Background
Heart diseases are the leading cause of death and disability all over the world, especially in the elderly population [1]. Sinus node dysfunction is a common finding in this age group [2]. Sinus bradycardia is more significant in elderly people because it can signify conduction abnormality or any serious cardiac disease which can potentially be treatable and can be life-saving if carried out at a specific time period [3]. Patients usually present with symptoms like dizziness, easy fatigue-ability, and memory impairment [1]. Patients with bradyarrhythmias or sinus node dysfunction without any reversible cause are candidates for permanent pacemaker implantation which can readily improve their symptoms [4].
We present one such case in which permanent pacemaker implantation had significantly improved the patient’s symptoms, especially memory improvement.
Case Presentation
A 71-year-old educated male with no previously established pre-morbids presented at the outpatient Department of Cardiology in our hospital with complaints of dizzy spells, easy fatigue-ability, shortness of breath, and memory impairment for the last 3 months. These symptoms were progressive in nature and were affecting the patient’s life, to the extent that he was functional class I and now he deteriorated to functional class III in just 3 months time. Patient’s attendants gave the history that his memory impairment had worsened to the extent that he cannot recognize his family members and simple directions of his own home and does not remember his own name and name of the months. There was no history of fever or intake of any drugs or medicines. On examining the patient, he had severe memory impairment and he did not remember his name. He could not recognize his family members and place of his presence. He was vitally stable: blood pressure was 125/84 mmHg, pulse rate was 50 bpm, afebrile, oxygen saturation was 98% at room temperature, respiratory rate was 16/minute, JVP was not raised, no lymphadenopathy, and no signs of dehydration or pedal edema. On cardiovascular examination, his pulse was regular, normal volume, but with small occasional pauses. Both heart sounds were audible with no additional heart sound. Chest was bilaterally clear with normal vesicular breathing. Central nervous system examination showed no neurological deficit or signs of Parkinsonism, but mini mental state examination showed severe dementia, with a score of 9/30. On investigation, his complete blood count, liver function tests, renal function tests, serum electrolytes, urine routine examination, and chest x-ray were normal. Electrocardiogram (ECG) showed sinus bradycardia with sinus pauses (Figure 1).
His CT-scan of the brain was also done to rule out any central cause of his symptoms, but that was also normal. His thyroid function tests were also normal. Echocardiography was also normal with 60% ejection fraction. Considering sinus bradycardia and sinus pauses, a 24-hour Holter monitoring was done, which showed multiple sinus pauses with an average of 3.15 seconds (Figure 2).
So, keeping in view the typical presentation and investigations, our final diagnosis was sinus node dysfunction causing sinus pauses and leading to cardiogenic dementia. Depending upon our diagnosis, we managed our patient with the implantation of a permanent pacemaker device (Figure 3). The whole procedure was done safely with good final results and with no complications. The patient’s heart rate was set at 60 bpm and was permanent pacemaker-dependent. The patient was stable and discharged after 1 day post-procedure. After 2 weeks, the patient came for follow-up and he was reassessed and was well oriented with time, place, and person, and his family members told that his memory functioning has improved rapidly and he started doing his all chores by himself again. He was maintaining his vitals with a pulse rate of 60 bpm. His mini mental state examination had improved from 9/30 to 23/30. The patient was advised for follow-up interrogation of pacemaker.
Discussion
Our patient was finally diagnosed as case of sinus node dysfunction, revealing itself as sinus pauses and complicated as progressive memory impairment. He was an old man in his early seventies with no established pre-morbids and presented with dizzy spells and memory impairment. His Holter monitoring showed sinus pauses of 3.15 seconds. To the best of our knowledge, most of the cases published, to date, showed that patients usually present with dizzy spells and shortness of breath. Our patient had a distinct clinical presentation of memory impairment which improved rapidly after pacemaker implantation.
| ONE POINT FOR EACH ANSWER | BEFORE PPM | AFTER PPM |
|---|---|---|
| Orientation | ||
| Year Season Month Date Time | 2/5 | 5/5 |
| Country Town District Hospital Ward/Floor | 2/5 | 5/5 |
| Registration Examiner names three objects (apple, table, and penny) and ask the patient to repeat (1 point for each correct. Then the patient learns three names repeating until correct) | 2/3 | 3/3 |
| Attention and calculation Subtract 7 from 100, then repeat the result. Continue five times: 100, 93, 86, 79, and 65. (Alternative: spell WORLD backwards: DLROW) | 0/5 | 3/5 |
| Recall Ask for the names of three objects learned earlier. | 0/3 | 1/3 |
| Language Name two objects (e.g., pen and watch) Repeat “no, ifs, ands, or buts” Give a three-stage command: score 1 for each stage.(e.g., hold the paper, fold it twice, and then put it on the table) Ask the patient to read and obey a written command on a piece of paper. The written instruction is “close your eyes.” Ask the patient to write a sentence. Score 1 if it is sensible and has a subject and a verb. | 1/2 0/1 1/3 1/1 0/1 | 2/2 0/1 2/3 1/1 1/1 |
Copying Ask the patient to copy a pair of intersecting pentagons  | 0/1 | 0/1 |
| Total | 09/30 | 23/30 |
Ppm = permanent pacemaker.
Heart diseases are the leading cause of significant morbidity and mortality worldwide, especially in the elderly [1]. Sinus node dysfunction and bradycardia are included in these diseases and are prevalent in the elderly population [2]. Increasing age is related to progressive idiopathic fibrosis of sinoatrial node and atrioventricular conduction system, which lead to sinus node dysfunction and bradycardia [5]. Common symptoms of sinus node dysfunction include dizziness, shortness of breath, easy fatigue-ability, and rarely memory impairment [1]. Bradycardia results in symptomatic cerebral hypoperfusion, especially in the elderly people [6]. The regulation of cerebral blood flow is significantly related with heart rate. Studies have shown that severe bradycardia results in the decline of cognitive functioning, especially in older people [7]. Vascular dementia can be described as the decline in thinking skills caused by cardiac conditions that block or reduce cerebral blood flow. Cardiovascular risk factors which cause cerebral hypoperfusion lead to disturbed hemodynamic flow, which ultimately results in ischemic disruption of microstructural integrity of neurons causing vascular dementia [8]. Studies have shown that cerebral autoregulation does not necessarily protect the brain from chronic brain hypoperfusion that is caused by low cardiac output or hypotension. It is especially worrisome in older people because the mechanism of cerebral autoregulation may become impaired with old age [1].
If there is no reversible cause found on investigating the patient for bradycardia, as was the case in our patient, permanent pacemaker implantation is the ultimate answer for patients with symptomatic bradycardia [5]. Indications for permanent pacemaker implantation come under the umbrella of four classes: (l) mandatory, (lla) raisonable, (llb) possible, and (lll) contraindicated [2]. In our case, there was class l indication: sinus node dysfunction with documented symptomatic bradycardia, including frequent sinus pauses that produce symptoms. Implantation of permanent pacemaker is highly cost-effective, safe, and simple to carry out. It can be implanted in all age groups, but it is especially prevalent in older people because of the increase in cardiac conduction abnormalities in this age group [9]. Koide et al. [7] described in their study that cognitive impairment can be reversed by cardiac pacing. It is attributed to the fact that maintaining adequate heart rate can improve cerebral perfusion and hence cognitive functioning [1,6].
Because of the fragility of conditions in elderly people, basic knowledge of bradyarrhythmias and decision of pacemaker implantation are crucial elements for the treating physician [10].
Conclusion
Bradycardia is a common manifestation of cardiovascular diseases with different presentations. These cases should be thoroughly investigated for the cause and should be treated early and accordingly to prevent any further life-threatening complications.
Our patient was having sinus bradycardia complicated by sinus pauses and memory impairment: cardiogenic dementia was successfully treated with permanent pacemaker implantation.