Deaths After Readmissions are Mostly Attributable to Failure-to-Rescue in EGS Patients

INTRODUCTION

We have recently shown that readmission after EGS procedures carries a 4-fold higher mortality rate when compared to those not readmitted. Understanding factors associated with death after readmission is paramount to improving outcomes for EGS patients. We aimed to identify risk factors contributing to failure-to-rescue (FTR) during readmission after EGS. We hypothesized that most post-readmission deaths in EGS are attributable to FTR.

METHODS

A retrospective cohort study using the NSQIP database 2013-2019 was performed. Patients who underwent 1 of 9 urgent/emergent surgical procedures representing 80% of EGS burden of disease, who were readmitted within 30 days post-procedure were identified. The procedures were classified as low- and high-risk. Patient characteristics analyzed included age, sex, BMI, ASA score comorbidities, postoperative complications, frailty, and FTR. The population was assessed for risk factors associated with mortality and FTR by uni- and multivariate logistic regression.

RESULTS

Of 312,862 EGS cases, 16,306 required readmission. Of those, 10,748 (3.4%) developed a postoperative complication. Overall mortality after readmission was 2.4%, with 90.6% of deaths attributable to FTR. Frailty, high-risk procedures, pulmonary complications, AKI, sepsis, and the need for reoperation increased the risk of FTR.

DISCUSSION

Death after a complication is common in EGS readmissions. The impact of FTR could be minimized with the implementation of measures to allow early identification and intervention or prevention of infectious, respiratory, and renal complications.

Management of choledocholithiasis in the elderly: Same-admission cholecystectomy remains the standard of care

BACKGROUND

Current guidelines recommend that patients with choledocholithiasis undergo same-admission cholecystectomy. The compliance with this guideline is poor in elderly patients. We hypothesized that elderly patients treated with endoscopic retrograde cholangiopancreatography (ERCP) alone would have higher complication and readmission rates than the patients treated with cholecystectomy.

METHODS

The Nationwide Readmissions Database was queried for all patients aged ≥65 years with admission for choledocholithiasis January to June 2016. The patients were divided based on index treatment received: (1) no intervention; (2) ERCP alone; or (3) cholecystectomy. Multivariate analyses identified predictors of cholecystectomy during index admission and of readmissions.

RESULTS

A total of 16,121 patients with choledocholithiasis were admitted; 38.4% underwent cholecystectomy, 37.6% endoscopic retrograde cholangiopancreatography alone, and 24.0% no intervention. The patients not receiving a cholecystectomy were more likely to be older, female, have a higher Elixhauser score, do-not-resuscitate status, and at a teaching hospital (all P < .001). Emergency readmissions for recurrent biliary disease were lowest in patients undoing a cholecystectomy (2.2% vs 9.2% endoscopic retrograde cholangiopancreatography and 12.4% no intervention, P < .001), as were readmissions for complications (3.6% vs 5.5% and 7.8%, P < .001). Cholecystectomy reduced rates of readmissions for recurrent disease (odds ratio 0.168, P < .001), for complications (odds ratio 0.540, P < .001), and death during readmission (odds ratio 0.503, P = .007); endoscopic retrograde cholangiopancreatography alone reduced only rates of readmissions. Age was not a predictor of readmission or death.

CONCLUSION

Index admission cholecystectomy is associated with a lower risk of readmission for biliary disease or complications, as well as death during readmission, in elderly patients. Age alone is not predictive of outcomes; surgical intervention should be guided by clinical condition, comorbidities, and patient preference.

Communication and Palliation in Trauma Critical Care: Impact of Trainee Education and Mentorship

BACKGROUND

Surgical residency training requires Advance Care Planning (ACP) and Palliative Care (PC) education. To meet education needs and align with American College of Surgeons guidelines, our Surgical Intensivists and PC faculty developed courses on communication and palliation for residents (2017-18) and fellows (2018-19). We hypothesized that education in ACP would increase ACP communication and documentation.

METHODS

The trauma registry of an academic, level 1trauma center was queried for ICU admissions from 2016-2019, excluding incarcerated and pregnant patients. A retrospective chart review was performed, obtaining frequency of ACP documentation, ACP meetings, time from admission to documentation, and PC consultation. We collected ICU quality measures as secondary outcomes: ICU Length Of Stay (LOS), hospital LOS, ventilator days, invasive procedures, discharge disposition, and mortality. Comparisons were made between years prior to (Y 1) and following implementation (Y 2: residents, Y 3: fellows).

RESULTS

For 1732 patients meeting inclusion criteria, patient demographics, injuries, and injury severity score were comparable. ACP documentation increased from 19.5% in Y 1 to 57.2% in Y 3 (P < 0.001). Time to ACP documentation was reduced from 47.6 to 13.1 h (P < 0.001) from time of admission. ICU LOS decreased from 6 to 4.8 d (P = 0.004). Patients in Y 3 had fewer tracheostomies and percutaneous endoscopic gastrostomies. PC consultations decreased. Mortality was unchanged.

CONCLUSION

Following trainee education, we observed increases in ACP documentation, earlier communication and improvements in ICU quality measures. Our findings suggest that trainee education positively impacts ACP documentation, reduces LOS, and improves trauma critical care outcomes.

Heart block in children. Evaluation of subsidiary ventricular pacemaker recovery times and ECG tape recordings

To evaluate subsidiary ventricular pacemaker function in 20 children with congenital or surgically induced complete heart block, we measured recovery times following overdrive ventricular pacing. Long-term ECG tape recordings were performed in eight of these children. Ages ranged from 1 month to 17 years. The resting R-R intervals ranged from 595 to 1,740 msec. The ventricles were paced at various cycle lengths of 400 to 1,000 msec with either transvenous electrode catheters or surgically implanted epicardial electrodes. His bundle recordings showed that the site of block did not allow separation of patients with symptoms from those without symptoms. Prolonged recovery times were present in patients with block above the His bundle recording site who had symptoms of syncope or dizziness, as well as in patients who had a wide QRS. However, some asymptomatic patient with heart block above the His bundle recording site also had long recovery times. None of the asymptomatic patients who had ECG tape recordings had paroxysmal tachycardia in more than 300 hours of recordings. However, one symptomatic patient with congenital heart block and a prolonged recovery time had brief episodes of paroxysmal ventricular tachycardia that produced no symptoms at the time of recording. The results suggest that the coexistence of prolonged recovery times and paroxysmal tachycardia may be predisposing factors to the development of symptoms in patients with complete heart block. We believe that further electrophysiologic investigation of this possibility is warranted in patients with heart block.

Sodium channel abnormalities are infrequent in patients with long QT syndrome: identification of two novel SCN5A mutations

Long QT syndrome (LQTS) is a heterogeneous disorder caused by mutations of at least five different loci. Three of these, LQT1, LQT2, and LQT5, encode potassium channel subunits. LQT3 encodes the cardiac-specific sodium channel, SCN5A. Previously reported LQTS-associated mutations of SCN5A include a recurring three amino acid deletion (DeltaKPQ1505-1507) in four different families, and four different missense mutations. We have examined the SCN5A gene in 88 index cases with LQTS, including four with Jervell and Lange-Nielsen syndrome and the remainder with Romano-Ward syndrome. Screening portions of DIII-DIV, where mutations have previously been found, showed that none of these patients has the three amino acid deletion, DeltaKPQ1505-1507, or the other four known mutations. We identified a novel missense mutation, T1645M, in the DIV; S4 voltage sensor immediately adjacent to the previously reported mutation R1644H. We also examined all of the additional pore-forming regions and voltage-sensing regions and discovered another novel mutation, T1304M, at the voltage-sensing region DIII; S4. Neither T1645M nor T1304M were seen in a panel of unaffected control individuals. Five of six T1304M gene carriers were symptomatic. In contrast to previous studies, QT(onset-c) was not a sensitive indicator of SCN5A-associated LQTS, at least in this family. These data suggest that mutations of SCN5A are responsible for only a small proportion of LQTS cases.

Efferent projections of the neonatal cat superior colliculus: facial and cerebellum-related brainstem structures

The superior colliculus develops its influence over eye and pinna movements gradually during postnatal maturation. Because superior colliculus cells respond earlier in postnatal life to nonvisual than to visual cues, it seemed likely that efferents involved in pinna movements would develop earlier than those involved in eye movements. In the present study, we examined the projections of the superior colliculus to structures related to the cerebellum and facial nucleus believed to be involved in eye-head coordination and pinna movements. We did this by using the autoradiographic and horseradish peroxidase tracing techniques in 11 kittens, ranging in age from several hours to 14 days postnatal, and in seven adult cats. Even in the youngest animals studied, a dense projection was observed from the superior colliculus to each of the target structures examined. These included the parabigeminal nucleus, paralemniscal zone, dorsolateral pons, and inferior olive. Surprisingly, the only projection observed to undergo any postnatal maturational changes was the one to the paralemniscal zone (involved in the pinna-movement circuit of the superior colliculus), and the changes appeared as a reorganization of the terminal field rather than an increase in the density of transported label. Thus, no evidence was obtained to support our expectation that the superior colliculus efferents involved in orientation of the pinnae would develop earlier than those involved in visual orientation. Instead, each of the efferent projections of the superior colliculus examined in this study appears to be laid down prenatally and becomes adultlike long before functional maturity is reached. Presumably, then, the formation and elaboration of synaptic connections are the protracted postnatal processes that limit the functional properties of these neonatal efferent pathways.

Autoradiographic studies of the projections of the midbrain reticular formation: descending projections of nucleus cuneiformis

The descending projections of nucleus cuneiformis in the cat were traced by autoradiography in the transverse and sagittal planes following stereotaxically placed injections of 3H-leucine. Many descending axons are organized into distinct fiber systems, of which the largest and most well-defined crosses directly in the midbrain and descends through the ventromedial tegmentum of the brain stem. This fiber system first terminates profusely in n. reticularis tegmenti pontis and then proceeds through the rhombencephalic tegmentum emitting transversely oriented branches to n. reticularis pontis caudalis and gigantocellularis, the raphe magnus and the facial nucleus...

Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat

Substantial corticotectal (and corticothalamic) projections from the cortex of the anterior ectosylvian sulcus (AES) were demonstrated in the cat using the axonal transport methods of autoradiography and horseradish peroxidase. The corticotectal projection arises nearly exclusively from medium-large pyramidal cells in lamina V. One of the densest projecting areas of the AES is the rostral aspect of its superior bank, where a fourth somatotopic representation (SIV) has recently been demonstrated. It terminates in the intermediate and deep laminae of the superior colliculus, where somatic cells are located. The pathway is bilateral but much heavier ipsilaterally than contralaterally. In contrast to the substantial corticotectal projection from SIV and adjacent tissue, there was no unequivocal evidence for a corticotectal projection from traditional somatosensory cortex SI-SIII. This finding, that somatosensory projections to the cat superior colliculus arise from an area outside of SI-SIII, was unexpected on the basis of what is known about visual corticotectal projections. However, it is consistent with the patterns of other cortical projections that terminate in the intermediate and deep laminae of this structure and with the absence of demonstrable corticotectal influences from SI to SIII in this animal. These data are in contrast to demonstrations by other investigators that there is a corticotectal projection from SI cortex in rodents. Apparently there is a fundamental species difference in the organization of descending somatosensory pathways. A corticothalamic projection of the AES was also observed. This descending projection appeared to form a shell of labeled cells and fibers around the ventrobasal complex, but unequivocal terminal labeling within the ventrobasal complex could not be demonstrated. Dense terminal labeling was apparent in the posterior group of thalamic nuclei (PO) where thalamocortical afferents to the AES originate.

Efferent projections of the neonatal superior colliculus: extraoculomotor-related brain stem structures

The development of eye movements is a prolonged process which presumably involves the efferents of the superior colliculus. In the present study we sought to determine which, if any, of the colliculus efferents that influence eye movements in adult cats were present in neonatal kittens. The autoradiographic and orthograde horseradish peroxidase tracing methods were employed in kittens ranging from 6 h to 5 weeks of age and in adult cats. Surprisingly, most of the known projections from the superior colliculus which are believed to be involved in eye movements were already present in the youngest animals studied. These included projections to (a) the ventral central gray matter overlying the oculomotor nucleus, and (b) those portions of the pontine and medullary reticular formation which provide excitatory and inhibitory inputs to abducens neurons. Apparently, the pathways over which the superior colliculus influences eye movements are elaborated quite early in life. However, in the predorsal bundle and pontomedullary reticular areas the density of transported label was less in 1-day-old kittens than in older animals. Thus, anatomical as well as functional development of portions of this circuitry appear to require a significant period of postnatal maturation.

A comparison of the intranigral distribution of nigrotectal neurons labeled with horseradish peroxidase in the monkey, cat, and rat

The location of neurons in the substantia nigra's pars reticulata (SNR) that send their axons to the superior colliculus was compared in the monkey, cat, and rat using the horseradish peroxidase (HRP) retrograde cell-labeling method. Although several cases of large, unilateral HRP deposits in the superior colliculus show that in all three species, the nigrotectal cells are confined, for the most part, to the rostral one-half of SNR, the following differences were noted in the precise location of the nigrotectal neurons and in the degree of bilaterality of the nigrotectal projection. In the monkey, labeled nigrotectal cells were particularly numerous in the extreme rostrolateral portion of SNR. From this region of high concentration, a progressively decreasing number of cells spreads medially in a ventral stratum immediately dorsal to the pes pedunculi. No labeled cells were found in the extreme medial part of SNR. A substantial number of HRP-positive cells were present in the contralateral SNR in a similar distribution. In the cat, labeled cells were less selectively localized in SNR's mediolateral expanse, being distributed more or less randomly in its middle portion with a scattering of cells in both medial and lateral parts of SNR. Although some cell labeling occurred in the contralateral SNR, it was less substantial than in the monkey. In the rat, the HRP-positive cells were especially concentrated throughout the mediolateral extent of a ventral stratum of SNR immediately dorsal to the pes pedunculi. Although some cells were located more dorsally, they were far fewer in number and consistently less heavily labeled. Only one or two labeled cells could be detected in the contralateral SNR of the rat. These anatomical differences suggest that the influence of the corpus striatum on the tectal control of orienting responses may vary considerably from one mammalian species to the next.

Accessory atrioventricular pathway in an infant: prediction of location with body surface maps and ablation with cryosurgery

A 10-month-old infant with multiple muscular ventricular septal defects, congestive heart failure, Wolff-Parkinson-White syndrome, and supraventricular tachycardia is presented. The site of ventricular pre-excitation was predicted by analysis of ST-T wave isopotential body surface maps to be in the posterior free wall of the right ventricle. The site was confirmed by epicardial mapping of the ventricles during surgery. The pathyway was cryoblated and the ventricular defects were closed. The patient has been free of pre-excitation and supraventricular tachycardia for over two years since surgery.

The force-interval relationship of the left ventricle

We have carried out a quantitative analysis of the force-interval relationship of the human left ventricle and compared it to previous studies done in both intact subjects as well as isolated muscle. The characteristics of the force-interval relationship of the normal patient resembed those of normal isolated mammalian muscle (except when exposed to high levels of catecholamines). The relationship in group 2 (patients with increased left ventricular dimensions and normal pressure indices) resembled those obtained from isolated muscles from hypertrophied hearts. The relationship from group 3 (patients with increased left ventricular EDDs and depressed pressure indices, two of whom were in clinical heart failure) resumbled those induced in normal muscles exposed to high levels of catecholamines, and those obtained from experimentally induced heart failure. The force-interval relationships of the four patients who fell into the third group were strikingly different from the other groups. This suggests that the force-interval relationship may be useful to describe changes in the inotropic state of the patient's heart.

Sources of subcortical projections to the superior colliculus in the cat

A comprehensive search for subcortical projections to the cat superior colliculus was conducted using the retrograde horseradish peroxidase (HRP) method. Over 40 different subcortical structures project to the superior colliculus. The more notable among these are grouped under the following categories. Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior commissure). Auditory structures: inferior colliculus (external and pericentral nuclei), dorsomedial periolivary nucleus, nuclei of the trapezoid body, ventral nucleus of the lateral lemniscus. Somatosensory structures: sensory trigeminal complex (all divisions, but mainly the gamma division of nucleus oralis), dorsal column nuclei (mostly cuneate nucleus), and the lateral cervical nucleus. Catecholamine nuclei: locus coeruleus, raphe dorsalis, and the parabrachial nuclei. Cerebellum: medial, interposed, and lateral nuclei, and the perihypoglossal nuclei. Reticular areas: zona incerta, substantia nigra, midbrain tegmentum, nucleus paragigantocellularis lateralis, and the hypothalamus. Evidence is presented that only the parabigeminal nucleus, the nucleus of the optic tract, and the posterior pretectal nucleus project to the superficial collicular layers (striatum griseum superficiale and stratum opticum), while all other afferents terminate in the deeper layers of the colliculus. Also presented is information concerning the rostrocaudal distribution of some of these afferent connections. These findings stress the multiplicity and diversity of inputs to the deeper collicular layers, and more specifically, identify multiple sources of the physiologically well-known representations of the somatic and auditory modalities in the colliculus.

Corticotectal and other corticofugal projections in neonatal cat

Adult physiological properties of cat superior colliculus cells develop gradually during the first two months of life. Since many of the neuronal properties in the adult cat appear to depend upon the integrity of visual cortex, it was postulated that the maturation of superior colliculus cells is, in large part, a reflection of corticotectal maturation. An attempt was made to study the development of the corticotectal pathway with the autoradiographic tracing technique. Injections of [3H]leucine were made in the visual cortex of kittens 6 h to 12 days of age and animals were sacrificed 20-24 h later. A dense projection from visual cortex to the superior colliculus and to the lateral geniculate nucleus was noted in all animals. Both projections appeared to be topographically organized. In addition, cortical projections to the lateral posterior-pulvinar region and sparse projections to the contralateral visual cortex were noted. Two, non-mutually exclusive, explanations for the presence of a corticotectal pathway in the absence of mature cell properties in the superior colliculus are most apparent: (a) corticotectal synapses are incompletely formed at birth and require many weeks to develop, and (b) corticotectal cells are immature during early postnatal life and cannot impress adult-like characteristics upon the superior colliculus cells until they, themselves, 'mature'.

The superior colliculus control of pinna movements in the cat: possible anatomical connections

Possible anatomical pathways mediating superior colliculus control of pinna movements were determined in the cat using the orthograde autoradiographic tracing method and the retrograde horseradish peroxidase technique. This was done in the following manner. First, the division of the facial nucleus that innervates the pinna muscles was determined by injecting the pinna muscles with HRP and surveying the facial nucleus for retrogradely filled cells. Second, the brainstem regions that project the facial nucleus were identified using the horseradish peroxidase method. Third, the superior colliculus projections to these areas were studied using the autoradiographic tracing method. The results suggest that superior colliculus control of pinna movements is mediated entirely by indirect connections with the facial nucleus and that these connections occur mainly in a paralemniscal zone in the lateral midbrain. Of all the brainstem regions shown by the horseradish peroxidase experiments to project to the facial nucleus only this midbrain paralemniscal zone received a projection from the superior colliculus that was dense and overlapped precisely the region containing facial projecting neurons. Further autoradiographic tracing revealed that the facial nucleus was the primary brainstem target of this paralemniscal zone and that all paralemniscal fibers projecting to the facial nucleus ended in the subdivision that innervates the pinna muscles. Other paralemniscal efferents terminate in the opposite paralemniscal zone. The data suggest that other connections between the superior colliculus and the facial nucleus may occur in the cuneiform nucleus of the midbrain, the region around the oculomotor complex, and the reticular formation dorsal to the superior olive.

Ventricular tachyarrhythmia due to cardiac sarcoidosis in a child

Cardiac involvement by systemic sarcoidosis is well known, but occurs rarely. It usually manifests as either heart block, heart failure due to direct myocardial involvement, or cor pulmonale. We present the case of a patient with cardiac sarcoidosis who had ventricular tachycardia and congestive heart failure. Although there was other organ system involvement, the cardiac manifestation was the first to become clinically apparent. Therapy consisted of quinidine sulfate to control the arrhythmias and chronic diuretic therapy to control congestive heart failure. Steroid therapy was initially associated with recurrence of the ventricular tachycardia and was discontinued. It was reinstituted 18 months later when other organ system involvement developed with no recurrence of the ventricular tachyarrhythmia. The patient responded well to therapy and is currently doing well. This case is presented to illustrate a somewhat unusual, but nevertheless important, etiology of ventricular tachyarrhythmias. The recognition of underlying sarcoidosis is critical because of the propensity for other organ system involvement by this disease process.

Thoracoabdominal ectopia cordis with mosaic Turner's syndrome: Report of a case

A child was treated for thoracoabdominal ectopia cordis and an associated chromosomal defect. Contrary to most cases in which death is due to the externally situated heart and abdominal viscera, this patient died from congenital heart disease.

Superior colliculus connections with the extraocular motor nuclei in the cat

Direct and indirect projections from the cat superior colliculus to the extraocular motor nuclei were studied using the orthograde autoradiographic tracing method, the retrograde horseradish peroxidase technique, and Golgi methods. The results show that the superior colliculus projects to the central gray matter directly overlying the oculomotor complex. This projection arises almost entirely from the rostral third of the colliculus, and it terminates most heavily over the rostral half of the oculomotor complex. Dendrites of oculomotor cells extend into this tectal termination zone, making direct tecto-oculomotor contacts possible. Central gray cells within this termination zone project bilaterally to the abducens nuclei. It is proposed that the superior colliculus projection to the supraoculomotor central gray matter and the projection from the central gray matter to the abducens nuclei play a role in convergent eye movements. The superior colliculus projects lightly to a cell group directly ventrolateral to the trochlear nucleus. The superior colliculus sends a small direct projection to the contralateral abducens nucleus and a substantial projection to wide regions of the reticular formation that have been shown previously to project, in turn, to the abducens nucleus. Colliculus cells projecting to the abducens nucleus and adjacent reticular formation are located only in the caudal three-fourths of the colliculus, where they become increasingly concentrated at successively more caudal levels. It is proposed that the graded density of the cells of origin of this projection is the basic structural mechanism by which the colliculus generates horizontal foveating saccades of different amplitudes. Laminar analysis of the origin of all the superior colliculus projections to the extraocular motor regions described here revealed that they arise mostly from the stratum griseum intermedium.

The commissural projection of the superior colliculus in the cat

The origin, course, and termination of the commissural projection of the superior colliculus were studied using the orthograde and autoradiographic tracing method and the retrograde method utilizing horseradish peroxidase. The complementary and mutually confirming sets of data showed that the commissural fibers interconnect a restricted region of the colliculi. This region includes the strata grisea intermedium and profundum and to a lesser degree the stratum opticum. It extends throughout only the rostral part of the colliculus where it ends abruptly at a level slightly less than half the distance from the anterior border of the deep gray layers. By using the needle used for isotope injection to record multiunit responses to somatic and visual stimuli, direct evidence was obtained that this region falls within that functional area of the colliculus devoted to face representation and central vision. The results also suggested that more commissural fibers arise from lateral than medial parts of this region and that many fibers interconnect corresponding points in the colliculi. In addition to intertectal connections, the commissural projection contains decussating axons which terminate in tegmental structures and within a restricted zone of the central gray matter directly overlying the oculomotor complex. The results are discussed in relation to the possible role the commissural projection plays in the regulation of eye and head movement.

Autoradiographic studies of the projections of the midbrain reticular formation: ascending projections of nucleus cuneiformis

The ascending projections of the cuneiform nucleus in the cat were traced by autoradiography in the transverse and sagittal planes following stereotaxically placed injections of (3)H-leucine. The ascending fibers are almost exclusively ipsilateral and enter the diencephalon as a wide radiation. At the mesodiencephalic junction fibers enter the nucleus of the posterior commissure and pretectal nuclei, and others cross in the posterior commissure to distribute to these structures on the contralateral side. More ventrally directed fibers distribute to the fields of Forel and then spread into the posterior hypothalamus and zona incerta. At the caudal level of the ventral thalamic group, the ascending fibers diverge and follow two separate courses. One division of fibers continues forward beneath the ventral thalamic group and distributes to the zpna incerta and dorsal hypothalamic area. It rapidly diminishes in size as it attains more rostral levels where it is found in the bed nuclei of the stria terminalis and the anterior commissure. Other fibers of this division spread laterally to innervate the ventral lateral geniculate nucleus, the lateral hypothalamus, and preoptic area, and still others follow the entire confirmation of the thalamic reticular nucleus. The second division of fiber ascends through midline and intralaminar nuclei, completely encircling the mediodorsal nucleus, which is uninnervated except for a small ventral region. The distribution of this division is heaviest to the paraventricular, parafascicular, and central dorsal nuclei. Neither division is conspicuous rostral to the anterior commissure. No projections to neostriatum or specific thalamic nuclei were evident.

Left ventricular pressure-volume characteristics in congenital heart disease

The continuous pressure-volume relationships throughout the cardiac cycle were evaluated in children with tetralogy of Fallot, isolated ventricular septal defect, and patent ductus arteriosus. Biplane cineangiocardiography and simultaneous left ventricular pressures were utilized for data acquisition. Normal pressure-volume loops demonstrated only small changes in left ventricular volume during the isovolumic periods. In tetralogy of Fallot, there was a decrease in left ventricular volume during the interval of the "isovolumic" contraction with 12 to 43% of the total stroke volume being ejected during this phase. A decrease in left ventricular volume during this time was also found in large ventricular septal defects; however, volume changes during this interval were minimal in those patients judged to have small defects.

With large left-to-right shunts of comparable magnitude, the relative area of the pressure-volume loop was greater in patent ductus arteriosus as compared with ventricular defects. Both conditions demonstrated marked increase in stroke volume, with peak systolic pressures rising higher in those patients with patent ducus arteriosus as compared to those with ventricular septal defect.