Biventricular pacing in hypertrophic obstructive cardiomyopathy: a pilot study.
BACKGROUND
Right ventricular apex pacing for gradient reduction in hypertrophic obstructive cardiomyopathy (HOCM) with severe left ventricular (LV) obstruction has yielded conflicting results.


OBJECTIVE
The purpose of this study was to assess the feasibility and effectiveness of biventricular pacing in HOCM.


METHODS
Transvenous biventricular pacing was attempted in 12 severely symptomatic HOCM patients. Optimal intervals were programmed after implant. Echocardiographic LV pressure gradient and synchrony were assessed. LV lead implantation was successful in 9 patients. Optimal pacing mode was biventricular in 6 patients, left ventricular only in 2 patients, and right ventricular only in 1 patient.


RESULTS
Functional capacity and quality of life progressively improved. New York Heart Association functional class decreased from 3.2 ± 0.4 at baseline to 1.9 ± 0.3 at 3 months and to 1.4 ± 0.5 at 1 year (P <.05); 6-minute walk test increased from 349 ± 116 m at baseline to 454 ± 144 m at 3 months and to 517 ± 206 m (P <.05); and quality of life increased from 54 ± 16 points at baseline to 28 ± 13 points at 3 months and 27 ± 15 points at 1 year (P <.05). There was also a progressive reduction in LV gradient from 74 ± 23 mmHg at baseline to 50 ± 27 mmHg acutely, 40 ± 26 mmHg at 3 months, and 28 ± 17 mmHg at 1 year (P <.05). Gradient reduction was associated with diminished peak longitudinal displacement of the LV septum and earlier displacement of the lateral wall. A progressive reduction of LV mass was observed, from 356 ± 110 g at baseline to 315 ± 70 g at 3 months (P = .13) and to 284 ± 42 g at 1 year (P <.05).


CONCLUSIONS
Biventricular pacing is feasible and usually the best configuration for gradient reduction in HOCM. Biventricular pacing reduces LV hypertrophy.
Cardiology Department, Thorax Institute, Hospital Clinic, Barcelona, Spain. berruezo@clinic.ub.es
Antonio
A
Berruezo
Radu
R
Vatasescu
Lluis
L
Mont
Marta
M
Sitges
Diego
D
Perez
Giorgi
G
Papiashvili
Giorgi
G
Papiashvilli
Barbara
B
Vidal
Antonio
A
Francino
Juan
J
Fernández-Armenta
Etelvino
E
Silva
Bart
B
Bijnens
Jose Ramón
JR
González-Juanatey
Josep
J
Brugada
D000328:Adult; D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology*