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.
Cardiology Division, Department of Medicine, University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, ROC.
Chu-Pak
CP
Lau
Serge
S
Barold
Hung-Fat
HF
Tse
Kathy Lai-Fun
KL
Lee
Hon-Wah
HW
Chan
Katherine
K
Fan
Elaine
E
Chau
Cheuk-Man
CM
Yu
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