Structured reporting in fetal magnetic resonance imaging with congenital diaphragmatic hernia.

OBJECTIVE: We aim to provide a template structured report of fetal Magnetic Resonance Imaging in congenital diaphragmatic hernia (CDH) that was locally validated by the CDH study group in Mannheim. METHODS: A selection of 50 fetal MRIs of patients with an isolated diaphragmatic hernia and associated radiology reports from five different senior radiologists from a single center resulted in a primary structured report, which was put into practice by using dedicated software. A questionnaire survey of the interdisciplinary CDH study group Mannheim was used to adapt the report to the clinical requirements. RESULTS: There was a huge variability in how deep the free text reports go into detail. The side of the hernia was named in 94% of cases. In 58%, both the lung volume and the total lung volume were reported. A comparison with the expected lung volume was reported in 66% of cases. Additional findings, such as herniated organs, were reported in 96% of cases. Overall satisfaction with the newly established structured report was high within the CDH study group with a mean of 4.7. CONCLUSIONS: The use of the structured report of this study can optimize the interdisciplinary dialog, the standardization of report content, increase report completeness and improve quality.

Region of interest-based versus whole-lung segmentation-based approach for MR lung perfusion quantification in 2-year-old children after congenital diaphragmatic hernia repair.

OBJECTIVE: With a region of interest (ROI)-based approach 2-year-old children after congenital diaphragmatic hernia (CDH) show reduced MR lung perfusion values on the ipsilateral side compared to the contralateral. This study evaluates whether results can be reproduced by segmentation of whole-lung and whether there are differences between the ROI-based and whole-lung measurements. METHODS: Using dynamic contrast-enhanced (DCE) MRI, pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) were quantified in 30 children after CDH repair. Quantification results of an ROI-based (six cylindrical ROIs generated of five adjacent slices per lung-side) and a whole-lung segmentation approach were compared. RESULTS: In both approaches PBF and PBV were significantly reduced on the ipsilateral side (p always <0.0001). In ipsilateral lungs, PBF of the ROI-based and the whole-lung segmentation-based approach was equal (p=0.50). In contralateral lungs, the ROI-based approach significantly overestimated PBF in comparison to the whole-lung segmentation approach by approximately 9.5 % (p=0.0013). CONCLUSIONS: MR lung perfusion in 2-year-old children after CDH is significantly reduced ipsilaterally. In the contralateral lung, the ROI-based approach significantly overestimates perfusion, which can be explained by exclusion of the most ventral parts of the lung. Therefore whole-lung segmentation should be preferred. KEY POINTS: • Ipsilaterally, absolute lung perfusion after CDH is reduced in whole-lung analysis. • Ipsilaterally, the ROI- and whole-lung-based approaches generate identical results. • Contralaterally, the ROI-based approach significantly overestimates perfusion results. • Whole lung should be analysed in MR lung perfusion imaging. • MR lung perfusion measurement is a radiation-free parameter of lung function.

Adjunctive therapies for treatment of severe respiratory failure in newborns.

BACKGROUND: Severe respiratory failure of the newborn requires adjunctive therapies as application of surfactant, inhalation of nitric oxide (iNO), high frequency oscillatory ventilation (HFOV), or extracorporeal membrane oxygenation (ECMO). We designed this study to analyze the the usage and effectiveness of adjunctive therapies and the mortality of severe respiratory failure. PATIENTS AND METHODS: The survey in Germany was done in collaboration with the "Erhebungseinheit für seltene pädiatrische Erkrankungen" (ESPED). 397 patients within 2 years were included into the study. Effectiveness of each adjunctive therapy was judged by the treating physician. RESULTS: The most frequent diagnosis was respiratory distress syndrome (RDS) with 36.8%, followed by pneumonia sepsis (16.4%), meconium aspiration syndrome (MAS) and congenital diaphragmatic hernia (CDH). Surfactant was applied in 77.3% of all cases with a reported effectiveness of 71.6%. More than 40% of all patients were treated with iNO, which led to an improvement in every second case. HFOV was used in every third case with a response rate of about 60%. ECMO was performed on one in 7 patients and was successful with a survival rate of nearly 80%. The overall mortality was 10.3%. 29 patients in total died without ECMO. 10 of them might actually have been contraindicated, but 19 cases with a potential benefit from ECMO were not transferred for ECMO. CONCLUSION: Our study-data suggests that more newborns suffering from respiratory failure should be transferred to centers offering ECMO.

High temporal versus high spatial resolution in MR quantitative pulmonary perfusion imaging of two-year old children after congenital diaphragmatic hernia repair.

OBJECTIVES: Congenital diaphragmatic hernia (CDH) leads to lung hypoplasia. Using dynamic contrast-enhanced (DCE) MR imaging, lung perfusion can be quantified. As MR perfusion values depend on temporal resolution, we compared two protocols to investigate whether ipsilateral lung perfusion is impaired after CDH, whether there are protocol-dependent differences, and which protocol is preferred. METHODS: DCE-MRI was performed in 36 2-year old children after CDH on a 3 T MRI system; protocol A (n = 18) based on a high spatial (3.0 s; voxel: 1.25 mm(3)) and protocol B (n = 18) on a high temporal resolution (1.5 s; voxel: 2 mm(3)). Pulmonary blood flow (PBF), pulmonary blood volume (PBV), mean transit time (MTT), and peak-contrast-to-noise-ratio (PCNR) were quantified. RESULTS: PBF was reduced ipsilaterally, with ipsilateral PBF of 45 ± 26 ml/100 ml/min to contralateral PBF of 63 ± 28 ml/100 ml/min (p = 0.0016) for protocol A; and for protocol B, side differences were equivalent (ipsilateral PBF = 62 ± 24 vs. contralateral PBF = 85 ± 30 ml/100 ml/min; p = 0.0034). PCNR was higher for protocol B (30 ± 18 vs. 20 ± 9; p = 0.0294). Protocol B showed higher values of PBF in comparison to protocol A (p always <0.05). CONCLUSIONS: Ipsilateral lung perfusion is reduced in 2-year old children following CDH repair. Higher temporal resolution and increased voxel size show a gain in PCNR and lead to higher perfusion values. Protocol B is therefore preferred. KEY POINTS: • Quantitative lung perfusion parameters depend on temporal and spatial resolution. • Reduction of lung perfusion in CDH can be measured with different MR protocols. • Temporal resolution of 1.5 s with spatial resolution of 2 mm (3) is suitable.

[Prenatal diagnosis of and therapy for congenital diaphragmatic hernia]. / Pränatale Diagnostik und Therapie bei kongenitaler Zwerchfellhernie.

Congenital diaphragmatic hernia is a malformation presenting with varying degrees of severity. An accurate prediction of outcome is crucial for parental counselling and therapeutic planning. In selected cases, foetal endoscopic tracheal occlusion (FETO) can improve foetal outcome. Timely referral to a highly specialised centre is important when the requirement for extracorporeal membrane oxygenation (ECMO) is expected.

[Prognosis and therapy of congenital diaphragmatic hernia depending on the time of clinical presentation - experience of a highly specialized referral centre]. / Prognose und Therapie der angeborenen Zwerchfellhernie abhängig vom Zeitpunkt der klinischen Präsentation - Erfahrungen eines hochspezialisierten Zentrums.

Congenital diaphragmatic hernia (CDH) is a diagnosis with multiple, mostly unknown origin. Therefore its clinical presentation is highly variable. In case of prenatal detection prognosis and amount of interventions in neonatal intensive care is predictable. The results reported by high volume centres for CDH improved continuously during the last years. In neonates suffering from CDH without prenatal diagnosis severe respiratory distress is the leading clinical sign. Presenting symptom of late-onset CDH can also be gastrointestinal problems. Due to more subtle symptoms late presenting CDH is more difficult to diagnose. Prognosis is good, but it still requires surgical intervention to alleviate the symptoms.

Preferential streaming of the ductus venosus toward the right atrium is associated with a worse outcome despite a higher rate of invasive procedures in human fetuses with left diaphragmatic hernia.

PURPOSE: Preferential streaming of the ductus venosus (DV) toward the right atrium has been observed in fetuses with left diaphragmatic hernia (LDH). The purpose of this retrospective study was to compare survival rates to discharge between a group with preferential streaming of the DV toward the right heart and a group in which this abnormal flow pattern was not present. MATERIALS AND METHODS: We retrospectively searched our patient records for fetuses with LDH in whom liver position, DV streaming and postnatal outcome information was available. 55 cases were found and divided into two groups: Group I fetuses exhibited abnormal DV streaming toward the right side of the heart; group II fetuses did not. Various prognostic and outcome parameters were compared. RESULTS: 62 % of group I fetuses and 88 % of group II fetuses survived to discharge (p = 0.032). Fetoscopic tracheal balloon occlusion (FETO) was performed in 66 % of group I fetuses and 23 % of group II fetuses (p = 0.003). Postnatal ECMO therapy was performed in 55 % of group I fetuses and 23 % of group II infants (p = 0.025). Moderate to severe chronic lung disease in survivors was observed in 56 % of the survivors of group I and 9 % of the survivors of group II (p = 0.002). CONCLUSION: Preferential streaming of the DV toward the right heart in human fetuses with left-sided diaphragmatic hernia was associated with a poorer postnatal outcome despite a higher rate of invasive pre- and postnatal procedures compared to fetuses without this flow abnormality. Specifically, abnormal DV streaming was found to be an independent predictor for FETO.

Quantitative pulmonary perfusion imaging at 3.0 T of 2-year-old children after congenital diaphragmatic hernia repair: initial results.

OBJECTIVE: To investigate whether dynamic contrast-enhanced MR imaging of the lung following congenital diaphragmatic hernia repair is feasible at 3.0 T in 2-year-old children and whether associated lung hypoplasia (reflected in reduced pulmonary microcirculation) can be demonstrated in MRI. METHODS: Twelve children with a mean age 2.0 ± 0.2 years after hernia repair underwent DCE-MRI at 3.0 T using a time-resolved angiography with stochastic trajectories sequence. Quantification of lung perfusion was performed using a pixel-by-pixel deconvolution approach. Six regions of interest were placed (upper, middle and lower parts of right and left lung) to assess differences in pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) while avoiding the inclusion of larger pulmonary arteries and veins. RESULTS: The difference in PBF and PBV between ipsilateral and contralateral lung was significant (P < 0.5). No significant differences could be detected for the MTT (P = 0.5). CONCLUSION: DCE-MRI in 2-year-old patients is feasible at 3.0 T. Reduced perfusion in the ipsilateral lung is reflected by significantly lower PBF values compared with the contralateral lung. DCE-MRI of the lung in congenital diaphragmatic hernia can help to characterise lung hypoplasia initially and in the long-term follow-up of children after diaphragmatic repair. KEY POINTS: Congenital diaphragmatic hernia often leads to lung hypoplasia and secondary pulmonary hypertension. Dynamic contrast-enhanced 3-T magnetic resonance can assess these complications in 2-year-olds. The affected ipsilateral lung shows reduced perfusion and lower pulmonary blood flow. Thoracic DCE-MRI helps characterise lung hypoplasia in children after hernia repair.

Serum cytokine levels in neonates with congenital diaphragmatic hernia.

Cytokines play an important role in immune regulation and fetal lung development. The systemic inflammatory response in newborns with congenital diaphragmatic hernia (CDH) has not been characterized so far. We compared various concentrations of cytokines in serum from newborns with CDH and in healthy term neonates. We analyzed cytokine patterns of CDH newborns under extracorporeal membrane oxygenation (ECMO) and mechanical ventilation (MV).38 newborns with CDH were included: ECMO group (n=13) and non-ECMO group (n=25). Healthy term neonates served as controls (n=13). Serum samples were obtained prospectively after birth and during therapy.Concentrations of IFN-α, IL-3,-6,-7,-8,-10, MIP-1α,-1ß and TNF-α in serum of newborns with CDH were higher than in umbilical cord blood of term neonates. Infants with severe CDH requiring ECMO therapy had higher postnatal IL-8,-10, and MIP-1α levels than newborns with milder disease in the non-ECMO treated group. IL-10 progressively decreased during the first 3 days following birth under ECMO. In contrast, the chemokine MIP-1α remained elevated during ECMO therapy compared to mechanically ventilated CDH newborns.The pattern of cytokines in the serum of newborns with CDH showed significant elevations compared to term neonates. Our findings indicate that CDH is associated with systemic inflammatory response immediately after birth. ECMO and MV show a similar increase of IL-1α and IP-10 in CDH newborns assuming a persistent pulmonary inflammatory reaction irrespective of the conducted treatment.

Angiotensin II receptor blocker induced fetopathy: 7 cases.

BACKGROUND: During a period of 12 months 7 newborns with a partially severe fetopathy caused most probably by maternal sartan-intake in pregnancy were treated in 5 German teaching hospitals. Sartans antagonize the effect of angiotensin II at the AT1-receptor and are used to treat arterial hypertension. METHOD: We presented 2 cases at the yearly GNPI meeting 2010 and we were informed about similar cases in other German teaching hospitals which we brought together in this publication. RESULTS: In the presented cases, maternal sartan intake was noticed at different times in pregnancy and was in part discontinued some weeks before delivery. In all pregnancies oligohydramnios was present and fetal kidneys displayed a hyperechogenic structure on ultrasound. The newborns' postnatal course varied: oligohydramnios sequence with lung hypoplasia, arterial hypotension and renal insufficiency were the predominant problems of the first days of life. The majority (4/7) of infants did not survive this period, in other cases there was a complete (1/7) recovery of renal function whereas others survived with renal impairment (2/7), in part requiring chronic dialysis. Further distinctive features seen frequently were disturbances of cranial ossification and flaccid paralysis of hands and feet with deviations as well as sensorineural hearing loss. CONCLUSION: These case reports again underline the hazardousness of maternal sartan intake with potential fatal outcome for the newborn. Though the use of sartans in pregnancy is contraindicated and several case reports of sartan induced fetopathies exist, the risk of sartan treatment generally seems to be underestimated.

Actual outcome in infants with congenital diaphragmatic hernia: the role of a standardized postnatal treatment protocol.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly with a high rate of mortality and morbidity. OBJECTIVE: Our aim was to determine a possible effect of standardized treatment on outcome in infants with CDH. METHODS: All prenatally diagnosed patients with unilateral CDH born alive between January 2006 and December 2009 at the Erasmus MC or the University Hospital Mannheim were eligible for inclusion. Patients who underwent a fetal tracheal occlusion were excluded. From November 1, 2007, all CDH patients were treated according to a standardized treatment protocol. Patients were divided into two chronological groups according to their date of birth: without standardized treatment (group 1, Jan 2006-Oct 2007) and with standardized treatment (group 2, Nov 2007-Dec 2009). Outcome measures were mortality by day 28, bronchopulmonary dysplasia (BPD), defined as oxygen dependency at day 28, and need for extracorporeal membrane oxygenation (ECMO) therapy. Uni- and multivariate analyses were performed. RESULTS: 167 patients were included. By day 28, 18% of the infants had died. Of the patients who were alive at day 28, 49% had BPD. An ECMO procedure was performed in 31% of the patients. Overall mortality for all included patients was 22%. In group 1, overall mortality was 33% and in group 2 overall mortality was 12% (p = 0.004). A standardized treatment protocol was independently associated with a reduced risk for mortality by day 28 (OR 0.28, 95% CI 0.11-0.68). Higher observed-to-expected lung-to-head ratios were independently associated with a lower risk for mortality by day 28 (OR 0.97, 95% CI 0.95-0.99), BPD (OR 0.97, 95% CI 0.94-0.98) and need for ECMO (OR 0.98, 95% CI 0.96-0.99). An intrathoracic position of the liver was independently associated with an increased risk for BPD (OR 3.12, 95% CI 1.41-6.90) and need for ECMO therapy (OR 3.25, 95% CI 1.54-6.88). CONCLUSION: Survival rates in patients with CDH increased significantly after the implementation of a standardized treatment protocol.

Implication of pulse oxymetry screening for detection of congenital heart defects.

BACKGROUND: In newborns congenital heart defects can take an asymptomatic course, causing a diagnostic gap in the routine examination. Therefore pulsoxymetric screening is under discussion, as it could close this diagnostic gap. PATIENTS AND METHODS: Non-invasive postductal peripheral oxygen saturation assessment was carried out in 3 364 term neonates, 6-36 h of age, in 2008. In asymptomatic neonates with values > or = 95%, no further steps were applied. In those with values between 90% and 94% and no clinical abnormalities, a check-up was carried out 4-6 h later. Echocardiography was performed when the initial value was below 90% or persisted < 95 %. RESULTS: A total of 18 (0.5%) abnormal pulse oximetry values requiring echocardiographic investigation were found in the 3 364 neonates examined. 9 congenital heart defects that had not been recognized prenatally were diagnosed. 4 of these children were also found to have anomalies at the clinical examination. Persistent fetal circulation was noted in 2 of the neonates.In addition neonatal infections has been detected in 7 newborns. 1 neonate with stenosis of the aortic isthmus and 1 with pulmonary stenosis were missed in the screening program, with pulse oximetry saturation levels >95%. These data represent a sensitivity of 82% and a specificity of 99.9%, with a positive predictive value of 50% and a negative predictive value of 99.9%. CONCLUSIONS: Together with the clinical examination, pulse oximetry in neonates is a screening method that has high levels of sensitivity and specificity for early diagnosis of congenital heart defects. The risk-benefit profile may favour pulse oximetry to be standardized and universally used.

[Massive increase of foetal abdominal circumference due to hereditary polycystic kidney disease]. / Massive fetale Bauchumfangszunahme bei hereditärer Zystennierenerkrankung.

Autosomal recessive polycystic kidney disease (ARPKD) is a rare condition with a poor prognosis. We report on a 30-year-old primagravid woman in the 34th) week of gestation who was admitted to our hospital. ARPKD of the foetus had been sonographically suspected since the 26th week of gestation. Ultrasound examination showed big polycystic kidneys on both sides. The non-consanguineous parents wanted a maximum therapy for the infant. Foetal digitalisation because of heart insufficiency and prophylactic lung maturation was started. In the further course, Doppler sonographic values worsened and a Caesarean section was performed in the 34th week of gestation at the demand of the parents and due to the expected problems in case of a vaginal delivery. The weight of the newborn was 3,780 g and the abdominal circumference was 50 cm. The newborn was intubated immediately after birth and artificial ventilation was performed. Extracorporeal membrane oxygenation was not possible due to the bad cardial condition. The boy died 16 h after delivery. The parents refused genetic examination and autopsy of the newborn. ARPKD is a severe disease that may have obstetric relevance, due to the massively increased abdominal circumference. Therefore, termination of pregnancy or preterm induction of labor should be considered in order to avoid Caesarean section. Additionally, early prenatal diagnosis with genetic analysis of PRKD1 in cases of suspected ARPKD can be helpful.

[Maturation of the autonomic nervous system: differences in heart rate variability at different gestational weeks]. / Reifung des Autonomen Nervensystems: Unterschiede in der Herzfrequenzvariabilität in unterschiedlichen Gestationswochen.

AIMS: Heart rate variability (HRV) reveals information on the functional state of the autonomic nervous system (ANS). This study was initiated to assess the physiological and maturational development of the ANS by comparing HRV data of a large number healthy foetus of different gestational ages from the 24(th) to the 42(nd) week. METHODS: Cardiotocogram (CTG) recordings of HRV of 172 healthy foetus (24-42 weeks' gestation) were performed to establish normative data. Frequency domain HRV parameters were computed in three frequency bands. RESULTS: The gestational ages of the foetuses correlate with HRV. Lower gestational age in weeks showed lower frequency domain parameters than higher gestational age in weeks. The most significant differences were discerned for HRV parameters reflecting sympathetic activity in LF (low frequency) and VLF (very low frequency), due to the adrenergic system. CONCLUSIONS: Maturation of the ANS is accompanied by increasing HRV with a pronounced increase of sympathetic activity. These changes are measurable by CTG recordings with a computer algorithm which can calculate short-term variability on the basis of CTG data. Problems of the CTG signal, as shown before, were the parameters of the time domain, which could only be well detected by ECG or foetal magnetocardiography (FMCG).

Persistent cyanosis in a 4 month old infant with severe pneumonia and haemoglobin M.

M haemoglobinaemia is a rare cause of persistant cyanosis. We report a four months old infant who suffered from severe pneumonia and respiratory distress syndrome. After return of normal respiration, cyanosis persisted. Oxygen saturation on pulse oximetry never exceeded 85%. Finally, we succeeded in isolating a haemoglobin M Saskatoon. HbM Saskatoon is normally a harmless variant. However, in conjunction with severe pneumonia, we assume that it did not only affect clinical evaluation, but also exacerbated pneumonia by reducing the oxygen binding capacity.

Fetal MR lung volumetry in congenital diaphragmatic hernia (CDH): prediction of clinical outcome and the need for extracorporeal membrane oxygenation (ECMO).

BACKGROUND: Despite the ultrasound (US) based lung-to-head ratio (LHR) and first results of fetal lung volume (FLV) determination in magnetic resonance imaging (MRI), there is no reliable prenatal parameter for the clinical course and outcome of fetuses with congenital diaphragmatic hernia (CDH), in particular for the need of extracorporeal membrane oxygenation (ECMO). PATIENTS AND METHOD: MR FLV measurement was evaluated in 36 fetuses with CDH using T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE) imaging. FLV and liver herniation, respectively, were correlated with survival and the need for ECMO therapy. A total of 18 healthy fetuses served as controls. MR FLV measurement was applied to predict survival and the need for neonatal ECMO therapy and to assess liver herniation as a prognostic parameter. RESULTS: On MRI there was a highly significant correlation of the FLV and patients' survival (p=0.0001) and ECMO requirement, respectively (p=0.0029). Compared to normal controls mean FLV in infants who died was 10% (9.4+/-5.8 ml) and 32% in surviving infants (25+/-9.7 ml). Liver herniation significantly decreased lung volume and negatively impacted clinical outcome (p<0.0005). CONCLUSION: The MR FLV is a strong predictor of survival in CDH patients. MR FLV measurements are also valuable to identify patients who may benefit from ECMO therapy. Upward liver herniation is the most important additional prognostic parameter.

Isolated impact of liver herniation on outcome in fetuses with congenital diaphragmatic hernia - A matched-pair analysis based on fetal MRI relative lung volume.

PURPOSE: To evaluate liver-herniation as individual parameter on outcome in children with congenital diaphragmatic hernia. MATERIALS AND METHODS: In a retrospective matched-pair analysis based on observed to expected fetal lung volume (o/e FLV), birth weight, gestational age at time-point of examination, status of tracheal occlusion therapy and side of the defect the individual impact of liver-herniation on survival, need for extracorporeal membrane oxygenation (ECMO) therapy and chronic lung disease (CLD) was investigated. In total 61 pairs (122 patients) were included. Fisher's exact test was used to evaluate influence of liver-herniation and a p-value of <0.05 was defined as statistically significant. The study was approved by the local review board. RESULTS: Children with liver-herniation have lower survival rates (78.7% vs. 95.1%; p = 0.0073), need ECMO-therapy more often (41.0% vs. 16.4%; p = 0.0027) and are more likely to develop CLD (71.7% vs. 37.9%; p = 0.0004) than their corresponding matched-pair without liver-herniation. CONCLUSION: Liver-herniation itself and not further lung-volume restriction due to liver-herniation is responsible for poor outcome in CDH.

Cardiac conditioning ameliorates cardiac dysfunction associated with renal hypertension in rats.

To explore the effect of physiologic hypertrophy superimposed on pathologic hypertrophy, hearts from female control rats (C), renal hypertensive rats (H), rats conditioned with a 10-12 wk swimming program (Sw), and hypertensive rats trained by the swimming program (H-Sw) were perfused in an isolated working rat-heart apparatus. Systolic blood pressure was approximately 100 mmHg in C and Sw and was 160 mmHg in H and H-Sw. The swimming program had no effect on blood pressure. Compared with C, heart weight was increased by 30% in Sw, 47% in H, and 77% in H-Sw. At high preload and afterload, cardiac output (milliliters per gram dry LV weight) was decreased in H, increased in Sw, and partially restored towards normal in H-Sw. Ejection fraction, percent fractional shortening, and mean velocity of circumferential fiber shortening were enhanced in Sw, depressed in H, and normalized in H-Sw when compared with C. Coronary flow and myocardial oxygen consumption in this series of hearts were depressed in H, with no restoration in H-Sw, but coronary effluent lactate/pyruvate ratios were only elevated in the hearts of H-Sw. Coronary vascular responses were examined in a second series of experiments which used microspheres. In this series, the depressed coronary flow observed in H was partially restored towards normal in H-Sw and the inner/outer myocardial flow ratio was normal when hearts were perfused at 140 cm aortic pressure but was somewhat depressed in both H and H-Sw when the hearts were perfused at 80 cm aortic pressure. These studies demonstrate that hypertrophic hearts from renal hypertensive rats have diminished coronary flow and depressed cardiac function when they are studied in the isolated working heart apparatus, yet there is no evidence of myocardial ischemia. Superimposition of a chronic swimming program results in increased hypertrophy but restoration of cardiac function partially or completely to normal. Thus, pathologic and physiologic hypertrophy are biologically distinct entities. Physiologic hypertrophy may partially ameliorate the defects associated with pathologic hypertrophy.

Physiologic cardiac hypertrophy corrects contractile protein abnormalities associated with pathologic hypertrophy in rats.

To evaluate the combined effects of cardiac overload imposed by hypertension and by chronic exercise, male and female rats were made hypertensive by unilateral renal artery stenoses and made to exercise in an 8-10-wk swimming program. Sedentary normotensive animals, sedentary hypertensive animals and normotensive animals exposed to the swimming program were also studied. Hypertension was associated with the development of cardiac hypertrophy, and this was exaggerated in hypertensive swimmers. Actomyosin, Ca2+-myosin, and actin-activated Mg2+-myosin ATPase activities were enhanced in normotensive swimmers, depressed in hypertensives and were normal or increased in hypertensive swimmers. Myosin isoenzyme analysis showed a predominant V1 pattern in normals; an increase in percent V1 isoenzyme is swimmers; a predominant V3 pattern in hypertensives; and a return to the predominant V1 pattern in hypertensive swimmers. These findings suggest that the hypertrophy imposed by hypertension and hypertrophy imposed by physical training using a chronic swimming program are distinctly different biological phenomena. Physical training by swimming prevents the changes in cardiac myosin induced by hypertension despite the exaggeration of hypertrophy.

Effects of experimental diabetes on adrenergic and cholinergic receptors of rat myocardium.

To more fully characterize the alterations in myocardial adrenergic and cholinergic receptors induced by the diabetic state, we investigated the binding characteristics of (--) [3H] dihydroalprenolol to beta adrenergic receptors (bAR), [3H] prazosin to alpha adrenergic receptors (aAR), and [3H] quinuclidinyl-benzilate to muscarinic cholinergic receptors (MCR) in myocardial membranes derived from rats 8 wk after treatment with streptozotocin. We also studied an equal number of animals from three control groups: free-eating nondiabetics, pair-weighted nondiabetics, and streptozotocin-treated animals treated daily with insulin. Diabetic hearts demonstrated 27% fewer bAR (P less than 0.01) and 31% fewer aAR (P less than 0.01) than free-eating controls, without changes in MCR, and without changes in antagonist affinity, agonist affinity, or agonist slope factor (pseudo-Hill coefficient) for any class of receptors. Food restriction had no effect on receptor characteristics, and treatment of diabetic rats with insulin prevented any downregulation of cardiac bAR or aAR. The parallel decrease in both bAR and aAR suggests that streptozotocin-induced hypothyroidism is not the primary causative factor of bAR downregulation in this model, since hypothyroidism produces upregulation of aAR. Furthermore, the lack of change in cardiac MCR suggests that the adrenergic receptor alterations are not the result of nonspecific abnormalities of protein synthesis in the diabetic heart. Further studies are required to establish the physiologic significance of these receptor alterations, but these data support the hypothesis that altered adrenergic receptor properties may underlie, at least in part, the chronotropic and inotropic abnormalities of cardiac performance that are associated with the diabetic state.