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.

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: Medical therapy based on FFR measurement is associated with low incidences of MACE at long-term follow-up.

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.

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.

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.

A single-center experience of transitioning from a routine transfemoral to a transradial intervention approach in ST-elevation myocardial infarction: Impact on door-to-balloon time and clinical outcomes.

BACKGROUND: In the emergent setting of ST-elevation myocardial infarction (STEMI), transradial intervention (TRI) is less frequently employed than transfemoral intervention (TFI). Because of the greater technical complexity of TRI, a potential compromise in door-to-balloon (DTB) time remains a major concern of centers adopting TRI for STEMI. METHODS: We performed a propensity-matched analysis, with 1:1 matching of TRI and TFI patients comparing DTB time, 30-day major adverse cardiac event (MACE), and bleeding outcomes of 1052 consecutive STEMI patients managed at our center during a 2-year transition program from routine TFI to TRI access for STEMI. RESULTS: From January 2008 to April 2010, 359 (34.1%) STEMI patients underwent TRI and the remaining 693 (65.9%) STEMI patients underwent TFI. In 283 propensity score matched pairs of TRI and TFI patients, TRI was associated with shorter DTB time (63.6min vs 69.4min, p=0.027) and more patients having DTB time<90min (88.3% vs 82.3%, p=0.043). Thirty-day MACE occurred in 1.0% in the TRI group and 3.0% in the TFI group (p=0.129). There was no significant difference in major (p=0.313) or minor bleeding (p=0.714) between the TRI and TFI groups. There was a twofold greater use of glycoprotein (GP) IIb/IIIa inhibitor in the TRI group (68.5%) compared with the TFI group (36.4%) (p<0.001). CONCLUSION: Compared with TFI, TRI was not associated with longer DTB time during our center's transition from routine TFI to TRI in STEMI. Our experience suggests that the transition to TRI in STEMI can be safely achieved with DTB times that are comparable and possibly better than propensity-matched TFI cases.

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.

Nationwide improvement of door-to-balloon times in patients with acute ST-segment elevation myocardial infarction requiring primary percutaneous coronary intervention with out-of-hospital 12-lead ECG recording and transmission.

STUDY OBJECTIVE: Reducing door-to-balloon times for acute ST-segment elevation myocardial infarction (STEMI) patients has been shown to improve long-term survival. We aim to reduce door-to-balloon time for STEMI patients requiring primary percutaneous coronary intervention by adoption of out-of-hospital 12-lead ECG transmission by Singapore's national ambulance service. METHODS: This was a nationwide, before-after study of STEMI patients who presented to the emergency departments (ED) and required percutaneous coronary intervention. In the before phase, chest pain patients received 12-lead ECGs in the ED. In the after phase, 12-lead ECGs were performed by ambulance crews and transmitted from the field to the ED. Patients whose ECG showed greater than or equal to 2 mm ST-segment elevation in anterior or greater than or equal to 1 mm ST-segment elevation in inferior leads for 2 or more contiguous leads and symptom onset of less than 12 hours' duration were eligible for percutaneous coronary intervention activation before arrival. RESULTS: ECGs (2,653) were transmitted by the ambulance service; 180 (7%) were suspected STEMI. One hundred twenty-seven patients from the before and 156 from the after phase met inclusion criteria for analysis. Median door-to-balloon time was 75 minutes in the before and 51 minutes in the after phase (median difference=23 minutes; 95% confidence interval 18 to 27 minutes). Median door-to-balloon times were significantly reduced regardless of presentation hours. Overall, there was significant reduction in door-to-activation, door-to-ECG, and door-to-cardiovascular laboratory times. No significant difference was found pertaining to adverse events. CONCLUSION: This study describes a nationwide implementation of out-of-hospital ECG transmission resulting in reduced door-to-balloon times, regardless of presentation hours. Out-of-hospital ECG transmission should be adopted as best practice for management of chest pain.

Angiographic and platelet reactivity outcomes with prasugrel 60 mg pretreatment and clopidogrel 600 mg pretreatment in primary percutaneous coronary intervention.

Pretreatment with 60 mg of prasugrel is more effective than 300 mg of clopidogrel in reducing thrombotic complications with primary percutaneous coronary intervention (PCI). We compared angiographic outcomes and platelet reactivity between treatment with 60 mg of prasugrel and 600 mg of clopidogrel administered before primary PCI. In this single centre non-randomized study, 65 consecutive Asian patients with ST-elevation myocardial infarction (STEMI) received 60 mg of prasugrel before primary PCI. The pre- and post-PCI corrected thrombolysis in myocardial infarction frame count (CTFC) and the 8-h post-treatment platelet vasodilator-stimulated phosphoprotein (VASP) index was compared with a matched historical Asian STEMI cohort (n = 65) receiving 600 mg of clopidogrel pretreatment. Comparing the prasugrel and clopidogrel groups, the mean age was 54.1 ± 10.2 versus 55.5 ± 11.8 years, P = 0.238, and the mean body mass index was 24.6 ± 2.0 versus 24.7 ± 2.8 kg m(-2), P = 0.393. The mean pre-PCI CTFC was 82.1 ± 30.2 versus 86.1 ± 27.6, P = 0.045, and the mean post-PCI CTFC was 21.1 ± 13.9 versus 20.1 ± 9.2, P = 0.309. Pre-PCI coronary thrombi were visualised in 6.3 versus 18.1 %, P = 0.038. The median VASP index was 22.2 ± 24.5 versus 70.5 ± 17.5 %, P < 0.001, and high on-treatment platelet reactivity (VASP index > 50 %) was observed in 13.8 versus 84.3 %, P = 0.001. Rescue intracoronary glycoprotein inhibitors were administered to 29.7 versus 51.0 %, P = 0.018, respectively. Treatment with 60 mg of prasugrel before primary PCI was associated with lower platelet reactivity, a modest trend towards better pre-PCI angiographic outcomes, less pre-PCI coronary thrombi and less rescue glycoprotein inhibitor use compared with 600 mg of clopidogrel. The very high frequency of high on-clopidogrel platelet reactivity with 600 mg of clopidogrel in this Asian STEMI cohort deserves further study.

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'.

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.

Effectiveness and safety of the genous endothelial progenitor cell-capture stent in acute ST-elevation myocardial infarction.

The endothelial progenitor cell (EPC)-capture stent promotes endothelialization and preliminary studies have suggested its safety and feasibility in ST-elevation myocardial infarction (STEMI). Detailed late clinical follow-up and angiographic analyses are, however, limited. We sought to determine late angiographic and clinical outcomes of the Genous EPC-capture stent in primary angioplasty. EPC-capture stents were implanted during primary angioplasty in 489 consecutive patients presenting with STEMI from 2004 through 2008. The first 100 consenting patients undergoing successful stent implantation scheduled to undergo relook coronary angiography at 6 to 12 months were enrolled. Ninety-five patients with 96 lesions were analyzed independently. Mean duration of follow-up coronary angiography was 245 days. In-stent late luminal loss measured 0.87 ± 0.67 mm. Binary restenosis (defined as >50% diameter stenosis) was 28%, with diffuse in-stent restenosis (Mehran class II) as the predominant pattern. Of 27 patients with binary restenosis, 14 (52%) were symptomatic, with 10 patients undergoing target lesion revascularization. Asymptomatic patients had significantly larger reference vessel and in-stent minimal luminal diameters (2.77 ± 0.39 vs 2.54 ± 0.44 mm, p = 0.040; 2.74 ± 0.34 vs 2.31 ± 0.72 mm, p = 0.004, respectively). Follow-up late loss and diameter stenoses were also in favor of the asymptomatic group. Major adverse cardiac event rate was 16% at a mean follow-up of 34 months. There were no cases of Academic Research Consortium-defined stent thrombosis. In conclusion, implantation of the EPC-capture stent during primary angioplasty is associated with a favorable late clinical outcome but with higher than anticipated angiographic late loss.

Angiographic no-reflow and six-month mortality in elderly (>/= 75 years old) Asian patients undergoing primary percutaneous coronary intervention: A single center experience from 1998 to 2007.

BACKGROUND: We sought to report the incidence of angiographic no-reflow and clinical outcomes of elderly patients who have undergone primary percutaneous coronary intervention at a tertiary institution in Singapore over a period of 10 years. METHODS: A total of 141 patients (60% male) aged 75 or above underwent primary PCI between 1998 and 2007. Their average age was 80+/-5 years. Cardiogenic shock complicating STEMI on presentation accounted for 15% of the patients. RESULTS: At baseline, 103 (73%) patients have impaired TIMI flow grade (TIMI 0-2), and 38 (27%) have normal flow (TIMI 3). At the end of the procedure, 44 (31.2%) patients had no-reflow phenomenon (TIMI 0-2), whereas 97 (68.8%) achieved normal antegrade flow. Post-procedure corrected TIMI frame count was analyzable in 66% (n=93) of the patients. Post-procedure corrected TIMI frame count was>28 in 37.6% (n=35) of patients. In-hospital, 30-day and six-month mortalities were 20.6, 25.5% and 27.7%, respectively. Multivariable analysis showed that age 80 or above, low systolic blood pressure and final TIMI 0-2 flow independently predicted six-month mortality. CONCLUSIONS: We found that one-third of the treated patients developed no-reflow phenomenon. Six-month mortality was 27.7%, most were cardiac deaths that occurred during index hospitalization.

New set of intravascular ultrasound-derived anatomic criteria for defining functionally significant stenoses in small coronary arteries (results from Intravascular Ultrasound Diagnostic Evaluation of Atherosclerosis in Singapore [IDEAS] study).

We sought to determine the intravascular ultrasound-derived anatomic criteria for functionally significant lesions in small coronary arteries with a reference segment diameter <3 mm. A fractional flow reserve (FFR) of <0.75, as determined by pressure wire using high-dose (100 to 150 microg) intracoronary adenosine, was used as the reference standard for functional significance. For the 94 patients/lesions involved in the present study, the average reference vessel diameter was 2.72 mm. The FFR was <0.75 in 38 patients (40.4%) and > or =0.75 in 56 patients (59.6%). Logistic regression analysis identified the minimal lumen area, plaque burden, and lesion length as the 3 most important determinants of the FFR. Using classification and regression tree analysis, the best cutoff values for these determinants to discriminate a FFR of <0.75 versus > or =0.75 were a minimal lumen area of < or =2.0 mm(2) (sensitivity 82.35%, specificity 80.77%), plaque burden of > or =80% (sensitivity 87.9%, specificity 78.9%), and lesion length of > or =20 mm (sensitivity 63.6%, specificity 78.9%). A significant increase was found in the area under the receiver operating characteristic curve of the combined parameters (minimal lumen area plus plaque burden plus lesion length) compared to the plaque burden (p = 0.014) and other individual parameters (p <0.001). In conclusion, we found that intravascular ultrasound-derived anatomic criteria are able to predict the functional significance of intermediate lesions in small coronary arteries. A minimal lumen area of < or =2.0 mm(2), plaque burden of > or =80%, and lesion length of > or =20 mm predicted a FFR of <0.75 with good sensitivity and specificity.

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

INTRODUCTION: 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. MATERIALS AND METHODS: 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). RESULTS: 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]. CONCLUSIONS: 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.