Tachyarrhythmia management

A 62 year old man visits his GP. He suffers from palpitation (feeling of rapid heart beat), head pressure, dizziness and shortness of breath. He also feels weak and incapable. Patient describes that there is "one engine working". His medical history is significant for hypertension, diabetes, MI and ischemic heart disease with decreased ejection fraction of left ventricle 35 %. What are you going to do with him next?
62
years
man
RR
17 /min
HR
147 /min
SpO2
90 %
BP
110/60 (77) mmHg
Examination
Medical history: diabetes mellitus type II- oral antidiabetics and diet, hypertension, stp. recent myocardial infarction, with residual hypokynesis of heart documented by transthoracic echocardiography, asthma bronchiale;

Medication: Siofor 500mg 1-0-1, Anopyrin 100mg 1-0-0, Sortis 40mg 0-0-1, Betaloc ZOK 50mg 1-0-0, Tritace 2,5mg 1-0-0, Berodual 2 inh. 1-0-0, Ventolin 2 inh. when needed
Glycaemia
Gly
5,3  mmol/L
Complete blood count
HGB
147  g/L
ERC
4,2  x1012/L
LEU
6,5  x109/L
PLT
278  x109/L
Glycaemia
Take a sample
Complete blood count
Take a sample