Advances in devices for cardiac resynchronization in heart failure.
Patients with advanced heart failure have a high mortality and morbidity despite medical therapy. Depending on the underlying heart disease and severity of heart failure, 3.7 to 52.8% of patients have a QRS complex > or =120 ms who may have interventricular and intraventricular dyssynchrony correctible by cardiac resynchronization therapy (CRT). The latter is usually achieved with biventricular pacing, with the left ventricular lead placed in a tributary of the coronary sinus (CS), with a reported success rate between 88-92%. The technical advances for implantation include preformed guide sheaths to cannulate the CS, over the wire leads with passive fixation mechanism, and surgical placement methods. Device-specific CRT features include optimizing heart failure through insurance of a high percentage of pacing, heart failure monitoring, atrioventricular and interventricular timing, and avoiding double ventricular sensing. Furthermore, arrhythmic co-morbidities of heart failure such as atrial fibrillation and ventricular tachyarrhythmias can also be managed. Recent prospective trials suggest that there is a 30% reduction in heart failure hospitalization with CRT, and preliminary results suggest a survival benefit with CRT and implantable cardioverter defibrillator over optimal medical therapy.
Lau
Chu-Pak
CP
Cardiology Division, Department of Medicine, University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, ROC.
Barold
Serge
S
Tse
Hung-Fat
HF
Lee
Kathy Lai-Fun
KL
Chan
Hon-Wah
HW
Fan
Katherine
K
Chau
Elaine
E
Yu
Cheuk-Man
CM
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods; D002986:Clinical Trials as Topic; D003131:Combined Modality Therapy; D017147:Defibrillators, Implantable; D006329:Heart Conduction System / Q000473:pathology / Q000601:surgery; D006333:Heart Failure / Q000628:therapy; D006352:Heart Ventricles / Q000473:pathology / Q000601:surgery; D006801:Humans; D010138:Pacemaker, Artificial
D000806:Angiotensin-Converting Enzyme Inhibitors