Cardiac contractility modulation: first experience in heart failure patients with reduced ejection fraction and permanent atrial fibrillation.
OBJECTIVE
Cardiac contractility modulation (CCM) is an electrical therapy for heart failure (HF) with reduced ejection fraction. Sinus rhythm is deemed necessary for effective treatment because the current CCM signal delivery algorithm requires sequential sensing of a p wave, followed by depolarizations at each ventricular lead. In case of atrial fibrillation (AF) CCM is inhibited. This study demonstrates the feasibility of CCM therapy in patients with permanent AF by circumventing the requirement for sensing of a natural p wave.


RESULTS
Five CCM patients with AF received a pacemaker or implantable cardioverter/defibrillator (ICD) upgrade to cardiac resynchronization therapy (CRT) with low atrial sensitivity, which resulted in compulsory atrial stimulation followed by biventricular pacing. The CCM system recognized the atrial stimuli as p waves, which led to CCM signal delivery. Three patients developed permanent AF after a mean follow-up of 40 months of CCM therapy. Two patients had permanent AF at the time of CCM device implantation. All pacemaker or ICD devices were successfully upgraded to CRT. Cardiac resynchronization therapy stimulation rates of ≥96% and CCM stimulation rates between 60% and 95% were achieved. Clinical condition of the patients improved (mean NYHA class -0.7, left ventricular ejection fraction +2%, Minnesota living with HF questionnaire -15.6 points).


CONCLUSIONS
CCM signal delivery is feasible in HF patients with permanent AF by sequential atrial-ventricular pacing, so that the atrial pacing spike is interpreted as a p wave by the CCM signal delivery algorithm. This experimental approach can be considered in individual cases. A new CCM algorithm, which does not require an atrial electrode, is desirable.
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany susanroeger@hotmail.com.
Susanne
S
Röger
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Raphaela
R
Schneider
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Boris
B
Rudic
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Volker
V
Liebe
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Ksenija
K
Stach
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Rainer
R
Schimpf
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Martin
M
Borggrefe
I. Medical Department, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim D-68167, Germany.
Jürgen
J
Kuschyk
D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D004562:Electrocardiography; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D011788:Quality of Life; D013318:Stroke Volume; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left
Atrial fibrillation; Cardiac contractility modulation; Cardiac resynchronization therapy; Heart failure