Improved Exercise Tolerance in an Adolescent Female After Failed Fontan and Subsequent Biventricular Conversion.

We report a case of improved exercise tolerance in a single-ventricle patient following biventricular conversion. An 11 year old with a fenestrated extracardiac failing Fontan was accepted for a biventricular conversion repair at an out-of-town institution. The patient had multiple adverse cardiac events following Fontan surgery including recurrent pleural effusions, arteriovenous malformations, protein-losing enteropathy, and marked exercise intolerance. Serial cardiac catheterizations revealed chronic elevated pulmonary artery and Fontan pressures, normal left ventricular end-diastolic pressure and an adequately sized left ventricle. Cardiopulmonary exercise testing demonstrated severely reduced exercise tolerance due to ventilatory and cardiac limitations with significant arterial desaturations during exercise. Following a successful biventricular conversion, exercise tolerance improved remarkably, as evidenced by improved oxygen uptake and ventilatory efficiency. Our case demonstrates that biventricular conversion surgery may offer improvement in quality of life and exercise capacity in selected patients with failing Fontan physiology.

A Novel Patent Ductus Arteriosus Severity Score to Predict Clinical Outcomes in Premature Neonates.

Background: Patent Ductus Arteriosus (PDA) in premature neonates has been associated with comorbidities including chronic lung disease (CLD), and death. However, the treatment of PDA remains controversial. There have been several echocardiographic variables previously used to determine the hemodynamic significance of PDA but their utility in early prediction of clinical outcomes is not well studied. Objective: The objective of our study was to evaluate the use of a severity scoring system incorporating markers of systemic under perfusion, pulmonary over perfusion and left ventricular (LV) function in predicting clinical outcomes in premature neonates. Methods: It is a single center prospective observational study involving newborns < 32 weeks' gestation. An echocardiogram was done within seven days of life to measure variables previously known to predict severity of shunting in PDA including pulmonary perfusion index (PPI). Predictors of CLD/death were identified using multivariate logistic regression. A severity score was derived and its ability to predict clinical outcomes was tested using a receiver operating characteristic curve. Results: We studied 98 infants with a mean (SD) gestation of 28.9 ± 1.91 weeks and birth weight of 1228.06 ± 318.94 g, respectively. We identified five echocardiographic variables along with gestational age that was independently associated with the outcome variable (PPI, LV output, Superior Mesenteric Artery [SMA] Velocity Time Integral [VTI], Peak diastolic flow velocity in Pulmonary Vein [PV Vd], and reversal of flow in diastole in descending aorta [DFR]). The range of severity score was 0 (low risk) to 12 (high risk). A higher score was associated with the primary outcome variable of CLD/death (7.5 [1.2] vs. 3.6 [1.5], p < 0.001). Our severity score had an area under the curve of 0.97 (95% CI 0.93−0.99, p < 0.001) for predicting CLD/death. Conclusion: Our new PDA severity score of 5.5 has a sensitivity and specificity of 94% and 93%, and positive and negative predictive values of 94% and 93%, respectively.

A Proposed Etiology for Atrial Tachyarrhythmia in Neonates with Atrial Septal Aneurysms.

An atrial septal aneurysm (ASA) is an increasingly recognized entity that involves septal tissue significantly bulging into either atria instead of remaining in a relatively neutral position. ASAs may be described based on the length of the segment of atrial septal tissue involved as well as the distance and direction of excursion into the atria throughout the cardiac cycle. Complications associated with ASA include arrhythmias and thromboembolic events with the latter usually in the context of atrial shunting. While the presence of an ASA has been implicated in the development of atrial tachyarrhythmias, no clear mechanism has been elucidated to-date. In this case, we document one of the previously proposed mechanisms of atrial arrhythmia using echocardiography imaging.

Use of Speckle Tracking Echocardiography to Assess Left Ventricular Systolic Function in Patients with Surgically Repaired Tetralogy of Fallot: Global and Segmental Assessment.

Patients with repaired Tetralogy of Fallot (rToF) can have significant right and left ventricular dysfunction which can impact clinical outcome. Conventional echocardiographic evaluation using ejection fraction can be limited in detecting early stages of deteriorating left ventricular (LV) systolic function. Speckle-tracking echocardiography (STE) provides a promising emerging tool for early detection of LV systolic dysfunction. The aim of this cross-sectional study is to evaluate the left ventricular global and regional function using STE in rToF patients with preserved left ventricular ejection fraction to detect early signs of LV dysfunction. The study is a retrospective review of the medical records and transthoracic echocardiograms of rTOF patients who were seen in the pediatric cardiology clinic at our institution from August 2016 till May 2018. The rTOF group was compared with a matched healthy control group. Offline strain analysis of TTE studies was completed in each subject according to mode set by the American Society of Echocardiography. Twenty-two patients with rTOF and 22 age-matched controls (rTOF 18.7 ± 6 years and control 14.6 ± 9.6 years, P value 0.19) were included during the study period. The rTOF group consisted of 12 males and 10 females, whereas the control group consisted of 15 males and 7 females. There was no significant difference in terms of LV ejection fraction using both 2-chamber as well as 4-chamber views. Global LV longitudinal strain was significantly lower in the rTOF group compared with the control group (rTOF - 15.92 ± 3.16 vs control - 22.79 ± 2.45, P value 0.00). All 17 segments showed significantly lower longitudinal strains in rTOF group compared with the control group. Global circumferential left ventricle strain was significantly lower in the rTOF patients compared with the control group (- 17.24 ± 5.86 vs - 22.74 ± 3.99, P value 0.001). 13 out of 16 segments had lower circumferential strains in the rTOF patients compared with controls. Asymptomatic surgically repaired TOF patients exhibited abnormal segmental and global left ventricle longitudinal and circumferential strains despite having normal left ventricle ejection fraction. Our findings suggest subclinical damage to the left ventricle systolic function post-surgical repair of TOF. 2-D speckle-tracking echocardiography may be used as a valuable method in the early recognition of left myocardial systolic function impairment in patients after TOF repair. The application of this method to guide clinical decision and management of rTOF patients such as earlier pulmonary valve replacement or risk stratification for sudden cardiac death needs further investigation.

Determination of the Frequency of Right and Left Internal Mammary Artery Embolization in Single Ventricle Patients: A Two-Center Study.

Embolization of systemic to pulmonary artery collaterals to regulate pulmonary arterial flow or pressure of the cavopulmonary circulation in patients with single ventricle is a common practice. The relative incidence and impact of this practice on future interventions like coronary artery bypass grafting is poorly understood. This study aims to evaluate the frequency and implications of internal mammary artery (IMA) embolization in the single ventricle (SV) population. A retrospective chart review was performed of SV patients who underwent cardiac catheterization before and after Fontan procedure between February 2007 and 2017. Data were collected from two tertiary care centers in the Midwest. Of the 304 SV patients, 62 (20.4%) underwent embolization of one or more IMAs, whereas 242 (79.6%) did not. The rate of embolization of IMA was 40.5% in one center and 14.5% in the second center. Among patients who received IMA embolization, left internal mammary artery (LIMA) embolization was seen in 6 (9.7%) patients. Majority of patients underwent either right internal mammary artery (RIMA) embolization (n = 25; 40.3%) or RIMA and LIMA embolization (n = 27; 43.5%). IMA embolization in SV patients is common. Embolizing IMAs early in life will likely eliminate a valuable graft option for coronary artery bypass grafting should it be required in the future care of these patients. Multi-center, prospective, nation-wide studies are warranted to examine coronary artery disease in the SV population and true frequency of IMA embolization. Delineation of which IMAs were embolized is a necessary in surgical and cardiac intervention national data, such as Society of Thoracic Surgeons (STS) database. All measures should be taken to preserve IMAs patency, if deemed feasible and safe.

Routine Cardiac Catheterization Prior to Fontan Operation: Is It a Necessity?

Prior to the Fontan procedure, patients with single ventricle physiology with Glenn shunt are typically referred for cardiac catheterization to assess hemodynamics and potentially provide interventional measures. Currently, echocardiography provides detailed information which together with other non-invasive imaging such as CT scan and MRI may obviate the need for routine cardiac catheterization prior to the Fontan procedure. In this study, we examine the findings in cardiac catheterization in this population to determine: (a) the accuracy of echocardiography in providing adequate information prior to the Fontan procedure, particularly in identifying those in need of per-catheter intervention, and (b) the percentage of patients requiring interventional procedures during cardiac catheterization. We performed a retrospective chart review of echocardiographic and cardiac catheterization data for patients who underwent pre-Fontan cardiac catheterization at our center in the period from 02/01/2008 to 02/28/2017. We aimed to re-examine the necessity of routine cardiac catheterization in all single ventricle patients. This was performed through examining pre-catheterization echocardiography reports and comparing them to findings of the subsequent cardiac catheterization reports. Echocardiography reports were evaluated for accuracy in identifying significant anatomical or hemodynamic findings, which may impact success of Fontan procedure as well as the ability of echocardiography to predict findings important to know prior to the Fontan procedure. In this cohort of 40 children, 3 patients were found to have significant hemodynamic findings through cardiac catheterization which were not previously known by echocardiography. In addition, 28 out of 40 patients (70%) required interventional procedures to address significant abnormalities (systemic to pulmonary arterial collaterals, pulmonary artery stenosis, aortic arch stenosis, etc.). All cases of aortic arch stenosis were detected by echocardiography, however, all patients who required systemic to pulmonary arterial or left SVC embolization were not detected by echocardiography. Furthermore, echocardiography did not detect the need for branch pulmonary artery stenosis in 50% of cases. Cardiac catheterization appears to be an essential part of patient assessment prior to Fontan completion in patients with single ventricle physiology. This current practice may change in the future if a non-invasive screening tool is found to have high positive and negative predictive values in identifying the subset of patients who require potential intervention in pre-Fontan cardiac catheterization.

The Use of Fecal Calprotectin Levels in the Fontan population.

The Fontan procedure was first performed in the seventies as a palliation for patients with single ventricle physiology. A feared complication after a Fontan procedure is the development of protein losing enteropathy (PLE). Systemic inflammation has a negative effect on the intestinal barrier integrity, which has supported the use of steroids in this setting. To the best of our knowledge there are no studies linking intestinal inflammation in patients with PLE after Fontan. The objective of this study was to identify the presence of intestinal inflammation measured by FC in patients with PLE after a Fontan procedure. A cross-sectional analysis was performed examining 23 stool samples from 23 Fontan patients for both Fecal alpha-1-antitrypsin (FA1AT) and FC with and without PLE. The median FC was 21 mcg/gm of stool (IQR: 15.7-241 mcg/gm of stool), and the median FA1AT was 40 mg/dL (IQR: 30-220 mg/dL). The median FC and FA1AT were significantly higher in the PLE group than in the Non-PLE group (p = 0.002 and p < 0.0001, respectively). Significantly elevated levels of FC were demonstrated in Fontan patients with PLE, which correlated with the elevated levels of FA1AT. Inversely, levels of FC in Fontan patients without suspected PLE were within the normal range. To our knowledge, this is the first study to demonstrate intestinal inflammation using FC in the setting of PLE within this cohort, and may prove to be useful as a diagnostic tool in its treatment.

Can the Pulmonary Artery Wedge Pressure be Used Reliably as a Surrogate for the Left Atrial Mean Pressure in Pre-Fontan Evaluation?

The correlation between mean pulmonary artery wedge pressure (PAWP) and left atrial mean pressure (LAMP) has been poorly studied in patients with single ventricle (SV) physiology (Bernstein et al. in Pediatr Cardiol 33: 15-20 2012). The aim of this study is to determine if the PAWP can be used safely as a surrogate to the LAMP to calculate the pulmonary vascular resistance (PVR) during the pre-Fontan evaluation. Also, we aimed to understand if the presence of significant systemic-to-pulmonary collaterals (SPCs) is a confounding factor for accurate estimation of the LAMP. From February 2007 to February 2017, forty-one patients were eligible for inclusion in the study. These patients were varied in terms of underlying cardiac malformation. Sex distribution was equal with 20 males and 21 females. Median weight was 11.8 kg, median body surface area was 0.51 m2, median age at catheterization was 2 years, and the median age at Glenn surgery was 5 months. We found the left and right PAWP and LAMP correlated strongly and the differences in the measurements were negligible. Similar findings were observed when calculating PVRs using PAWP and LAMP. These findings were more pronounced in the absence of significant SPCs. PAWP and LAMP correlation was still valid in the presence of significant SPCs; however, the correlation among the calculated PVRs was more attenuated.

Chronic Low Dose Prostaglandin and Neonatal Heart Block.

Long-term prostaglandin use is commonly associated with side effects such as cortical proliferation of the bones, hypertrophic pyloric stenosis, and soft tissue swelling of the extremities. We report a neonate with critical coarctation of the aorta, who developed second and third degree atrioventricular blocks associated with prolonged prostaglandin E1 (PGE1) infusion. Interestingly, these conduction blocks only occurred at low PGE1 dose. The rhythm disturbances resolved promptly with the discontinuation of PGE1 following surgical repair.

Hypoplastic Left Heart Syndrome with Congenital Complete Heart Block.

Congenital complete atrioventricular block (CCAVB) is a rare condition with an incidence of 1 of 20,000 live births. Hypoplastic left heart syndrome (HLHS) occurs more frequently than CCAVB and occurs in 1 of 5000 live births. HLHS in association with CCAVB is exceedingly rare. In this report, we describe a rare case of HLHS and CCAVB diagnosed in utero. Postnatal diagnosis, management and outcome are presented as well as review of the medical literature.

Coronary Sinus Defect Following Transcatheter Closure of ASD Using Amplatzer Septal Occluder: Potential Erosion by the Device.

We present a case of small coronary sinus defect detected after transcatheter device closure of a large secundum atrial septal defect. Although device erosion of the dilated coronary sinus is suspected, the defect in the coronary sinus may have been present prior to ASD device closure. Dilated coronary sinus may be a risk factor when closing a secundum ASD with a device. To the best of our knowledge, coronary sinus erosion by an ASD device has not yet been reported in the medical literature.

Frequency of Mammary Artery Coiling in Single-Ventricle Patients and Future Coronary Artery Grafting.

Pre-Fontan coil closure of aorto-pulmonary collaterals decreases single-ventricle volume load and improves outcome. Coiling of right and left internal mammary arteries may present a challenge to cardiothoracic surgery teams caring for these patients when future coronary artery bypass grafting is needed for SV patients. The goal of this study was to determine the frequency of internal mammary artery coil closure in SV patients in a single tertiary care center. A retrospective review of all pediatric single-ventricle patients who underwent cardiac catheterization between March 2009 and October 2015 at Rush Center for Congenital Heart Disease was performed. Fifty-one patients' charts were reviewed. Twenty-five patients received coil closure of one or more internal mammary artery (coil group) and 26 received no coil closure (no-coil group). In the coil group, 21 (84 %) had their collateral vessels coiled in the pre-Fontan period and 4 (16 %) had their vessels coiled in the post-Fontan period. In the coil group, 18 (72 %) had their right internal mammary artery coiled and 7 (28 %) had both right and left internal mammary arteries coiled. None of the coil group had isolated coil closure of the left internal mammary artery. This study is the first to verify the frequency of right and/or left internal mammary artery coil closure in SV patients and the potential impact on future coronary artery bypass grafting. Extensive peri-Fontan coiling of the internal mammary arteries presents a significant potential challenge for subsequent management of SV patients as older adults.

Extended Application of the Hybrid Procedure in Neonates with Left-Sided Obstructive Lesions in an Evolving Cardiac Program.

The hybrid approach to management of hypoplastic left heart syndrome (HLHS) was developed as an alternative to neonatal Norwood surgery, providing a less invasive initial palliation for HLHS. We describe our experience in extending the concept of the hybrid procedure to palliate neonates with anatomically compromised systemic arterial blood flow in a variety of congenital cardiac anomalies and supporting its application as first-line palliation in centers developing their HLHS programs. Retrospective review of patients undergoing therapy for HLHS at a single institution from June 2008 to December 2014 was performed. Subject demographics, clinical and procedural data, along with follow-up, were collected. Thirteen patients had initial hybrid palliation for HLHS during the time frame indicated at a median age of 8 days (range 1-29 days) and median weight of 3.4 kg (range 2.4-4.6 kg). Diagnoses included typical HLHS (n = 6), right-dominant unbalanced atrioventricular septal defect with arch hypoplasia (n = 4), double outlet right ventricle [subpulmonic VSD (n = 1) and intact ventricular septum (n = 1)] with hypoplastic transverse aortic arch and borderline left ventricular dimensions. Standard approach with bilateral pulmonary artery banding and ductal stenting was carried out in all thirteen patients. Two patients required two ductal stents at the time of index procedure. There were no intraprocedural complications. Median intubation length post-procedure was 4 days (range 1-74 days). Median hospital stay post-procedure was 47 days (range 15-270 days). The overall mortality rate on follow-up through comprehensive stage 2 over the 6-year experience was 38 % (5 out of 13). Of note, the mortality rate was significantly lower in the latter 3 years of the study period when the procedure was adopted as a primary palliation for HLHS (14 % or 1 out of 7) compared to the initial 3-year period when it was reserved for higher risk cohorts (67 % or 4 out of 6). Median time to subsequent surgery was 3 months (range 1-4 months). One patient required further ductal stenting on follow-up and developed subsequently airway compression. On median follow-up of 24 months, two patients required pulmonary artery arterioplasty. The hybrid procedure may be used for palliation for a variety of cardiac lesions to avoid high-risk surgery in the neonatal period. This approach may be also an alternative in centers performing lower number of Norwood surgery, which has been associated with higher mortality.

The use of intracardiac echocardiography during percutaneous pulmonary valve replacement.

High-quality live imaging assessment of cardiac valves and cardiac anatomy is crucial for the success of catheter-based procedures. We present our experience using Intracardiac echocardiography (ICE) during transcatheter Percutaneous Pulmonary Valve replacement (tPVR).This is a retrospective study that included 35 patients who underwent tPVR between April 2008 and June 2012. Thirty-one of these patients had the procedure performed under continuous ICE guidance. Pre-procedure transthoracic echocardiography (TTE) was obtained in all patients. ICE was performed at baseline, during the procedure, and at the conclusion of the procedure. Comparisons between the pre-procedure TTE and baseline ICE data and between post-procedure ICE data and the following day TTE were performed. Total of 35 patients had tPVR during the above-mentioned time period. Twenty-one patients received the Edwards Sapien valve and 14 patients had the Melody valve. Thirty-one patients had the procedure performed under continuous ICE guidance. The mean Pre-TTE peak gradient (PG) and Pre-ICE-PG were 45.5 ± 20 vs 33 ± 13 mmHg (p < 0.001) and the mean Pre-TTE mean gradient (MG) and Pre-ICE-MG were 27.7 ± 13 vs 21 ± 18 mmHg (p < 0.001). The mean Post-TTE- PG and Post-ICE-PG were 24.3 ± 11 vs 15.3 ± 7 mmHg (p < 0.001) and the mean of the Post-TTE-MG and Post-ICE-MG were 14.2 ± 7 vs 8.4 ± 4 mmHg (p < 0.001). There was a good correlation between peak ICE and TTE gradient at baseline and after valve placement. For the degree of pulmonary regurgitation, there was no significant difference between TTE and ICE. ICE is an important modality to guide tPVR in patients with dysfunctional homograft valve between the right ventricle and pulmonary artery and should be used to assess valve function before, during and immediately after the procedure.

Inositol-1,4,5-trisphosphate induced Ca2+ release and excitation-contraction coupling in atrial myocytes from normal and failing hearts.

KEY POINTS: Impaired calcium (Ca(2+)) signalling is the main contributor to depressed ventricular contractile function and occurrence of arrhythmia in heart failure (HF). Here we report that in atrial cells of a rabbit HF model, Ca(2+) signalling is enhanced and we identified the underlying cellular mechanisms. Enhanced Ca(2+) transients (CaTs) are due to upregulation of inositol-1,4,5-trisphosphate receptor induced Ca(2+) release (IICR) and decreased mitochondrial Ca(2+) sequestration. Enhanced IICR, however, together with an increased activity of the sodium-calcium exchange mechanism, also facilitates spontaneous Ca(2+) release in form of arrhythmogenic Ca(2+) waves and spontaneous action potentials, thus enhancing the arrhythmogenic potential of atrial cells. Our data show that enhanced Ca(2+) signalling in HF provides atrial cells with a mechanism to improve ventricular filling and to maintain cardiac output, but also increases the susceptibility to develop atrial arrhythmias facilitated by spontaneous Ca(2+) release. ABSTRACT: We studied excitation-contraction coupling (ECC) and inositol-1,4,5-triphosphate (IP3)-dependent Ca(2+) release in normal and heart failure (HF) rabbit atrial cells. Left ventricular HF was induced by combined volume and pressure overload. In HF atrial myocytes diastolic [Ca(2+)]i was increased, action potential (AP)-induced Ca(2+) transients (CaTs) were larger in amplitude, primarily due to enhanced Ca(2+) release from central non-junctional sarcoplasmic reticulum (SR) and centripetal propagation of activation was accelerated, whereas HF ventricular CaTs were depressed. The larger CaTs were due to enhanced IP3 receptor-induced Ca(2+) release (IICR) and reduced mitochondrial Ca(2+) buffering, consistent with a reduced mitochondrial density and Ca(2+) uptake capacity in HF. Elementary IP3 receptor-mediated Ca(2+) release events (Ca(2+) puffs) were more frequent in HF atrial myoctes and were detected more often in central regions of the non-junctional SR compared to normal cells. HF cells had an overall higher frequency of spontaneous Ca(2+) waves and a larger fraction of waves (termed arrhythmogenic Ca(2+) waves) triggered APs and global CaTs. The higher propensity of arrhythmogenic Ca(2+) waves resulted from the combined action of enhanced IICR and increased activity of sarcolemmal Na(+)-Ca(2+) exchange depolarizing the cell membrane. In conclusion, the data support the hypothesis that in atrial myocytes from hearts with left ventricular failure, enhanced CaTs during ECC exert positive inotropic effects on atrial contractility which facilitates ventricular filling and contributes to maintaining cardiac output. However, HF atrial cells were also more susceptible to developing arrhythmogenic Ca(2+) waves which might form the substrate for atrial rhythm disorders frequently encountered in HF.

Congenital left ventricular outpouchings: a systematic review of 839 cases and introduction of a novel classification after two centuries.

BACKGROUND: Congenital left ventricular outpouchings (LVOs) are reported under five overlapping and poorly defined terms including left ventricular accessory chamber, left ventricular aneurysm (LVA), left ventricular diverticulum (LVD), double-chambered LV, and accessory left ventricle. Diagnostic criteria are frequently mixed and not mutually exclusive. They convey no information regarding treatment strategy and prognosis. OBJECTIVES: The aim of this systematic review is to provide a clear and inclusive classification, with therapeutic and prognostic implications, for congenital LVOs. DATA SOURCES: We performed three separate sets of search on three subjects including "congenital left ventricular outpouchings," "important and simply measurable markers of left ventricular function," and "relationship of mechanics of intraventricular blood flow and optimal vortex formation in left ventricle and elliptical geometry of LV." STUDY ELIGIBILITY CRITERIA: We enrolled case series, review articles, and case reports with literature review. All types of acquired LVO's were excluded. STUDY APPRAISAL AND SYNTHESIS METHODS: We studied the abstracts of all searched articles. We focused on diagnostic criteria and patients' outcome. To examine the validity and reliability of the novel classification, fifteen previous studies were revisited using the novel classification. RESULTS: A total of 20 papers from 11 countries fulfilled our inclusion criteria. The age of patients ranged from prenatal age to geriatric age range. Diagnostic criteria were clearly stated only for two of the above five terms (i.e., congenital LVA and congenital LVD). Cases with mixed diagnostic criteria were frequent.Elliptical geometry of left ventricle was found to have significant impact on effective blood flow mechanics in LV. A simple inclusive classification for congenital LVOs, with therapeutic and prognostic implications, was introduced. CONCLUSION: The cornerstone of this classification is elliptical LV geometry. Large-type IIc LVO have dismal prognosis, if left untreated. LVO type I and small LVO type IIa have the best prognosis.

Metastatic osteosarcoma to the interventricular septum: an unusual presentation in a child.

Whereas primary cardiac tumors are reported in only 0.17 % of pediatric patients, malignant cardiac tumors are even less common in children. This report presents a 10-year-old child with relapsed osteosarcoma manifesting as metastatic lesions to the interventricular septum.

NFAT transcription factor regulation by urocortin II in cardiac myocytes and heart failure.

Urocortin II (UcnII), a cardioactive peptide with beneficial effects in normal and failing hearts, is also arrhythmogenic and prohypertrophic. We demonstrated that cardiac effects are mediated by a phosphatidylinositol-3 kinase (PI3K)/Akt kinase (Akt)/endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) signaling pathways. Nuclear factor of activated T-cells (NFAT) transcription factors play a key role in the regulation of gene expression in cardiac development, maintenance of an adult differentiated cardiac phenotype, and remodeling processes in cardiac hypertrophy and heart failure (HF). We tested the hypothesis that UcnII differentially regulates NFAT activity in cardiac myocytes from both normal and failing hearts through the PI3K/Akt/eNOS/NO pathway. Isoforms NFATc1 and NFATc3 revealed different basal subcellular distribution in normal and HF rabbit ventricular myocytes with a nuclear NFATc1 and a cytosolic localization of NFATc3. However, in HF, the nuclear localization of NFATc1 was less pronounced, whereas the nuclear occupancy of NFATc3 was increased. In normal myocytes, UcnII induced nuclear export of NFATc1 and attenuated NFAT-dependent transcriptional activity but did not affect the distribution of NFATc3. In HF UcnII facilitated nuclear export of both isoforms and reduced transcriptional activity. NFAT regulation was mediated by a PI3K/Akt/eNOS/NO signaling cascade that converged on the activation of several kinases, including glycogen synthase kinase-3ß (GSK3ß), c-Jun NH2-terminal kinase (JNK), p38 mitogen-activated kinase (p38), and PKG, resulting in phosphorylation, deactivation, and nuclear export of NFAT. In conclusion, while NFATc1 and NFATc3 reveal distinct subcellular distribution patterns, both are regulated by the UcnII-PI3K/Akt/eNOS/NO pathway that converges on the activation of NFAT kinases and NFAT inactivation. The data reconcile cardioprotective and prohypertrophic UcnII effects mediated by different NFAT isoforms.