shortened SURV who failed to increase SURV with sulfinpyrazone, 11 (31%) had embolism; none of 59 (0%) with an increase of SURV with sulfinpyrazone had thromboembolism. These results suggest that patients with thromboembolism after prosthetic cardiac valve replacement have shortened SURV and that patients treated with slufinpyrazone who have thromboembolism do not have an increased SURV.
Electrophysiologic studies in patients with ventricular inversion and "corrected transposition".
Authors: Gillette P C , Busch U , Mullins C E , McNamara D G
Published: June 2012

We evaluated the intracardiac conduction intervals using His bundle recordings in 40 patients with ventricular inversion and 1-transposition of the great arteries. Twenty-nine subjects had 1:1 atrioventricular (AV) conduction. In 15 of those with normal PR intervals and QRS durations, the conduction intervals were not different from those of subjects with normal hearts. In the 14 patients with first-degree AV block, the block was located between the sinus node and AV node in four, between the low right atrium and bundle of His in seven, and below the common bundle of His in four. In 11 subjects with complete AV block, the stie of block was above the site of the His potential in four, below in two and within the His bundle in one. In four patients we could not record a His potential and thus could not localize the site of block. Complete block below the His recording site was associated with syncope in one patient and sudden death in another. His bundle recording is a safe technique for studying the conduction system in children with ventricular inversion and 1-transposition of the great arteries.
Normal electrocardiographic waveform characteristics during treadmill exercise testing.
Authors: Wolthuis R A , Froelicher V F , Hopkirk A , Fischer J R , Keiser N
Published: June 2012

Forty asymptomatic male patients at low risk for cardiovascular disease completed maximal treadmill testing. Electrocardiograms from leads CC5, CM5, V5, Yh and Z were recorded across multiple pretest, exercise and recovery conditions. ECG waveforms were subsequently digitized, averaged and processed to provide Q-, R-, S- and T-wave amplitudes, ST-segment means and slopes, and QS- and RT-interval durations. Average R-wave amplitude increased during early exercise and then dramatically decreased to maximum effort. Average S-wave amplitude became greater as exercise progressed. Average J junction was slightly positive before exercise, became negative during exercise (except lead Z) and returned to zero after exercise. The ST-segment slope increased dramatically with progressive exercise. The response of T-wave amplitude, RT and QS intervals are also described. Separately, 22 asymptomatic male subjects each completed two maximal treadmill tests 2 weeks apart. ECG data acquisition and processing were similar to those noted above. Pooled, within-subject estimates of variability were computed for the ECG leads, ECG measurements and protocol conditions. These variability estimates are useful for interpreting ECG responses to exercise testing.
Cross-sectional echocardiography. I. Analysis of mathematic models for quantifying mass of the left ventricle in dogs.
Authors: Wyatt H L , Heng M K , Meerbaum S , Hestenes J D , Cobo J M , Davidson R M , Corday E
Published: June 2012

Cross-sectional echocardiography was used to quantify left ventricular mass noninvasively in 21 dogs. Short- and long-axis cross-sectional images of the left ventricle were reproducibly traced at endocardial and epicardial borders during stop-motion video-tape replay. We used area, length and diameter measurements to calculate left ventricular mass by seven mathematic models, including the standard formulas used with M-mode echocardiography and cineangiography. Calculated mass was compared with excised weight of the left ventricle by regression and percent error analyses. Formulas using short-axis areas and long-axis length resulted in higher correlation coefficients (0.94--0.95) and lower mean errors (6--7%) than for standard formulas. Since short-axis areas account for regional left ventricular irregularities, noninvasive quantification of left ventricular mass by cross-sectional echocardiography in dogs is most accurate with formulas using short-axis areas.
Two-dimensional echocardiographic demonstration of left atrial thrombi in patients with prosthetic mitral valves.
Authors: Mikell F L , Asinger R W , Rourke T , Hodges M , Sharma B , Francis G S
Published: June 2012

Although M-mode echocardiography (MME) is not a reliable method for detecting left atrial thrombi, recent reports suggest that two-dimensional echo (2DE) may be more effective than MME in identifying intracardiac thrombi. In three patients with prosthetic mitral valves who presented with either arterial embolization or prosthetic valvular dysfunction, 2DE demonstrated left atrial masses consistent with thrombi, while MME was either negative (two patients) or suspicious (one patient) for left atrial thrombus. Thrombi were documented by surgical or postmortem examination in all cases. Clear delineation of the atrial cavity and the margins of the masses, visualization on multiple echocardiographic views and comparison of serial examinations were helpful in identifying these masses as thrombi. In addition, the masses visualized had certain patterns of motion which seem unique and may allow characterization of atrial masses as thrombi.
Computer diagnosis of supraventricular and ventricular arrhythmias. A new esophageal technique.
Authors: Jenkins J M , Wu D , Arzbaecher R C
Published: June 2012

Computerized arrhythmia monitors recognize only a few of the significant arrhythmias and generally fail to detect arrhythmias of supraventricular origin. This is because conventional surface leads, which are sufficient for QRS recognition, are highly inadequate for automated P-wave detection. A new two-lead system, which includes a swallowable capsule-electrode for esophageal monitoring of atrial activity, is used in an on-line arrhythmia monitor. Three interval measurements (AA, AR and RR) and a QRS shape measurement provide the foundation for a detailed interpretation of each beat. Building on the single-beat analysis, a contextual diagnostic algorithm then recognizes and reports on-line the following arrhythmias: couplets, bigeminy, trigeminy, ventricular tachycardia, supraventricular tachycardia, atrial flutter, atrial fibrillation, ventricular tachycardia with retrograde conduction to the atria, first-degree block, second-degree block, Wenckebach periodicity, advanced block, third-degree block and sinus bradycardia.
Significance of block distal to the His bundle induced by atrial pacing in patients with chronic bifascicular block.
Authors: Dhingra R C , Wyndham C , Bauernfeind R , Swiryn S , Deedwania P C , Smith T , Denes P , Rosen K M
Published: June 2012

Twenty-one of 496 (4%) patients with chronic bifascicular block, studied and followed prospectively, had block distal to the His bundle (BDH) induced by atrial pacing during initial electrophysiologic studies. In six, BDH was noted during pacing-induced atrioventricular (AV) nodal Wenckebach periods (at paced rates of 150--190 beats/min), with BDH in the short HH cycles after the AV nodal blocked P (lond cycle). The AH interval was normal in all six patients and HV was normal in four. None of the six patients has developed AV block during a mean follow-up of 5.33 +/- 0.48 years. In 15 patients, pacing-induced BDH was noted during intact AV nodal conduction (paced rate of 80--200 beats/min). The AH interval was prolonged in one, and HV was prolonged in 10 of the 15 patients. During a mean follow-up of 3.4 +/- 0.59 years, seven of these patients developed AV block, one had treadmill-provoked AV block, and two died suddenly (major morbid event in 10 of 15 patients). In conclusion, BDH induced by atrial pacing is an infrequent finding in patients with bifascicular block, and can be a functional as well as a pathologic response. The latter is associated with a high risk of major morbid events (AV block and sudden death).
Research related to underlying mechanisms in atherosclerosis.
Authors: Steinberg D
Published: June 2012

A brief resume of advances in atherosclerosis research over the past 30 years is presented, emphasizing the multidisciplinary origins of those advances. A somewhat more detailed review of progress in the lipoprotein field is presented as an example to illustrate the pace of research related to atherosclerosis. Finally, an attempt is made to identify some of the research areas that promise to yield valuable new insights in the next 30 years.
Characteristics of reflection as a mechanism of reentrant arrhythmias and its relationship to parasystole.
Authors: Antzelevitch C , Jalife J , Moe G K
Published: June 2012

A model of "reflection" was developed in a sucrose gap preparation of Purkinje fibers. In this preparation, a driven impulse on the proximal side of a sucrose gap is electrotonically transmitted after a delay to the tissue distal to the gap. When the delay is long enough, electrotonic transmission in the reverse direction over the same blocked segment can reexcite the proximal segment. Frequency-dependent alterations of patterns of ectopic activity were qualitatively similar to those of a parasystolic model and to those described in previous in vivo demonstrations presumed to represent circus movement reentry. Moderate changes of frequency or in the degree of block were shown to convert a manifest bigeminal rhythm to a trigeminal or more complex rhythm with or without intervening periods of silence. Our observations suggest that reflection and parasystolic pacemaker activity are examples of a continuous spectrum of ectopic impulse generation.
Myocardial lactate extraction: multi-determined metabolic function.
Authors: Gertz E W , Wisneski J A , Neese R , Houser A , Korte R , Bristow J D
Published: June 2012

Myocardial lactate production indicates anaerobic metabolism resulting from hypoxia or anoxia. Clinically, myocardial lactate extraction of less than 10% has also been used as an indicator of ischemia. Sixteen healthy young male volunteers underwent coronary sinus and aterial catheterization. A coronary sinus pacing catheter was used to obtain blood samples and increase the heart rate to twice the resting rate. Hemodynamic measurements and blood samples for lactate, free fatty acids and glucose were obtained at rest and during pacing. Seven of 16 sujects (44%) had lactate extraction of less than 10% at rest and/or at miximal pacing. No subject produced lactate. There was no correlation between myocardial lactate extraction and arterial glucose. However, lactate extraction correlated inversely with the arterial levels of free fatty acids (r = 0.67; p less than 0.01). In addition, a positive correlation was present between lactate extraction and the arterial lactate level (r = 0.78; p less than 0.01). In conclusion, myocardial lactate extraction is dependent on multiple metabolic parameters and any absolute value short of production cannot be considered abnormal.
Hemodynamic factors that affect calculated orifice areas in the mitral hancock xenograft valve.
Authors: Ubago J L , Figueroa A , Colman T , Ochoteco A , Duran C G
Published: June 2012

From June 1974 to December 1978, 714 Hancock valves have been placed in 605 patients. One hundred seventy-five patients with a mitral xenograft have been restudied. The results were questionable due to the wide scatter and disparity between the calculated and the theoretical orifice of each valve size. To elucidate these differences, the hemodynamic data of 40 isolated, normal functioning mitral Hancock valves were reviewed. Early, middle and late diastolic mitral valve gradients were measured by planimetry and their corresponding flows were estimated by angiography. The paired data were fitted to exponential functions and specific lines for each Hancock valve size were obtained. By superimposing Gorlin's pressure and flow curves on these lines, the instantaneous effective orifice for each Hancock valve can be determined. We concluded that 1) the Hancock valve effective orifice is flow related and always lower than its theoretical opening; 2) normal function frequently cannot be firmly established by the mean effective area; and 3) the nomogram described may help in determining the time-related variations of a particular valve.
Ethmozin, a new antiarrhythmic drug for suppressing ventricular premature complexes.
Authors: Podrid P J , Lyakishev A , Lown B , Mazur N
Published: June 2012

Ethmozin, a phenothiazine derivative, is an antiarrhythmic drug synthesized in the USSR. Preliminary data suggest that it is effective against a diversity of ectopic arrhythmias. The present study, carried out in the USSR, was designed to assess efficacy and patient tolerance of this new drug. Thirty-seven patients with chronic, persistent, frequent and symptomatic ventricular premature complexes (VPCs) were studied. VPCs were exposed by means of 24-hour ambulatory monitoring and exercise stress testing. Two drug schedules were used. Group 1, consisting of 11 patients, received 225 mg/day of ethmozin, while group 2, consisting of 26 patients, received 600 mg/day. Acute drug testing with a single large dose of ethmozin was followed by multiple dosing for a minimum of 4 days. Placebo was given in a single-blind fashion only to responders. Only two patients in group 1 had a significant reduction in VPCs as evaluated by both monitoring and exercise testing. Fourteen patients in group 2 (54%) showed striking suppression of VPCs. Mild and transiet effects were encountered in only four of the 37 patients. We conclude that ethmozin appears to be a well-tolerated, relatively effective agent for controlling VPCs.
Observations on the optimum time for operative intervention for aortic regurgitation. I. Evaluation of the results of aortic valve replacement in symptomatic patients.
Authors: Henry W L , Bonow R O , Borer J S , Ware J H , Kent K M , Redwood D R , McIntosh C L , Morrow A G , Epstein S E
Published: June 2012

Fifty consecutive patients undergoing aortic valve replacement for isolated aortic regurgitation were studied prospectively by echocardiography, electrocardiography and cardiac catheterization. Good quality echocardiograms were obtained in 49 of the 50 patients. Left ventricular (LV) dilatation was present in all 49 patients. LV systolic function, as assessed by echocardiographic percent fractional shortening, was normal in many patients but was moderately to severely reduced (less than 25%) in 14 patients (29%). Echocardiographic studies 6 months postoperatively revealed significant reductions in LV end-diastolic dimension (73.8 mm vs 58.7 mm; p less than 0.01), and serial echocardiographic studies early and late after operation revealed that the decrease in LV size had occurred by the time of the early study (8-22 days postoperatively), with little additional change thereafter. Operative deaths occurred in three of the 49 patients (6%). Eight of the 49 patients (16%) died of congestive heart failure (CHF) after hospital discharge at times ranging from 5-43 months after operation. Preoperative echocardiographic measurements of the LV end-systolic dimension and percent fractional shortening were strongly associated (p less than 0.01) with these late CHF deaths. Preoperative LV end-systolic dimension greater than 55 mm and fractional shortening less than 25% identified the high-risk group: nine of 13 patients (69%) in this group died either at operation or subsequently from CHF. In contrast, of 32 patients with LV end-systolic dimension less than 55 mm, only one died at operation and one died late from CHF. Thus, the population at high risk of late death from CHF was identified before operation by echocardiography.
The effect of concurrent oral administration of propranolol and disopyramide on cardiac function in healthy men.
Authors: Cathcart-Rake W F , Coker J E , Atkins F L , Huffman D H , Hassanein K M , Shen D D , Azarnoff D L
Published: June 2012

Sixteen healthy men were evaluated for left ventricular performance changes and beta-blockade after therapeutic oral doses of disopyramide and propranolol administered alone and concurrently. The volunteers were randomly assigned to receive one of two drug treatment regimens that differed in the sequence and duration of administration of the drugs. Left ventricular function was assessed by echocardiographically determined ejection fraction (EF) and systolic time intervals. Beta-blockade was assessed by changes in exercise heart rate. Both disopyramide and propranolol exhibited negative inotropic activity, as evidenced by significant, although clinically inconsequential, decreases in EF and increases in the ratio of preejection period to left ventricular ejection time. The negative inotropic effects of a single 200-mg dose of disopyramide and an 80-mg dose of propranolol were comparable, while chronic disopyramide therapy (200 mg every 6 hours for 1 week) had a greater negative inotropic effect than chronic propranolol therapy (80 mg every 8 hours for 1 week). Only propranolol had beta-adrenoceptor blocking activity. When the drugs were administered concurrently, the negative inotropic effects of oral propranolol and disopyramide were neither additive nor synergistic.
Use of catheter-tip velocity--pressure transducer to evaluate left ventricular function in man: effects of intravenous propranolol.
Authors: Klinke W P , Christie L G , Nichols W W , Ray M E , Curry R C , Pepine C J , Conti C R
Published: June 2012

A catheter-tip velocity transducer with two high-fidelity pressure manometers was used to evaluate the left ventricular (LV) hemodynamic effects of intravenous propranolol (10 mg). Nine patients without clinical evidence of heart failure were studied. Pulsatile ascending aortic blood flow velocity and pressure and LV pressure were measured continuously during drug administration. Beat-to-beat changes in stroke volume index, stroke work index, LV end-diastolic pressure, maximum blood flow velocity and acceleration, and maximum LV dP/dt were determined. Propranolol produced a decrease in maximum blood flow velocity (from 58 +/- 4.7 to 42 +/- 5.1 cm/sec, p less than 0.002), and acceleration (from 1181 +/- 130 to 847 +/- 117 cm/sec2, p less than 0.002, max dP/dt (from 1361 +/- 70 to 1146 +/- 63 mm Hg/sec, p less than 0.002), stroke volume index (from 47 +/- 3.0 to 38 +/- 3.2 ml/m2, p less than 0.002) and total stroke work index (from 702 +/- 33 to 603 +/- 44 mJ/m2 p less than 0.04), with little change in mean aortic pressure, peak systolic pressure and LV end-diastolic pressure. Depression in myocardial function was detectable within 1 minute after initiation of propranolol and persisted when negative chronotropic effects were eliminated by atrial pacing. The multisensor catheter technique allows rapid and safe detection of changes in cardiovascular function during propranolol administration in conscious man.
Intraaortic balloon counterpulsation with and without reperfusion for myocardial infarction shock.
Authors: DeWood M A , Notske R N , Hensley G R , Shields J P , O'Grady W P , Spores J , Goldman M , Ganji J H
Published: June 2012

Forty patients were treated for cardiogenic shock secondary to acute myocardial infarction. Twenty-one (group 1) were treated with intraaortic balloon counterpulsation and 19 (group 2) were treated with counterpulsation and coronary artery bypass grafting. The groups were similar in age, incidence of previous infarction, initial hemodynamics and coronary anatomy. The in-hospital mortality between group 1 (52.4%) and group 2 (42.1%) was not significantly different. The difference in long-term mortality between group 1 and group 2 was substantially different (71.4% vs 47.3%). The subset of group 2 (n = 12) that underwent reperfusion and counterpulsation within 16 hours from the onset of symptoms of infarction had a lower mortality (25.0%) than the subset (n = 7) that underwent operation more than 18 hours after the onset of symptoms (71.4%). The long-term mortality in the subset of group 2 patients operated on within 16 hours after the onset of infarction was significantly different from that in group 1 (25.0% vs 71.4%, p less than 0.03). The data suggest that reperfusion with counterpulsation is more effective when carried out early. Patients who develop shock more than 18 hours after the onset of symptoms of infarction appear to benefit most if treated with counterpulsation alone.
Test of a model of antiarrhythmic drug action. Effects of quinidine and lidocaine on myocardial conduction.
Authors: Hondeghem L , Katzung B G
Published: June 2012

The effects of quinidine and lidocaine on the maximum upstroke velocity (Vmax) of the ventricular myocardial action potential were compared with the effects predicted by a model over a wide range of driving rates, rhythm disturbances and holding potentials. These rate-, rhythm- and voltage-dependent effects were accurately predicted by the proposed model. The model was also able to predict several previously undocumented properties of the drugs: 1) If lidocaine decreases Vmax of a pulse train, the steady state is reached within a few action potentials. 2) The poststimulation recovery of Vmax in the presence of lidocaine or quinidine can occur in a multiexponential fashion, if the membrane potential is kept at the potential where both the fast (operating mainly at more negative membrane potentials) and the slow (operating at more positive potentials) recovery processes are operative. 3) Hyperpolarization markedly attenuates the rate-dependent drug effects. 4) Combinations of lidocaine and quinidine have a superadditive effect on the Vmax of early extrasystoles.
Epicardial and endocardial activation during sustained ventricular tachycardia in man.
Authors: Horowitz L N , Josephson M E , Harken A H
Published: June 2012

Ventricular activation during ventricular tachycardia was studied by intraoperative epicardial and endocardial mapping in 21 patients with coronary artery disease and previous myocardial infarction who underwent operation for recurrent ventricular tachycardia. Twenty-nine morphologically distinct tachycardias were mapped; 18 tachycardias had a right bundle branch block morphology and 11 had a left bundle branch block morphology. After cannulation for bypass, the tachycardias were induced and electrograms were recorded at 55-75 epicardial sites. After starting cardiopulmonary bypass, the infarction was incised and electrograms were recorded at 28-55 left ventricular endocardial sites during ventricular tachycardia. All mapping data were analyzed with three simultaneously recorded ECG lead and two reference electrograms. Earliest activation in all tachycardias occured on the endocardial surface of the infarction. In each tachycardia, endocardial electrical activity was recorded before the onset of the QRS complex. Earliest epicardial activation in the 29 tachycardias occurred 10 msec after the onset of QRS complex. Epicardial breakthrough occurred on the right (19 tachycardias) as well as the left ventricle (10 tachycardias). We conclude that ventricular tachycardia associated with ischemic heart disease originates near the endocardial surface of the left ventricle along the border of the infarction and that epicardial mapping alone is insufficient to identify the site of origin of these tachycardias.
Anatomic substrate of impaired antegrade conduction over an accessory atrioventricular pathway in the Wolff-Parkinson-White syndrome.
Authors: Klein G J , Hackel D B , Gallagher J J
Published: June 2012

We present a patient with Wolff-Parkinson-White syndrome who died of a myocardial infarction 19 months after clinical electrophysiologic studies. These studies suggested the presence of a left atrioventricular accessory pathway that sustained conduction well in the retrograde direction but only intermittently in the antegrade direction. Postmortem examination of the heart revealed three accessory atrioventricular pathways in proximity to each other in the posterolateral atrioventricular region. One pathway showed complete fibrosis and two showed patchy fibrosis. The fibrosis suggests an anatomic basis for the impaired antegrade conduction observed in life.
Corrected transposition with severe intracardiac deformities with Wolff-Parkinson-White syndrome in a child. Electrophysiologic investigation and surgical correction.
Authors: Benson D W , Gallagher J J , Oldham H N , Sealy W C , Sterba R , Spach M S
Published: June 2012

This is a report of a 10-year-old child who underwent surgery for complex congenital heart disease consisting of corrected transposition of the great vessels, ventricular septal defect, patent ductus arterisus, severe left-sided atrioventricular (AV) valve insuffieicney (Ebstein's deformity) and Wolff-Parkinson-White syndrome. The site of his accessory AV connection was localized preoperatively at a left anterolateral site by isopotential body surface maps and by intracardiac electrophysiologic studies. He successfully underwent surgery for closure of the ventricular septal defect, ligation of the patent ductus arteriosus, replacement of the left-sided AV valve, and interruption of the accessory AV pathway. Unavoidable complete AV block acquired at surgery required subsequent permanent pacemaker therapy.
Single arterial trunk arising from the aortic arch.
Authors: McDowell D E , Grant M A , Gustafson R A
Published: June 2012

A 59-year-old male with a single, arterial trunk arising from the aortic arch is reported. No orther cases of this anomaly have been confirmed; a review of the literature does not reveal another reported case of this abnormal arterial configuration.
Detecting left main coronary artery disease by apical, cross-sectional echocardiography.
Authors: Chen C C , Morganroth J , Ogawa S , Mardelli T J
Published: June 2012

To test the feasibility of imaging the left main coronary artery (LMCA) noninvasively as a means of detecting left main coronary artery disease, we studied 73 patients who underwent cardiac catheterization and cross-sectional echocardiography. Fifty-two had a normal LMCA (controls) and 21 had significant obstruction (greater than or equal to 50% luminal reduction). The apical, tomographic, cross-sectional, phased-array, echocardiographic approach was used, and the LMCA was imaged in 52 of 73 patients (71%). In 34 of 36 controls (94%) the LMCA was correctly judged as having no luminal obstruction. In the other two, and asymmetric, high-intensity echo in one wall of the artery suggested atherosclerotic disease, but coronary angiography revealed no obstruction. In 12 of 16 patients (75%) in whom significant LMCA disease was imaged, obstruction was predicted by echocardiographic criteria of either luminal irregularity or an asymmetric, high-intensity echo in the arterial wall. This preliminary study suggests that cross-sectional echocardiography appears to be a feasible, noninvasive technique to image the LMCA and to detect hemodynamically significant luminal obstruction.
Two-dimensional echocardiographic recognition of left ventricular pseudoaneurysm.
Authors: Catherwood E , Mintz G S , Kotler M N , Parry W R , Segal B L
Published: June 2012

Five consecutive patients with proved left ventricular pseudoaneurysm (PA) and 22 patients with true aneurysm (TA) were studied by two-dimensional echocardiography (2DE). In four of the five patients with PA, 2DE successfully displayed the PA. The unique 2DE characteristics of PA include: (1) a sharp discontinuity of the endocardial image at the site of the PA communication with the left ventricular cavity; (2) a saccular or globular contour of the PA chamber; and (3) the presence of a relatively narrow orifice in comparison with the diameter of the PA fundus. In addition, 2DE detected the presence of thrombotic material within the extraventricular chamber in three of four cases. By deriving the ratios of the end-systolic orifice to diameter measurements for the patients with PA (0.37 +/- 0.07) compared with TA (1.00 +/- 0.08), we found that 2DE reliably differentiated PA from TA (p < 0.001). We conclude that 2DE is a useful noninvasive method for revealing left ventricular PAs and for distinguishing PA from TA. Considering the high risk of spontaneous rupture associated with pseudoaneurysms, this noninvasive capability is of paramount clinical importance.
Temporary transvenous pacing and femoral vein thrombosis.
Authors: Nolewajka A J , Goddard M D , Brown T C
Published: June 2012

The true incidence of thrombosis and pulmonary embolism in patients requiring temporary transvenous pacing via the femoral vein in unknown. Twenty-nine patients, mean age 66.2 years (range 38-79 years) who required temporary pacing were studied by bilateral contrast venography and perfusion lung scanning after removal of the pacing catheter. The patients were subdivided into two subgroups based on hemodynamic status. There was no statistical difference between the two groups with respect to mean age or the time the pacer catheter was in place and all patients were placed on low-dose heparin therapy. Ten patients (34%) had venographic evidence of thrombosis; six of them (60%) showed lung scan evidence of pulmonary emboli. The hemodynamically compromised group consisted of seven patients, six (85%) of whom had thrombosis; three of these six (50%) had pulmonary emboli. Of the 22 patients in the hemodynamically stable group, four (18%) had thrombosis and two of these (50%) had pulmonary emboli. Venous thrombosis, with subsequent pulmonary emboli, is a serious complication of temporary transvenous pacing using the femoral approach, despite the use of prophylactic low-dose heparin.
A new method for evaluating antiarrhythmic drug efficacy.
Authors: Sami M , Kraemer H , Harrison D C , Houston N , Shimasaki C , DeBusk R F
Published: June 2012

To develop standards for distinguishing antiarrhythmic drug effect from spontaneous variability of premature ventricular complexes (PVCs), 21 males (mean age 56 +/- 8 years) with chronic ischemic heart disease and PVCs underwent symptom-limited treadmill exercise testing and 24-hour ambulatory monitoring before and after 2 weeks of placebo medication. Linear regression analysis was used to describe the relationship between baseline and placebo PVC frequency for various indexes of ventricular ectopic activity and to establish 95% and 99% one-tailed confidence intervals for this relationship within the group of 21 patients. The lower limit of baseline PVC frequency for which the procedure could distinguish a placebo from a true drug response, termed the "sensitivity threshold," was an average frequency of 2.2 PVCs/hour for ambulatory electrocardiographic monitoring and 1.2 PVCs/min for treadmill exercise testing. All patients exceeded the sensitivity threshold on baseline ambulatory ECGs, but only 38% of patients did so on baseline treadmill exercise tests. To establish antiarrhythmic efficacy with 95% confidence, the minimal percent reduction of PVCs between baseline and placebo visits was 68% for treadmill exercise testing and 65% for ambulatory electrocardiography. Although these standards were developed in patients with chronic ischemic heart disease, the model can be used to establish antiarrhythmic drug efficacy in any patient group.
Preoperative exercise capacity in symptomatic patients with aortic regurgitation as a predictor of postoperative left ventricular function and long-term prognosis.
Authors: Bonow R O , Borer J S , Rosing D R , Henry W L , Pearlman A S , McIntosh C L , Morrow A G , Epstein S E
Published: June 2012

Forty-five symptomatic patients with aortic regurgitation underwent graded treadmill exercise testing before operation. Twenty-seven patients (group A) could not complete stage I of the National Institutes of Health exercise protocol because of limiting symptoms (exercise duration less than or equal to 22.5 minutes); 18 patients (group B) completed this stage without limiting symptoms (exercise duration > 22.5 minutes). Patients in group A had higher resting pulmonary capillary wedge pressures (mean 19 vs 13 mm Hg, p < 0.05) and left ventricular (LV) end-diastolic pressures (mean 24 vs 16 mm Hg, p < 0.05) than those in group B, but did not differ with respect to LV systolic dimension or fractional shortening by echocardiography or LV ejection fraction at rest or during exercise by radionuclide cineangiography. Among 32 patients with subnormal preoperative LV fractional shortening on echo, nine of 17 in group A and 0 of 15 in group B have died (p < 0.01); seven of the nine deaths were from late congestive heart failure. Group A patients also had less decrease postoperatively in LV diastolic size by echocardiography (mean decrease 8 vs 23 mm, p < 0.001) and less increase postoperatively in LV ejection fraction during exercise by radionuclide cineangiography (mean increase 11% vs 23%, p 0.05) than group B patients. No group A patient and 60% of group B patients had normal exercise ejection fractions postoperatively (p < 0.01). The differences in postoperative mortality and function were not predicted by the differences in preoperative hemodynamics between the two groups. Thus, exercise capacity is imprecise in assessing preoperative LV function in symptomatic patients with aortic regurgitation, but is useful in predicting long-term survival after operation and reversibility of LV dilatation and systolic dysfunction.
Echocardiographic study of the paradoxical arterial pulse in chronic obstructive lung disease.
Authors: Settle H P , Engel P J , Fowler N O , Allen J M , Vassallo C L , Hackworth J N , Adolph R J , Eppert D C
Published: June 2012

In nine subjects with chronic obstructive pulmonary disease (COPD) and pulsus paradoxus, M-mode echocardiograms showed inspiratory augmentation of right ventricular dimensions and inspiratory decrease of left ventricular diastolic dimensions. In five subjects in whom the echocardiographic transistor was in the subxiphoid position, mean right ventricular dimensions increased during inspiration from 1.4 +/- 0.20 to 2.96 +/- 0.38 cm (p < 0.01). With inspiration, mean left ventricular diastolic dimensions decreased from 4.8 +/- 0.61 to 3.7 +/- 0.63 cm (p < 0.01) in these five subjects. Two-dimensional echocardiograms, performed in three subjects, confirmed inspiratory augmentation of right ventricular cross-sectional area. Similar changes were produced in two normal volunteers by artificial obstruction to breathing. Left ventricular ejection time measurements demonstrated an inspiratory decline in left ventricular stroke volume. Inspiratory filling of the right ventricle is not hampered, but rather is exaggerated in patients with COPD and pulsus paradoxus, and left ventricular stroke volume is reduced during inspiration. Exaggerated variations in intrathoracic pressure alone did not explain pulsus paradoxus. Increased right ventricular filling and stroke volume during inspiration probably play a part.
The Urinary Output of Catechol Derivatives Including Adrenaline in Normal Individuals, in Essential Hypertension, and in Myocardial Infarction
Authors: NUZUM FRANKLIN R. , BISCHOFF FRITZ
Published: June 2012

Based on Shaw's specific test, the adrenaline content of the urine of some normal individuals was considerably higher than has been reported by those using the von Euler technic (adsorption at an alkaline pH, elution and bioassay). One patient with myocardial infarction showed highly significant amounts on four occasions. The marked elevation in the Kroneberg-Schümann catechol ratio for hypertension patients as compared with normals, reported by these authors, was not confirmed by our findings. In three cases of myocardial infarction the ratio was elevated. Our ratios for normals confirm the original work.
Effect of Cortisone on the Size of Experimentally Produced Myocardial Infarcts
Authors: JOHNSON ARAN S. , SCHEINBERG SCHAYEL R. , GERISCH ROBERT A. , SALTZSTEIN HARRY C.
Published: June 2012

In a total of 57 dogs the anterior descending branch of the left coronary artery was doubly ligated. Cortisone apparently (1) reduced the area of residual fibrosis; (2) increased the vascularity of the heart.
Cardiovascular Lesions in Arachnodactyly
Authors: GOYETTE EDWIN M. , PALMER PAUL W.
Published: June 2012

The cardiovascular lesions in 34 cases of Marfan's syndrome which were studied post mortem are reviewed. Recent reports show that the most common and most important lesion is cystic necrosis of the media which results in aneurysmal formations of the ascending aorta. The aneurysm may be fusiform and the aortic ring dilated, producing a marked aortic insufficiency, or there may be a dissecting aneurysm, either recent or chronic. Valvular lesions are common but probably not important. Septal defects are occasionally encountered but are not functionally significant.
Management of Shock in Acute Myocardial Infarction
Authors: GOOTNICK ABRAHAM , KNOX FREDERICK H.
Published: June 2012

Shock complicating acute myocardial infarction contributes materially to the over-all mortality. The wisdom of combating the shock has been a matter of dispute, many clinicians holding that the fall in blood pressure has the salutary effect of reducing the work of an acutely injured heart. This report deals with a four-year experience in active intervention for shock. The data suggest that timely intervention for shock is frequently life-saving, and may be instrumental in halving themortality of the sickest patients.
Studies in Peripheral Arterial Occlusive Disease
Authors: WESSLER STANFORD , SCHLESINGER MONROE J. , SPILBERG MARCIA
Published: June 2012

A new technic is described for the study of the arterial circulation of amputated extremities. The method is based on the use of a radiopaque injection mass containing lead and gelatin, and a procedure for unrolling the extremity so that the major arteries lay in one plane. Data are presented concerning the extent and location of arterial occlusion, narrowing, calcification and interarterial anastomosis in 66 legs amputated because of arteriosclerotic gangrene.
The Bronchoscopic Measurement of Left Auricular Pressure
Authors: ALLISON P. R. , LINDEN R. J.
Published: June 2012

A specially adapted needle on the end of a Jackson's suction tube has been used to pierce the left auricle of the heart through the upper end of one of the main bronchi. Pressure measurements and wave forms have been recorded in patients suffering from lung disease with normal hearts, in those with mitral stenosis and mitral regurgitation. This preliminary communication describes the method and shows some typical results.
The Degree of Coronary Atherosclerosis in Bilaterally Oophorectomized Women
Authors: WUEST JOHN H. , DRY THOMAS J. , EDWARDS JESSE E.
Published: June 2012

The degree of coronary atherosclerosis in 49 hearts obtained from bilaterally oophorectomized women was compared with the degree of sclerosis in 600 hearts from women and in 600 hearts from men of comparable ages. On the average the degree of coronary sclerosis in the bilaterally oophorectomized women was greater than in control women but less than in control men.
Response to Psychologic Stress in Persons Who Are Potentially Hypertensive
Authors: HARRIS ROBERT E. , SOKOLOW MAURICE , CARPENTER LEWIS G. , FREEDMAN MERVIN , HUNT SAMUEL P.
Published: June 2012

College women who are prehypertensive and matched controls were exposed to emotion-provoking situations, psychologic tests, and psychiatric interviews. Patterns of response differentiating the groups were observed. The prehypertensives were less well controlled, more impulsive, more egocentric, and generally less adaptable in the stressful situations. In the psychiatric interviews, behavior similar to that of patients with hypertension was noted. The findings suggest that prehypertensives are more vulnerable in situations involving psychologic stress, and hence more subject to the autonomic concomitants of emotion, including repetitive rises of blood pressure.
Observations on the Hemodynamic Properties of a Thiophanium Derivative, Ro 2-2222 (Arfonad), in Human Subjects
Authors: ASSALI N. S. , DOUGLASS ROY A. , SUYEMOTO ROY
Published: June 2012

Observations on the hemodynamic properties of a thiophanium derivative (Arfonad) have been made on normotensive nonpregnant and pregnant subjects and on patients with hypertensive complications of pregnancy. The drug was given by single intravenous injections and by intravenous drip infusion. The hypotensive effects of single injections where compared with those of a standard tetraethylammonium chloride (TEAC) test. The authors observed that the hemodynamic effects of Arfonad were similar in some respects to those of tetraethylammonium chloride or spinal anesthesia. A fall in the cardiac output occurred when the blood pressure fell following Arfonad administration. The authors discuss these hemodynamic effects in terms of differences in response to ganglionic blocking agents of the various groups of subjects studied.