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Biomedical subjects

H C Coghlan

Publications and source records attributed to H C Coghlan.

At least 19 recordsLinked to original sources
PubMed2001

The structure and function of the helical heart and its buttress wrapping. I. The normal macroscopic structure of the heart.

The Gordian knot of anatomy has been the architectural arrangement of ventricular muscle mass, which may have finally become understood. The description of Francisco Torrent-Guasp's model of the helical heart is presented, which includes the cardiac structures that produce 2 simple loops that start at the pulmonary artery and end in the aorta. An unscrolled ventricular band is shown, achieved by blunt dissection that extends between the points of origin of the right ventricle, at the pulmonary artery root, to termination at the aortic root, in the left ventricle. These components include a spiral horizontal basal loop that surrounds the right and left ventricular cavities, and changes direction to cause a second spiral, produced by almost vertically oriented fibers, giving rise to the helical configuration of the ventricular myocardial band. These anatomic structures are successively activated, as with a peristaltic wave, starting at the right ventricle (just below the pulmonary artery) and progressing toward the aorta to produce a sequence of narrowing, caused by the basal loop contraction, shortening (related predominantly to the descendant segment contraction), lengthening (produced by the ascendant segment contraction), and widening, as a consequence of several factors that act during ventricular myocardium relaxation. These sequences control the ventricular events responsible for ejection to empty and suction to fill. These mechanical interactions of structure and function are defined in relation to chronologic location of the successive cardiac functional events in the aortic, left ventricular, and left atrial recordings.

Animals↗
PubMed2001

The structure and function of the helical heart and its buttress wrapping. III. The electric spiral of the heart: The hypothesis of the anisotropic conducting matrix.

The study of the dissemination of the electric impulse throughout the ventricular myocardium, which gave rise to the current theories, was performed without taking into consideration the complex architecture of the cardiac muscle elucidated by more recent researchers. We propose a novel hypothesis based on the special macroscopic structure of the heart, the anisotropic electric and mechanical behavior of the myocardium, the characteristics of the intercellular matrix and its very special collagen scaffolding, chemical composition, and biochemistry. The unique properties of the intercellular matrix would make it especially suited to function, in conjunction with the specialized conducting system (His-Purkinje system), as an efficient anisotropic conductor for the spread of electric activation in the heart, and to allow an optimal sequence of excitation-contraction coupling that results in the coordination of effective myocardial contraction in birds and mammals of the most varied known heart rates.

Animals↗
PubMed2001

The structure and function of the helical heart and its buttress wrapping. IV. Concepts of dynamic function from the normal macroscopic helical structure.

Torrent-Guasp's model of the helical heart is presented, which includes the cardiac muscular structures that produce 2 simple loops and that start at the pulmonary artery and end in the aorta. These components include a horizontal basal loop that surrounds the right and left ventricles, changes direction through a spiral fold in the ventricular band to cause a ventricular helix produced by now obliquely oriented fibers, forming a descending and ascending segment of the apical loop with an apical vortex. These anatomic concepts are successively activated to produce a sequence of narrowing by the basal loop, shortening by the descending segment, lengthening by the ascending segment, and widening in the cardiac cycle that causes ventricular ejection to empty and suction to fill. The factors responsible for internal torsional movements for cardiac output and suction are defined, together with mechanisms responsible for electromechanical activity produced during sequential changes in contraction and relaxation properties. These interactions of mechanical structure and function are defined in relation to pressure-related cardiac events observed from aortic, left ventricular, and left atrial recordings.

Animals↗
PubMed2001

The structure and function of the helical heart and its buttress wrapping. V. Anatomic and physiologic considerations in the healthy and failing heart.

A macroscopic structure of an elliptic heart, formed by the helix provided by the apical loop, is defined and related, initially, to normal function. To define the sequence of normal progressive muscular activity, cardiac pressure, magnetic resonance imaging (MRI), and multiple gated acquisition (MUGA) records are reviewed. This novel format of structure for the helical heart is then compared with historic studies of ventricular structure. New concepts will show how the basal loops cause initial isovolumetric contraction, together with factors responsible for contractile ventricular lengthening responsible for filling by suction. The interaction of these muscular-functional changes are correlated to basic studies of electrophysiology (excitation-contraction) to set the stage for alterations produced by changing the helical apex to a sphere during congestive heart failure. Macroscopic changes in heart failure, which convert the ellipse to a globe, are defined as the underpinning of dilated cardiomyopathy. It is our hypothesis that the commonality of this spheric left ventricular substrate becomes responsible for ischemic, idiopathic, and dilated ventricular cardiomyopathy.

Heart↗
PubMed2001

The structure and function of the helical heart and its buttress wrapping. VI. Geometric concepts of heart failure and use for structural correction.

The macroscopic basis for congestive heart failure is defined as conversion of a helical heart, whereby the apical loop fiber angle orientation that produces a 60% ejection fraction becomes more transverse to develop a spheric configuration. The geometric consequence is flattening of the apical loop architecture, so that the 15% shortening can produce only 30% ejection fraction. The fundamental shape change is alteration of normal relationships between the transverse basal loop and oblique apical loop, to make the apical loop become more basal through more transverse fiber orientation. These fundamental architectural changes are then used to evolve new procedures that restore a more normal, helical, ventricular architecture in ischemic and dilated cardiomyopathy. Direct intraoperative ventricular methods underlie surgical ventricular restoration or endoventricular surgical patch plasty procedures, the Batista procedure, and Pacopexy. These intraventricular objectives are then compared with external approaches without ventriculotomy (ie, reimplantation of cells, pericardial sleeve (acorn), surface radiofrequency ablation, and the myocor approaches). A survey of current direct ventricular clinical results that improve the underlying nondamaged muscle (ie, remote segment) is defined, and related to timing of procedures directed at rebuilding more normal ventricular shape before irreversible collagen and fibrosis develop. The overall intent is to convert the spheric heart into an elliptic configuration. Novel concepts are introduced to suggest an internal ventricular patch can be used as an intercavitary curtain, through covering nonscarred septal muscle (ie, normal but distended) to amplify left ventricular function through producing a more helical structure.

Cardiac Surgical Procedures↗
PubMed2001

The structure and function of the helical heart and its buttress wrapping. VII. Critical importance of septum for right ventricular function.

The macroscopic structure of the right ventricle includes a transverse basal loop for the free wall, and oblique septal components, originating from the descending and ascending segments of the apical loop. Data is presented that determines why right ventricular function is related principally to intraventricular septal function, and why right ventricular failure is magnified by septal stunning caused by poor myocardial protection. The background of this architectural/functional change can explain normal right ventricular function, the relationship of right ventricular performance to pulmonary vascular resistance, experimental studies that characterize right ventricular performance after architectural free wall ablation, right ventricular disconnection, right coronary occlusion, and free wall replacement. These basic science studies are related to perioperative right ventricular performance, involving methods of myocardial protection, protamine reaction, right coronary occlusion and reperfusion, right ventricular dyskinesia, chronic aortic and mitral valve replacement (MVR) replacement, congenital heart disease, right and left ventricular assist devices (LVADs), and transplantation. The predominant focus is related to the septum and how it can be evaluated perioperatively. Septal evaluation by echocardiogram should become an essential feature during intraoperative management.

Cardiovascular Diseases↗
PubMed2001

Cardiac architecture: Gothic versus Romanesque. A cardiologist's view.

The healthy left ventricle, with remarkable mechanical efficiency, has a gothic architecture, which results from the disposition of the myocardial fibers supported and maintained by a normal collagen matrix scaffold. This conclusion, arising from the analysis of roman and gothic buildings and from comparative biology of the left ventricles of different species, has been substantiated by the study of three-dimensional images obtained by MRI and analyzed with mathematic methods for measurements of the curvature and thickness of the ventricular walls. The assessment of left ventricular functional reserve based on the architecture has been very important in making therapeutic and surgical decisions in our patients and has important implications for the design of surgical strategies designed to try to improve ventricular function by restoring an architecture that allows more efficient ventricular mechanics. The structural approach and its combination with important advances in the knowledge of membrane channels, signaling pathways, cytokines, growth factors, neuroregulation, and targeted pharmacology, and with the advances in methods for reducing hemodynamic load and its cellular and structural consequences, is certain to bring about a dramatic change in the very serious and highly prevalent congestive failure associated with the Romanesque transformation of the diseased left ventricle.

Animals↗
PubMed1997

Autonomic regulation in asthmatics with gastroesophageal reflux.

STUDY OBJECTIVE: To study the role of autonomic regulation in asthmatics with gastroesophageal reflux (GER). DESIGN: Prospective study. SETTING: Autonomic function laboratory of a 908-bed university hospital. PARTICIPANTS: Fifteen nonsmoking asthmatics with GER (six men, nine women; average age, 36 years). INTERVENTIONS: Subjects were connected to an ECG monitor. BP was measured by sphygmomanometer at set intervals. After a resting period, each subject had heart rate and BP monitored during an 80 degrees passive tilt, Valsalva maneuver, quiet and deep breathing, handgrip, and an echo stress test of cortical arousal. Each autonomic function test was analyzed and defined as normal, hypervagal, hyperadrenergic, or mixed (a combination of hypervagal and hyperadrenergic responses) as compared with 23 age-matched normal control subjects from our laboratory (14 men, 9 women; average age, 35 years) and published normal control values. Each subject had an overall response score that was determined by the results of the tilt, Valsalva maneuver, and deep breathing maneuvers. RESULTS: All asthmatics with reflux had at least one autonomic function test display a hypervagal response. Overall response scores show that eight of 15 asthmatics with GER had an overall hypervagal response, and seven had a mixed response. Of the seven asthmatics with GER who had a mixed response score, two had a hypervagal predominant response. CONCLUSIONS: Asthmatics with GER have evidence of autonomic dysfunction. Heightened vagal tone may be partially responsible for the heightened airway responsiveness to esophageal acidification in asthmatics with reflux.

Adult↗
PubMed1988

Cortical blindness after left internal mammary artery to left anterior descending coronary artery graft angiography.

We describe a case of transient cortical blindness following internal mammary artery to left anterior descending coronary artery graft angiography. This dramatic, infrequent, and self-limiting complication so far has not been described in the cardiovascular literature. In the present era of internal mammary artery use for the left coronary artery grafting, the angiographer should be familiar with the diagnosis, prevention, and management of complications previously seen mostly during the posterior cerebral circulation angiography.

Angiography↗
PubMed1987

Coronary disease, cardioneuropathy, and conduction system abnormalities in the cardiomyopathy of Friedreich's ataxia.

Abnormalities of the heart are a frequent and possibly ubiquitous problem in patients with Friedreich's ataxia, but their pathogenesis is unclear. Postmortem findings are reported from the hearts of three patients with Friedreich's ataxia who died of congestive heart failure and atrial arrhythmias. Particular attention was paid to the following: the large and small coronary arteries, the nerves and ganglia, the conduction system, and the histological and cellular features of the cardiomyopathy. There were pleomorphic nuclei and focal fibrosis and degeneration throughout each heart including the conduction system. There were distinctive abnormalities of both large and small coronary arteries, and focal degeneration of nerves and ganglia. These observations suggest a mosaic concept for the pathogenesis for the cardiomyopathy of Friedreich's ataxia that involves the interplay of molecular faults, cardiomyopathy, cardioneuropathy, and coronary disease.

Adult↗
PubMed1986

Dizziness and the autonomic dysfunction syndrome.

Dizziness resulting from inner ear or CNS disease has been well described. However, there is a large number of patients for whom dizziness does not seem to be related to either the ears or the CNS. We postulate an abnormality in the autonomic nervous system of such patients and have used standard tilt testing and Valsalva methods to assess the abnormality. Based on the results of these tests, we can suggest therapeutic options.

Adolescent↗
PubMed1983

Influence of atrial mechanoreceptors upon the sympathetic efferent activity elicited during a cardiogenic chemoreflex in the dog.

Two different cardiogenic reflexes were studied for their effects upon the activity recorded from the thoracic cardiac nerves of 7 chloralose-anesthetized dogs. Sympathetic efferent activity in 5 right and 7 left anterior ansa multifiber preparations was quantitatively analyzed. A cardiogenic hypertensive chemoreflex was induced by administration of serotonin (100 micrograms/ml, 2 ml) into the left atrium before, during and after inflation of balloons in the right and/or left atrial appendages. Balloon inflations alone resulted in heart rate increases of 5-20 bpm but arterial blood pressure, pulse pressure and end diastolic pressure were not significantly affected. Control serotonin-induced efferent discharges were 174 +/- 10% (mean +/- S.E.M.) of resting activity with a duration of 5.2 +/- 0.4 s. During inflation of both atrial balloons, the serotonin-induced efferent discharges were 165 +/- 14% (N.S.) of resting activity with a duration of 7.8 +/- 0.7 s (P less than 0.01). Following release of the balloons, the serotonin-induced discharges were 152 +/- 17% (N.S.) of resting activity with a duration of 4.9 +/- 0.4 s (N.S.). These results suggest that afferent signals from atrial mechanoreceptors can act to increase the duration but not the total intensity of the efferent sympathetic discharges elicited during a cardiogenic chemoreflex.

Animals↗
PubMed1983

Angiographic differentiation of types of ventricular septal defects.

A retrospective study of 40 patients with 41 surgically repaired ventricular septal defects was performed in order to correlate the anatomic findings with the angiographic features seen by axial angiography. In 39 patients there were 32 perimembranous, three muscular, and four subarterial defects. One patient had both perimembranous and inlet muscular ventricular septal defects. Perimembranous defects as seen on left ventriculograms on long axial view are in continuity with the aortic valve. The relation of the defect to the tricuspid valve allows distinction of the extension of the perimembranous defect toward the inlet, trabecular, or infundibular zones. This relation was determined angiographically, using the course of the contrast medium from the left ventricle through the ventricular septal defect opacifying the right ventricle. Muscular defects are separated from the semilunar and atrioventricular valves. Subarterial defects are related to both semilunar valves, and they are best demonstrated by the elongated right anterior oblique view of the left ventriculogram. This study demonstrated that with axial views an experienced angiographer can define the location, size, and relations of the ventricular septal defects with high accuracy. In only two of the 41 defects there were differences between the retrospective angiographic prediction and the previous surgical findings.

Adolescent↗
PubMed1981

Improved cineangiographic evaluation of hypertrophic cardiomyopathy by caudocranial left anterior oblique view.

Seven patients with hypertrophic cardiomyopathy and one with discrete subaortic stenosis were studied with axial left ventriculography (caudocranial left anterior oblique view). In addition to the angiographic findings described on conventional views, the mitral valve, ventricular septum, and posterior left ventricular wall were better profiled than with conventional views and thus better evaluated. Systolic anterior motion of the anterior leaflet of the mitral valve was readily identifiable, which is usually not the case in nonangled views. From our experience, we strongly recommend that caudocranial left ventriculography be the procedure of choice in patients suspected of left ventricular outflow tract abnormalities and that biventricular angiography be abandoned for diagnostic purposes.

Adolescent↗
PubMed1981

Congenital heart malformations: sequential angiographic analysis.

A segmental angiographic analysis of congenital heart malformations has been developed with the intention of making evaluation of complex congenital heart anomalies as comprehensive as possible. Each vascular and cardiac segment is analyzed sequentially, considering morphology, connections, and relations. Additional associated cardiovascular abnormalities such as shunts, stenoses, hypoplasias, and atresias are also considered. Information analyzed and presented in this way has more immediate anatomic and physiologic meaning than ambiguous terms, often with obscure embryologic implications. Disagreements regarding definitions and nomenclature will continue; however, a logical framework that allows clear communication among cardiologists, surgeons, and angiographers is absolutely necessary and is provided by the orderly analysis presented here.

Coronary Vessel Anomalies↗
PubMed1981

Effects of selectively produced changes in cardiac rhythm or conduction upon flow in the superior vena cava.

The effects of changes in cardiac rhythm or conduction on the rate of volume flow in the superior vena cava (SVC) were studied in 25 dogs anesthetized with sodium pentobarbital. Slowing of sinus rate from 145 +/- 16 to 114 +/- 12 beats/min was achieved by selective perfusion of Ringer's solution into the sinus node artery. During sinus slowing there was a continuous change in the systolic-diastolic flow ratio measured in the SVC. At control sinus rate (net), total forward flow as 6.3 ml/beat with a systolic volume of 6.5 ml and a diastolic volume of -0.2 ml. At the slowest bradycardia, total forward flow had increased by 25%. Since there was no significant change in the systolic volume, the entire 25% increase in forward flow occurred during ventricular diastole. During atrioventricular (AV) block (second-degree or complete), achieved by selective perfusion of eserine into the AV node artery, unimpaired acceleration of flow was readily demonstrable in the SVC even in the absence of ventricular contraction. Thus systolic ventricular suction (vis a fronte) has little or no effect on right atrial filling. During high-degree AV block, the normal atrial contraction readily opened the tricuspid valve, and when both atrium and ventricle were filled to or near maximum capacity, atrial contraction was consistently vigorous enough to propel blood into the pulmonary artery. Given appropriate hemodynamic circumstances, these results confirm the remarkable effectiveness of right atrial contractile performance.

Animals↗