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[Effects of age, sex and coronary heart disease on the autonomic modulation of the heart].

PURPOSE: To establish the influence of age, sex and the presence of coronary heart disease on heart rate variability. METHODS: The heart rate variability was studied in the time and frequency domain in 77 normal (group I) and 30 coronary heart disease patients (group II). The ECG was recorded during 300 seconds with the patients breathing at their spontaneous rate and at a rate between 10 and 15/ minutes (0.16 to 0.25 Hz). RESULTS: Both time and frequency domain variables were lower in group II than in group I. Energy content in spectral bands decreased with increasing age. No change was observed in relation to the patient's gender. During controlled breathing we found that in both groups the energy concentrated in the range of 0.17 to 0.25 Hz but it only increased in group I. CONCLUSION: Heart rate variability is an important tool for studying the influence of the autonomic system on heart rate modulation. These influences decrease with age and with the presence of coronary heart disease. The controlled breathing maneuver enabled us to precisely separate normal from coronary heart disease patients.

Adult↗

Effects of dopexamine on heart function of isolated hypoxic rabbit heart and in comparison with fenoldopam and procaterol.

AIM: To study the effects of dopexamine hydrochloride (Dop) on heart functions and coronary flow (CF) of normal and hypoxic isolated perfusing heart and compare the effects of Dop with those of fenoldopam hydrochloride (Fen) and procaterol hydrochloride (Pro). METHODS: The isolated rabbit normal and hypoxic hearts were perfused with Krebs-Henseleit (K-H) solution via aorta at 37 +/- 0.5 degree C. The drug were added into the K-H solution. RESULTS: Dop increased the CF, left ventricular contractile function (+ dp/dtmax etc) and heart rate (HR) in normal heart; Fen increased the heart function more potently, but increased the CF to a lesser degree than Dop did, whereas the effects of Pro was the least. In simple hypoxic group, at 30 min of perfusion, the + dp/dtmax and CF decreased by 66 +/- 4% and 48.1 +/- 1.0%, respectively. Dop remarkably attenuated the decreases in both CF and heart function during hypoxia as it decreased the + dp/dtmax by 32.0 +/- 2.4% and CF by 28 +/- 3%. Fen was less potent than Dop in attenuating the diminution of CF, while Pro was the least effective. CONCLUSION: Dop has a better prospect in the treatment of ischemic heart disease in view of its dual action of increasing CF and inotropism.

Adrenergic beta-Agonists↗

Neurochemical indices of autonomic innervation of heart in different experimental models of heart failure.

Parasympathetic neural regulation of the failing heart is impaired. In order to investigate parasympathetic mechanisms in experimental heart failure, measurements were made of choline acetyltransferase (CAT) activity and [3H]-quinuclidinyl benzilate (QNB) binding in hearts of 1) hamsters with skeletal and cardiac myopathy, 2) dogs with pulmonary artery constriction and tricuspid avulsion, and 3) guinea pigs with pulmonary artery constriction. Tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) activities and norepinephrine levels served as indices of sympathetic innervation. In myopathic hearts, total CAT activity decreased (P less than 0.05) compared to age-matched controls. In canine and guinea pig right heart failure, total CAT activity was normal in contractile and specialized tissues. Alterations in [3H]-QNB binding paralleled CAT activity being decreased (P less than 0.05) only in myopathic hearts. In all three models, indices of sympathetic innervation were altered in ways qualitatively different from parasympathetic indices; TH and DBH activities were increased (P less than 0.05) in myopathic ventricles, decreased (P less than 0.05) in hypertrophied canine and guinea pig ventricles and non-hypertrophied canine ventricles, and normal in non-hypertrophied guinea pig ventricles. These results indicate that alterations in cardiac parasympathetic indices vary depending on the etiology of heart diseases and differ qualitatively from alterations in sympathetic indices. Selective determinants are necessary to explain the varied changes.

Animals↗

Diastolic ventricular interaction in chronic heart failure: relation to heart rate variability and neurohumoral status.

It is likely that abnormal baroreflex control mechanisms are at least partially responsible for autonomic dysfunction in chronic heart failure. We recently demonstrated that diastolic ventricular interaction is associated with impaired baroreflex control of vascular resistance in heart failure. We reasoned that by constraining left ventricular filling, such interaction would decrease baroreflex activity and, thereby, increase sympathetic and decrease parasympathetic outflow. We hypothesized, therefore, that diastolic ventricular interaction in chronic heart failure patients would be associated with autonomic dysfunction. We used radionuclide ventriculography to measure changes in left and right ventricular end-diastolic volumes during acute volume unloading achieved by -30 mm Hg lower-body negative pressure in 30 patients with chronic heart failure. An increase in left ventricular volume in association with a reduction in right ventricular volume indicates diastolic ventricular interaction (a larger increase indicating a greater degree of interaction). We also measured heart rate variability (n = 23) and resting venous plasma norepinephrine (n = 24), epinephrine (n = 24), and atrial natriuretic peptide (ANP) (n = 14). During lower-body negative pressure, while right ventricular volume decreased in all patients (P < 0.001), left ventricular end-diastolic volume increased (from 152 +/- 25 to 157 +/- 36 ml/m2, P = 0.01). The change in left ventricular volume was positively correlated with resting plasma norepinephrine (P < 0.01) and ANP (P < 0.005), and negatively correlated with the standard deviation of normal to normal R-R intervals (P < 0.005), the root-mean-square of differences between successive normal to normal R-R intervals (P < 0.05), total power (P < 0.01), low-frequency power (P < 0.01), and high-frequency power (P < 0.05). Diastolic ventricular interaction in patients with chronic heart failure is associated with sympathetic nervous system activation evidenced by increased plasma norepinephrine and reduced heart rate variability.

Atrial Natriuretic Factor↗

Brain natriuretic peptide is produced both by cardiomyocytes and cells infiltrating the heart in patients with severe heart failure supported by a left ventricular assist device.

BACKGROUND: Brain natriuretic peptide (BNP) is a cardiac neurohormone synthesized in cardiac ventricles as a result of increased wall stress. Left ventricular assist device (LVAD) support in patients with end-stage heart failure results in reduced wall stress and therefore may change BNP levels in the heart. METHODS: BNP plasma levels were measured in 17 patients with end-stage HF before LVAD implantation and at 1 week, 1 month, and 3 months after LVAD support. BNP-messenger RNA (mRNA) expression in cardiac biopsy specimens of 27 patients before and after LVAD support was determined by quantitative polymerase chain reaction. Immunohistochemistry (IHC) and IHC-double staining was used in biopsy specimens from 32 patients before and after LVAD support to localize the BNP protein expression in the heart. RESULTS: BNP plasma levels significantly decreased from 1,872 +/- 1,098 pg/ml before implantation to 117 +/- 91 pg/ml at 3 months after LVAD implantation. This decrease in plasma levels was accompanied by a significant decrease in mRNA expression (relative quantity) in the heart. IHC and IHC-double staining showed BNP immunoreactivity in the cardiomyocytes, endothelial cells, infiltrating T cells, and macrophages. CONCLUSIONS: The significant decrease in serum BNP concentration after LVAD support coincides with a decrease in BNP mRNA and protein expression in the heart. BNP is produced in the left ventricle not only by cardiomyocytes but also by endothelial cells, T cells, and macrophages. Unloading of the left ventricle by a LVAD results in decreased BNP expression in the heart and plasma and may play an important role in the reverse remodeling process of the heart.

Adult↗

Neuropeptide Y receptor 1 (NPY-Y1) expression in human heart failure and heart transplantation.

Neuropeptide Y (NPY) is a neurotransmitter released from cardiac sympathetic nerve terminals along with catecholamines. It influences vascular tone and cardiac function, probably through the receptor subtype Y1. The present study examined the expression of Y1 in patients with end-stage heart failure and in heart transplant recipients. Y1 mRNA was analyzed in right ventricular endomyocardial biopsies taken from 12 donor hearts prior to implantation (controls), 15 patients with end stage heart failure at time of transplantation, and 16 patients more than 1 year after transplantation. RT-PCR (reverse transcription polymerase chain reaction) was used to detect mRNA for the Y1 receptor, the beta1-adrenergic-receptor, and beta-actin. Y1 mRNA was present in biopsies of all donor hearts, but was observed significantly less frequently in the two patient groups; only 5 out of 15 (P < 0.01) heart failure and 9 out of 16 (P < 0.05) transplant recipients demonstrated visible PCR product. In contrast, mRNA for the beta1-adrenergic receptor and beta-actin were detected by RT-PCR in all samples. Our results provide the first evidence for altered regulation of the neuropeptide Y1 receptor in heart failure and transplant patients, and suggests that loss of signal transduction by this receptor may be adaptive in both groups.

Actins↗

The effect of short-term coronary perfusion using a perfusion apparatus on canine heart transplantation from non-heart-beating donors.

BACKGROUND: We investigated the effects of briefly perfusing hearts from non-heart-beating donors (NHBDs) with a Celsior solution before cardiac transplantation. METHODS: Donor hearts were left in situ for 20 minutes after cardiac arrest was induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into 2 groups, the simple immersion (SI, n = 6) group and the coronary perfusion (CP, n = 6) group. Both groups underwent coronary flushing with Celsior, after which hearts from the SI group were stored using simple immersion for 4 hours and hearts from the CP group underwent 1 hour of further perfusion followed by storage for 3 hours. Orthotopic transplantation was then performed. We measured cardiac output, end-systolic maximal elastance (E(max)), left ventricular pressure, and rate pressure product 1 and 2 hours after weaning from cardiopulmonary bypass (CPB). Two hours after weaning from CPB, the hearts were harvested for histopathologic study and to determine the percentage of water content. RESULTS: The cardiac output (CO) recovery rate was significantly higher in the CP group than in the SI Group 1 hour after weaning from CPB (p < 0.05). The CO recovery rate, E(max), and rate pressure product were significantly higher and the percentage of water content was significantly lower in the CP group than in the SI Group 2 hours after weaning from CPB (p < 0.05). Histopathologic damage was more severe in the SI group. CONCLUSIONS: The results of this study suggest that short-term coronary perfusion with a Celsior solution may be useful for heart transplantation from NHBDs.

Animals↗

Leukemia inhibitory factor is augmented in the heart in experimental heart failure.

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that induces cardiac myocyte hypertrophy through the signal transducing molecule, glycoprotein 130. To date, localization of LIF in the heart and regulation of cardiac LIF expression in congestive heart failure (CHF) remain undefined. The present study investigates the potential activation of LIF expression in the failing canine heart that was produced by progressive rapid ventricular pacing. Immunohistochemistry for LIF revealed that LIF immunoreactivity was present in the atrial and ventricular myocytes of the normal heart and was markedly increased in the failing heart as compared to the normal heart. Northern blot analysis demonstrated that cardiac LIF mRNA was increased in both atrium and ventricle in CHF as compared to the normal heart (P<0.01). Linear regression analysis revealed a positive correlation between atrial LIF mRNA and atrial pressure (r=0.87, P<0.001 in right atrium and r=0.86, P<0.001 in left atrium). Positive correlations between left ventricular LIF mRNA and left ventricular dimensions (r=0.91, P<0.0001 in end-systolic diameter; r=0.86, P<0.001 in end-diastolic diameter), and an inverse correlation between left ventricular LIF mRNA and left ventricular ejection fraction (EF) were observed (r=-0.93, P<0.0001). There was a positive correlation between left ventricular LIF mRNA and left ventricular mass index (LVMI) (r=0.85, P<0.001). The present study demonstrates that cardiac LIF immunoreactivity and its gene expression are increased in a canine model of experimental CHF and suggests a potential role for LIF in the pathophysiology of CHF.

Animals↗

The pathogenesis of heart failure in infants with congenital heart disease.

BACKGROUND: The clinical symptoms of heart failure in infants with left-to-right shunts are thought to be explained by well-known hemodynamic disturbances such as pulmonary hypertension and overcirculation, but previous studies have not, thus far, found the expected correlations with hemodynamic and clinical parameters. Based on the neurohormonal model of heart failure, we hypothesised that the clinical symptoms of infants with left-to-right shunts are also related to neurohormonal disorders. METHODS: We compared various neurohormonal and hemodynamic parameters measured invasively in 70 infants with left-to-right shunts to the respiratory rate and gain in weight over a corresponding period of time. Heart rate correlated significantly with respiratory rate (r = 0.62***, p < 0.001) and gain in weight (r = -0.31*, p = 0.015), but more conventional measures of severity, such as the ratio of pulmonary to systemic flows, failed to show comparable correlations with clinical symptoms. Respiratory rate was related to levels of norepinephrine (r = 0.47***, p < 0.001) and plasma renin activity (r = 0.65***, p < 0.001). The important impact of autonomic imbalance on respiratory rate was underlined by an analysis of variability of heart rate in 26 infants that showed significantly reduced values for the domains of time and frequency. We were not able to find a conclusive multiple regression model with which to explain the symptom "failure to thrive". CONCLUSIONS: A increased heart rate, reduced variability in heart rate, and elevated levels of norepinephrine and renin are significant predictors of clinical symptoms such as tachypnea in infants with congenital cardiac malformations. The neurohormonal hypothesis, in which heart failure is interpreted not only as a hemodynamic derangement but also as a neurohormonal disorder, may be valid for infants with congenital cardiac malformations.

Failure to Thrive↗

[Heart murmur--auscultation or echocardiography in the diagnostic assessment of congenital or valvular heart disease?].

The incidence of patients with degenerative valvular but also of patients with congenital heart disease surviving until adulthood or even old age will increase in the next decades. Auscultation with the stethoscope remains an important diagnostic means in the detection and treatment of heart disease. Heart murmurs (especially systolic heart murmurs) are extremely common. There are helpful clues to differentiate heart murmurs. It can occasionally be relatively simple to differentiate a systolic murmur due to valvular heart disease from an innocent, ejection murmur; however, there are important limitations of auscultation. Overall, auscultation and clinical examination alone do not suffice to correctly diagnose and treat patients with heart failure or a murmur Clinically significant aortic stenosis, aortic regurgitation and mitral regurgitation as well as hypertrophic cardiomyopathy are not uncommonly missed or misinterpreted. An echocardiographic exam is mandatory in all patients with more than a soft systolic murmur, any diastolic murmur, cardiac symptoms and/or ECG changes.

Auscultation↗

Heart rate monitors and abnormal heart rhythm detection.

We test the accuracy of two third generation heart rate monitors (HRM), Accurex Plus and Vantage NV and compare these data with those of an older monitor, PE 4000. Then we investigate responses of the HRM's to abnormal heart rhythms (HR). Accurex Plus and Vantage NV, and PE 4000 were tested in the laboratory under both stable and transient conditions. The Phantom 320 HR simulator gave 7 stable heart rates, each lasting 3 min. The responses of the HRM's to abnormal heart rhythms were tested with an automatic arrhythmia program lasting 17 min. The new HRM's, Accurex Plus and Vantage NV, were more accurate (89 to 94% and over 98% at +/-3 beats per min) in the stable state than the PE 4000. They all showed a smoothing effect in transient measurements, which was stronger in decelerating HR (1st case) than in accelerating HR (2nd case). - 1st case: Accurex Plus =Vantage NV >PE 4000 -2nd case: PE 4000 >Accurex =Vantage. Most isolated heart rhythm disorders (missing beat, pause < 4 s, SVEA, and SVT) were either not detected or rejected. Signal changes such as changes in QRS (ventricular bigeminy) may cause detection losses, and so modify calculated heart rate. HR signal rising/dropping slopes caused by sudden heart rhythm disorders, was notably attenuated, with a consequent loss of HR accuracy. Although the usefulness of HRM's in detecting HR disorders is limited, they have some value with serious disorders, like pause >4 s, important bradycardia or tachycardia.

Adult↗

A non-heart-beating donor model to evaluate functional and morphologic outcomes in resuscitated pig hearts.

A non-heart-beating donor model was considered to examine whether pig hearts from the abattoir could be resuscitated by whole blood reperfusion. For preservation, machine perfusion using University of Wisconsin (UW) solution was compared with storage on ice. Nineteen hearts from abattoir pigs, harvested 25 +/- 3 min after exsanguination, were harvested and transported to the laboratory. Controls (n = 7) were immediately reperfused with homologous whole pig blood in an isolated heart model for 60 min with monitoring of left ventricular developed pressure (LVDP), contractility, and coronary flow. UW solution hearts (UW, n = 6) were perfused for 4 h with 10 degrees C cold UW solution before blood reperfusion. In the cold storage group (CS, n = 6), the organs were stored for an additional 4 h on ice before blood reperfusion. In all hearts, histology was performed after 60 min of blood reperfusion to evaluate myocardial reperfusion injury. All three groups showed significant increases in LVDP (p <.001), although this functional recovery was earliest in the control group and latest in the UW group. Significant declines were observed for both LVDP and contractility from the peak values in each group to the end of blood reperfusion. Coronary flow increased steadily over the time course for the UW group, whereas in the control and CS groups flow increased during the first 15 min of blood reperfusion and then decreased. In the UW and CS groups, there were significant positive correlations between coronary flow and LVDP (p <.001). Microscopic examination revealed no differences between the three groups. Thus, hearts from an abattoir with 25 min of warm ischemic time can be resuscitated. For storage of these organs, continuous machine perfusion with UW solution is superior to cold storage on ice.

Adenosine↗

Effects of adding P38 mitogen-activated protein-kinase inhibitor to celsior solution in canine heart transplantation from non-heart-beating donors.

BACKGROUND: The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in ischemia-reperfusion injury. This study evaluated the effects of p38 MAPK inhibition using FR167653, a novel p38 MAPK inhibitor, as an additive to Celsior solution in canine heart transplantation from non-heart-beating donors (NHBDs). METHODS: Donor hearts were left in situ for 20 minutes after cardiac arrest, which was induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into two groups: the control and FR167653 (FR) groups (n=6 each). In both groups, the grafts were subjected to coronary flushing and immersed in Celsior solution for 4 hours with or without FR167653. Orthotopic heart transplantation was then performed. Cardiac output (CO), left ventricular pressure (LVP), and end-systolic maximal elastance (Emax) were measured 2 hours after weaning from cardiopulmonary bypass (CPB), and the hearts were then harvested for histopathologic study. The activation of p38 MAPK was evaluated in another 20 mongrel dogs. RESULTS: In the FR group, CO, LVP recovery rate, and Emax were significantly (P<0.05) higher 2 hours after weaning from CPB, histopathologic damage was attenuated, and the activation of p38 MAPK was significantly (P<0.05) inhibited 10 minutes after reperfusion compared with the control group. CONCLUSIONS: The addition of FR167653 to Celsior solution improved heart-graft viability, probably by way of the inhibition of p38 MAPK activation, which may attenuate ischemia-reperfusion injury in heart transplantation from NHBDs.

Animals↗

Beat-to-beat modulation of heart rate is coupled to coronary perfusion pressure in the isolated heart.

A goal of clinicians caring for heart transplant recipients has been to use heart rate variability as a noninvasive means of diagnosing graft rejection. The determinants of beat-to-beat variability in the surgically denervated heart have yet to be elucidated. We used an isolated, blood buffer-perfused porcine heart preparation to quantitatively assess the relationship between coronary perfusion and sinus node automaticity. Hearts (n = 9) were suspended in a Langendorff preparation, and heart rate (HR) fluctuations were quantified while perfusion pressure was modulated between 70/50, 80/60, 90/70, and 100/80 mmHg at 0.067 Hz. In 32 of 32 recordings, the cross spectrum of perfusion pressure vs. HR showed the largest peak centered at 0.067 Hz. In eight of nine experiments during nonpulsatile perfusion, HR accelerated as perfusion pressure was increased from 40 to 110 mmHg (mean increase 24.2 +/- 3.0 beats/min). HR increased 0.34 beats/min per mmHg increase in perfusion pressure (least squares linear regression y = -25.8 mmHg + 0.34x; r = 0.88, P < 0.0001). Administration of low- and high-dose nitroglycerin (Ntg) resulted in a modest increase in flow but produced a significant decrease in HR and blunted the response of HR to changes in perfusion pressure (HR increase 0.26 beats. min-1. mmHg-1, r = 0.87, P < 0.0001 after low-dose Ntg; 0.25 beats. min-1. mmHg-1, r = 0.78, P < 0.0001 after high-dose Ntg). These experiments suggest that sinus node discharge in the isolated perfused heart is mechanically coupled to perfusion pressure on a beat-to-beat basis.

Animals↗

Artificial hearts and blood pumps in the treatment of profound heart failure.

The recent clinical use of a pneumatic artificial heart at the University of Utah has focused attention on the role of blood pumps in the support of the circulation. Pneumatically powered assist pumps are now in clinical trials in patients with profound but reversible heart failure after open-heart surgery; survival rates as high as 50% in a heretofore lethal condition have been encouraging. The results of animal studies with the pneumatic artificial heart suggest that these devices are ready for clinical trials; the major application is likely to be as a bridge to cardiac transplantation. Implantable electric motor-driven assist pumps and artificial hearts are being evaluated in animals as permanent cardiac support or replacement devices; clinical use is projected to begin late in this decade. Initially, these devices will be employed in patients with end-stage cardiac disease who are not suitable candidates for cardiac transplantation or for whom donor hearts are not available. The availability of compact blood pumps will offer new forms of therapy to patients with certain types of profound heart failure.

Animals↗

Response of atrial natriuretic factor to acute and chronic increases of atrial pressures in experimental heart failure in dogs. Role of changes in heart rate, atrial dimension, and cardiac tissue concentration.

BACKGROUND: This study evaluated the role of changes in heart rate, atrial pressure, volume, and cardiac tissue atrial natriuretic factor (ANF) concentration in the modulation of plasma ANF concentration in a model of pacing-induced heart failure. METHODS AND RESULTS: The effects of acute right ventricular pacing (250 beats/min), acute volume expansion (35 ml/min), and volume expansion after 1 week of right ventricular pacing on plasma ANF concentration were compared in eight dogs (group 1). As shown during right ventricular pacing previously, volume expansion produced significant increases in cardiac filling pressures and left atrial volume. Right ventricular pacing and volume expansion produced similar increments in plasma ANF concentration: from 32 +/- 12 to 168 +/- 153 pg/ml (p less than 0.05) and from 32 +/- 9 to 137 +/- 113 pg/ml (p less than 0.05), respectively. When pacing was initiated after volume expansion, plasma ANF concentration increased further to 462 +/- 295 pg/ml (p less than 0.05) despite little change in filling pressures and left atrial volume. With repeated volume expansion after 1 week of pacing, there were no significant further increases in left atrial volume and plasma ANF concentrations (from 332 +/- 121 to 407 +/- 113 pg/ml) despite significant increases in filling pressures. Atrial and ventricular tissue samples were also obtained from 21 dogs paced to severe heart failure (group 2) and from 14 normal dogs (controls). In all groups, atrial ANF was higher than ventricular ANF concentration. At 1 week (group 1), left atrial appendage ANF concentration (6.2 +/- 2.5 versus 16.1 +/- 10.3 ng/mg) was reduced, whereas left ventricular free wall ANF concentration (0.62 +/- 0.31 versus 0.24 +/- 0.16 pg/mg) was increased compared with that of controls (both p less than 0.001). At severe heart failure (group 2), atrial ANF remained low, whereas ventricular ANF concentration was similar to that of the controls. CONCLUSIONS: These data indicate that in pacing-induced heart failure, changes in heart rate, atrial pressure, and volume all contribute to the increased plasma ANF concentration. However, by 1 week (early heart failure), ANF release is attenuated, perhaps because of the inability of the atria to be stretched further and because of reduced atrial ANF concentration. In addition, the ventricle may be an additional source of ANF.

Animals↗

High-risk heart surgery in the heart transplant candidate.

Because of the limited supply of donor hearts, transplant physicians are searching for alternative treatments for patients referred for orthotopic heart transplantation. A group of 20 patients (7% of patients accepted for heart transplantation at Loyola University Medical Center) were nonrandomly sent for conventional heart surgery. Of 20 patients, 17 survived their hospitalization, and 11 of the original 20 have avoided heart transplantation or having their names added to the transplant list. This group represents a high-risk subset of patients. Patients with poor ventricular function and ventricular arrhythmias or with poor ventricular function who underwent first-time revascularization were well served by more conventional heart surgery (all 10 patients survived surgery). Patients with poor ventricular function who required redo bypass operation had a poor result (three of six died), and such patients should be considered carefully for initial heart transplantation.

Adult↗

Noninvasive assessment of donor and native heart function after heterotopic heart transplantation.

The contribution of the donor heart to total circulatory performance after heterotopic heart transplantation has been difficult to assess. First-pass nuclear angiocardiography and directional Doppler echocardiography were used to examine separately left and right ventricular function of the donor heart after heterotopic transplantation. A comparison was made between two patients, one with a low initial pulmonary vascular resistance and one with a high, relatively fixed pulmonary vascular resistance. In both cases, currently available noninvasive techniques allowed confirmation of the expectation that the donor left ventricle can function effectively as a left ventricular bypass. In neither case was recovery of the native heart demonstrated. The contribution of the donor right ventricle to total right ventricular output appeared to be dependent on the condition of the donor heart and on the pulmonary vascular resistance. In situations with a high pulmonary vascular resistance and end-stage right ventricular failure, it was concluded that the donor heart may not at first constitute an effective assist for the native right ventricle. Native right ventricular failure may then become a major factor influencing survival after heterotopic heart transplantation.

Adolescent↗