50 What is the role of permanent pacing in
hypertrophic cardiomyopathy?
Niall G Mahon and W McKenna
There are broadly two categories of indications for permanent pace-
maker insertion in patients with hypertrophic cardiomyopathy:
- Standard indications for pacing which apply to any patient.
- Reduction of left ventricular outflow tract gradient.
Indications for the use of dual chamber pacing with a short
programmed atrioventricular delay for this purpose remain to be
determined. Gradient reduction is thought to come about through
a variety of effects on septal and papillary muscle motion and
contractility. In general outflow gradients can be reduced by
approximately 50% but the translation of this benefit into clinical
improvement is variable and unpredictable. Initial enthusiasm
has been tempered by equivocal results from clinical trials. A
considerable placebo effect of the procedure has been observed in
at least two randomised studies.1,2Anecdotally, patients who may
benefit are symptomatic elderly patients with significant left
ventricular outflow tract obstruction who do not respond to
conventional therapy with beta blockers, verapamil or diso-
pyramide. The role of pacing in young patients is unclear and
methods of identifying patients likely to benefit from the
procedure have not been established.
RReeffeerreenncceess
1 Nishimura RA, Trusty JM, Hayes DL et al. Dual chamber pacing for
hypertrophic cardiomyopathy: a randomised double blind crossover
trial. J Am Coll Cardiol1997; 2299 : 435–41.
2 Kappenberger L, Linde C, Daubert Cet al. Pacing in hypertrophic
obstructive cardiomyopathy. A randomised crossover study. PIC study
group. Eur Heart J1997; 1188 : 1249–56.
FFuurrtthheerr rreeaaddiinngg
Elliott PM, Sharma S, McKenna WJ. Hypertrophic cardiomyopathy. In:
Yusuf S, Cairns JA, Camm AJ et al. Evidence based cardiology. London: BMJ
Books, 1998:722–43.