TABLE 6.

The top 22 keywords in co-occurrence frequency of sick sinus syndrome.

Rank	Keyword	Co-occurrence	TLS
1	Sick sinus syndrome	538	2701
2	Atrial fibrillation	340	1976
3	Sinus node dysfunction	334	1695
4	Pacemaker	327	1870
5	Atrial-fibrillation	258	1544
6	Heart-failure	216	1379
7	Sick-sinus syndrome	164	1080
8	Bradycardia	164	1026
9	Arrhythmias	154	842
10	Sinoatrial node	153	791
11	Arrhythmia	148	806
12	Dysfunction	139	767
13	Trial	138	909
14	Disease	137	736
15	Fibrillation	135	795
16	Dual-chamber	130	911
17	Heart failure	129	921
18	Heart	115	527
19	Follow-up	113	693
20	Therapy	110	645
21	Sinoatrial pacemaker cells	82	665
22	Aging	39	306

TLS, total link strength.