Electrocardiographic findings in pulmonary embolism

Pulmonary embolism (PE) poses a challenge to physicians, as it can be difficult to diagnose but results in significant mortality and morbidity in patients. Diagnosing PE requires an integrated approach using clinical findings, electrocardiography (ECG), blood investigations and imaging modalities. Abnormalities in ECG are common among patients with massive acute PE and can serve as a prognostic indicator. In this article, we describe the ECG presentations of two patients diagnosed with PE, and review the literature on the various types of ECG presentations and their role in predicting the prognosis of PE.

Long-term Outcomes of Medical Therapy Versus Coronary Revascularisation in Patients with Intermediate Stenoses Guided by Pressure Wire

<p><b>INTRODUCTION</b>This study aimed to examine the long-term clinical outcomes of coronary fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) in a real-world population in an Asian tertiary centre.</p><p><b>MATERIALS AND METHODS</b>All patients who underwent FFR measurement for intermediate coronary lesions in our centre from June 2002 to December 2009 were enrolled. A threshold of FFR ≤0.75 was used for revascularisation. All the patients were prospectively followed-up for major adverse cardiac events (MACE) of death, myocardial infarction (MI), target vessel revascularisation (TVR) and stent thrombosis.</p><p><b>RESULTS</b>Based on FFR measurement, 368 (57%) patients were treated medically while 278 (43%) underwent revascularisation. At a mean follow-up duration of 29.7 ± 16 months, 53 (14.4%) patients in the medical therapy group and 32 (11.5%) patients in the revascularised group experienced MACE (P = 0.282). There were no statistical differences in all the clinical endpoints between the 2 groups.</p><p><b>CONCLUSION</b>Medical therapy based on FFR measurement is associated with low incidences of MACE at long-term follow-up.</p>

Electrocardiography series. Narrow QRS-complex tachycardia: part 2

We discuss two cases of incessant atrial tachycardia (AT), including the presentation and clinical course. It is important to differentiate AT from other causes of supraventricular tachycardia, such as atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT), as it would have implications on clinical management. Electrocardiographic features of AT, especially the presence of an AV Wenckebach phenomenon with 'grouped beating', are critical for differentiating AT from AVRT and AVNRT. It is also vital to identify the P waves and their relations to QRS on electrocardiography, as this would aid in the differentiation of various supraventricular tachycardias.

Importance of QT interval in clinical practice

Long QT interval is an important finding that is often missed by electrocardiogram interpreters. Long QT syndrome (inherited and acquired) is a potentially lethal cardiac channelopathy that is frequently mistaken for epilepsy. We present a case of long QT syndrome with multiple cardiac arrests presenting as syncope and seizures. The long QTc interval was aggravated by hypomagnesaemia and drugs, including clarithromycin and levofloxacin. Multiple drugs can cause prolongation of the QT interval, and all physicians should bear this in mind when prescribing these drugs.

Diabetes mellitus and heart disease

Diabetes mellitus is responsible for diverse cardiovascular complications such as accelerated atherosclerosis, increased plaque burden and diffuse coronary lesions. It is also a major risk factor for myocardial infarction, stroke and peripheral vascular disease. Here, we present two cases. The first patient had subtle changes in the ECGs, with severe coronary artery disease requiring coronary artery bypass grafting, while the second had deep T wave inversion in the ECG and was found to have normal coronary arteries and nonischaemic cardiomyopathy. Although ECG failed to show the severity of the disease, it is invaluable as a simple, noninvasive test to aid in diagnosis. Our two cases stress the importance of a high index of suspicion and the low threshold for investigations in the diabetic population.

ECG P wave abnormalities

P wave abnormalities are commonly found on ECG. However, they are seldom discussed and may also be neglected during ECG interpretion. In this article, we discuss two common types of P wave abnormalities, 'P mitrale' and 'P pulmonale'. The former was found in a patient with mitral valve stenosis, while the latter was from a patient with pulmonary hypertension. Echocardiography is important in evaluating the causes of P wave abnormalities.

Electrocardiography series. Electrocardiographic T wave abnormalities

The causes of abnormal T waves on electrocardiography are multiple and varied. Careful clinical history taking and physical examination are necessary for accurate identification of the cause of such abnormalities. Subsequent targeted specialised cardiac investigations, such as echocardiography or coronary angiography, may be of importance in the diagnosis of the underlying cardiac pathology. We present two cases of T wave inversions with markedly different aetiologies.

ECGs with small QRS voltages

The causes of low voltage complexes on the electrocardiogram (ECG) are variable; however, they are not commonly discussed. An ECG with small QRS amplitudes may initially look unremarkable to the unwary, but some of the underlying conditions may be critical. Although imperfect, the ECG is still a useful, noninvasive and readily available tool for the screening of these underlying conditions. We present two cases with low voltage complexes in the ECG. The first case highlights how the findings on ECG and subsequent echocardiogram led to the diagnosis of a rare case of cardiac amyloidosis. In the second case, a screening electrocardiogram alerted the physicians to a life-threatening condition, that of a large pericardial effusion with cardiac tamponade.

Electrocardiography series. Non-ischaemic causes of ST segment elevation

ST segment elevation is one of the most important electrocardiographic features that need to be recognised. Although ST segment elevation myocardial infarction is one of the main causes of this abnormality, there are other non-ischaemic causes that are also important. We discuss reversible apical ballooning syndrome or Takotsubo cardiomyopathy, pericarditis and a case of ST segment elevation due to 'early repolarisation pattern'.

Reperfusion strategy and mortality in ST-elevation myocardial infarction among patients with and without impaired renal function

<p><b>INTRODUCTION</b>Several randomised controlled trials have demonstrated better outcomes with primary percutaneous coronary intervention (PCI) over fibrinolytic therapy in the treatment of patients with ST-segment elevation myocardial infarction (STEMI) and normal renal function. Whether this benefit extends to patients with impaired renal function is uncertain.</p><p><b>MATERIALS AND METHODS</b>We studied 1672 patients with STEMI within 12 hours of symptom onset who were admitted to 2 major public hospitals in Singapore from 2000 to 2002. All patients received either upfront fibrinolytic or PCI as determined by the attending cardiologist. Serum creatinine was measured on admission and the glomerular filtration rate (GFR) was determined using the Modification of Diet in Renal Disease equation. The impact of reperfusion strategy on 30-ay mortality was then determined for patients with GFR > or =60 mL min-(1) 1.73 m-(2) and GFR <60 mL min-(1) 1.73 m-(2).</p><p><b>RESULTS</b>The mean age was 56 +/- 12 years (85% male) and mean GFR was 81 +/- 30 mL min-(1) 1.73 m-(2). Unadjusted 30-day mortality rates for fibrinolytic-treated vs primary PCI-treated patients were 29.4% vs 17.9%, P <0.05, in the impaired renal function group and 5.4% vs 3.1%, P <0.05, in the normal renal function group. After adjusting for covariates, primary PCI was associated with a significantly lower mortality in the normal renal function group [odds ratio (OR), 0.41; 95% confidence interval (CI), 0.19-0.89] but not in the impaired renal function group [OR, 0.70; 95% CI, 0.31-1.60].</p><p><b>CONCLUSIONS</b>Primary PCI was associated with improved 30-day survival among patients with normal renal function but not among those with impaired renal function. Randomised trials are needed to study the relative efficacy of both reperfusion strategies in patients with impaired renal function.</p>