Factors Associated With Sinoatrial Reinnervation After Heart Transplantation.

Background: Factors associated with sympathetic and parasympathetic sinoatrial reinnervation after heart transplantation (HTx) are inadequately studied. Methods: Fifty transplant recipients were examined at 7 to 12 wk (index visit), 6, 12, 24, and 36 mo after HTx. Supine rest heart rate variability in the low-frequency (LF) domain (sympathetic and parasympathetic sinoatrial reinnervation) and the high-frequency (HF) domain (parasympathetic sinoatrial reinnervation) were measured repeatedly and related to selected recipient, donor, and perisurgical characteristics. We primarily aimed to identify index visit factors that affect the sinoatrial reinnervation process. Secondarily, we examined overall associations between indices of reinnervation and repeatedly measured recipient characteristics to generate new hypotheses regarding the consequences of reinnervation. Results: LF and HF variability increased time dependently. In multivariate modeling, a pretransplant diagnosis of nonischemic cardiomyopathy (P = 0.038) and higher index visit handgrip strength (P = 0.028) predicted improved LF variability. Recipient age, early episodes of rejection, and duration of extracorporeal circulation were not associated with indices of reinnervation. Study average handgrip strength was positively associated with LF and HF variability (respectively, P = 0.005 and P = 0.029), whereas study average C-reactive protein was negatively associated (respectively, P = 0.015 and P = 0.008). Conclusions: Indices of both sympathetic and parasympathetic sinoatrial reinnervation increased with time after HTx. A pretransplant diagnosis of nonischemic cardiomyopathy and higher index visit handgrip strength predicted higher indices of mainly sympathetic reinnervation, whereas age, rejection episodes, and duration of extracorporeal circulation had no association. HTx recipients with higher indices of reinnervation had higher average handgrip strength, suggesting a link between reinnervation and improved frailty. The more reinnervated participants had lower average C-reactive protein, suggesting an inhibitory effect of reinnervation on inflammation, possibly through enhanced function of the inflammatory reflex. These potential effects of reinnervation may affect long-term morbidity in HTx patients and should be scrutinized in future research.

Predictors of Hypertension Development 1 Year After Heart Transplantation.

BACKGROUND: Hypertension after heart transplantation (HTx) is common. We investigated predictors of and mechanisms for hypertension development during the first year after HTx, with particular attention toward immunosuppressive agents, reinnervation processes, and donor/recipient sex. METHODS: Heart transplant recipients (HTxRs) were consecutively enrolled 7 to 12 wk after surgery and followed prospectively for 12 mo. Ambulatory blood pressure recordings and autonomic cardiovascular control assessments were performed at baseline and follow-up. Possible predictors of posttransplant hypertension development were investigated in bivariate linear regression analyses followed by multiple regression modeling. RESULTS: A total of 50 HTxRs were included; 47 attended the follow-up appointment at 12 mo. Mean systolic and diastolic blood pressure increased significantly during the observational period (systolic blood pressure from 133 to 139 mm Hg, P = 0.007; diastolic blood pressure from 81 to 84 mm Hg, P = 0.005). The blood pressure increment was almost exclusively confined to HTxRs with a female donor heart, doubling the cases of systolic hypertension (from 6 to 13/14; 46% to 93%, P = 0.031) and diastolic hypertension (from 7 to 14/14; 54% to 100%, P = 0.031) in this subgroup. Autonomic cardiovascular control assessments suggested tonically constricted resistance and capacitance vessels in recipients with female donor hearts. Immunosuppressive agents and reinnervation markers were not associated with hypertension development. CONCLUSIONS: Blood pressures increase during the first year after HTx, with female donor sex as a strong predictor of recipient hypertension development. The underlying mechanism seems to be enhanced peripheral vasoconstriction caused by attenuated cardiovascular homeostasis capabilities. Further studies are needed to confirm the results.

Strong evidence for parasympathetic sinoatrial reinnervation after heart transplantation.

BACKGROUND: Heart transplantation (HTx) surgically denervates the heart. We examined indices of sinoatrial reinnervation, with emphasis on (1) the occurrence and timing of parasympathetic reinnervation, and (2) the consequences of reinnervation for heart rate (HR) responsiveness and arterial baroreceptor sensitivity. METHODS: Fifty HTx recipients were prospectively followed for 36 months after surgery. Hemodynamic variables and heart rate variability were continuously recorded at supine rest, 60 degrees head-up-tilt, during the Valsalva maneuver and during handgrip isometric exercise. RESULTS: Suggesting parasympathetic reinnervation: at baseline rest, root of the mean squared differences of successive RR intervals increased from median 3.9(5.9) to 7.1(5.1) ms (p < 0.001); high-frequency power increased from 4.0(12) to 5.7(18.9) ms2 (p = 0.018); and baroreceptor sensitivity increased from 0.04(0.36) to 1.3(2.4) ms/mmHg (p < 0.001). Suggesting sympathetic reinnervation: at baseline rest low-frequency power increased from 0.49(2.5) to 7.5(18.1) ms2 (p < 0.001); and HR responses to sympathetic stimulation during (1) head-up tilt increased from 1.9(4.2) to 9.1(8.2) bpm (p < 0.001), (2) Valsalva increased from 1.6(1.4) to 8.3(10.8) bpm (p < 0.001) and (3) handgrip increased from 0.3(0.6) to 1.9(5.1) bpm (p < 0.001). Signs of sympathetic reinnervation emerged within 6 months, while signs of parasympathetic reinnervation emerged by 24 months. CONCLUSIONS: Root of the mean squared differences of successive RR intervals, high-frequency and low-frequency variability, HR responsiveness and arterial baroreflex sensitivity all increased after HTx, suggesting functional parasympathetic and sympathetic sinoatrial reinnervation. Accordingly, the pathological regulatory state present in heart transplant recipients, which is responsible for a host of functional and clinical abnormalities, is being partially offset over time by restored autonomic control of the heart in many heart transplant recipients.

Current-Era Outcomes of Balloon Aortic Valvotomy in Neonates and Infants.

Background: The optimal initial treatment pathway for aortic valve stenosis remains debated. Objectives: The objective of this study was to review current outcomes of balloon aortic valvotomy (BAV) in neonates and infants. Methods: Neonates and infants with a biventricular circulation treated with BAV between 2004 and 2019 were reviewed. Results: One hundred thirty-nine infants (48% neonates) with median (Q1, Q3) age of 33(7, 84) days and weight 4.0 (3.4, 5.1) kg were followed up for 7.1 (3.3, 11.0) years. BAV reduced peak-to-peak gradient from mean (SD) 52 (16) mmHg to 18 (12) mmHg; P < 0.001. Aortic regurgitation (AI) increased with time after BAV. Three children died during follow-up. Fifty-one reinterventions (26 BAV, 19 aortic valve replacements [AVRs], and 6 surgical valvotomies) were performed on 40 children. Freedom from AVR (95% CI) was 96% (93%-99%) at 1, 91% (86%-96%) at 5, and 86% (79%-93%) at 10 years. The predictors of AVR were a unicommissural valve (hazard ratio [HR] [95% CI]: 3.7 [1.4-9.6]; P = 0.007) and moderate to severe AI after index BAV (HR [95% CI]: 3.3 [1.1-9.7]; P = 0.029). Freedom from reintervention was 84% (78%-90%) at 1, 76% (69%-83%) at 5, and 69% (60-78%) at 10 years. Main predictors of reintervention were age below 1 month (HR [95% CI]: 2.1 [1.1-4.1]; P = 0.032) and postdilation peak-to-peak gradient (per 10-mmHg increase; HR [95% CI]: 1.36 [1.02-1.79]; P = 0.032). Conclusions: BAV is a safe and effective treatment for aortic valve stenosis in neonates and infants. Outcomes are competitive with contemporary published data on aortic valve repair in relation to mortality, gradient relief, long-term AVR, and reintervention rates. In the absence of significant AI, surgery can be reserved for those with gradients resistant to valve dilation.

Paediatric cardiac catheterisation in Norway: rates and types of complications in new terms.

We determined the incidence, type, and severity of complications after cardiac catheterisation in children with heart disease in Norway, and we present the results in terms of the International Paediatric and Congenital Cardiac Code (IPCCC) nomenclature for complications. All paediatric cardiac catheterisations in Norway are performed in one clinical centre. All procedures performed during a 5-year period beginning in 2010 were prospectively registered, and medical records for cases with complications were reviewed to confirm the event and to re-classify the type, severity, and attributability of the complication according to the IPCCC nomenclature. Univariate and multivariate analyses were performed to identify possible risk predictors. A total of 1318 catheterisations performed on 941 patients were included in the present study, of which 68% were interventional. The complication and major complication rates were 5.5 and 1.4%, respectively. Trauma to the vessels or the myocardium, haemodynamic adverse events, and arrhythmias were the most common types of complications. In the multivariate model, weight <4 kg (odds ratios, 3.0; 95% confidence intervals: 1.6-5.8) and risk category 5 (odds ratios, 5.1; 95% confidence intervals: 2.1-12.3) were significant risk predictors for any complication. In spite of a high rate of interventions, the complication rates in this study were similar to older studies, but diverging methods and terminology limit the comparability. We strongly suggest general use of the proposed IPCCC classification system for registration and reports of complications for paediatric cardiac catheterisations.

[Occurrence of arrhythmias related to treatment of myocardial infarction]. / Forekomsten av arytmi ved behandling av hjerteinfarkt.

BACKGROUND: Percutaneous coronary catheter intervention (PCI) reduces mortality in ST-elevation myocardial infarction (STEMI) more than fibrinolysis. However, it remains uncertain whether PCI reduces the incidence of early post-infarction arrhythmias. MATERIAL AND METHODS: We compared the incidence of arrhythmias in two groups of consecutive STEMI-patients who underwent continuous ECG monitoring. One group was treated with PCI in 2006-07, while a historic control group received thrombolysis in 1996-98. RESULTS: 93 (38%) PCI patients and 97 (53%) of the thrombolysed patients (p = 0.001) had arrhythmias. 27% of the patients in the PCI group were treated for arrhythmias vs. 34% of the thrombolysed (n.s.). Significantly fewer PCI-treated patients had atrial fibrillation (5% vs. 16%), AV-block II/III (0% vs. 6%) and asystole (0% vs. 5%), but an increased frequency of ventricular tachycardia was recorded (10% vs. 5%). 41% of all arrhythmic and 63% of treated events occurred in the first hour after PCI; corresponding results for thrombolysis were 23% and 28% (p = 0.000). Mortality was greater in the thrombolysed group (11% vs. 2%, p = 0.006), but patients were older, had more risk factors and larger emit ions of cardiac enzymes. After adjustment for the confounding effects of age, gender, score for ST-elevation and infarct localization, there was still a reduction in total arrhythmias in the PCI-treated group (odds ratio 0.37, 95% confidence interval 0.19-0.73, p = 0.004). INTERPRETATIONS: PCI-treatment seems to reduce early post-STEMI arrhythmias, but a non-randomized design and the use of historical controls, reduce the strength of this conclusion.