G. William Henry

Anatomically sound, simplified approach to repair of “complete” atrioventricular septal defect

BACKGROUND There are few congenital anomalies of the heart that have benefited more from thorough anatomic analysis than the complex anomaly known as atrioventricular septal defect in the setting of common atrioventricular junction. Recent advances in understanding the anatomy of this lesion have led to alternative methods of repairing these defects. METHODS The medical records of 21 consecutive patients undergoing repair of complete atrioventricular septal defect have been reviewed. Nine of these patients had a standard one- or two-patch repair, and 12 had direct closure of the ventricular element of the defect. RESULTS Direct closure resulted in significantly shorter pump and cross-clamp times. Follow-up for an average of 34 months suggests that when direct closure can be performed, the results are comparable with those of the more standard technique. CONCLUSIONS Our initial success with this approach is encouraging; however, longer follow-up is required to establish whether it will be broadly applicable.

Pulmonary blood velocity profile variability in open-chest dogs: Influence of acutely altered hemodynamic states on profiles, and influence of profiles on the accuracy of techniques for cardiac output determination

SummaryClinical investigations focused on finding characteristics of noninvasively obtained measurements of pulmonary blood velocity that can be used to quantitate pulmonary blood flow and/or pulmonary pressure have often yielded results whose imprecision has been attributed to flow pattern variability. To determine flow pattern variability in an in vivo animal model in varying hemodynamic states, main pulmonary artery blood velocity waveforms were recorded in 17 dogs at 2-mm intervals along an anterior to posterior wall-oriented axis using a 20-MHz pulsed Doppler needle probe. Control data were obtained before the animals were subjected to altered flow (atrial level shunts) and pressure (10% O2 inhalation) states. Instantaneous velocity profiles were computed throughout the cardiac cycle. Estimates of pulmonary blood flow were obtained assuming an elliptical model of the pulmonary artery which allowed computation of velocity at all points in the cross section, based on the measured values along the axis. Model-based estimates were compared to measured values and estimates obtained in the traditional fashion, i.e., the product of centerline velocity and cross-sectional area. Results clearly showed marked interanimal variability, even in control states. Reverse flow in the posterior half of the vessel, which tended to become more pronounced with increased pulmonary artery pressure, was observed during late systole and early diastole. Elevated pulmonary blood flow tended to increase the maximum velocities along the anterior wall relative to midline velocities. Neither estimate of cardiac output yielded consistently accurate results (r=0.77 for model-based method,r=0.80 for area times central velocity method). Findings of this study, which highlight the dependency of waveform characteristics on sampling site, the large degree of intersubject variability, and the need for large or multiple sample volumes for pulmonary blood flow determination, help clarify inconsistencies observed by clinicians and suggest that future work with animal models will facilitate a greater understanding of the determinants of human pulmonary velocity waveforms.

Morphologic aspects of complete transposition.

SummaryComplete transposition is a morphologic entity which exists by virtue of a concordant atrioventricular connection co-existing with a discordant connection at the ventriculoarterial level. If diagnosed in this manner, all variants can be described simply and unambiguously in terms of associated malformations along with variations in relationships and infundibular morphology.

Cardiovascular Effects of Positive End-Expiratory Pressure (PEEP) after Pneumonectomy in Dogs

Little is known regarding the hemodynamic effect of positive end-expiratory pressure (PEEP) following pneumonectomy. To investigate this, 9 mongrel dogs underwent PEEP before and after lung resection. With the chest closed, the dog anesthetized, and partial pressure of carbon dioxide constant, PEEP was added in increments of 2 mm Hg until the animals condition became hemodynamically unstable. At each level of PEEP, aortic, pulmonary, left atrial, and central venous pressures were monitored while aortic flow (cardiac output) was determined with an electromagnetic probe and airway pressure was measured with a Millar catheter in the respiratory tubing. Pneumonectomy was then performed, PEEP was again sequentially added, and the same measurements were recorded. Both before and after pneumonectomy, a strong positive linear correlation exists between the level of PEEP and pulmonary vascular resistance (PVR) (r greater than 0.74; p less than 0.05). Also, there is a high negative linear correlation between the level of PEEP and cardiac output (r greater than -0.76; p less than 0.05). At 0 mm Hg of PEEP, the PVR is higher after pneumonectomy than before (p less than 0.02). The incremental elevation in PVR persists after pneumonectomy at each level of PEEP, and in 5 of the 9 dogs the slope of the linear regression line relating PVR to PEEP was steeper following resection (p less than 0.05), thereby demonstrating an exaggerated effect of PEEP on PVR. In addition, all animals had a lower cardiac output at each comparable level of PEEP following pneumonectomy (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

DIASTOLIC SHAPE OF THE RIGHT VENTRICLE OF THE HEART

Knowledge of right ventricular (RV) shape is important to the understanding of RV mechanical function and for the improvement of clinically important RV volume estimation techniques. Refinements to the simplest conceptions of RV shape are presented statistically here, based on a quantitative analysis of three‐dimensional magnetic resonance (MR) images of excised lamb hearts.

The problems that exist when considering the anatomic variability between the channels that permit interventricular shunting

Although steps are being taken to produce a universally acceptable coding system for categorisation of the congenitally malformed hearts, obstacles remain in the search for consensus. One of the groups of lesions continuing to produce the greatest problems is those that permit interventricular shunting. The difficulties relate partly to the words used to describe the group itself, as those using Germanic languages describe the holes as ventricular septal defects, whereas those using Romance languages consider them to represent interventricular communications. The two terms, however, are not necessarily synonymous. Further disagreements relate to whether the lesions placed within the group should be sub-categorised on the basis of their geographical location within the ventricular mass, as opposed to the anatomic nature of their borders. In reality, attention to both the features is necessary if we are to recognise the full extent of phenotypic variability. In this review, we first review the evolution and theories of analysis naming the channels that permit interventricular shunting. We then demonstrate that embryologic techniques provide evidence that the changing morphology of the developing murine heart parallels the anatomy of the different lesions encountered in the congenitally malformed human heart. We suggest that, with attention paid to the temporal development of the normal murine heart, combined with a strict definition of the plane of separation between the right and left ventricular cavities, it will be feasible to produce a categorisation that is acceptable to all.

Maturation of pulmonary input impedance spectrum in infants and children with ventricular septal defect

To determine whether pulmonary vascular disease can be detected in infants with ventricular septal defect (VSD) by the presence of an increase in the frequency of the impedance modulus minimum of the pulmonary input impedance spectrum, as has been implied for older children, spectra of 25 infants (2 years or younger) (group 1) were compared with spectra of 20 children (ages 2 to 7 years) (group 2). Groups were subdivided according to mean pulmonary artery (PA) pressure: those with moderate pressure levels (35 mm Hg or less, groups 1A and 2A) and those with high pressure levels (at least 40 mm Hg, groups 1B and 2B). Pulmonary vascular resistance, characteristic impedance and frequency of the modulus minimum were significantly lower in group 2A than in group 1A. The decrease in pulmonary vascular resistance and characteristic impedance with increasing age was consistent with body surface area increases; however, the shift in frequency of the modulus minimum could be more easily related to a decrease in the pulse wave velocity than to a shift in the primary reflection site. Pulmonary vascular resistance, characteristic impedance and the frequency of the first modulus minimum were comparable in groups 1B and 2B; however, none of the patients in group 1B had evidence of pulmonary damage, whereas 3 of 4 group 2B patients had microscopically apparent pulmonary vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Unusual opening of coronary sinus in atrioventricular septal defects

The coronary sinus is an important landmark for the position of the atrial component of the atrioventricular conduction axis and, thus, assumes special relevance to the surgeon in the operating room. We describe here 2 patients with atrioventricular septal defect characterized by an unusual termination of the coronary sinus within the left atrium. We discuss the potential importance of this finding to the disposition and surgical avoidance of the conduction tissues.

The Transmitral Approach to Left Ventricular Outflow Tract Obstruction

Left ventricular outflow tract obstruction is a particularly vexing problem in patients with complete transposition (atrioventricular concordance and ventriculoarterial discordance) and intact ventricular septum. Previous techniques, such as resecting the obstructive lesion through the pulmonary valve or bypassing the obstruction, have not given entirely satisfactory results. An alternative approach of resection through the left atrium and the retracted mitral valve has recently been proposed. We have used this new technique to achieve excellent relief of this condition in three patients with different types of obstruction.

From the Editor and Publisher

1 마태복음 Matthew 12:3-9 씨를 뿌리는 자가 뿌리러 나가서 뿌릴새 더러는 길 가에 떨어지매 새들이 와서 먹어버렸고 더러는 흙이 얇은 돌밭에떨어지매 흙이 깊지 아니하므로 곧 싹이 나오나 해가 돋은 후에 타져서 뿌리가 없으므로 말랐고 더러는 가시떨기 위에 떨어지매 가시가 자라서 기은을 막았고 더러는 좋은 땅에 떨어지매 혹 백배, 혹 육십배, 혹 삽십배의 결실을 하였느니라 귀있는 자는 들으라 하시니라 A Farmer went out to sow his seed. As we was scattering the seed, some fell along the path, and the birds came and ate it up. Some fell on rocky places, where it did not have much soil. It sprang up quickly, because the soil was shallow. But when the sun came up, the plants were scorched, and they withered because they had no root. Other seed fell among thorns, which grew up and choked the plants. Still other seed fell on good soil, where it produced a crop – a hundred, sixty or thirty times what was sown. He who has ears, let him hear. Journal of Korean American Ministries & Theology