Malcolm Barlow

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

Optimal Right Ventricular Pacing 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.

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.

Pain in the neck

A 76-year-old man presented with a 4-week history of recurrent syncope in July, 2000. Syncope was heralded by a sensation of lightheadedness and occasionally by a mild burning sensation in the left side of his throat. Loss of consciousness was associated with urinary incontinence and generalised rigidity. There was no relationship to posture. Recovery was followed by nausea and vomiting. His past history included diabetes mellitus, peripheral vascular disease, cerebrovascular disease with left carotid endarterectomy 4 months earlier, hypertension, chronic obstructive airways disease, and excision of multiple cutaneous squamous-cell carcinomas. He was a former smoker. No significant findings were noted on examination apart from a left Horner’s syndrome attributed to the previous endarterectomy. A 12-lead electrocardiogram was normal. A computed tomograph (CT) of his head showed a small right-sided subdural haematoma without evidence of raised intracranial pressure. He was admitted to hospital. He continued to have syncopal episodes every day, associated with the absence of a palpable pulse or recordable blood pressure. Upright tilt-table testing and carotid sinus massage failed to provoke syncope. 24-h ambulatory electroencephalography was normal but 24-h Holter monitoring showed transient episodes of asymptomatic complete atrioventricular dissociation. Trials of fludrocortisone, phenytoin, salt tablets, fluoxetine, and cessation of antihypertensive therapy had no effect. An atrioventricular pacemaker was implanted and he was discharged from hospital. He returned the following day with another syncope. Pacemaker function was normal and during syncopal episodes, telemetry showed atrioventricular sequential pacing at the programmed lower rate. Cardiac catheterisation showed normal left ventricular function and a chronically occluded right coronary artery. A contrast-enhanced CT of his neck was done on the suspicion that syncope was related to a neck tumour. The CT showed a large soft-tissue mass arising from the fossa of Rosenmuller extending into the left parapharyngeal space. The tumour infiltrated the skull base and the carotid sheath with erosion of the foramen lacerum and jugular foramen, and compression of the internal jugular vein (figure). Further examination showed a midline soft palate which moved on the right side only, and slight wasting of the left sternocleidomastoid muscle. Nasoendoscopy showed left vocal cord paralysis and a large lesion in the left nasopharyngeal area. A diagnosis of malignancy with jugular foramen syndrome was made. A biopsy specimen

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.

Diathermy-induced ventricular fibrillation with Riata high-voltage lead insulation failure.

We report a case of diathermy-induced ventricular fibrillation as a result of insulation failure in high-voltage lead at the level of thepectoral muscles.A 76-year-old man presented to a small peripheral hospital after a series of six shocks in quick succession from his implanted biven-tricular defibrillator (St Jude Medical Promote Accel RF device; right atrial, right ventricular, and left ventricular leads were SJM1688T,SJM1570 Riata, and SJM1258T, respectively). A short period of palpitations and pre-syncope preceded the shocks and symptoms per-sisted despite the shocks. Initial 12-lead electrocardiogram revealed ventricular tachycardia at 180 b.p.m. A retrieval team deliveredone 200 J shock with successful return to sinus rhythm. The man was then transferred to our institution.His last implantable cardioverter defibrillator follow-up 2 months prior to the present episode was normal.Interrogation of the device revealed that the device had been reset. Neither the episodes nor the therapies delivered were access-ible. The data could not be retrieved despite interrogation by the company’s technical services division. The parameters differed fromthose 2 months earlier (high-voltage lead impedance 14 vs. 42 V, thresholds for right ventricular, left ventricular, and right atrial leadswere 2.75 vs. 0.75 V, 4.75 vs. 1.5 V, and 3.25 vs. 1.25 V, respectively). The therapies were disabled.The patient was taken to the cardiac catheterization lab for a replacement.During dissection to free the leads, ventricular fibrillation was noted immediately following diathermy application. Three external200 J shocks were required to return to sinus rhythm. The diathermy knife was ,1 cm from the leads at the time of ventricularfibrillation onset. It is worth noting that diathermy to subcutaneous tissue earlier on during the procedure did not have anyadverse outcome. Further dissection without diathermy revealed a clear insulation failure of the high-voltage lead (Figure 1).The defective lead was cut and capped. A new high-voltage lead (Medtronic Sprint Secure 6935) and a new device (MedtronicConcerto II) were implanted with excellent parameters on all three leads.We postulate the following sequence of events in the absence of recorded data. Because of the insulation defect in the high-voltagelead, there was no effective current delivered to the heart during the initial series of six shocks. Instead, all or most of the current‘short circuited’ between the lead defect and the device. The external shock not only terminated the ventricular tachycardia, butalso reset the device, quite probably by current entering through the exposed lead and travelling retrograde to the device. Diathermyclose to the exposed lead carried alternating current to the left ventricle inducing ventricular fibrillation.The company has issued a recall for the Riata and Riata ST silicone endocardial leads due to insulation failure.

An Alternative to QRS Alternans: FITZGERALD et al.

A 25-year-old woman with episodes of palpitations exacerbated during two previous pregnancies was referred for electrophysiology study +/- ablation. She had previously documented narrow complex tachycardia and a normal transthoracic echocardiogram. This article is protected by copyright. All rights reserved.

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.

Clinical problem solving: Maneuvering around a narrow complex tachycardia in a patient with Mustard repair for transposition of the great arteries

Case report The patient was initially palliated with balloon atrial septostomy before undergoing Mustard repair at age 1. The subsequent course was complicated by both inferior vena cava baffle stenosis and obstruction to pulmonary venous flow requiring surgical correction. Following these procedures, a dual-chamber permanent pacemaker was implanted for bradycardia at age 22 owing to presumed sinus node dysfunction. Echocardiography confirmed satisfactory systemic (morphologic right) ventricular function with ventriculoarterial discordance noted. There was no evidence of recurrent baffle obstruction. Echocardiographic imaging was consistent with an excellent hemodynamic result from an atrial switch repair for d-TGA. Owing to ongoing symptoms despite sotalol therapy, the patient was referred for an electrophysiology (EP) study. Catheter positions at EP study are shown in Figure 1A. The decapolar catheter was positioned in the systemic atrial appendage because the coronary sinus could not be identified and often empties into the pulmonary venous atrium (detailed surgical notes were not available to confirm this). Figure 1B shows a permanent pacemaker rhythm strip from a typical tachycardia episode (rate 180 beats/min). The electrocardiogram (ECG) during sinus rhythm is shown in

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.

An atrial fibrillation suppression algorithm encourages angina

An 86-year-old man presented to hospital with non-ST elevation myocardial infarction, having had a dual-chamber permanent pacemaker inserted 1 year prior for mixed sinus and atrio-ventricular node disease (St Jude Zephyr XL, model 5826). A rhythm strip at admission showed tracked atrial …