Muhammad Ilyas ( Muhammadi Hospital, Peshawar. )
A case of sick sinus syndrome, which was originally diagnosed during 1958, had an extensive follow-up for over 20 years by several clinicians. He showed a wide spectrum of associated rhythm disorders includ-tng sinus irregularity, extrasystoles, paroxysmal supraventricular tachycardia and Wenkebach\'s phenomenon. He remained physically fit and active, and did not require active medications, and died in an air crash.
Sick sinus syndrome (SSS), disorderly sinus inactivity with or without escape activity, was first reported by Ferrer (1968), and several reports have since been published (Narula et al., 1972; Akhtar, 1973; Conde et al., 1974; Ilyas et al., 1974; Marmor and Block, 1980). Ironically, ten years earlier Yousaf (1958) had documented a case of this disorder but missed the opportunity of naming it or publishing it. This communication spotlights a 21 years follow-up of Yousaf\'s original case of SSS.
M.A., a young doctor of Lahore, who used to be perturbed with palpitation since childhood, consulted his teacher, Prof. Muhammad Yousaf K.E. Medical College Lahore, in 1958. On examination the pulse rate was 40-60/min and irregular, B.P. was 120/75 mm Hg, heart sounds were normal and chest X-ray showed no abnormality. The electrocardiogram, recorded on Dec. 16, 1958, was reported to have "marked sinus arrhythmia, prolonged P-R interval and missing beats\'\' and "an unusual case" (Figs. 1-2).
The doctor was advised to reduce tea intake and to take phenobarbitone gr. 1/2 two or three times a day, with no obvious benefit. He was a non-Smoker. He remained otherwise well and active except for palpitation and episodes of paroxysmal supraventricular taehycardia. During the following years, as a surgeon, he continued to work 10-12 hours a day. Several electrocardiograms were taken on different occasions; one recording during 1963 demonstrated nodal escape activity (Fig. 3)
and a recording during 1974 showed 2:1 A-V block with Wenkebach\'s phenomenon (Fig. 4).
An electrocardiogram recorded during 1978 showed sinus irregularity with nodal escape activity. He died, in an air crash during 1979.
SSS has existed undiscovered due to low specificity of the clinical symptoms and low sensitivity of morphological patterns. The term sick sinus was coined by Lown (1967) for failure of sinus rhythm after cardioversion and a complete account on the syndrome was reported by Ferrer (1968). SSS is commoner in older age groups but also occurs in young, and both sexes are equally affected. SSS may manifest as sinus bradycardia or sinus arrest. Chronic atrial fibrillation may replace ceased sinus rhythm and ventricular rate may also be slow. Lone artial fibrillation, without cardiac abnormality specially in the young, may also be due to sick sinus syndrome.
Sinoatrial node may die slowly or more abruptly in coronary heart disease. Prognosis of SSS is influenced by asystolic episodes, congestive cardiac failure and by the type and response to treatment. Yousaf\'s case, which was originally diagnosed during 1958, remained well for over 21 years. SSS may be associated with congential deafness and may be the cause of death in young athletes (James, 1967). In-creased alertness after exercise may be the only manifestation of SSS (Marmor and Block, 1980).
Provocative tests include response to intravenous atropine and isoprenaline, and rapid atrial pacing (Narula et al., 1972). Atropine and isoprenaline are both used as provocative test and for short term treatment. Demand ventri-cu\'ar pacemaker is the treatment of choice (Code et al., 1974), and for associated tachyarrhythmias beta-blocking is required
Digoxin does not necessarily influence sinus bradycardia in SSS, but with coexisting A-V block it should be used with implanted pacemaker. Digoxin administered after atropine (vagal bloekade) in patients with sinus node dysfunction increased sinus cycle length, sinoatrial couduction time and maximal corrected sinus recovery time (Reiffel et al., 1975).
I record my gratitude to Prof. Yoshio Watanabe M.D. Fujita-Gakuen University, Aichi, Japan for preview of this case report.
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