Investigating the efficacy of chest pressure for direct current cardioversion in atrial fibrillation: a randomised control trial protocol (Pressure-AF).

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. Direct current cardioversion is commonly used to restore sinus rhythm in patients with AF. Chest pressure may improve cardioversion success through decreasing transthoracic impedance and increasing cardiac energy delivery. We aim to assess the efficacy and safety of routine chest pressure with direct current cardioversion for AF. METHODS AND ANALYSIS: Multicentre, double blind (patient and outcome assessment), randomised clinical trial based in New South Wales, Australia. Patients will be randomised 1:1 to control and interventional arms. The control group will receive four sequential biphasic shocks of 150 J, 200 J, 360 J and 360 J with chest pressure on the last shock, until cardioversion success. The intervention group will receive the same shocks with chest pressure from the first defibrillation. Pads will be placed in an anteroposterior position. Success of cardioversion will be defined as sinus rhythm at 1 min after shock. The primary outcome will be total energy provided. Secondary outcomes will be success of first shock to achieve cardioversion, transthoracic impedance and sinus rhythm at post cardioversion ECG. ETHICS AND DISSEMINATION: Ethics approval has been confirmed at all participating sites via the Research Ethics Governance Information System. The trial has been registered on the Australia New Zealand Clinical Trials Registry (ACTRN12620001028998). De-identified patient level data will be available to reputable researchers who provide sound analysis proposals.

Effect of Outcome Measures on the Apparent Efficacy of Ablation for Atrial Fibrillation: Why "Success" is an Inappropriate Term.

INTRODUCTION: Different endpoint criteria, different durations of follow-up and the completeness of follow-up can dramatically affect the perceived benefits of atrial fibrillation (AF) ablation. METHODS: We defined three endpoints for recurrence of AF post ablation in a cohort of 200 patients with symptomatic AF, refractory to antiarrhythmic drugs (AADs). A 'Strict Endpoint' where patients were considered to have a recurrence with any symptomatic or documented recurrence for ≥30 seconds with no blanking period, and off their AADs, a 'Liberal Endpoint' where only documented recurrences after the blanking period, either on or off AADs were counted, and a 'Patient-defined Outcome endpoint' which was the same as the Liberal endpoint but allowed for up to two recurrences and one repeat ablation or DCCV during follow-up. We also surveyed 50 patients on the waiting list for an AF ablation and asked them key questions regarding what they would consider to be a successful result for them. RESULTS: Freedom from recurrence of atrial tachyarrhythmias (AT) at 5 years was 62% for the Strict Endpoint, 73% for the Liberal Endpoint, and 80% for the Patient-defined Outcome endpoint (p<0.001). Of the 50 patients surveyed awaiting AF ablation, 70% said they would still consider the procedure a success if it required one repeat ablation or one DCCV (p=0.004), and 76% would be accepting of one or two recurrences during follow-up (p<0.001). CONCLUSION: In this study, the majority of patients still considered AF ablation a successful treatment if they had up to two recurrences of AF, one repeat procedure or one DCCV. Furthermore, a 'Patient-defined' definition of success lead to significantly different results in this AF ablation cohort when compared to conventionally used/guideline directed measures of success.

Complete Heart Block Complicating Takotsubo Syndrome: Case Report and Literature Review.

An 81-year-old woman presents with shortness of breath resulting in a diagnosis of picornavirus and complete heart block. Troponin was elevated and there was concern about acute coronary syndrome. The final diagnosis after echocardiogram and coronary angiogram was Takotsubo syndrome in addition to the heart block which required pacemaker insertion.

Mycotic Coronary Aneurysms.

BACKGROUND: Mycotic coronary aneurysms (MCA) are rare but often lead to significant morbidity and mortality. Evidence on the topic is limited to case reports and small case series. A systematic review was performed to improve understanding of this challenging diagnosis. A case report prompting this review is also included. METHODS: Relevant articles were identified by searching databases Medline and Google Scholar for terms 'mycotic coronary aneurysm'. Manual searching from article references identified further case reports. RESULTS: Ninety-seven (97) published cases of MCA were identified between 1812 and 2017; 80 cases since the introduction of percutaneous coronary intervention (PCI) with stents in 1986. The most common associations were PCI (40.0%) and infective endocarditis (IE) (40.0%). Complications including aneurysm rupture (28.9%), pericardial effusion (37.3%) and myocardial infarction (39.8%) were frequent. Short-term mortality was high at 42.6%. The most common treatment was surgical resection of the aneurysm with bypass grafting. CONCLUSIONS: We present a case and the largest systematic review to date of this rare diagnosis, identifying 97 published case reports. Clinical scenarios in which to consider MCA include febrile illness after recent PCI, febrile illness (particularly infective endocarditis) with evidence of coronary ischaemia, and purulent pericarditis. Given the high rate of complications and mortality, immediate surgical referral is recommended.

Comparison of Outcomes Using the First and Second Generation Cryoballoon to Treat Atrial Fibrillation.

BACKGROUND: Pulmonary vein isolation using cryoballoon ablation is an effective treatment for patients with atrial fibrillation. We sought to compare outcomes with the first and second generation cryoballoon, with the second generation balloon incorporating the Achieve Lasso catheter, in terms of freedom from symptomatic recurrence and major complications. METHODS: The first 200 patients who underwent cryoballoon ablation with the first generation balloon were compared with the first 200 patients using the second-generation balloon. All patients had symptomatic atrial fibrillation and had failed at least one antiarrhythmic drug. The primary efficacy endpoint was freedom from symptomatic recurrence of atrial fibrillation (AF) after a single pulmonary vein isolation (PVI) procedure using the cryoballoon. The primary safety endpoint was major procedural complications. RESULTS: At 12 months, freedom from symptomatic AF after a single procedure in the first generation cohort was 64.3% compared with 78.6% in the second-generation cohort (p = 0.002). At 24 months, freedom from symptomatic AF in the first generation cohort was 51.3% compared with 72.6% in the second-generation cohort (p < 0.001). Procedural time (150 min vs 101 min; p < 0.001) and fluoroscopy time (32.5 min vs 21.4 min; p < 0.001) was lower in the second-generation group. The rate of major complications was comparably low in both groups. CONCLUSIONS: The second-generation cryoballoon was associated with improved freedom from symptomatic AF with reduction in procedure and fluoroscopy time, with a similar low rate of major complications.

Groin Haemostasis With a Purse String Suture for Patients Following Catheter Ablation Procedures (GITAR Study).

BACKGROUND: The most frequent complications from percutaneous electrophysiology procedures relate to vascular access. We sought to perform the first randomised controlled trial for femoral venous haemostasis utilising a simple and novel purse string suture (PSS) technique. METHODS: We randomised 200 consecutive patients who were referred for electrophysiology procedures at two different hospitals to either 10minutes of manual pressure or a PSS over the femoral vein and determined the incidence of vascular access site complications. RESULTS: The mean age was 61.8±12.1years and 138 (69%) were male. Bleeding requiring addition pressure or a FemStop (Abbott Laboratories, Abbott Park, IL, USA) for complete haemostasis occurred in 17/99 (17%) patients in the PSS arm and 19/101 (19%) patients in the manual pressure arm (p=0.72). There were no cases of haematoma prolonging hospital stay, arterio-venous fistula, pseudoaneurysm or retroperitoneal bleeding. The mean duration to achieve haemostasis was 45seconds in the PSS arm and 10minutes 44seconds in the manual pressure arm (p<0.001). Pain/discomfort associated with haemostasis occurred in 15/99 (15%) patients in the PSS arm and in 29/101 (29%) patients receiving manual pressure (p=0.03). CONCLUSIONS: In this randomised trial we demonstrate that an easy to perform PSS is as effective at achieving haemostasis as 10minutes of manual pressure for catheter ablation procedures. The PSS is considerably faster to perform and is more comfortable for patients than manual pressure.

Persistent iatrogenic atrial septal defects after pulmonary vein isolation: long-term follow-up with contrast transesophageal echocardiography.

PURPOSE: Pulmonary vein isolation using cryoballoon ablation is an established approach to treating atrial fibrillation. The procedure involves insertion of a 15-Fr sheath into the left atrium across the interatrial septum. This creates an iatrogenic atrial septal defect, which may have important long-term clinical relevance, especially in younger patients. We sought to determine the long-term incidence of these defects and determine the direction of shunt using contrast transesophageal echocardiography. METHODS: Individuals who had undergone a single pulmonary vein isolation procedure were invited to attend for transesophageal echocardiography (TOE). Patients who had undergone more than one procedure involving puncture of the interatrial septum were excluded. The interatrial septum was interrogated using two-dimensional imaging, color flow Doppler, and microbubble contrast study. RESULTS: A total of 27 patients were recruited with a median follow-up time of 553 days from pulmonary vein isolation to TOE. Seven patients had persistent iatrogenic atrial septal defects with three demonstrating right to left shunt either at rest or with Valsalva. There were no reported adverse events during the study period. CONCLUSIONS: Persistent iatrogenic atrial septal defects are relatively common following cryoballoon ablation procedures. Right to left shunting can be observed using microbubble contrast in a subset of patients with iatrogenic atrial septal defect (iASD). Further studies that longitudinally assess shunt fraction, pulmonary artery pressure, and the incidence of paradoxical embolism are needed to better understand the clinical impacts of such defects.

Long Term Follow-up of Pulmonary Vein Isolation Using Cryoballoon Ablation.

BACKGROUND: Cryoballoon ablation is an established catheter-based approach to treating atrial fibrillation (AF). There is little data regarding the long-term efficacy of this approach. METHODS: We enrolled 200 consecutive patients with symptomatic AF who had failed therapy with at least one anti-arrhythmic medication and followed them for five years. The primary efficacy endpoint was symptomatic recurrence of AF after a single cryoballoon ablation procedure. RESULTS: Two hundred patients formed the study group. Median follow-up was 56 months. Following a single procedure, 46.7% of patients with paroxysmal AF remained free of symptomatic recurrence of AF compared to 35.6% of patients with persistent AF. When allowing for repeat ablations, at the end of the follow-up period 53.3% of patients in the paroxysmal group remained free of symptomatic AF compared to 47.5% in the persistent group. The rate of complications was low. CONCLUSIONS: Cryoballoon ablation is an effective catheter-based approach for treating symptomatic AF with a low risk of complications.

Radiofrequency ablation for pre-excitation syndromes and AV nodal re-entrant tachycardia.

Radiofrequency catheter ablation for supraventricular tachycardia was introduced in 1990. Since then it has become the standard for definitive treatment of pre-excitation syndromes and atrioventricular re-entrant tachycardia. In general, catheter ablation of supraventricular tachycardia results in improved outcomes compared to pharmacologic treatment. Over 95% of patients will be successfully treated with catheter ablation with less than a 5% chance of recurrence and <1% risk of major complications.

Treating atrial fibrillation: pulmonary vein isolation with the cryoballoon technique.

BACKGROUND: Cryoballoon ablation is a recently introduced technique to isolate the pulmonary veins in patients with atrial fibrillation (AF). It can potentially reduce procedural times and serious complications associated with radiofrequency ablation. METHOD: We present data for 200 consecutive patients who underwent cryoballoon ablation for symptomatic AF with a mean follow-up of 16 months. RESULTS: Over 214 procedures that involved cryoballoon technique the mean procedure and fluoroscopy times fell to 130 and 30 min, respectively. 93.6% of pulmonary veins targeted were isolated with the cryoballoon only and 97.7% could be isolated with the addition of a radiofrequency ablation catheter. At one year 70% of patients in the paroxysmal AF group and 59% of patients in the persistent AF group were free from symptomatic recurrence. Three percent of patients experienced phrenic nerve palsy that persisted beyond the procedure. The major complication rate in this study was 0.9%. CONCLUSION: This represents the earliest and largest experience with cryoballoon ablation for AF in Australia. The major complication rate was low with no pulmonary vein stenosis, atrio-oesophageal fistula, stroke or cardiac tamponade in this series. The majority of patients were free from symptomatic recurrence at two years follow up.

Long-term mechanical consequences of permanent right ventricular pacing: effect of pacing site.

INTRODUCTION: Long-term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long-term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. METHODS: Fifty-eight patients who were prospectively randomized to long-term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18-segment time-to-peak longitudinal systolic strain and 12-segment time-to-peak systolic tissue velocity. Intra-LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time-to-onset of systolic flow in the RVOT and LV outflow tract. Septal A' was measured using tissue velocity images. RESULTS: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end-systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT-paced group over the RVA-paced patients. RVA-pacing was associated with greater interventricular mechanical dyssynchrony and intra-LV dyssynchrony than RVOT-pacing. Septal A' was adversely affected by intra-LV dyssynchrony (P < 0.05). CONCLUSIONS: Long-term RVOT-pacing was associated with superior indices of LV structure and function compared with RVA-pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing.

Cardiogenic shock complicating subarachnoid haemorrhage diagnosed as Tako Tsubo cardiomyopathy: a cautionary tale.

Tako Tsubo or "stress" cardiomyopathy and its variants are well recognised as potential causes of acute coronary presentations, with manifestations including chest pain, cardiac failure and arrhythmia. Similarly, subarachnoid haemorrhage may be associated with cardiac abnormalities. Tako Tsubo cardiomyopathy is a diagnosis of exclusion with typical left ventricular dysfunction in the absence of epicardial coronary disease, but importantly also after exclusion of an intracerebral insult. We describe a case of unrecognised intracerebral haemorrhage with left ventricular dysfunction consistent with both variant Tako Tsubo cardiomyopathy and subarachnoid haemorrhage in a patient treated with intra-aortic balloon pump counterpulsation and associated heparinisation.

Cryoablation versus radiofrequency ablation in the treatment of atrial flutter trial (CRAAFT).

INTRODUCTION: Atrial flutter is frequently treated with radiofrequency (RF) ablation with excellent results. While RF ablation remains the gold standard for catheter based treatment of atrial flutter, cryoablation has potential advantages including painless ablation and cryoadherence to the myocardium. We performed a prospective randomised trial comparing cryoablation and RF ablation in the treatment of atrial flutter. METHODS AND RESULTS: We randomised 32 consecutive patients with typical atrial flutter to either radiofrequency ablation using an 8 mm tip Blazer II XP catheter (EP Technology, San Jose, USA) or cryoablation using a 9 French 8 mm tip Freezor Max catheter (CryoCath Technologies Inc, Kirkland, QU, Canada). Twenty eight patients were then followed up for a mean of 14.7 months. The procedure was successful in producing isthmus block in all but one patient in the cryoablation group. Cryoablation was associated with a significantly longer procedure (171 vs 99 min) and ablation duration (59 vs 12.7 min), however fluoroscopy exposure was similar (30 vs 29 min). Cryoablation was associated with reduced pain scores compared with RF (mean pain score 0.4 vs 3.5). There were two recurrences of atrial flutter during follow-up, both in the cryoablation group. CONCLUSIONS: Cryoablation has improved patient tolerability compared to RF ablation, however is associated with longer procedure and ablation durations. Further trials are required to confirm whether cryoablation has similar acute and chronic efficacy to RF ablation.

Intracardiac extension of metastatic pulmonary leiomyosarcoma.

Leiomyosarcomas are uncommon malignancies of soft tissue associated with a poor prognosis due to local and metastatic disease. We describe an example of metastatic pulmonary leiomyosarcoma with intracardiac extension in a patient who had previously undergone resection of a primary retroperitoneal mass. Distinguishing metastatic malignancy within the heart from a primary tumour, such as atrial myxoma, may be difficult, with the use of various imaging modalities assisting in diagnosis and management. In this case, the patient's course was complicated by dramatic progression with widespread emboli resulting in peripheral arterial occlusion and stroke.