Atrial Fibrillation Ablation in Congenital Heart Disease: Therapeutic Challenges and Future Perspectives

The increasing prevalence of atrial fibrillation (AF) in adults with congenital heart disease raises significant questions regarding its management. The unique underlying anatomic and physiological background further adds to the difficulty in eliminating the AF burden in these patients. Herein, we provide an overview of the current knowledge on the pathophysiology and risk factors for AF in adult congenital heart disease, with a special focus on the existing challenges in AF ablation. Emerging imaging modalities and ablation techniques might have a role to play. Evidence regarding the safety and efficacy of AF ablation in adult congenital heart disease is summarized, especially for patients with an atrial septal defect, Ebstein anomaly of the tricuspid valve, tetralogy of Fallot, and Fontan circulation. Finally, any remaining gaps in knowledge and potential areas of future research are highlighted.

Characterization of the Mechanism and Substrate of Atrial Tachycardia Using Ultra-High-Density Mapping in Adults With Congenital Heart Disease: Impact on Clinical Outcomes

Background

Atrial tachycardia (AT) is common in patients with adult congenital heart disease and is challenging to map and ablate. We used ultra‐high‐density mapping to characterize the AT mechanism and investigate whether substrate characteristics are related to ablation outcomes.

Methods and Results

A total of 50 ATs were mapped with ultra‐high‐density mapping in 23 procedures. Patients were followed up for up to 12 months. Procedures were classified to group A if there was 1 single AT induced (n=12) and group B if there were ≥2 ATs induced (n=11 procedures). AT mechanism per procedure was macro re‐entry (n=10) and localized re‐entry (n=2) in group A and multiple focal (n=6) or multiple macro re‐entry (n=5) in group B. Procedure duration, low voltage area (0.05–0.5 mV), and low voltage area indexed for volume were higher in group B (159 [147–180] versus 412 [352–420] minutes, P<0.001, 22.6 [12.2–29.8] versus 54.2 [51.1–61.6] cm², P=0.014 and 0.17 [0.12–0.21] versus 0.26 [0.23–0.27] cm²/mL, P=0.024 accordingly). Dense scar (<0.05 mV) and atrial volume were similar between groups. Acute success and freedom from arrhythmia recurrence were worse in group B (100% versus 77% P=0.009 and 11.3, CI 9.8–12.7 versus 4.9, CI 2.2–7.6 months, log rank P=0.004). Indexed low voltage area ≥0.24 cm²/mL could predict recurrence with 100% sensitivity and 77% specificity (area under the curve 0.923, P=0.007).

Conclusions

Larger low voltage area but not dense scar is associated with the induction of multiple focal or re‐entry ATs, which are subsequently associated with longer procedure duration and worse acute and midterm clinical outcomes.

Outcomes and costs of left atrial appendage closure from randomized controlled trial and real-world experience relative to oral anticoagulation

AIMS

The aim of this study was to analyse randomized controlled study and real-world outcomes of patients with non-valvular atrial fibrillation (NVAF) undergoing left atrial appendage closure (LAAC) with the Watchman device and to compare costs with available antithrombotic therapies.

METHODS AND RESULTS

Registry data of LAAC from two centres were prospectively collected from 110 patients with NVAF at risk of stroke, suitable and unsuitable for long-term anticoagulation (age 71.3 ± 9.2 years, CHADS2 2.8 ± 1.2, CHA2DS2-VASc 4.5 ± 1.6, and HAS-BLED 3.8 ± 1.1). Outcomes from PROTECT AF and registry study LAAC were compared with warfarin, dabigatran, rivaroxaban, apixaban, aspirin, and no treatment using a network meta-analysis. Costs were estimated over a 10-year horizon. Uncertainty was assessed using sensitivity analyses. The procedural success rate was 92% (103/112). Follow-up was 24.1 ± 4.6 months, during which annual rates of stroke, major bleeding, and all-cause mortality were 0.9% (2/223 patient-years), 0.9% (2/223 patient-years), and 1.8% (4/223 patient-years), respectively. Anticoagulant therapy was successfully stopped in 91.2% (93/102) of implanted patients by 12 months. Registry study LAAC stroke and major bleeding rates were significantly lower than PROTECT AF results: mean absolute difference of stroke, 0.89% (P = 0.02) and major bleeding, 5.48% (P < 0.001). Left atrial appendage closure achieved cost parity between 4.9 years vs. dabigatran 110 mg and 8.4 years vs. warfarin. At 10 years, LAAC was cost-saving against all therapies (range £1162-£7194).

CONCLUSION

Left atrial appendage closure in NVAF in a real-world setting may result in lower stroke and major bleeding rates than reported in LAAC clinical trials. Left atrial appendage closure in both settings achieves cost parity in a relatively short period of time and may offer substantial savings compared with current therapies. Savings are most pronounced among higher risk patients and those unsuitable for anticoagulation.

Left Atrial Appendage Electrical Isolation and Concomitant Device Occlusion to Treat Persistent Atrial Fibrillation

Background—

Left atrial appendage (LAA) electric isolation is reported to improve persistent atrial fibrillation (AF) ablation outcomes. However, loss of LAA mechanical function may increase thromboembolic risk. Concomitant LAA electric isolation and occlusion as part of conventional AF ablation has never been tested in humans. We therefore evaluated the feasibility, safety, and efficacy of LAA electric isolation and occlusion in patients undergoing long-standing persistent AF ablation.

Methods and Results—

Patients with long-standing persistent AF (age, 68±7 years; left atrium diameter, 46±3 mm; and AF duration, 25±15 months) underwent AF ablation, LAA electric isolation, and occlusion. Outcomes were compared with a balanced (1:2 ratio) control group who had AF ablation alone. Among 22 patients who underwent ablation, LAA electric isolation was possible in 20. Intraprocedural LAA reconnection occurred in 17 of 20 (85%) patients, predominantly at anterior and superior locations. All were reisolated. LAA occlusion was successful in all 20 patients. There were no major periprocedural complications. Imaging at 45 days and 9 months confirmed satisfactory device position and excluded pericardial effusion. One of twenty (5%) patients had a gap of ≥5 mm requiring anticoagulation. Nineteen of twenty (95%) patients stopped warfarin at 3 months. Without antiarrhythmic drugs, freedom from AF at 12 months after a single procedure was significantly higher in the study group (19/20, 95%) than in the control group (25/40, 63%), P =0.036. Freedom from atrial arrhythmias was demonstrated in 12 of 20 (60%) and 18 of 20 (90%) patients after 1 and ≤2 procedures (mean, 1.3), respectively.

Conclusions—

Persistent AF ablation, LAA electric isolation, and mechanical occlusion can be performed concomitantly. This technique may improve the success of persistent AF ablation while obviating the need for chronic anticoagulation.

Clinical Trial Registration—

URL: https://clinicaltrials.gov . Unique identifier: NCT02028130.

NGAL and ST2 levels in ambulatory patients with chronic heart failure. Clinical and echocardiographic correlates

AIM

Neutrophil gelatinase-associated lipocalin (NGAL) and ST2 receptor, a member of the interleukin-1 receptor family, are novel biomarkers with a potential role in the diagnosis and risk stratification of patients with chronic heart failure (CHF). There is however scarce data on their relation with clinical characteristics and cardiac function in patients with CHF.

METHODS

Consecutive ambulatory patients with CHF were studied. All patients underwent clinical and echocardiographic assessment, and blood samples were collected for the estimation of ST2 and NGAL serum levels during the same assessment.

RESULTS

A total of 76 patients (79% male, mean age: 63 ± 14 years), with CHF and left ventricular ejection fraction of 28 ± 7% were included. Median NGAL was 0.16 (0.09-0.275) mg/L and median ST2 was 0.0125 (0.0071-0.0176) mg/L. No association between NGAL and ST2 was observed. Multivariate analysis revealed tissue Doppler-derived right ventricular systolic velocity as an independent predictor of ST2, and the duration of HF and serum creatinine levels as independent predictors of NGAL.

CONCLUSIONS

NGAL levels depend on the renal function and the duration of HF, while ST2 levels are affected by the right but not the left ventricular function and show no association with clinical indices of HF.

Utility of noninvasive arrhythmia mapping in patients with adult congenital heart disease

Arrhythmia management in patients with adult congenital heart disease (ACHD) is a challenge on many levels, as tachycardic episodes may lead to hemodynamic impairment in otherwise compensated patients even if episodes are only transient. Recently several technical advances, including 3-dimensional (3D) image integration, 3D mapping, and remote magnetic navigation, have been introduced to facilitate curatively intended ablation procedures in patients with ACHD. This review attempts to outline the role of a novel technology of simultaneous, noninvasive mapping in this patient cohort, and gives details of the authors' single-center experience.

Efficacy and safety of high dose versus low dose furosemide with or without dopamine infusion: the Dopamine in Acute Decompensated Heart Failure II (DAD-HF II) trial

AIMS

The role of low-dose dopamine infusion in patients with acute decompensated heart failure (ADHF) remains controversial. We aim to evaluate the efficacy and safety of high- versus low-dose furosemide with or without low-dose dopamine infusion in this patient population.

METHODS AND RESULTS

161 ADHF patients (78 years; 46% female; ejection fraction 31%) were randomized to 8-hour continuous infusions of: a) high-dose furosemide (HDF, n=50, 20mg/h), b) low-dose furosemide and low-dose dopamine (LDFD, n=56, 5mg/h and 5 μg kg(-1)min(-1) respectively), or c) low-dose furosemide (LDF, n=55, furosemide 5mg/h). The main outcomes were 60-day and one-year all-cause mortality (ACM) and hospitalization for HF (HHF). Dyspnea relief (Borg index), worsening renal function (WRF, rise in serum creatinine (sCr) ≥ 0.3mg/dL), and length of stay (LOS) were also assessed. The urinary output at 2, 4, 6, 8, and 24h was not significantly different in the three groups. Neither the ACM at day 60 (4.0%, 7.1%, and 7.2%; P=0.74) or at one year (38.1%, 33.9% and 32.7%, P=0.84) nor the HHF at day 60 (22.0%, 21.4%, and 14.5%, P=0.55) or one year (60.0%, 50.0%, and 47%, P=0.40) differed between HDF, LDFD, and LDF groups, respectively. No differences in the Borg index or LOS were noted. WRF was higher in the HDF than in LDFD and LDF groups at day 1 (24% vs. 11% vs. 7%, P<0.0001) but not at sCr peak (44% vs. 38% vs. 29%, P=0.27). No significant differences in adverse events were noted.

CONCLUSIONS

In ADHF patients, there were no significant differences in the in-hospital and post-discharge outcomes between high- vs. low-dose furosemide infusion; the addition of low-dose dopamine infusion was not associated with any beneficial effects.

General anesthesia versus sedation for implantation of a biventricular pacing device for cardiac resynchronization therapy

OBJECTIVE

Heart failure carries significant risk for major noncardiac surgery. Whether this risk is transferable to minor surgery is less well-documented. Thus, the aim of this study was to assess the outcome of a contemporary cohort of heart failure patients undergoing cardiac resynchronization therapy (CRT) device insertion under general anesthesia or sedation.

DESIGN

Retrospective observational study.

SETTING

Tertiary cardiac specialist hospital.

PARTICIPANTS

Heart failure patients.

INTERVENTIONS

CRT insertion under general anesthesia or sedation.

MEASUREMENTS AND MAIN RESULTS

Anesthesia, heart failure, and outcome data were collected on a consecutive series of patients having CRT device insertion between 2002 and 2010. A total of 242 patients were managed by the anesthesia department during the study period. After exclusion criteria were applied, data for 183 patients were analyzed. Immediate perioperative (<24 hours) mortality was zero; 30-day mortality of 138 patients was 2.2%. One patient (0.5%) required unplanned intensive care admission. A comparison was made between the sedation (n = 76) group and the general anesthesia (GA) group (n = 107). When compared with the sedation group, the GA group had more intraoperative hypotension (26.2% versus 4.0%, p<0.00001). There was no difference between the GA and sedation groups with regard to 30-day mortality (1.4% versus 3.1%, p = 0.57), unplanned intensive care admission (0% versus 1.3%, p = 0.42), and length of stay in days (3 versus 3, p = 0.82).

CONCLUSION

The authors found that patients with heart failure undergoing CRT insertion with concurrent general anesthesia or sedation had minimal immediate perioperative risk and that there was no difference in postoperative outcome between general anesthesia and sedation.

A de novo novel cardiac ryanodine mutation (Ser4155Tyr) associated with catecholaminergic polymorphic ventricular tachycardia

We describe the case of a 14-year-old girl with a history of syncopal episodes triggered by stress or exercise. Catecholaminergic polymorphic ventricular tachycardia was diagnosed with the aid of an implantable loop recorder. The genetic testing of the patient and her family revealed a de novo novel missense mutation (Ser4155Tyr) in the exon 90 of the ryanodine receptor gene. This mutation affects a highly conserved residue (S4155) and results to replacement of serine (S) with tyrosine (Y) leading to change in physical and chemical properties. The girl was treated with an implantable defibrillator, metoprolol and flecainide. Over 1 year of follow-up she had no recurrence of ventricular tachycardia.

Successful Right Ventricular Tachycardia Ablation in a Patient with Left Ventricular Non-compaction Cardiomyopathy

We report a case of a 67-year old male with a recent diagnosis of left ventricular non-compaction (LVNC), initially presenting with symptomatic ventricular ectopy and runs of non-sustained ventricular tachycardia (VT). This ventricular arrhythmia originated in a structurally normal right ventricle (RV) and was successfully localized and ablated with the aid of the three-dimensional mapping and remote magnetic navigation.

Magnetic navigation in adults with atrial isomerism (heterotaxy syndrome) and supraventricular arrhythmias

AIMS

We analysed the type and mechanism of supraventricular arrhythmias encountered in a series of symptomatic adults with atrial isomerism undergoing catheter ablation procedures.

METHODS AND RESULTS

The study population included consecutive adults with atrial isomerism who had previously undergone surgical repair or palliation of the associated anomalies. Patients underwent electrophysiological study for symptomatic arrhythmia in our institution between 2010 and 2012 using magnetic navigation in conjunction with CARTO RMT and three-dimensional (3D) image integration. Eight patients (five females) with a median age of 33 years [interquartile range (IQR) 24-39] were studied. Access to the cardiac chambers of interest was obtained retrogradely via the aorta using remotely navigated magnetic catheters in six patients. Radiofrequency ablation successfully targeted twin atrioventricular (AV) nodal reentrant tachycardia in two patients, atrial fibrillation (AF) in three, focal atrial tachycardia (AT) mainly originating in the left-sided atrium in four patients, and macro-reentrant AT dependent on a right-sided inferior isthmus in three patients. The median fluoroscopy time was 3.0 min (IQR 2-11). After a median follow-up of 10 months (IQR 6-21), five of the ablated patients are free from arrhythmia; two patients experienced episodes of self-terminated AF and AT, respectively, within one month post-ablation; the remaining patient had only non-sustained AT during the electrophysiological study and was managed medically.

CONCLUSION

Various supraventricular tachycardia mechanisms are possible in adults with heterotaxy syndrome, all potentially amenable to radiofrequency ablation. The use of remote magnetic navigation along with 3D mapping facilitated the procedures and resulted in a short radiation time.

Accessory pathway ablation in a 6-year-old girl using remote magnetic navigation as an alternative to cryoablation

A 6-year-old girl with evidence of a parahisian accessory pathway on a baseline electrocardiogram underwent successful catheter ablation using magnetic navigation. Magnetic remote controlled ablation eliminated the parahisian pathway with the first radiofrequency application. A second anterolaterally located concealed pathway was successfully ablated in the same session, resulting in exclusively atrioventricular nodal conduction bidirectionally (total fluoroscopy, 4 min; 25 μGy).

Wavelet variability of SA node originated P waves in atrial fibrillation and in signals with ectopic beats

Atrial fibrillation (AF) is one of the most common cardiac arrhythmia. Electrical properties of the atrial myocardium may be related to the appearance of this type of arrhythmia. However ectopic beats, occurring normally in healthy people, disturb cardiac rhythm. Those beats arise from fiber outside the region of SA node. With this work we aim at highlighting differences in the atrial activity between healthy subjects, healthy subjects presenting many ectopic events and patients with AF. The X-Y-Z leads of vectorcardiography recordings are considered. Wavelet-based parameters are extracted from a window which represents atrial activity originated from SA node and compared between signals of the three groups. Results show differences potentially related to the conduction system of the atrium between healthy people and people with AF, as well as between healthy people and people with ectopic events. No difference was found from the analysis of SA node beats between people with AF and healthy with ectopic events.

Advanced ablation strategies for management of post-surgical atrial arrhythmias

Post-surgical arrhythmias include a wide range of arrhythmias occurring late after cardiac surgery and represent a complex substrate for catheter ablation either because of extended scar and remodeling or because of limited access to the area of interest. Novel image integration and ablation tools have made the catheter ablation in this population both feasible and successful. We review a structured approach to catheter ablation of post-surgical atrial arrhythmias in various patient cohorts including the most common congenital heart defects.

Increased right atrial volume index predicts low Duke activity status index in patients with chronic heart failure

INTRODUCTION

The aim of the present study was to examine the value of the right atrial volume index (RAVI) as predictor of functional capacity in patients with heart failure.

METHODS

A total of 51 patients with stable chronic heart failure of ischaemic or non-ischaemic aetiology were prospectively enrolled. The systolic function of the right ventricle was quantified using the tricuspid annular plane systolic excursion (TAPSE). Right atrial volume was measured in the apical 4-chamber view and was indexed to body surface area. The functional capacity was assessed by the Duke Activity Status Index (DASI).

RESULTS

Patients with a low functional capacity (DASI<10) had lower TAPSE (1.4 ± 0.3 cm versus 2.0 ± 0.4 cm, p<0.001), higher RAVI (42 ± 15 ml/m(2) versus 22 ± 9 ml/m(2), p<0.001), higher estimated right ventricular systolic pressure (61 ± 13 mmHg versus 40 ± 16 mmHg, p<0.001), larger right ventricular end-diastolic diameter (4.7 ± 0.8 cm versus 3.6 ± 0.7 cm, p<0.001) and lower left ventricular ejection fraction (26 ± 6% versus 30 ± 7%, p=0.022). Multivariate analysis revealed that TAPSE was the single independent predictor of DASI. In the subgroup of patients with reduced right ventricular systolic function (TAPSE<2 cm), RAVI was the single independent predictor of low DASI. In the overall population RAVI=30.6 ml/m(2) had 75% sensitivity and 83% specificity in predicting DASI<10. Within the subgroup of patients with TAPSE<2 cm, RAVI=30.6 ml/m(2) had better sensitivity and specificity (79% and 90% respectively) in predicting DASI<10.

CONCLUSIONS

Increased right atrial volume index predicts low functional capacity quantified by the Duke Activity Status Index in patients with stable chronic heart failure.

Gender-related differences in patients with acute heart failure: management and predictors of in-hospital mortality

AIM AND METHODS

Gender-related differences in clinical phenotype, in-hospital management and prognosis of acute heart failure (AHF) patients have been previously reported in European and US registries. The ALARM-HF survey is the first to include a cohort of 4953 patients hospitalized for AHF in 666 hospitals in 6 European countries, Mexico and Australia.

RESULTS

Women accounted for 37% of the study population, were older and had higher rates of de novo heart failure (45% vs 36%, p<0.001) than men. An acute coronary syndrome (ACS) was the predominant precipitating factor in both genders, but to a lesser extent in females (30% vs 42%, p<0.001). Between genders comparison showed higher incidence of atrial fibrillation, valvular heart disease, diabetes, obesity, anemia and depression in women (p<0.05). Similarly, women had higher left ventricular ejection fraction (LVEF) on admission (42 ± 15% vs 36 ± 13%, p<0.001) and systolic blood pressure (135 ± 40 mm Hg vs 131 ± 39 mm Hg, p=0.001) than men. On the other hand, men had more often coronary artery disease, renal failure and chronic obstructive pulmonary disease (p<0.05). Importantly, in-hospital mortality was similar in both genders (11.1% in females vs 10.5% in males, p=0.475), and its common predictors were: systolic blood pressure at admission, creatinine>1.5mg/dL and diabetes. Furthermore, recent ACS, valvular heart disease and dementia contributed to prognosis in women, while LVEF, hypertension and anemia were independent predictors in men.

CONCLUSION

Among patients with AHF, there are significant differences in co-morbidities, precipitating factors and predictors of in-hospital mortality between genders. Nevertheless, in-hospital mortality remains similar between genders.

Differences in Clinical Presentation and Findings between Idiopathic Dilated and Ischaemic Cardiomyopathy in an Unselected Population of Heart Failure Patients

We explored the differences in epidemiologic, clinical, laboratory and echocardiographic characteristics between idiopathic dilated (IDCM) and ischaemic cardiomyopathy (ICM).

Consecutive patients with stable chronic heart failure evaluated at a tertiary cardiac centre were enrolled. Clinical examination, blood tests and echocardiographic study were performed.

A total of 76 patients (43 IDCM, 33 ICM) were studied. IDCM patients were younger (p<0.001) and female gender was more prevalent (p=0.022). NYHA class and left ventricular ejection fraction were similar. IDCM patients had lower rates of dyslipidaemia (p<0.001) but smoked more than ICM patients (p=0.023) and had higher rates of family history of sudden cardiac death (p=0.048). Blood pressure was similar but resting heart rate was higher in IDCM patients (p=0.022). IDCM patients presented less frequently with peripheral oedema or ascites (p=0.046 and 0.020, respectively) and showed better right ventricular function on echocardiogram. QRS duration was similar between groups but only in IDCM patients there was a positive correlation between QRS duration and age (r=0.619, p<0.001). Cardiac output was similar but functional capacity assessed by the Duke Activity Status Index was better in IDCM (p=0.036). Despite these differences, IDCM and ICM patients received similar treatments.

Patients with IDCM were younger, presented lower rates of right ventricular dysfunction and clinical right ventricular failure and had better functional capacity. Additional differences in clinical and laboratory findings exist pointing to a different patient population with diverse prognosis and potential need for individualized management.

Somatostatin analogue scintigraphy in a patient with viral myocarditis

Myocarditis may present clinically with a wide range of manifestations and often remains unrecognized. The diagnosis of myocarditis traditionally has been based on histological findings, but endomyocardial biopsy has a low sensitivity and clinicians are reluctant to proceed with an invasive diagnostic technique. Among newer diagnostic approaches, cardiac magnetic resonance imaging has gained acceptance as an efficient noninvasive tool to determine myocardial inflammation. In this context, imaging with radiolabeled somatostatin analogues could also be relevant because of their ability to delineate inflammatory sites. In conclusion, a case is presented in which somatostatin receptor imaging of the myocardium with (99m)Tc-depreotide tomography was used in the assessment of viral myocarditis.

Radiofrequency ablation procedures in Greece: initial experience and results from the national registry 2008-2010

INTRODUCTION

In 2008 the radiofrequency ablation procedures (RFA) registry of the Hellenic Cardiological Society (HCS) was created. This is a dynamic, web-based application, which acts as the interface for storing and retrieving patients' demographic data and ablation procedures. Access to the site is permitted only to registered users. The purpose of this study is to report the results of RFA procedures performed in Greece over the 2008-2010 period.

METHODS

There are 27 centers in 24 hospitals that are licensed to perform RFA in Greece. During the period 2008-2010, 3541 RFA procedures were performed in 3344 patients in 23 centers. Four centers did not contribute data at all for various reasons. It is interesting that nearly 50% of the total number of procedures were performed at 3 high volume centers (>100 cases/year).

RESULTS

The most common procedure was slow pathway ablation for atrioventricular reentrant tachycardia, the second was ablation of accessory pathway related tachycardias, and the third was ablation of atrial fibrillation. Success rates were high (92.1%), the complication rate was 3% (serious complications <1%) and total relapse rate was 8.7% at six months' follow up.

CONCLUSIONS

The electronic RFA registry in Greece confirmed that all RFA procedures are performed in Greece with high success and low complication rates, comparable to the European and US standards. The experience and results from the first three-year period using the registry are very interesting and encouraging, thus indicating the need for development of similar databases at the national level.

Ibutilide for the Cardioversion of Paroxysmal Atrial Fibrillation during Radiofrequency Ablation of Supraventricular Tachycardias

Direct current electrical cardioversion (DC-ECV) is the preferred treatment for the termination of paroxysmal atrial fibrillation (AF) that occurs during radiofrequency ablation (RFA) of supraventricular tachycardias (SVT). Intravenous Ibutilide may be an alternative option in this setting. Thirty-four out of 386 patients who underwent SVT-RFA presented paroxysmal AF during the procedure and were randomized into receiving ibutilide or DC-ECV. Ibutilide infusion successfully cardioverted 16 out of 17 patients (94%) within 17.37 ± 7.87  min. DC-ECV was successful in all patients (100%) within 17.29 ± 3.04  min. Efficacy and total time to cardioversion did not differ between the study groups. No adverse events were observed. RFA was successfully performed in 16 patients (94%) in the ibutilide arm and in all patients (100%) in the DC-ECV arm, p = NS. In conclusion, ibutilide is a safe and effective alternative treatment for restoring sinus rhythm in cases of paroxysmal AF complicating SVT-RFA.

Cardiac resynchronization therapy for critically ill patients with left ventricular systolic dysfunction

BACKGROUND

The experience of cardiac resynchronization therapy (CRT) in critically ill patients with cardiogenic shock or advanced heart failure is limited and inadequately described in literature.

METHODS

CRT implants performed in patients on the cardiothoracic intensive care unit (ICU) at a tertiary cardiac centre during 2007-2010 were retrospectively studied.

RESULTS

We identified 24 patients, 17 male, of median age 76 years (IQR 11) treated with a CRT pacemaker (n=10) or CRT defibrillator (n=14). Prior to implantation median left ventricular ejection fraction (LVEF) was 26% (IQR 13) and median QRS duration 146 ms (IQR 29). Eleven (46%) patients were post elective cardiac surgery and 8 (33%) post emergency cardiac surgery or intervention with high prevalence of co-morbidities. Nineteen patients required inotropic support pre-implantation, 8 patients were on mechanical circulatory support and 18 were on mechanical ventilation. Post CRT LVEF improved from 26% to 39% (p=0.027) and the estimated glomerular filtration rate increased from 42 ml/min/1.73 m(2) (IQR 26) to 63 ml/min/1.73 m(2) (IQR 48, p=0.001). All but one patient were successfully weaned from inotropic support within a median of 4 days (IQR 5) post CRT and 22/24 (92%) survived to hospital discharge. After a median follow up of 392 days (IQR 538), 7 (33%) patients died. In-hospital and one year mortality rates were 8.3% and 29.4% respectively. Ten out of 12 patients (83%) were alive at long-term (22 ± 9 months) follow up.

CONCLUSIONS

CRT may assist weaning from circulatory and respiratory support in critically ill patients with left ventricular systolic dysfunction.

Effects of renin-angiotensin system inhibition on right ventricular function in patients with mild essential hypertension

Introduction: Systemic hypertension is known to affect both left and right ventricular (RV) function. Little is known about the effect of the renin—angiotensin system (RAS) inhibition on global RV function in patients with essential hypertension.

Materials and methods: Forty patients (17 male, mean age 47 ± 10 years) with mild hypertension free of cardiovascular disease were assessed by echocardiography at baseline and after nine months of antihypertensive treatment with RAS inhibitors. Tissue Doppler imaging derived myocardial performance index (MPI) of the left and right ventricle was used as an index of global ventricular function.

Results: Both left ventricular (LV) and RV MPI were increased at baseline and were reduced after treatment (LV MPI reduced from 0.42 ± 0.06 to 0.39 ± 0.05, p < 0.001 and RV MPI was reduced from 0.34 ± 0.06 to 0.32 ± 0.05, p < 0.005). There was a positive correlation between mitral and tricuspid E/A ratio both at baseline and at month nine after treatment ( r = 0.661, p < 0.001 and r = 0.503, p < 0.005 respectively). LV mass index and interventricular septum thickness were decreased after treatment. No correlation was found between MPI improvement and blood pressure reduction.

Conclusions: RAS inhibition in patients with mild hypertension results in an improvement of RV global function which is unrelated to the reduction in blood pressure.

An interesting case of cardiac amyloidosis initially diagnosed as hypertrophic cardiomyopathy

Cardiac involvement occurs frequently in primary amyloidosis and is associated with heart failure hospitalizations and poor survival. The initial presentation of the disease may be misleading, resulting in under-diagnosis of cardiac amyloidosis and late initiation of treatment. We present a case of cardiac amyloidosis initially misdiagnosed as hypertrophic cardiomyopathy and we discuss the key findings of the disease along with the latest evidence regarding the management and prognosis of cardiac amyloidosis.

Spontaneous dissection of right coronary artery manifested with acute myocardial infarction

Spontaneous coronary artery dissection is a rare cause of acute ischemic coronary events and sudden cardiac death. It usually occurs in young women without traditional risk factors for coronary artery disease during pregnancy or postpartum period. However, it has also been reported in patients with atherosclerotic coronary disease. We present a case of spontaneous right coronary artery dissection in a 48-year male with recent myocardial infarction and previous percutaneous coronary intervention.

Arrhythmias, sudden cardiac death and incapacitation of pilots

Inflight medical emergencies occur at a rate of 20 to 100 per million passengers, with a death rate of 0.1 to 1 per million. Cardiac, neurologic, and respiratory complaints comprise the more serious emergencies, as defined by aircraft diversion or use of ground-based medical assistance. In this paper, we review changes seen in the resting electrocardiogram in normal individuals exposed to high altitude, alongside important implications for patients with heart diseases in high altitude exposures and the possible effects of high altitude to permanent cardiac pacemakers. Arrhythmias in pilots and public safety are revisited together with the guidelines of the Joint Aviation Requirements (JAR) in Europe. The situation of Military flights is also discussed. Physicians ought to become knowledgeable about the specific medical job standards for their patients when asked to render opinions regarding fitness to fly. A database must be established to obtain prospective data that defines the risk of accidents in patients who are or were being treated for arrhythmias. Current guidelines could then be updated and revised as appropriate.