Abstract
Diagnosis of myocardial infarction or acute coronary syndrome is difficult, especially in atypical presentation at an emergency department, and sometimes results in serious legal issues. Symptoms of atypical presentation include shortness of breath, dyspnoea on exertion, toothache, abdominal pain, back pain and throat pain. As of now, reports of a headache, especially exertional headache, as the only presentation of acute cardiac ischaemia are rare and only have case reports. We present two patients with a cardiac source of headache and analyse 32 patients with similar situations from MEDLINE search from 1966 to the present. Cardiac cephalalgia is benign in general, but potential risks for death should be considered. If the patient has increased risk of atherosclerosis with exertional headache, anginal headache should be highly suspected and further work-up should be undertaken.
Keywords
Introduction
We present two cases of cardiac headache and analyse 32 cases from MEDLINE or internet resources that presented a headache as one of the myocardial symptoms. Cardiac origin of a headache is extremely rare and has only case reports. Potential risk of mortality exists.
Case report 1
A 36-year-old man visited the Emergency Department (ED) due to an intolerable and refractory headache. Before this attack, he had suffered from headache with increasing frequency and intensity for 3 weeks. During this time, he visited the neurologist frequently, but had no relief. The site of the headache was around the vertex and extended to the bilateral occipital region. He had experienced cerebral infarction of an unknown nature several months prior to this attack. He reported the onset of a new headache 3 weeks prior to visiting the ED, so it was treated as a post-infarction headache, but without success. He was referred to a cardiologist with the possibility of a ‘heart-related headache’. A general survey of ECG and chest X-ray (CXR) revealed no positive findings, so he was reassured. The headache was dull, with rapid progression at the ED, so pethidine hydrochloride was injected intramuscularly due to intolerable and increasing pain. After the injection, ventricular fibrillation with cardiac arrest was noted in < 1 min. Defibrillation and cardiopulmonary resuscitation were done immediately. Post-resuscitation electrocardiogram revealed a significant ST segment elevation at the precordial leads from V2 to V6 (Figs 1, 2). CxR showed pulmonary oedema and the coronary angiogram showed 90% stenosis at the proximal left descending artery. A bare metal stent was deployed to the infarct-related culprit lesion. After the percutaneous coronary interventional procedure and a week's hospitalization, the headache had still not recurred at follow-up.
Electrocardiographic strip during collapse and loss of consciousness at the emergency department. Ventricular flutter was recorded during attack and soon progressed to ventricular fibrillation. After defibrillation, transient idioventricular rhythm was noted.
After the defibrillation and cardiopulmonary resuscitation, arterial pulsation and blood pressure were restored. The post-resuscitation electrocardiogram reveals sinus rhythm and ST segment elevation in the left anterior descending artery (LAD) territory with reciprocal change.
Case report 2
An 85-year-old female was referred because of typical effort angina pectoris. There was no cold sweating. Repeated significant right eyeball pain was associated with most chest pain attacks. The chest pain and right eyeball pain were relieved soon by rest or sublingual nitroglycerine use from local general practising doctors. Physical examination revealed no significant positive finding except mild atypical systolic murmur at the left ventricular apex. There was no history of diabetes, hyperlipidaemia or smoking. Due to significant regional perfusion defect from the thallium perfusion study, a coronary angiogram with left ventriculogram was arranged after failed medical therapy. The coronary vessels were patent and the left ventriculogram revealed apical hypertrophy. After modification of medication, the symptoms improved.
Discussion
1. Mechanisms and pathways of cardiac cephalalgia
Only case reports of cardiac cephalalgia are available from the current medical resources. In a study of 150 consecutive ambulatory patients with angina pectoris (1), 6% had a documented history of headache and no one presented a headache as the sole presentation of cardiac pain. The mechanisms of cardiac cephalalgia are unclear and not yet identified (1–4). New criteria of cardiac cephalalgia were released by the International Headache Society in 2003 (5). It states: ‘A. Headache, which may be severe, aggravated by exertion and accompanied by nausea and fulfilled criteria by C and D, B. Acute myocardial ischemia has occurred, C. Headache developed concomitantly with acute myocardial ischemia, D. Headache resolves and does not recur after effective medical therapy for myocardial ischemia or coronary revascularization’.
Proposed mechanisms of cardiac headache may be related to a variation of neural convergence (1–4). Cardiac pain requires sympathetic or parasympathetic afferent fibres for transportation of pain signals. Somatic and sympathetic impulses converge in the posterior horn of the spinal cord, mixing neural supply to cervical area and cranial vessels. These meet the refer pain of the somatic structures of the neck, face and eyes. The vague has variable synaptic inputs to the descending sensory nucleus (pars caudalis) of the trigeminal nerve. Thus, convergence could occur at this level with referred pain to any trigeminal nerve distributed territory.
Other possible mechanisms of cardiac headache include transient increases of intracardiac pressure that cause intracranial pressure elevation and severe headache. Transient intracardiac pressure elevation includes any changes that are caused by systolic dysfunction, reduction of cardiac output and an increase in right atrial pressure occurring in myocardial ischaemia and functioning ventricular mode pacemaker. The functioning ventricular pacemaker could also produce the headache, which could be relieved by conversion of pacing system from VVI mode to the atrioventricular sequential pacing system (6).
2. Pooled data analysis
We searched the medical literature for cardiac headaches from 1978 to 2007 (5–39) (Table 1). The keywords of ‘anginal headache, cardiac cephalalgia, myocardial infarction, or cardiac headache’ were used in English language literature. Including our patients in this article, 32 patients who presented acute headache as the initial presentation of cardiac ischaemia have been analysed. We analysed the incomplete data from those sources and made a pooled data analysis.
Cardiac headache: cases reported in English publications
In site column: BT, bitemporal regions of head; F, frontal; V, vertex; HC, hemicranial; O, occipital. In angiography column: SVD, single vessel disease; DVD, double vessel disease; TVD, triple vessel disease. In treatment column: PCI, percutaneous coronary intervention; CABG, coronary artery bypass surgery. In risk factors column: A, age; L, lipidaemia; H, hypertension; S, smoking; O, obesity; ND, not done; NR, not recorded; VF, ventricular fibrillation; AMI, acute myocardial infarction; NSTEMI, non-ST-segment elevation myocardial infarction; STEMI, ST-segment elevation myocardial infarction; RCA, right coronary artery; LAD, left anterior descending artery; LCxA, left circumflex artery; OM, obtuse marginal branch of left circumflex artery.
The data reveal that the mean age of the patients included in our study was 62.5 ± 12.7 years; 20 (68.7%) patients were male; in risk factors, most (84.3%) patients were elderly. Seventeen (53.1%) patients' symptoms were exertional. There were 18 (60%) patients whose headaches were revealed as the sole presentation of myocardial ischaemia. Anti-anginal, mostly nitrate-like, agents will release headache in 18 (56.3%) patients. In clinical cardiovascular events, three (9.4%) patients presented with ventricular fibrillation, 15 (46.9%) had myocardial infarction and 11 (34.4%) suffered from some degree of angina. In general, mortality rates of cardiac cephalalgia were 12.5% (four of 32 patients). All symptoms of headaches disappeared after revascularization or conservative treatment. Out of four deceased patients, two received medical therapy. There were no treatment strategies for the other two deceased patients from the available records.
Conclusion
The possibilities of failed diagnosis of acute cardiac ischaemia at EDs are increased by atypical presentation or membership of a special subgroup that includes non-Whites, elderly men, and normal electrocardiographic findings (40–42). So far, acute headache as the initial presentation of myocardial ischaemia is extremely rare. Therefore, we do not recommend myocardial ischaemia as the initial differential diagnosis for acute headache. If the patient has symptoms of unexplained typical exertional headache with increased risk factors of atherosclerosis, angina headache should be considered a potential diagnosis and the cardiovascular specialist should be called in for further consultation.