Pacemakers are associated with a higher risk of late death and transplantation in the Fontan population.

BACKGROUND: The need for permanent pacing has been identified as a predictor of poor outcomes in the late survivors of Fontan surgery. However, it is not clear if the need for a pacemaker is a surrogate marker of a declining Fontan state, or if pacing is deleterious to the Fontan circulation. OBJECTIVES: We sought to compare the long-term outcomes of propensity-matched Fontan patients with and without a permanent pacemaker. METHODS: Patients who have survived Fontan completion with a documented history of cardiac arrhythmia were identified from the Australia and New Zealand Fontan Registry. Pacemaker insertion details, cardiac function and electrophysiological data were obtained for the patients with a permanent pacemaker. Survival analysis was performed with propensity score matching to compare late survival and outcomes in patients with versus without a pacemaker. RESULTS: There was a total of 310 patients with a history of cardiac arrhythmia, of which 126 (41%) had a permanent pacemaker. After propensity-score matching, 99 pairs were generated (n = 198). Patients with a permanent pacemaker had a higher risk of death (HR 3.32 95% CI 1.60-6.90, p = 0.001) and death or transplantation (HR 3.55 95% CI 1.87-6.73, p < 0.001). Patients who were only paced atrially were not at a significantly increased risk of death or transplantation. However, patients who were ventricular paced >50% of the time were much more likely to encounter late death or transplantation (HR 3.82 95% CI 1.64-8.95, p = 0.002). CONCLUSIONS: Having a permanent pacemaker and needing ventricular pacing is likely associated with an increased risk of death and transplantation in patients with a Fontan circulation.

Clinical Outcomes in Adolescents and Adults After the Fontan Procedure.

BACKGROUND: Long-term outcomes of Fontan patients who survive to age ≥16 years have not been well characterized. The Australian and New Zealand Fontan Registry (ANZFR) provides a unique opportunity to understand survival and complication rates in Fontan patients who transition to adult congenital heart disease centers. OBJECTIVES: This study sought to describe the survival and complications of adult patients who have had a Fontan procedure. METHODS: The study analyzed outcomes in patients ≥16 years of age who were prospectively enrolled in the ANZFR. RESULTS: Data from all 683 adult survivors from the ANZFR were analyzed. Mortality status was confirmed from the National Death Index. There were 201 atriopulmonary (AP) connections and 482 total cavopulmonary connections (249 lateral tunnels and 233 extracardiac conduits). For these subjects, the survival rate at age 30 years was 90% (95% CI: 87% to 93%), and it was 80% (95% CI: 75% to 87%) at 40 years of age. Survival at age 30 years was significantly worse for the patients with AP connections (p = 0.03). At latest follow-up, only 53% of patients were in New York Heart Association functional class I. After the age of 16 years, 136 (20%) had experienced at least 1 new arrhythmia, 42 (6%) required a permanent pacemaker, 45 (7%) had a thromboembolic event, and 135 (21%) required a surgical reintervention. Only 41% (95% CI: 33% to 51%) of Fontan patients were free of serious adverse events at 40 years of age. CONCLUSIONS: This comprehensively followed cohort showed that a variety of morbid complications is common in Fontan adults, and that there is a substantial incidence of premature death, particularly in patients with AP connections.

CT sizing for left atrial appendage closure is associated with favourable outcomes for procedural safety.

AIMS: We evaluated the utility of computerized tomography (CT) with respect to sizing work-up for percutaneous left atrial appendage (LAA) closure, and implications for procedural safety and outcomes. METHODS AND RESULTS: Contrast-enhanced multi-detector CT was routinely conducted to guide sizing for LAA closure in addition to transoesophageal echocardiography (TOE). Procedural safety and efficacy were prospectively assessed. Across 73 consecutive cases there were no device-related procedural complications, and no severe leaks. Systematic bias in orifice sizing by TOE vs. CT was significant on retrospective analysis (bias -3.0 mm vs. maximum diameter on CT; bias -1.1 mm vs. mean diameter on CT). Importantly, this translated to an altered device size selection in more than half of all cases, and median size predicted by CT was one interval greater than that predicted by TOE (27 mm vs. 24 mm). Of particular note, gross sizing error by TOE vs. CT was observed in at least 3.4% of cases. Degree of discrepancy between TOE and CT was correlated with LAA orifice eccentricity, orifice size, and left atrial volume. Mean orifice size by CT had the greatest utility for final Watchman device-size selection. CONCLUSIONS: In this single-centre registry of LAA closure, routine incorporation of CT was associated with excellent outcomes for procedural safety and absence of major residual leak. Mean orifice size may be preferable to maximum orifice size. A particular value of CT may be the detection and subsequent avoidance of gross sizing error by 2D TOE that occurs in a small but important proportion of cases.

Left Atrial Appendage Eccentricity and Irregularity Are Associated With Residual Leaks After Percutaneous Closure.

OBJECTIVES: Predictors of residual leak following percutaneous LAA closure were evaluated. BACKGROUND: Left atrial appendage (LAA) closure aims to exclude this structure from the circulation, typically using a circular occluder. A noncircular orifice is frequently encountered however, and fibrous remodeling of the LAA in atrial fibrillation may restrict orifice deformation. Noncircularity may thus be implicated in the occurrence of residual leak despite an appropriately oversized device. METHODS: Pre-procedural multislice computerized tomography was used to quantify LAA orifice eccentricity and irregularity. Univariate predictors of residual leak were identified with respect to the orifice, device, and relevant clinical variables, with the nature of any correlations then further evaluated. RESULTS: Eccentricity and irregularity indexes of the orifice in 31 individuals were correlated with residual leak even where the device was appropriately oversized. An eccentricity index of 0.15 predicted a residual leak with 85% sensitivity and 59% specificity. An irregularity index of 0.05 predicted a significant residual leak ≥3 mm with 100% sensitivity and 86% specificity. Orifice size, device size, degree of device oversize, left atrial volume, and pulmonary artery pressure were not predictors of residual leak. CONCLUSIONS: Eccentricity and irregularity of the LAA orifice are implicated in residual leak after percutaneous closure even where there is appropriate device over-size. Irregularity index in particular is a novel predictor of residual leak, supporting a closer consideration of orifice morphology before closure.

Assessment of atrial septal defects in adults comparing cardiovascular magnetic resonance with transoesophageal echocardiography.

BACKGROUND: Many adult patients with secundum-type atrial septal defects (ASDs) are able to have these defects fixed percutaneously. Traditionally, this has involved an assessment of ASD size, geometry and atrial septal margins by transoesophageal echocardiography (TOE) prior to percutaneous closure. This is a semi-invasive technique, and all of the information obtained could potentially be obtained by non-invasive cardiovascular magnetic resonance (CMR). We compared the assessment of ASDs in consecutive patients being considered for percutaneous ASD closure using CMR and TOE. METHODS: Consecutive patients with ASDs diagnosed on transthoracic echocardiography (TTE) were invited to undergo both CMR and TOE. Assessment of atrial septal margins, maximal and minimal defect dimensions was performed with both techniques. Analyses between CMR and TOE were made using simple linear regression and Bland Altman Analyses. RESULTS: Total CMR scan time was 20 minutes, and comparable to the TOE examination time. A total of 20 patients (M:F = 5:15, mean age 42.8 years +/- 15.7) were included in the analyses. There was an excellent agreement between CMR and TOE for estimation of maximum defect size (R = 0.87). The anterior inferior, anterior superior and posterior inferior margins could be assessed in all patients with CMR. The posterior superior margin could not be assessed in only one patient. Furthermore, in 1 patient in whom TOE was unable to be performed, CMR was used to successfully direct percutaneous ASD closure. CONCLUSIONS: CMR agrees with TOE assessment of ASDs in the work-up for percutaneous closure. Potentially CMR could be used instead of TOE for this purpose.

Percutaneous closure of atrial septal defects leads to normalisation of atrial and ventricular volumes.

BACKGROUND: Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR) is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. METHODS: Consecutive patients (n = 23) underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV) and end systolic volumes (ESV). Data is presented as mean +/- SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p < 0.05. RESULTS: There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 +/- 76.7 vs. 140.6 +/- 60.4 mL, p < 0.0001) and RVEF was significantly increased (RVEF 35.5 +/- 15.5 vs. 42.0 +/- 15.2%, p = 0.025). There was a significant increase in the left ventricular volumes (LVEDV 84.8 +/- 32.3 vs. 106.3 +/- 38.1 mL, p = 0.003 and LVESV 37.4 +/- 20.9 vs. 46.8 +/- 18.5 mL, p = 0.016). However, there was no significant difference in LVEF and LV mass post-ASD closure. There was a significant reduction in right atrial volumes at 6 months post-ASD closure (pre-closure 110.5 +/- 55.7 vs. post-closure 90.7 +/- 69.3 mL, p = 0.019). Although there was a trend to a decrease in left atrial volumes post-ASD closure, this was not statistically significant (84.5 +/- 34.8 mL to 81.8 +/- 44.2 mL, p = NS). CONCLUSION: ASD closure leads to normalisation of ventricular volumes and also a reduction in right atrial volume. Further follow-up is required to assess how this predicts outcomes such as risk of atrial arrhythmias after such procedures.

Transthoracic echocardiography to identify or exclude cardiac cause of shock.

BACKGROUND: Transesophageal echocardiography (TEE) is often still considered the echocardiographic test of choice in the general ICU patient population to establish the presence or absence of cardiac cause of shock, and is often requested and performed as the initial and only echocardiographic test. This premise is based on older studies in which transthoracic echocardiography (TTE) commonly offered inadequate images in ICU patients. STUDY OBJECTIVES: We hypothesized that current TTE imaging alone is adequate to identify or exclude cardiac cause of shock in the great majority of cases. METHODS: One hundred consecutive shock cases in which an echocardiogram was requested were prospectively analyzed by two blinded echocardiographers for image adequacy, and the absence or presence of cardiac cause of shock (defined as one or more of the following: severe left ventricular (LV) or right ventricular systolic dysfunction, tamponade, severe left-sided valve disease, or a postinfarction mechanical complication), and compared to a clinical standard of presence/absence of cardiac cause of shock as determined by autopsy, surgery, or objective testing. Shock was defined as systolic BP < 100 mm Hg or fall in BP >/= 25%, and inotrope use or evidence of low output or venous congestion. Cardiac output was determined by the LV outflow tract (LVOT) Doppler method. RESULTS: Sixty-three percent of cases had a cardiac cause of shock. TTE image quality was adequate in 99% cases. Among the 99% of cases in which the imaging was adequate, the sensitivity of TTE for cardiac cause of shock was 100%, the specificity was 95%, the positive predictive value was 97%, and the negative predictive value was 100%. There were relative contraindications to TEE in 15% of cases. Stroke volume index (15 +/- 6 mL/m(2) vs 31 +/- 7 mL/m(2) [mean +/- 1 SD]; p < 0.001) and cardiac index (1.6 +/- 0.5 mL/min/m(2) vs 2.9 +/- 0.9 mL/min/m(2); p < 0.001) were significantly less in the group with a cardiac cause of shock than in the group with a noncardiac cause of shock. CONCLUSIONS: In the general critical care population, current TTE imaging identifies the great majority of cardiac causes of shock. TTE should be considered not only the initial, but also the principal echocardiographic test in the critical care environment.

Biventricular pacing for severe mitral regurgitation following atrioventricular nodal ablation.

A 69-year-old woman developed acute pulmonary edema and severe mitral regurgitation (MR) 2 days following an uncomplicated AV nodal (AVN) ablation and insertion of VVI pacemaker for chronic atrial fibrillation. There was no history of significant mitral valve disease. Left ventricular function was normal and there was no evidence of an acute cardiac ischemic event. Transthoracic echo and right heart catheterization studies showed reduction in the severity of MR with biventricular pacing as opposed to RV pacing alone. A permanent pacemaker configured for biventricular pacing was implanted with complete resolution of symptoms and significant reduction in degree of MR.

A retrospective case study to assess the value of the implantable loop recorder for the investigation of undiagnosed syncope.

If not diagnosed by history, examination, or ECG, the diagnosis of syncope can be difficult with a low yield from echocardiography, ambulatory ECG recording, electrophysiological study, and tilt table testing. During 2 years, 48 patients with unexplained syncope or presyncope from three hospitals in one city underwent the implantation of a Medtronic Reveal implantable loop recorder capable of cardiac monitoring for 14 months. All patients had at least two prior episodes of syncope or presyncope. Fifty-two percent of patients had electrophysiological studies, all of which were negative. The implantable loop recorder remained implanted until a diagnostic event was recorded, or until the end of the battery life. After a mean follow-up of 5.6 +/- 5.7 months, symptoms reoccurred in 25 (52.1%) patients at a mean of 2.8 +/- 2.1 months after insertion of an implantable loop recorder. No further symptoms occurred in 23 (47.9%) patients. Of the 25 patients who had a symptom and recorded an event, an arrhythmia was seen in 10 (40%) patients. Seven patients had bradycardia; 4 with profound sinus bradycardia/sinus arrest, 1 with complete heart block, and 2 in association with the cardioinhibitory component of vasovagal syncope. Three patients had tachycardias; two with supraventricular tachycardia and one with atrialflutter. Fifteen (60%) of the 25 patients who activated their device due to syncope or presyncope were in sinus rhythm during the event. The implantable loop recorder was effective in making a cardiological or noncardiological diagnosis for unexplained syncope or presyncope in 52.1% of the patients.