Analysis of a five year experience of permanent pacemaker implantation at a Nigerian Teaching Hospital: need for a national database

Introduction Permanent pacemaker implantation is available in Nigeria. There is however no national registry or framework for pacemaker data collection. A pacemaker database has been developed in our institution and the results are analyzed in this study. Methods The study period was between January 2008 and December 2012. Patient data was extracted from a prospectively maintained database which was designed to include the fields of the European pacemaker patient identification code. Results Of the 51 pacemaker implants done, there were 29 males (56.9%) and 22 females (43.1%). Mean age was 68.2±12.7 years. Clinical indications were syncopal attacks in 25 patients (49%), dizzy spells in 15 patients (29.4%), bradycardia with no symptoms in 10 patients (17.7%) and dyspnoea in 2 patients (3.9%). The ECG diagnosis was complete heart block in 27 patients (53%), second degree heart block in 19 patients (37.2%) and sick sinus syndrome with bradycardia in 5 patients (9.8%). Pacemaker modes used were ventricular pacing in 29 patients (56.9%) and dual chamber pacing in 22 patients (43.1%). Files have been closed in 20 patients (39.2%) and 31 patients (60.8%) are still being followed up with median follow up of 26 months, median of 5 visits and 282 pacemaker checks done. Complications seen during follow up were 3 lead displacements (5.9%), 3 pacemaker infections (5.9%), 2 pacemaker pocket erosions (3.9%), and 1 pacemaker related death (2%). There were 5 non-pacemaker related deaths (9.8%). Conclusion Pacemaker data has been maintained for 5 years. We urge other implanting institutions in Nigeria to maintain similar databases and work towards establishment of a national pacemaker registry.


Introduction
Bradyarrhythmias are a cause of sudden death in Nigeria, though the precise incidence is unknown. Pacemaker implantation is an accepted intervention which has been shown to improve the quality of life and reduce mortality in patients with bradyarrhythmias.
Published experience in Nigeria has shown that implantation rates are low, the main indication for implantation is complete heart block (CHB) and most patients receive ventricular implants [1].
Pacemaker implantation is however not widely available, is difficult for the average Nigerian to access, and when available is often expensive [2]. Few institutions in Nigeria therefore offer pacemaker implantation or follow up services. It is of concern that the few implantations being performed are often not formally documented as there is currently no national framework for pacemaker data collection.
A pacemaker implantation and follow up service was established in our institution in 2008. The aim of this study was to review our experience by analysis of our pacemaker database.

Institutional Settings
Following patient referral the clinical indication for pacemaker therapy is established from the history and the diagnosis confirmed with a 12 lead ECG (and 24 hour holter if necessary). Cardiac function is assessed with a transthoracic echocardiogram.
Pacemaker implantation is performed in a dedicated theatre suite equipped with a fluoroscopic C arm. The implantation team is composed of a surgeon who performs the implantation, a cardiac physiologist who performs the checks of pacemaker parameters, a pacemaker technician to operate the fluoroscope for imaging and a scrub nurse. Monitored parameters are the heart rhythm, heart rate, non-invasive blood pressure and peripheral oxygen saturation. A standard subclavian approach is used after infiltration with local anaesthesia in all cases. Prior to lead fixation the R wave (P wave if atrial lead) and pacing threshold are checked. Target values are R wave greater than 6 millivolts (mV), P wave greater than 2 mV, lead impedance less than 1200 Ohms and pacing threshold less than 1 volt (V). Diaphragmatic pacing is checked at 10V. The pacemaker pocket is irrigated with 1g of ceftriaxone, the pacemaker lead connected to the pulse generator and the wound closed in layers.
An arm sling is used in all cases to restrict movement of the arm on the operation side (to reduce the risk of lead displacement) and the patient is transferred to the ward.
Patients are monitored on the ward for 48 hours to exclude lead displacement. After 48 hours a pacemaker check is done and the patient is given a copy of both the pacemaker implantation report ( Figure 1) and pacemaker check report (Figure 2) prior to discharge. Patients are counseled to maintain the arm sling for a week and return for pacemaker checks. Pacemaker check sequence is 6 weeks, 3 months, and then every 4 months for a year. After a year the checks are done every 6 months. Pacemaker checks are performed mainly by the cardiac physiologists and complications reported to the surgeon. A pacemaker check report is generated after each visit, and a copy is given to the patient and a copy kept on file. Contact details of all patients are maintained on the database so that contact can be made if any appointment is missed.

Patient Data
A Microsoft Access database was designed and has been maintained prospectively since the inception of the programme in January 2008.
Data storage covers the fields recommended by the European pacemaker patient identification codes [3]. Sample snapshots from the database are shown in

Results
Of the 51 patients implanted there were 29 males (56.9%) and 22 females (43.1%). Ages ranged from 22-92 years with a mean age of 68.2±12.7 years. Age distribution is as shown in Figure 5.

Discussion
There are currently 10 centres in Nigeria known to implant pacemakers. There are 3 centres in Lagos and 1 each in Enugu, Ibadan, Abuja, Port Harcourt, Calabar, Ife and Ilorin (personal data). To date a centre in Lagos [1] and the centre in Enugu [4] have published their experience. In the experience of Thomas [5].
The mean age in our series was 68 years with 56.9% being male and 43.1% female. This is within the mean age range of 65 to 75 years reported in the 11 th World survey of cardiac pacing and implantable cardioverter-defibrillators [6]. Additionally the 11 th world survey showed that there are slightly more males receiving implants than females (about 55% male, 45 % females) which is similar to our experience. The use of dual chamber pacing in 43.1% of patients in our series is considerably higher than reported in other West African series and reflects the worldwide trend of increased use of dual chamber pacing seen in the 11 th th World survey. Similar to the findings of other West African series, most patients in our environment are diagnosed with CHB and about 50% present having had syncopal attacks. This is unlike the pattern in the Western World where 30% or less of patient present with CHB and Sinus Node Dysfunction (SND) is the predominant indication for cardiac pacing [6].
Maintaining a stock of pacemakers locally makes it easier to proceed directly to permanent pacemaker implantation. In this series of 51 patients, only one temporary pacemaker was implanted. This is unlike the earlier experience from Lagos [1] where 6 patients required temporary pacing as a bridge to permanent pacemaker implantation due to delays in procuring the pacemaker. At the period of that publication pacemaker implantation services were still being developed. In the ensuing 5 years since that publication some progress has been made and some pacemaker manufacturers now have local representation in Nigeria, enabling purchase of pacemakers locally as opposed to waiting weeks for importation. It has been recommended that it is unnecessary to implant a temporary pacemaker if there is immediate access to a permanent pacemaker [7] and this is our current practice.
In our practice there has been a progressive decrease in the use of single chamber ventricular pacing and an increase in dual chamber pacing over the last 5 years of our experience. In the 1990s initial recommendations urged more use of dual chamber pacing as it was thought that the hemodynamic benefits of AV synchrony would translate into improved longevity, improved quality of life and reduction in strokes [8]. The first randomized controlled trial by with no report of pacemaker syndrome [1] which is similar to the experience from Senegal where 87% of patients had ventricular implants and only 1 pacemaker syndrome was reported [4]. The increased use of ventricular pacing in West Africa is driven largely by cost as cardiac pacing is not covered by insurance and is largely self funded [2]. Since ventricular pacing appears to be well tolerated and is cheaper, should this be the preferred option for our patients?
Complication rates seen in this study are comparable to other West African series. The major complications of pacemaker pocket infection in 3 patients (5.9%) and lead displacement in 3 patients (5.9%) compares favorably with the experience from Senegal where Page number not for citation purposes 5 the pacemaker infection rate was 5.4% of patients [5]. This is however higher than the 1.5% pacemaker infection rate in a series of 1,286 implants in the UK reported recently [7]. Of note is the fact that every patient implanted in our series is followed up closely, enabling complications to be promptly addressed (table 2) We noted that all the pacemaker infections occurred in dual chamber implants. It has been shown that there can be a higher complication rate with dual chamber implants [13]. We will monitor this closely as if this trend persists it could be a further deterrent to using dual chamber implants as it puts more of a financial burden on the patient and relations who would need to raise further funds for a second implant .
We have considered the re-use of pacemakers as there is some evidence that it is safe and could reduce costs for patients [16].
Average implantation rates in our series was 10 implants per year, whereas in the Senegal experience the implant rate was as high as 30 implants a year, due to the high use of donated recycled pacemakers [5]. This may be an option worth considering unless pacemaker manufacturers can substantially reduce the cost of pacemakers in Nigeria to make this life saving intervention more accessible.
Only 1 pacemaker related death occurred in this series. This occurred in an elderly patient who received a Pacetronix implant (VVI) with a tined, non-steroid eluting endocardial lead. Over a period of 2 years there was a gradual rise in pacing threshold from implantation level of 0.8V to 2.5V. Pacing amplitude had been increased to 5V and the patient advised on a change of implant. She however declined and died suddenly, presumably from sudden failure to capture. This singular experience informed our current practice where we no longer use Pacetronix implants and all pacemaker leads used are steroid eluting and active fixation.
Of the 5 non-pacemaker related deaths, 4 were reported as being secondary to myocardial infarctions. Diagnosis of myocardial infarction was made by cardiac enzymes and electrocardiogram changes in 1 patient, and purely from ECG changes in the other 3 patients. The incidence of Ischaemic heart disease (IHD) is known to be on the increase in Nigeria [17] so the co-existence of IHD and bradycardia needs to be considered in elderly patients presenting for pacemaker therapy.
There is great variability in implantation rates between different countries as shown in the 11th World survey of cardiac pacing and implantable cardioverter-defibrillators [6]. In the midst of this great variability in the number of pacing centres and implants done per country, it is of great concern that Nigeria was not included in this survey. This stresses the urgency in establishment of a framework for a national registry so that the efforts of various implanting institutions in Nigeria can be captured.

Conclusion
A pacemaker implantation and follow up service has been established in our institution and a robust database has been developed and maintained. Early results show that the main indications for implantation are complete heart block and second degree heart block. Use of dual chamber pacing is higher than has been reported from other West African Centres. Continued patient follow up may be able to address questions of pacemaker therapy unique to our environment. Complications rates have been low.
Complete follow up information is available for 49 patients (96%).
We urge other implanting institutions in Nigeria to maintain similar databases and work towards establishment of a national pacemaker registry.

Competing interests
The authors declare that they have no competing interests.