Effect of biventricular pacing on symptoms and cardiac remodelling in patients with end-stage hypertrophic cardiomyopathy.

BACKGROUND: Biventricular (BiV) pacing is an established therapy for heart failure in ischaemic and dilated cardiomyopathy. Its effects in end-stage hypertrophic cardiomyopathy (HCM) are unknown. AIMS: To assess the potential benefits of BiV pacing in patients with symptomatic end-stage HCM. METHODS: Twenty patients with non-obstructive HCM (12 male, mean age 57+/-13 years), left bundle branch block and symptoms of heart failure refractory to medical therapy underwent implantation of a BiV device. NYHA class, echocardiographic parameters and exercise capacity were assessed before and after implantation. RESULTS: At a mean follow-up of 13+/-6 months, an improvement of at least one NYHA class was reported in 8 (40%) patients. A clinical response was associated with an increase in ejection fraction (from 41+/-14% to 50+/-12%, p=0.009), and reductions in left ventricular end-diastolic diameter (from 57+/-6 mm to 52+/-7 mm, p=0.031) and left atrial diameter (from 65+/-8 mm to 57+/-6 mm, p=0.005). Percentage predicted peak oxygen consumption was unchanged in responders but significantly declined in non-responders (p=0.029). CONCLUSIONS: BiV pacing improved heart failure symptoms in a significant proportion of patients with end-stage HCM. Symptomatic improvement was associated with reverse remodelling of the left atrium and ventricle.

Biventricular device implantation in a patient with congenitally corrected transposition and left-sided superior vena cava.

An increasing number of patients with congenital heart disease are surviving into adulthood and some have indications for device therapy. Complex anatomical abnormalities may hinder the operator and require the adaptation of standard implantation techniques. We present the first report of successful biventricular ICD implantation in a patient with mesocardia, congenitally corrected transposition of the great arteries, pulmonary atresia, and a left superior vena cava draining into the coronary sinus. This case posed challenges in lead placement due to both complex anatomy and the risk of inappropriate device therapies secondary to far-field oversensing.

Successful coronary sinus lead replacement despite total venous occlusion using femoral pull through, two operator counter-traction and subclavian venoplasty.

The majority of patients presenting for lead extraction have indications for a replacement lead. Venous stenosis is common in recipients of pacing leads and can impede ipsilateral lead replacement. Recanalization through an existing tract after lead extraction allows successful lead placement but may require complex hybrid lead extraction and revascularization techniques. We present a case in which a combination of femoral lead extraction with complete guidewire pull-through, two operator external counter-traction and subclavian venoplasty was used to successfully replace a coronary sinus lead in a patient with total subclavian venous occlusion.

Right atrial angiography facilitates transseptal puncture for complex ablation in patients with unusual anatomy.

OBJECTIVE: The number of transseptal punctures performed worldwide has increased exponentially with the development of ablation therapies for atrial arrhythmias. Safe access into the left atrium in these procedures is often complicated by abnormal anatomy. We assessed the potential of right atrial angiography to facilitate transseptal puncture for atrial ablation. METHODS AND RESULTS: We examined all transseptal punctures performed for complex left atrial ablation in our centre over a 29-month period. In cases where conventional transseptal techniques failed, we performed orthogonal right atrial angiography to define cardiac anatomy and orientation. During the study period, 255 transseptal procedures were performed. Of these, 16 cases were complicated by distorted atrial anatomy, extreme cardiac rotation or unexpected location of the atria in relation to the diaphragm, preventing left atrial access using conventional fluoroscopy. The application of right atrial angiography facilitated successful transseptal puncture in all patients when use of conventional mapping catheters and fluoroscopy proved unhelpful. There were no complications relating to right atrial angiography. CONCLUSION: These cases highlight a number of difficulties encountered when performing transseptal punctures. Previously reported adjunctive techniques require specialised equipment, general anaesthesia or multiple catheters that may be unavailable or impede the procedure. Right atrial angiography is a simple and safe adjunct to conventional techniques to facilitate complex transseptal procedures.

A randomized double-blind crossover trial of triventricular versus biventricular pacing in heart failure.

AIMS: A significant proportion of patients implanted with biventricular (BiV) devices fail to respond. Clinical response may be improved by additional ventricular stimulation sites. This single-centre, double-blinded randomized crossover trial aimed to determine whether long-term multisite ventricular pacing is superior to conventional BiV pacing in heart failure patients. METHODS AND RESULTS: A total of 43 patients referred for cardiac resynchronization therapy (CRT) underwent transvenous implantation of a triventricular (TriV) device. Pacing leads were positioned in the right ventricular (RV) apex and a lateral coronary sinus (CS) branch, with a third ventricular lead implanted in a further lateral CS branch in 23 patients (group A) and on the high RV septum in 20 patients (group B). Devices were programmed in a randomized order to four pre-determined pacing configurations: conventional BiV, TriV, and dual-site and single-site left bentricular (LV) or RV pacing for 3-month periods with clinical and echo assessment at the end of each period. The primary endpoint was the comparison of 6 min walk distance (6MW) after 3 months of BiV vs. TriV pacing; secondary endpoints were Minnesota Living With Heart Failure (MLWHF) scores, and LV dimensions and function. The 12-month follow-up period was completed by 37 patients. Compared with BiV pacing, TriV pacing resulted in significant improvements in 6MW (451 ± 112 m vs. 425 ± 119 m, P = 0.008), MLWHF (32 ± 19 vs. 38 ± 24, P = 0.036), LV end-systolic volume (158 ± 79mL vs. 168 ± 76 mL, P < 0.05), and ejection fraction (30 ± 8% vs. 27 ± 8%, P < 0.05). CONCLUSIONS: TriV pacing was associated with significant improvements in clinical and echocardiographic parameters compared with BiV pacing.

Improving safety in the electrophysiology laboratory using a simple radiation dose reduction strategy: a study of 1007 radiofrequency ablation procedures.

BACKGROUND: The use of fluoroscopic screening involves exposure to ionising radiation for both patients and operators. OBJECTIVE: To assess the effects of radiation dose reduction manoeuvres (DRM) during radiofrequency ablation (RFA) procedures. DESIGN: Prospective study of DRM. SETTING: Tertiary cardiac centre. Interventions Two DRM were combined: removal of the secondary radiation grid and programming an ultra-low pulsed fluoroscopy rate. These methods were assessed using an anthropomorphic phantom model to measure skin entrance dose rates. Procedures were classified as complex (ablation of atrial fibrillation, ventricular tachycardia or complex congenital heart disease arrhythmias) or simple (all other RFA). MAIN OUTCOME MEASURES: Dose area product and screening times were compared for ablations performed before and after DRM. Equivalent doses to organs and malignancy risk were determined by computer modelling. RESULTS: Over a 39-month period, 1007 ablation procedures were performed (631 simple, 376 complex). Radiation dose was significantly reduced after DRM for both simple (20.4±26.9 Gycm(2) vs 8.0±10.3 Gycm(2), p<0.00001) and complex ablations (63.3±50.1 Gycm(2) vs 32.8±31.7 Gycm(2), p<0.00001) with no difference in screening times. The mean lifetime risk of fatal cancer attributable to radiation exposure per million procedures was reduced from 182 to 68 for simple ablations and from 440 to 155 for complex ablations. CONCLUSIONS: Significant reductions in radiation exposure during RFA were achieved using simple DRM, corresponding to a two-thirds reduction of the risk of excess fatal malignancy.