Comentario de artículo original: Atención Primaria: Evaluación y tratamiento de la bradicardia.

1. Bouman LN, Jongsma HJ. Structure and function of the sino atrial node: a review. Eur Heart j 1986;7:94 104.
2. Jose AD, Collison D. The normal range and determinants of the intrinsic heart rate in man. Cardiovasc Res 1970;4:160-7
3. Brodsky M, Wu D, Denes P, Kanakis C, Rosen KM. Arrhythmias doc-umented by 24 hour continuous elcctrocardiographic monitoring in 50 male medical students without apparent heart disease. Am 1 Cardiol 1977; 39:390-5.
4. Viitasalo MT, Kala R, Eisalo A. Ambulatory electrocardiographic record-ing in endurance athletes. Br Heart l 1982;47:213-20.
5. Spodick DH, Raju P, Bishop RL, Rifkin RD. Operational definition of normal sinus heart rate. Am J Cardiol 1992;69:1245-6.
6, Spodick DH. Survey of selected cardiologists for an operational definition of normal sinus heart rate. Am J Cardiol 1993;72:487-8.
7. Idem. Normal sinus heart rate: appropriate rate thresholds for sinus tachycardia and bradycardia. South Med J 1996;89:666-7
8. Kantelip JP, Sage E, Duchene-Marullaz P. Findings on ambulatory monitoring in subjects older than 80 years. Am J Cardiol 1986;57:398-401.
9. Scott O, Williams GJ, Fiddler GI. Results of 24 hour ambulatory mon-itoring electrocardiogram in 131 healthy boys aged 10 to 13 years. Br Heart 1 1980;44:304-8.
10. Dickinson DF, Scott O. Ambulatory electrocardiographic monitoring in 100 healthy teenage boys. Br Heart I 1984;51:179-83.
11. Southall DP, Johnston F, Shinebourne EA, Johnston PGB. 24-Hour electrocardiographic study of heart rate and rhythm patterns in population of healthy children. Br Heart J 1981;45:281-91.
12. Fleg JL, Kennedy HL. Cardiac arrhythmias in a healthy elderly popu-lation: detection by 24-hour ambulatory eectrocardiography. Chest 1982; 81:302-7
13. Hanne-Paparo N, Drory Y, Schoenfeld Y, Shapira Y, Kellermann JJ. Common ECG changes in athletes. Cardiology 1976;61:267-78.
14. Northcote RJ, Canning GP, Ballantyne D. Electrocardiographic findings in male veteran endurance athletes. Br Heart J 1989;61:155-60.
15. Gregoratos G, Cheitlin MD, Conill A, et al. ACC/AHA guidelines for implantation of cardiac pacemakers and antiarrhythmia devices: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Pacemaker Implantation). J M Coll Cardiol 1998;31:1175-209.
16. Stegman SS, Burroughs IM, Henthorn RW. Asymptomatic brady-arrhythmias as a marker for sleep apnea: appropriate recognition and treat-ment may reduce the need for pacemaker therapy. Pacing Clin Elcctrophysiol 1996;19:899-904.
17. Guilleminault C, Connolly SI, Winkle RA. Cardiac arrhythmia and conduction disturbances during sleep in 400 patients with sleep apnea syn-drome. Am. J Cardiol 1983;52:490-4.
18. Pollak A, Falk RH. Pacemaker therapy in patients with atrial fibrillation. Am Heart J. 1993;125:824-30.
19. Farshi R, Kismer D, Sarma ]SM, Longmate JA, Singh BN. Ventricular rate control in chronic atrial fibrillation during daily activity and programmed exercise: a crossover open-label study of five drug regimens. J Am Coll Cardiol 1999;33:304-10.
20. Recommendations for pacemaker prescription for symptomatic brady-cardia: report of a working party of the British Pacing and Electrophysiology Group. Br Heart I 1991;66:185-91.
21. Pitcher D, Papouchado M, lames MA, Recs JR. Twenty four hour ambulatory electrocardiography in patients with chronic atrial fibrillation. BMJ 1986;292:594.
22. Holden W, McAnulty JH, Rahimtoola SH. Characterisation of heart rate response to exercise in the sick sinus syndrome. Br Heart J 1978;40: 923-30.
23. Ellestad MH, Wan MR. Predicted implications of stress testing: filllow-up of 2700 subjects after maximum treadmill stress testing. Circulation 1975;51:363-9.
24. Corbelli R, Masterson M, Wilkoff BL. Chronotropic response to ex-ercise in patients with atrial fibriilation.