Robert Giles

Late cardiac, thyroid, and pulmonary sequelae of mantle radiotherapy for hodgkin's disease

Cardiac, thyroid and pulmonary function were evaluated in 25 patients aged 35 years or under, treated for Hodgkins disease by mantle radiotherapy 5-16 years previously. No patient had symptoms of heart disease. Although thallium myocardial perfusion scintigraphy was normal in all patients, abnormalities of myocardial function were detected in 6 (24%) patients using gated equilibrium rest and exercise radionuclide ventriculography. Resting left ventricular ejection fraction (LVEF) was abnormal in 1 patient, and in 3 patients there was an abnormal LVEF response to exercise. All 6 patients had right ventricular dilatation. Apical hypokinesia was present in 4 of these patients. A small asymptomatic pericardial effusion was detected by M-Mode echocardiography in only 2 (8%) patients. Twenty-three (92%) patients had evidence of abnormal thyroid function. Two (8%) patients had become clinically hypothyroid. Serum TSH was elevated in 13 (52%) patients and TRH stimulation test was abnormal in a further 10 (40%) patients in whom TSH was normal. Pulmonary function studies showed a moderate decrease in diffusing capacity (72% of predicted) and a minor reduction in lung volume. Although a high incidence of cardiac, thyroid and pulmonary abnormalities was detected, only the 2 patients who had become hypothyroid were symptomatic. Modification of the irradiation technique may reduce the incidence of cardiac abnormalities, but is unlikely to alter significantly the thyroid or pulmonary sequelae.

Regional left ventricular wall motion assessment: comparison of two-dimensional echocardiography and radionuclide angiography with contrast angiography in healed myocardial infarction.

The diagnostic ability of radionuclide angiography (RNA) and 2-dimensional echocardiography (2-D echo) to assess regional left ventricular (LV) wall motion was compared with contrast angiography in 52 patients with healed myocardial infarction. After 5 patients were excluded for inadequate 2-D echocardiographic studies, the LV images of 47 patients obtained by all 3 techniques were divided into 7 segments for analysis. Both 2-D echo and RNA showed close agreement with contrast angiography in assessing normal vs abnormal wall motion in the anterobasal (91%, 91%), anterolateral (87%, 79%) and posterolateral segments (77%, 79%). The sensitivity in detecting wall motion abnormalities was highest for 2-D echo and RNA in the anterolateral (83%, 77%) and apical (95%, 84%) segments and lowest for the inferior segment (48%, 48%). Specificity of 2-D echo and RNA was high, ranging from 94% in the anterolateral segment to 71% in the septal segment for 2-D echo, and from 91% in the inferior segment to 81% in the posterobasal and septal segments for RNA. Major discrepancies with contrast angiography occurred more often in the posterobasal, posterolateral, inferior and septal LV segments. Thus, in comparison with contrast angiography, 2-D echo and RNA are reliable for detecting anterior and apical wall motion abnormalities, but relatively less sensitive for detecting wall motion abnormalities involving the inferior, posterobasal and posterolateral LV segments.

Early Left Ventricular Dysfunction and Chelation Therapy in Thalassemia Major

Exercise radionuclide angiography was used to assess the incidence of subclinical abnormalities of left ventricular function in 23 asymptomatic patients with thalassemia major. Left ventricular ejection fraction (LVEF) at rest was normal in 18 patients and abnormal in 5. A normal LVEF response during exercise was shown in only 5 of the patients with normal resting left ventricular function. A normal response during exercise occurred more often in those patients who had received a smaller transfusional iron load and had a lower serum ferritin level (p less than 0.05). Twelve of the twenty-three patients were receiving chelation therapy with subcutaneous deferoxamine. Ejection fraction at rest was normal in 11 of these patients. During exercise a normal ventricular response was shown in 4 patients. After 1 year of intensive chelation therapy in these 12 patients, left ventricular function was reassessed. A normal exercise response was seen in an additional 4 patients; 3 of these showed an increase in peak exercise LVEF, and in the remaining patient no change of peak exercise LVEF was shown. The response during exercise was unchanged in 3 patients and had deteriorated in 1 patient.

Continuous monitoring of left ventricular performance with the computerized nuclear probe during laryngoscopy and intubation before coronary artery bypass surgery

Abstract Left ventricular performance was monitored serially in 25 patients during laryngoscopy and intubation in the anesthetic induction period before elective coronary artery bypass surgery using the labeled equilibrium blood pool and the computerized nuclear probe. Left ventricular ejection fraction was obtained preoperatively, after induction of anesthesia but before endotracheal intubation, immediately after intubation, and at 1 minute intervals thereafter for 10 minutes. In all patients, there was an immediate decrease (mean 16%) in left ventricular ejection fraction accompanying the reflex hypertension and tachycardia occurring during laryngoscopy and endotracheal intubation; it was significantly depressed for 3 minutes with the concomitant hemodynamic changes. Seven patients did not demonstrate a recovery of left ventricular ejection fraction to the preintubation value. In 10 healthy noncardiac patients undergoing orthopedic surgery, after an identical anesthetic induction sequence and intubation, there was a similar decrease in ejection fraction, but of shorter duration. In these patients the recovery of left ventricular performance preceded the recovery of blood pressure and heart rate. This study demonstrates that profound decreases in left ventricular performance accompany the reflex hypertension and tachycardia occurring during endotracheal intubation and that there is persisting depression of left ventricular function in some patients with coronary artery disease. These findings indicate the potential utility of the computerized nuclear probe for monitoring ventricular performance during this critical period.

Modifying fluoroscopic views reduces operator radiation exposure during coronary angioplasty

OBJECTIVES This three-part study examined the feasibility of reducing operator radiation exposure during coronary angioplasty. BACKGROUND As case loads and complexity increase, some cardiologists are receiving increasing radiation scatter doses. Techniques to reduce this are therefore becoming more important. METHODS First, the determinants of the operator dose were assessed by measuring the differences in scatter dose with different camera views. The relative contribution of fluoroscopy as opposed to cine was then quantified. Finally, operators were provided with these data, and subsequent changes in technique were evaluated. RESULTS Left anterior oblique views resulted in 2.6 to 6.1 times the operator dose of equivalently angled right anterior oblique views. Increasing steepness of the left anterior oblique view also resulted in a progressive increase in operator dose, with left anterior oblique 90 degrees causing eight times the dose of left anterior oblique 30 degrees and three times that of left anterior oblique 60 degrees. In the 45 coronary angioplasty cases prospectively analyzed, fluoroscopy was found to be a greater source of total radiation than cine by a 6.3:1 ratio (range 1.1 to 15.8). Once operators were made aware of the importance of left anterior oblique fluoroscopy, there was a marked reduction in its use. When this was not feasible, there was a reduction in the steepness of the angulation. Left anterior oblique fluoroscopy during angioplasty of the left anterior descending and circumflex coronary arteries was reduced from 40% of total screening time to approximately 5%, and left anterior oblique angulation for fluoroscopy during angioplasty of the right coronary artery decreased from 43.6 degrees (+/- 9.1 degrees) to 29.4 degrees (+/- 2.2 degrees). Success rates (90% vs. 89%) and screening times (19.5 vs. 20.7 min) remained unchanged in 200 coronary angioplasties performed after the study. Average operator radiation dose (measured by radiation badges worn under lead at waist level) was reduced from 32.6 to 14.3 microSv/operator per week despite a slight increase in case load. CONCLUSIONS Fluoroscopy is the major source of total radiation exposure during coronary angioplasty, with left anterior oblique views providing the highest dose. Modification of views is feasible and will result in significant reduction of operator radiation dose.

Early and long-term results of coronary artery bypass grafting with severely depressed left ventricular performance

The effects of coronary artery bypass grafting (CABG) on ventricular performance and long-term clinical status were studied in 18 consecutive patients with disabling angina pectoris and severely depressed left ventricular (LV) performance (ejection fraction [EF] 27 +/- 9%). All patients survived CABG, although 1 patient had a perioperative myocardial infarction. There was no change in LVEF at rest, 29 +/- 12%, in the other 17 patients. However, LVEF during peak exercise increased from 22 +/- 7% to 27 +/- 14% (p less than 0.05). The 17 patients were separated into 2 groups: those who increased their peak exercise LVEF by at least 10% (group A, 8 patients) and those who increased it by less than 10% (group B, 9 patients). Preoperatively, patients in group A had a higher LVEF at rest (p less than 0.001) and smaller end-systolic and end-diastolic volumes at rest (p less than 0.001) and during exercise (p less than 0.005). Preoperatively, the LVEF in group A decreased with exercise, from 36 +/- 4% to 27 +/- 5% (p less than 0.01), but was unchanged in group B (19 +/- 3% vs 17 +/- 4%, difference not significant). After CABG, patients in group A had a smaller increase in end-systolic volume with exercise than those in group B (13 +/- 7 vs 34 +/- 22 ml/m2, p less than 0.05), but the changes in end-diastolic volume with exercise were not significantly different. At 27 +/- 5 months after CABG, 5 of 8 patients in group A were asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-year experience of transvenous lead extraction at a single centre

AIMS Indications for cardiovascular implantable electronic devices continue to evolve, which has led to an increasing requirement for transvenous lead extraction. We explore the indications, complications, and success rates involved in the removal of pacemaker and implantable cardioverter-defibrillator (ICD) leads in a high-volume centre, over 20 years. METHODS AND RESULTS We performed a retrospective analysis of all consecutive patients undergoing transvenous lead extraction by a single operator at a single centre between 1993 and 2012. Patient characteristics, indications, and outcomes were analysed. A total of 1006 leads were removed from 510 patients. Seventy-two per cent of patients were males. The mean age was 64 years (range 14-96). Indications included systemic infection (25%), pocket infection (40%), lead failure (26%), chronic pain (3%), and other (6%). Ninety-six per cent of leads were completely removed. There was one procedure-related death, and the major complication rate was 0.3%. Infection was the only identified predictor of increased complication (χ² for difference between groups 20, P< 0.0001). CONCLUSION Pacing and ICD leads can be safely extracted with mechanical techniques. The presence of device infection appears to be the major predictor of procedural complications.

Clinical application of radionuclide quantitation of left to right cardiac shunts in children

Abstract The results of 341 radionuclide studies, using the method of Maltz and Treves to quantify left to right shunts, were reviewed to evaluate Its clinical usefulness in routine practice. In 245 children in whom a shunt was suspected, 140 were shown to have shunts at cardiac catheterlzatlon, the pulmonary to systemic blood flow ratio ( Q p Q s ) being greater than 1.15 in 121. In 92 of 105 normal children, the ratio was less than 1.05. Nineteen children with a shunt had a ratio in the borderline range of 1.05 to 1.15 as did 13 normal children. Only one normal child had a Q p Q s ratio greater than 1.10 whereas seven children with a shunt had a ratio of less than 1.10, including one with a ratio of less than 1.05. A highly significant correlation (r = 0.71) existed between the shunt sizes estimated with the radionuclide method and with oximetry. However, in 10 of these patients a small shunt shown with the radionuclide method was not detected with oximetry but observed on indocyanine green dye curves. In 41 children, therefore, shunt size measured with the radionuclide method, oximetry and indocyanine green dye curves was compared. The correlation of shunt size was comparable with the three techniques. The radionuclide estimation is therefore considered to be more sensitive than oximetry in the detection of small shunts. The procedure was also valuable in 96 children studied after cardiac surgery; a Q p Q s value greater than 1.15 was present in 17 children, 12 of whom have to date been shown to have a residual shunt.

Long‐Term Outcomes Following Transvenous Lead Extraction

Complications related to a cardiac implantable electronic device sometimes require transvenous lead extraction (TLE). We report long‐term follow‐up of patients undergoing TLE, particularly mortality, recurrent device infection, and need for repeat procedures.

Activated clotting time differential is a superior method of monitoring anticoagulation following coronary angioplasty

The standard high-range activated clotting time (sHR ACT) is used to monitor anticoagulation postangioplasty (PTCA), but may be unreliable. We assessed the accuracy of a new method we termed the ACT differential (ACT Diff), obtained by measuring the difference between an sHR ACT and a heparinase ACT from the same sample. Heparinase removes heparin from its sample and provides a current heparin-free baseline. For phase 1 of the study, the sHR ACT, ACT Diff, and laboratory APTT were measured in 250 samples from 75 PTCA patients. In 125 samples with an APTT prolonged but within measurement range, linear regression against the APTT was performed. The correlation coefficient was 0.74 for the ACT Diff and 0.24 for the sHR ACT. An ACT Diff of 15-25 sec was found to equal an APTT of 2.5-3.5 x control. In 50 samples with a normal activated partial thromboplastin time (APT), there was good differentiation by the ACT Diff of results from those adequately heparinized, with a value of 0.9 +/- 4.4 sec. The sHR ACT was 114 +/- 15.5 sec, and could not reliably distinguish between anticoagulated and nonanticoagulated samples. In 75 samples obtained with a high APTT (above measurement range), the ACT Diff was > 30 sec in 95% of samples, and again this allowed differentiation from therapeutic samples. The equivalent sHR ACT was 148 sec, and could not reliably distinguish between anticoagulated and overanticoagulated samples as the ACT Diff could. In phase 2, to examine the clinical usefulness of the ACT Diff, 286 patients were managed post-PTCA by starting heparin when ACT Diff fell to < 50 sec, maintaining ACT Diff at 15-25 sec during heparin infusions, and following cessation of heparin, by removing sheaths when the ACT Diff was < 7 sec. These patients were compared to a control group of 250 patients. Major bleeding (5% vs. 0.5%, P < 0.005) and minor bleeding (30% vs. 13%, P < 0.001) were significantly reduced in the group managed using the ACT Diff. The reduction in bleeding was thought to be due to the rapid availability of reliable results. Abrupt closure was low in both groups (0% with ACT Diff vs. 0.8%). No other thrombotic events occurred. Following phases 1 and 2, the ACT Diff replaced the APTT in all PTCA patients at this institution. In the 18 mo from July 1993, 1,104 patients were managed this way. Incidence of major bleeding (0.2%), transfusion requirement (0.1%), false anneurysm (0.6%), and abrupt closure during heparin infusion (0.1%) remained low. In conclusion, the ACT Diff is more accurate than an sHR ACT, and its clinical use in PTCA patients is associated with a very low incidence of complications from anticoagulation. Its routine use should be considered by units unable to obtain rapid APTT results.