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eLetters: Electronic letters published:
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Re: The Role of the Electrocardiogram in the Chest-Pain Clinic
- M Justin S Zaman (14 October 2008)
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The Role of the Electrocardiogram in the Chest-Pain Clinic
- John A. M. Morphet (14 October 2008)
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M Justin S Zaman
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j.zaman{at}ucl.ac.uk M Justin S Zaman
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We appreciate the comments of Dr Morphet, though would like to again reiterate that our study took place in a chest pain clinic investigating chronic stable angina rather than acute coronary syndromes. In these patients, the resting ECG is usually normal, and most of the work Dr Morphet cites comes from patients presenting with acute myocardial infarction. It should also be noted that Bangladeshi patients present with non- classic features of acute myocardial infarction and were treated less aggressively in a study in east London, UK. [K Barakat et al, Heart. 2003 Mar ;89 (3):276-9 12591830]The slower triage in the casualty department and delay in essential treatment is thus of importance. Conflict of Interest:None declared |
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John A. M. Morphet McMaster University
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gjmorphet{at}sympatico.ca John A. M. Morphet
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Just as patients with chest discomfort due to Angina Pectoris are frozen in countenance and habitus, they are often also frozen in verbalization, necessitating history-taking from the spouse and immediate family. The United Kingdom (1) and American (2) investigators have not concerned themselves with baseline Electrocardiography (ECG) but from a Canadian perspective this observer has always relied on same for help diagnostically, prognostically and therapeutically. The entire “ischemic burden” can be addressed in selected patients with linguistic impediments by way of an 18 lead ECG, targeting all cardiac projections, and which also has at least a passive role in the differentiation of cardiac, from non-cardiogenic pain (3).
Infra are four ECG scenarios, other than ST-T shifts, which will be of practical utility in all specialized chest-pain clinics.
Diagnostically, terminal negative “u” wave deflections (Fig.1), in the absence of Hypertension, connote the presence of myocardial ischemia due to coronary atherosclerotic occlusive or vasospastic disease (4).
Further, denoting eligibility for reperfusion therapy, is the recognition of early tall symmetric T-waves, without ST segment elevation (5), evolving transmural Q-wave or fractured QRS (5) injury in the first few days after infarction (Fig. 2).
Prognostically, as it is associated with triple-vessel disease, “Tombstoning” (Fig. 3) is attended by a high mortality rate (19.6% in the first 30 days) and a high rate of complications i.e, cardiogenic shock, ventricular arrhythmia and complete heart block (7).
Finally, the employ of an 18 lead ECG (standard 12 plus right heart V456R and true posterior V789) provides a fuller description of the extent of myocardial injury (thrombolytic candidacy) and the identification of the infarct-related-vessel (3). From a practical vantage-point these auxiliary leads are beneficial in signaling the potential for myocardial rupture (8) and, for example, in the case of the posterior leads (Fig. 4) incriminating the left circumflex in the pathogenesis of mitral regurgitation and congestive heart failure (9).
One last point: although the ECG is not a direct anatomic imaging technique, in the absence of a trustworthy patient history, it remains the centre of the decision pathway. I am sure Pardee (1920) (10) would more that agree.
John Morphet MD, FRCP©, FACC, FESC REFERENCES 1. Zaman MJ, Junghans C, Sekhri N, et al. Presentation of stable angina pectoris among women and South Asian people. CMAJ 2008;179:659-667. FIGURES
Conflict of Interest:None declared |
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