360 Cardiology Pacemaker syndrome Pacemaker therapy has become an important therapeutic option for patients with heart rhythm conditions worldwide. Te number of elderly patients needing pacemakers is on the increase due to an ageing population worldwide. Pacemaker syndrome consists of the cardiovascular signs and symptoms of heart failure and hypotension induced by right ventricular (RV) pacing. Dr Satnam Singh Research Registrar, University of Aberdeen, Level 3, Polwarth building, Aberdeen email [email protected] Pacemaker syndrome is a term syndrome occurring in dual trial was a single blinded study proposed in 1979 by Erbel and chamber modes.5,6 It can even enrolling around 2000 patients refers to symptoms and signs in occur with AAI pacing with long with sick sinus syndrome. the pacemaker patient caused by PR intervals. All patients were implanted inadequate timing of atrial and dual chamber pacemakers ventricular contractions.1 It was first programmed to VVIR or DDDR described in 1969 by Mitsui et al2 as Incidence before implantation. Pacemaker an iatrogenic disease characterised syndrome was a secondary by the disappearance of symptoms Te overall incidence of pacemaker endpoint studied. Severe with restoration of atrioventricular syndrome is very difficult to pacemaker syndrome developed synchrony (AV synchrony). estimate but is about 20% in a in nearly 20% of VVIR-paced It means if atria and ventricles landmark trial called the Mode patients and improved with contract at appropriate timings (as Selection Trial (MOST).7 It occurs reprogramming to the dual- close to physiological), pacemaker with equal frequency in both sexes chamber pacing mode. syndrome can be prevented. and can occur at any age.8 In this It has been postulated that trial 2010 patients were randomly the greater the AV dyssynchrony, assigned to VVIR (Ventricular Rate Clinical presentation the greater the incidence of this Modulated Pacing) versus DDDR syndrome. VVI pacing (Single (Dual Chamber Rate Adaptive Symptoms of pacemaker Chamber Ventricular Pacemaker) Pacemaker) pacing modes. This syndrome are non-specific and is the commonest pacemaker mode, but as it is a single chamber Key points pacing (Table 1), it can create AV dyssynchrony.3,4 The lack of normal • Pacemaker syndrome refers to symptoms and signs in the atrioventricular synchrony may pacemaker patient caused by inadequate timing of atrial and result in decreased cardiac output. ventricular contractions. In most cases this syndrome can • Te lack of normal atrioventricular synchrony may result in be cured by dual chamber pacing, decreased cardiac output. which relieves almost all the • Te strongest predictor of pacemaker syndrome appears to be symptoms. This is because dual a high percentage of ventricular paced beats according to the chamber pacing is more close to MOST trial. normal physiology than single • Quality of life improved significantly afer patients were chamber pacing. However, there upgraded to dual chamber pacing. are several reports of pacemaker GM | Midlife and Beyond | July 2011 www.gerimed.co.uk may be confused with the ageing process. Moreover elderly patients report less symptoms due to memory deficits or other reasons. Tere has been a considerable overlap among the signs and symptoms of pacemaker syndrome and physiological ageing symptoms. Nevertheless commonly patients present with the nonspecific symptoms ranging from fatigability to syncope and these occur during the time the ventricles are being stimulated by the pulse generator. Postulated mechanisms include loss of AV synchrony, vasodepressor reflexes, and retrograde atrial activation. The strongest predictor of pacemaker syndrome appears to be a high percentage of ventricular paced beats according to the MOST trial. Diagnosis Te diagnosis of pacemaker syndrome is based on the clinical features listed in table 2 especially in a patient with a VVIR pacemaker and the disappearance of all or most of the symptoms with upgrading of the pacemaker to a dual chamber one. Plasma ANP levels have also been used a marker of non-physiological pacing in the PASE trial and elevated levels (>90pgml) can be helpful in the diagnosis. On upgrading the pacemaker to DDDR, there should be a prompt decline in ANP levels and prompt resolution of symptoms.9–12 Pacemaker syndrome is more likely if the systolic blood pressure drops more than 20mmHg during ventricular pacing (VVIR).13 Despite attempts to identify clinical variables and biochemical markers that predict the development of pacemaker syndrome, multiple studies have failed to identify any consistency. Management In the past two decades, a vast majority of cardiologists have modified their practice by shifing away from VVI/VVIR pacing. Patients with pacemaker syndrome after VVIR pacing can be managed by upgrading to a DDDR system. Rarely, a patient with a dual chamber pacemaker may present with similar symptoms of pacemaker syndrome,5,6 which needs pacing clinic follow up for ensuring www.gerimed.co.uk Cardiology 363 Table 1: Types of pacemaker Table 2: Clinical features of pacemaker syndrome VVI pacing: Tis is by far Neurological: Dizziness, near syncope, and confusion the most common type of Heart failure: Dyspnoea, orthopnoea, paroxysmal nocturnal pacemaker mode. It senses dyspnoea, and peripheral oedema spontaneous ventricular Hypotension: Seizure, mental status change, diaphoresis, and signs impulses and paces the of orthostasis and shock ventricles only when needed. Low cardiac output: Fatigue, weakness, dyspnoea on exertion, Dual chamber pacing: Tis lethargy, and lightheadedness is said to happen when both Hemodynamic: Pulsation in the neck and abdomen, choking the atria and the ventricles sensation, jaw pain, right upper quadrant (RUQ) pain, chest colds, are paced with one lead in the and headache atria and the other lead in the Heart rate related: Palpitations associated with arrhythmias. ventricle. AAI pacing: Tis is a complete atrioventricular block. BMJ pacemaker similar to the VVI patients who will develop 296 except that it senses and paces 1988; : 94 pacemaker syndrome cannot be 6. Stangl K, Weil J, Seitz K, et al. the atria, thereby maintaining accurately identified at the time of Influence of AV synchrony on the the sequence of atrial and implantation, it may be advisable plasma levels of atrial natriuretic ventricular contraction. to treat all patients with atrial- peptide (ANP) in patients with total AV block. PACE 1988; 11: 1176–81 based pacemakers. VVI pacing 7. Lamas GA, Orav EJ, Stambler BS, et should be used only in patients al. Quality of life and clinical outcomes that the atrial lead is working and with chronic or persistent atrial in elderly patients treated with ventricular pacing as compared to by avoiding atrial non-tracking fibrillation with good chronotropic with dual chamber pacing. Pacemaker modes (DDI or DVI). Avoiding response to exercise, or with Selection in the Elderly Investigators. atrial non-pacing modes, reducing transient bradycardic arrhythmias. N Eng J Med 1998; 338: 1097–1104 the lower pacing rate to encourage 8. Lamas GA, Lee K, Sweeney M, et conduction of underlying rhythm, al. The mode selection trial (MOST) Conflict of interest: none in sinus node dysfunction: design, use of hysterisis (delaying pacing rationale, and baseline characteristics to maximize benefit to patient), References of the first 1000 patients. Am Heart J and withdrawal of any rate limiting 1. Erbel R. Pacemaker syndrome. Am J 2000; 140(4): 541–51 medications affecting sinus node Cardiol 1979; 44: 771–2 9. Noll B, Krappe J, Goke B, Maisch B. are all helpful. 2. Mitsui T, Hori M, Suma K, et al. The Influence of pacing mode and rate on “pacemaking syndrome” [abstract]. peripheral levels of atrial natriuretic In: Jacobs JE, eds. Proceedings peptide (ANP). PACE 1989; 12: of the eighth annual international 1763–68 Conclusion conference on medical and biological 10. Travill CM, Williams TDM, Vardas engineering. Chicago: Association P, et al. Hypotension in pacemaker The MOST trial showed no for the Advancement of Medical syndrome is associated with marked 29 baseline demographic, clinical Instrumentation 1969; : 3 atrial natriuretic peptide (ANP) 3. Witte J, Bondke H, Muller S. release [abstract]. PACE 1989;12: 93 or pacemaker implant variables The pacemaker syndrome: a 11. Liebert HP, O’Donoghue S, Tullner predictive of pacemaker syndrome. haemodynamic complication of WF, et al. Pacemaker syndrome in A high percentage of paced beats ventricular pacing. Cor Vasa 1988; 30: activity responsive VVIR pacing. Am J during follow up was the only 393–99 Cardiol 1989; 64: 124–26 independent predictor. Patients 4. Torresani J, Ebagosti A, Allard-Latour 12. Cunningham TM. Pacemaker noticed significant deterioration G. Pacemaker syndrome with DDD syndrome due to retrograde pacing. PACE 1984; 7: 1148–51 conduction in a DDI pacemaker. Am in their quality of life with the 5. Vardas PE, Travill CM, Williams Heart J 1988; 115: 478–89 syndrome and it improved TDM, et al. Effect of dual chamber 13. Ausubel K, Furman S. The pacemaker significantly afer being upgraded pacing on raised plasma atrial syndrome. Ann Intern Med 1985; 103: to dual-chamber pacing. Because natriuretic peptide concentrations in 420–29 www.gerimed.co.uk July 2011 | Midlife and Beyond | GM .