Table 1. Brief description of included articles.
AF - atrial fibrillation; CAD - coronary artery disease; CRF - chronic renal failure; CVA - cerebrovascular accidents; DM - diabetes mellitus; ESRD - end-stage renal disease; F - female; HTN - hypertension; IHD - ischemic heart disease; M - male, PCI - percutaneous coronary intervention; RBBB - right bundle branch block; TIA - transient ischemic attack; TKR - total knee replacement; TTP - thrombotic thrombocytopenic purpura
| No. | Authors (year) [Reference] | N (sex/age in years) | Atypical symptoms | Comorbidities |
| 1 | Madias et al. (2002) [12] | Two (M/75, M/62) | Fatigue and lightheadedness, intermittent epigastric discomfort without nausea or vomiting | HTN, RBBB, DM, ESRD, hyperlipemia |
| 2 | Timurkaynak et al. (2002) [13] | One (F/28) | Severe, sudden onset of localized back pain and tachypnoea | Smoking, oral contraceptive use, thyrotoxicosis |
| 3 | Wittlesey (2002) [14] | One (M/54) | Pleuritic chest pain, worsening with movement and deep breathing, weakness, and fatigue | DM, HTN, Reiter's syndrome |
| 4 | Dwyer (2003) [15] | One (F/64) | Mid-back pain, dizziness, persistent cough | Chronic renal infection, RBBB, atrial premature contractions |
| 5 | Ivanović et al. (2005) [16] | One (M/44) | Atypical chest pain during exercise | None |
| 6 | Zeina et al. (2006) [17] | One (M/23) | Intermittent left-sided atypical chest pain | Hyperlipidemia |
| 7 | Wei et al. (2008) [18] | Two (M/36, F/85) | Intolerable and refractory headache, eyeball pain, atypical chest pain | CVA |
| 8 | Lin et al. (2009) [19] | One (M/83) | Severe and diffuse bone pain | DM |
| 9 | Siau K. (2009) [20] | One (M/61) | Pain along the medial aspect of his left thigh | Recurrent reflux oesophagitis |
| 10 | Kohli et al. (2010) [21] | One (F/66) | Sudden onset of slurred speech preceded by dizziness and vomiting | None |
| 11 | Amirhaeri et al. (2010) [22] | One (F/53) | Earache and sore throat | Smoker, dyslipidemia, DM, post-PCI |
| 12 | Davenport et al. (2012) [23] | One (M/68) | Intractable hiccups causing insomnia | DM, HTN, tobacco use |
| 13 | Her et al. (2012) [24] | One (F/54) | Atypical chest pain | Papillary fibroelastoma of the aortic valve |
| 14 | Holm et al. (2012) [25] | One (M/48) | Leg pain due to arterial occlusion | Smoking |
| 15 | Khoroshikh (2013) [26] | One (M/57) | Atypical hand pain, shortness of breath while walking | HTN, hypercholesterolemia, smoking |
| 16 | Abdalla et al. (2014) [27] | One (M/65) | Progressive dyspnoea, presyncope | Morbid obesity, post gastric bypass, depression, alcohol dependence |
| 17 | Basic-Jukic et al. (2014) [28] | One (M/55) | Otalgia on post-op renal transplant day three | DM, coronary stent, post-renal transplant |
| 18 | Dundar et al. (2014) [29] | One (F/87) | Otalgia with sweating on head and neck | DM |
| 19 | Petrović et al. (2014) [30] | One (M/63) | TIA without chest pain, sinus tachycardia | HTN, smoking |
| 20 | Parekh et al. (2014) [31] | One (M/55) | Unexplained lethargy and anxiety | CAD, post-stent, and on dual antiplatelet |
| 21 | Wang et al. (2014) [32] | One (M/79) | Abdominal pain and fever | Gastric villous adenoma, TTP |
| 22 | Ajayi et al. (2015) [33] | One (M/58) | Shortness of breathing, aphasia, with hypoxia | Prostate cancer, HTN, hyperlipidemia, peripheral vascular disease, alcoholism, and past-smoker |
| 23 | Taylor (2015) [34] | One (M/44) | Recurrent short-duration atypical chest pain with no radiation and no associated symptoms | Smoking |
| 24 | Bharvin et al. (2016) [35] | One (M/34) | Abdominal discomfort, pain, vomiting, and mild breathlessness | Alcohol use |
| 25 | Chaturvedi et al. (2016) [36] | One (M/77) | Syncope | HTN, DM |
| 26 | Ebrahem et al. (2016) [37] | One (F/39) | Syncopal episodes | Post splenectomy |
| 27 | Castillo et al. (2016) [38] | One (F/61) | Right sides arm and scalp numbness | None |
| 28 | Ahmed et al. (2017) [39] | One (M/43) | Right otalgia associated with mild dyspnoea and fatigability | DM, dyslipidemia, heavy smoker, family history of HTN and, IHD |
| 29 | Anzai et al. (2017) [40] | Three (F/72, M/84, F/89) | Pharyngeal pain/sore throat | Patient 1 - none; patient 2 - CRF, TIA, DM, aortic aneurysm; patient 3 - unstable angina |
| 30 | Zhang et al. (2017) [4] | One (M/51) | Intractable hiccups and fever without chest pain | HTN, DM, asthma, and gastritis, marijuana addiction |
| 31 | Kyaw et al. (2018) [41] | One (F/74) | Isolated throat pain and Wellens' pattern in the initial EGG | DM, HTN, dyslipidemia, hypothyroidism |
| 32 | Ugalde et al. (2018) [42] | One (M/47) | Bilateral otalgia | HTN and CAD |
| 33 | Bouthillet et al. (2019) [43] | One (F/75) | Tiredness, nausea, dizziness | HTN, DM, hyperlipidemia, and obesity |
| 34 | Broughton et al. (2019) [44] | One (M/59) | Bout of hiccups during hospital admission for septic arthritis | DM |
| 35 | Gao et al. (2019) [45] | One (M/46) | Recurrent abdominal pain, constipation, persistent hiccups | Smoker, CVA, cholecystitis |
| 36 | Ghazzay et al. (2019) [46] | One (M/55) | Diarrhea, mild lower abdominal pain, and nausea | DM, dyslipidemia, smoking |
| 37 | Mehmood et al. (2019) [47] | One (F/25) | Atypical chest pain relieved by deep sternal massage, anxiety | DM |
| 38 | Rigueira et al. (2019) [48] | One (F/66) | Atypical chest pain, nausea, and hypersudorese, followed by syncope | Rheumatoid arthritis, HTN, and dyslipidemia |
| 39 | Zakaria et al. (2019) [49] | One (F/31) | Epigastric pain, belatedness, and nausea | Post-COVID-19 |
| 40 | Alahmad et al. (2020) [50] | One (M/35) | Palpitation with De Winter ECG pattern | Palpitation, AF |
| 41 | Harikrishnan et al. (2020) [51] | One (M/65) | Fever, cough, shortness of breath | COVID-19 |
| 42 | Mandal s et al. (2020) [52] | One (F/36) | Back pain in the thoracic region | Polycystic ovarian syndrome |
| 43 | Pickard et al. (2020) [53] | One (M/56) | Shortness of breath in the recovery ward after TKR | Follow-up case of TKR |
| 44 | Faridi et al. (2021) [54] | One (M/39) | Pain abdomen, palpitation, episodic headache, and shortness of breath | Pheochromocytoma with secondary cardiomyopathy |
| 45 | Hovey et al. (2021) [5] | One (M/62) | Persistent hiccups | HTN, DM, CVA |
| 46 | Khan et al. (2021) [7] | One (48/F) | Atypical chest pain | None |
| 47 | Mayfield et al. (2021) [55] | One (63/F) | Left shoulder pain, tender to touch | Smoking |
| 48 | Santana et al. (2021) [56] | One (M/36) | Agitation, auditory hallucination | None |
| 49 | Atere et al. (2022) [57] | One (M/58) | Abdominal pain | Myeloproliferative neoplasm |
| 50 | Benjanuwattra et al. (2022) [58] | One (M/53) | Haemoptysis | HTN, dyslipidemia |
| 51 | Cheema et al. (2022) [59] | One (M/28) | Retrosternal atypical chest pain | Marfan syndrome, post aortic root and arch replacement |
| 52 | Kirchner (2022) [60] | One (F/47) | Stressed, jaw pain | None |