Brian P. Bailey

Mechanism and significance of precordial ST-segment depression during inferior wall acute myocardial infarction associated with severe narrowing of the dominant right coronary artery

The mechanism and significance of precordial ST depression during inferior wall acute myocardial infarction (AMI) is debated. This study assessed the location and extent of arterial perfusion distribution responsible for this electrocardiographic finding. Intracoronary thallium-201 was injected in 11 patients with 1-vessel right coronary disease to delineate perfusion distribution that was quantitated by a new angiographic distribution score. The angiographic score correlated with posterior (r = 0.84), posterolateral (r = 0.88) and total (r = 0.73) extent of intracoronary thallium distribution. The angiographic distribution score was related to electrocardiographic changes in 16 patients showing an inferior ST-segment elevation during angioplasty (7 with and 9 without precordial ST depression), of which 6 received intracoronary thallium injection. None had thallium distribution in the anterior or septal segment, but there was a trend toward a greater angiographic distribution score and posterior segment thallium score in patients with precordial ST depression. In another 77 patients with inferior wall AMI due to right coronary occlusion (24 with concomitant left anterior descending narrowing), precordial ST depression was present in 16 with and 31 without left anterior descending narrowing (p = NS). The angiographic distribution score was higher in those with than without precordial ST depression (0.59 +/- 0.10 vs 0.44 +/- 0.11, p < 0.001) in both patients with and without left anterior descending disease. The magnitude of both inferior ST elevation and precordial ST depression correlated with the angiographic distribution score, but only precordial ST depression was independently related in multivariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous Tricuspid Valve Replacement for a Stenosed Bioprosthesis

Percutaneous replacement of the aortic and pulmonic valves has rapidly gained acceptance in clinical practice as a feasible alternative to open valve surgery in patients deemed to be at high operative risk.1,2 Total percutaneous tricuspid valve replacement (TVR), on the other hand, has not yet been documented in humans, although this approach has been described in experimental animals.3 Webb et al4 have recently reported 1 case of TVR, using a valve designed for percutaneous use but inserted through a thoracotomy with direct puncture of the right atrium. We describe a …

Abnormal Pulmonary Artery Stiffness in Pulmonary Arterial Hypertension: In Vivo Study with Intravascular Ultrasound

Background There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV) afterload in pulmonary arterial hypertension (PAH). We used intravascular ultrasound (IVUS) to evaluate the mechanical properties of the elastic pulmonary arteries (PA) in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. Method Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. Results At baseline, PAH subjects demonstrated greater stiffness in all measured indices compared to controls: compliance (1.50±0.11×10–2 mm2/mmHg vs 4.49±0.43×10–2 mm2/mmHg, p<0.0001), distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001), elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001), and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046). Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r2 = 0.82, p<0.0001), and also between mean PAP and distensibility (r2 = 0.79, p = 0.002). Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. Conclusion Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

ST monitoring for myocardial ischemia during and after coronary angioplasty.

We performed 12-lead electrocardiographic monitoring in 97 patients during coronary angioplasty (PTCA) of a single vessel to correlate ischemic ST changes with clinical, angiographic and coronary hemodynamic variables and to determine the optimum lead or combination of leads for their detection. Ischemia (chest pain or ST change, group A) occurred in 79 patients (80%), but in only 15 of 23 patients (65%) with collaterals (p less than 0.05). Ischemia occurred more often in left anterior descending and left circumflex PTCA than right coronary PTCA, but pain was the only manifestation more often in left circumflex and right coronary PTCA. Ischemic ST change was silent in 16% and this proportion did not differ in clinical or angiographic groups except for diabetes with 3 of 5 (60%) having silent ischemia (p less than 0.05). Patients in group A (ischemia) compared to group B (no ischemia) had less severe lesions (85 +/- 9 vs 91 +/- 7%, p less than 0.01), higher transstenotic gradients (62 +/- 19 vs 53 +/- 9 mm Hg, p less than 0.05) and lower distal occluded pressures (24 +/- 11 vs 33 +/- 10 mm Hg, p less than 0.01), suggesting less collateral flow. Compared with a 12-lead electrocardiogram, the best single lead for detecting ST change during PTCA in each artery had a sensitivity of 80% and this increased to 93% using the best 2 leads. The best 3 leads (V3/III/V5 for left anterior descending and III/V2/V5 for right coronary and left circumflex) increased sensitivity to 100%.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral stenosis in the Maroteaux-Lamy syndrome: a treatable cause of dyspnoea.

The case is reported of a young woman with the Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI) who presented with rapidly progressive dyspnoea due to mitral stenosis. Mitral valve replacement was performed and the appearance of the valve was typical of mucopolysaccharide infiltration. Dyspnoea in patients with the Maroteaux-Lamy syndrome may be due primarily to cardiac valve involvement, and in this setting, valve surgery is safe and effective.

ST-segment changes during transmural myocardial ischemia in chronic left bundle branch block.

Abstract The electrocardiographic diagnosis of acute myocardial infarction is difficult in the presence of left bundle branch block (BBB). The accuracy of electrocardiographic criteria derived from studies using either creatine kinase estimation,1–5 autopsy findings2–4 or thallium-201 scintigraphy1 to confirm infarction is debated, and may explain why such criteria have not been widely adopted. Percutaneous transluminal coronary angioplasty of 3 patients with chronic left BBB presented us with a unique opportunity to study the electrocardiographic changes of transmural ischemia simulating acute infarction. All 3 patients showed transient and characteristic ST changes during balloon occlusion of a coronary artery.

Angioplasty through a stent side door

Angioplasty was performed by entering a Gianturco-Roubin stent from the side through the coils of a previously-implanted hanging stent in an ostial lesion in a saphenous vein graft. No complications and no visible damage occurred to the stent. Although this method carries a possible risk of entrapment or damage to the stent, it is feasible when other options have failed.

Radiation Exposure During Cardiac Catheterisation is Similar for Both Femoral and Radial Approaches

OBJECTIVES Radial approach invasive coronary angiography has been shown to be superior to the femoral approach in terms of reducing vascular access complications and improving patient comfort. However, one major limitation has been the perception of higher patient radiation exposure, with guidelines recommending 7mSv as an appropriate average effective dose (E) for routine coronary angiography. Therefore, we sought here to assess differences in radiation exposure between the femoral and radial access routes in patients undergoing diagnostic coronary angiography with or without angioplasty (CA +/- PCI), as performed by two operators, experienced in both techniques. METHODS Consecutive patients (n=870) from July 2011-December 2012, undergoing routine CA +/- PCI at Royal Prince Alfred Hospital, Sydney by two experienced interventional cardiologists were identified. Radiation doses were automatically recorded as dose area products (DAPs) at procedure time and converted into E using a conversion factor of 0.18 mSv/(Gycm2), as validated by the National Radiological Protection Board (NRPB). RESULTS Of the 870 patients, 598 underwent diagnostic CA (347 femoral, 251 radial); and 272 underwent CA+ PCI (179 femoral, 93 radial). The mean age of the patients was 65±12 years and the majority (n=617, 71%) were male. Both groups were well matched with respect to baseline demographics, clinical presentation and angiographic characteristics, though there was an excess of patients with a history of coronary grafts in the femoral group, due to operator preference. In the patients who underwent diagnostic CA, there was no significant difference in the average effective radiation dose for femoral versus radial arterial access (E=7.9±8.2 vs. 8.3±10.6mSv; p=0.66). Similarly, there was also no difference in average effective radiation dose for femoral versus radial arterial access in patients undergoing CA+PCI (E=13.2±8.1 vs E=14.4±8.3 mSv; p=0.26). CONCLUSION In our high volume cardiac catheterisation laboratory, radiation doses for routine angiography were near UNSC targets. Patient radiation exposure was comparable between femoral and radial approaches, for both CA and CA +/- PCI. Thus, our results allay concerns that radial cardiac catheterisation might be associated with greater radiation exposure.

A safe and easy technique to sample the coronary sinus — Facilitating a closer look at cardiac disease

Step 1 The catheter is advanced from the right groin to the right atrium over a 0.035′′ guidewire, which is then removed, allowing the catheter to adopt its pre-formed configuration. The catheter tip might be either in the right ventricle or in the low right atrium, near the tricuspid valve (Fig. 1A and B). Step 2 Using a haemostatic valve, a 0.014′′ coronary wire (Balance middleweight, Abbott vascular, Santa Clara, USA) is advanced

The Effect of Procainamide on Delayed Activation Potentials in a Patient with Ventricular Tachycardia

In a patient with ventricular tachycardia and previous myocardial infarction, delayed activation potentials were recorded from a region of the posterolateral wall of the left ventricle at electrophysio‐logical study. Procainamide, administered intravenously, initially caused increased delay and later, in higher dosage, second‐degree block of the delayed potentials.