Superior vena cava syndrome and syncope in an implantable cardioverter defibrillator recipient.

We describe the case of a recipient of an implantable cardioverter defibrillator with multiple syncopal episodes due both to superior vena cava obstruction and electrical instability. These complications occurred in the presence of two transvenous implantable cardioverter defibrillator leads. The patient has been managed conservatively with anticoagulants and new antiarrhythmic drugs with improvement in both his clinical problems.     

Hyperlipidemia prevents the expected reduction of myocardial ischemia on repeated balloon inflations during angioplasty

BACKGROUND: Controversy exists regarding inhibition of ischemic preconditioning in hyperlipidemic animals. In this study, we tested the hypothesis that hyperlipidemia inhibits the normal reduction of myocardial ischemia on repeated balloon inflations (BIs) during angioplasty. METHODS: We studied 33 patients undergoing coronary angioplasty. All underwent a minimum of three BIs. Patients were grouped according to the following plasma cholesterol levels: 13 patients had total cholesterol levels < 200 mg/dL (the normal cholesterol group); and 20 patients had total cholesterol levels > or = 200 mg/dL (the elevated cholesterol group). Surface ST-segment elevations were recorded at the end of each BI. RESULTS: In the normal cholesterol group, the mean (+/- SD) ST-segment elevation decreased from 0.21 +/- 0.15 mV during the first BI to 0.11 +/- 0.11 mV during the third BI (p < 0.05). In the elevated cholesterol group, the respective decrease was from 0.18 +/- 0.16 to 0.14 +/- 0.15 mV (p = not significant) [between-group comparisons: F = 3.97; p = 0.02]. The decrease in ST-segment elevation was correlated with the total cholesterol levels (r = -0.48; p = 0.005), the low-density lipoprotein (LDL) cholesterol levels (r = -0.50; p = 0.003), and the high-density lipoprotein/LDL levels (r = 0.44; p = 0.01). CONCLUSION: Hyperlipidemia prevents the normal reduction of myocardial ischemia on repeated BIs during angioplasty. This leads to the clinical implication that reduction of cholesterol plasma levels, apart from its other known benefits, could also have a beneficial effect on cardioprotection.     

Atrial natriuretic peptide augments coronary collateral blood flow: A study during coronary angioplasty

Background and hypothesis: In vitro studies have shown that atrial natriuretic peptide (ANP) causes relaxation of pre-constricted blood vessel strips and inhibits the contraction of isolated vessels in response to norepinephrine and angiotensin II. The present study examined the effects of exogenous ANP on the coronary collateral blood flow during angioplasty. Methods: We studied 15 patients undergoing elective balloon angioplasty during the second and third balloon inflations. A Doppler flow guidewire was advanced distal to the lesion and used for the estimation of coronary blood flow velocity. After the second balloon inflation, 25 ng/kg/min of ANP were administered intracoronarily for 8 min. Electrocardiogram, pressure, and flow velocity were recorded immediately before each balloon deflation. Fourteen other patients served as controls and received normal saline infusion. Results: Velocity time integral increased from 65 ± 40 to 79 ± 46 mm (p < 0.05) during the third balloon inflation, whereas ST deviation decreased from 1.3 ± 0.9 to 0.7 ± 1.0 mV (p< 0.05). These variables did not change in the control group during the two tested balloon inflations. Conclusion: Exogenous ANP augments coronary collateral blood flow and ameliorates myocardial ischemia during angioplasty.     

G6PD Hillbrow: A New Variant of Glucose-6-Phosphate Dehydrogenase Associated with Drug-induced Haemolytic Anaemia

A new genetic variant of the red cell enzyme glucose-6-phosphate dehydrogenase is described. It was observed in a patient presenting with severe haemolytic anaemia and renal failure following ingestion of an overdose of Beserol (paracetamol and chlormezanone). The enzyme in the red cell had 12% of the activity of a normal B+ control, but only slightly lower activity in the kidney compared with a normal control. The red cell enzyme showed normal electrophoretic mobility and thermostability, a biphasic pH optimum curve, higher than normal utilization of the substrate analogues 2-deoxy-glucose-6-phosphate and deamino-NADP, and lower than normal Michaelis constants for both substrates, glucose-6-phosphate and NADP. The enzyme was strongly inhibited in vitro by high concentrations of paracetamol and chlormezanone. The extent of inhibition was similar to that for the enzyme from a normal B+ individual.     

Left main coronary artery aneurysm

Left main coronary artery aneurysms (LMCA) are usually asymptomatic and are rarely encountered during coronary angiography. The most serious complications include coronary thrombosis, acute myocardial infarction and sudden death. Atherosclerosis is the most common cause, although several autoimmune diseases and congenital abnormalities have been associated with the presence of coronary aneurysms. The case of a symptom-free 63-year-old man with a giant LMCA and severely ectatic coronary arteries is presented.     

Acute haemodynamic effects of oestrogen administration in male patients with chronic heart failure

BACKGROUND: Although there are many studies concerning the effects of long-term oestrogen administration on systemic haemodynamics in postmenopausal women, the effects of oestrogen in patients with chronic heart failure are not defined. AIM: The goal of this study was to evaluate the acute haemodynamic effects of oestrogen in male patients with chronic heart failure. METHODS AND RESULTS: We studied 15 men with advanced heart failure (NYHA II-IV, EF < 35%). A Swan-Ganz thermodilution catheter was advanced in their pulmonary artery and central haemodynamics were assessed at baseline, after placebo administration, and following 0.625 and 1.25 mg of oestrogen infusion. Simultaneously, all patients underwent limb plethysmography. Analysis of variance with repeated measures was used to compare the sequential measurements. Following oestrogen administration, right atrial, pulmonary artery and pulmonary capillary wedge pressures, as well as systemic, pulmonary and forearm vascular resistance were decreased; cardiac output, cardiac index, stroke volume, stroke volume index, stroke work index and forearm blood flow were increased. CONCLUSIONS: In male patients with chronic heart failure, acute oestrogen administration improves the indices of cardiac systolic performance and decreases pulmonary and systemic vascular resistance. These findings imply a beneficial effect of oestrogen in selected patients with chronic heart failure.     

QT-interval abnormalities in hypertrophic cardiomyopathy.

To examine whether QTc and QTc dispersion across the leads of a surface electrocardiogram (ECG) are different in patients with hypertrophic cardiomyopathy (HCM) compared with normal subjects, we measured QT and calculated QTc in all 12 leads of a surface ECG in 24 patients with HCM and in 20 age- and sex-matched normal control subjects. Maximal QTc was prolonged in HCM patients (465 +/- 24 ms) compared with controls (410 +/- 20 ms) (p < 0.001). QTc dispersion defined as the difference of maximum-minimum QTc was also greater in HCM patients (71 +/- 21 ms) compared with normals (35 +/- 11 ms) (p < 0.001). A correlation was found between the degree of left ventricular hypertrophy expressed by the maximal wall thickness and maximal QTc (r = 0.48, p < 0.02). However, QTc dispersion did not correlate with maximal wall thickness. Thus, patients with HCM show a prolonged QTc (> 440 ms) and increased QTc dispersion compared with normal subjects. In addition, the degree of left ventricular hypertrophy correlates with maximal QTc. The presence of a prolonged QT with increased regional dispersion may be associated with the occurrence of serious ventricular arrhythmia and sudden death in HCM.     

Discordance between echocardiographic and MRI findings in two cases of acute myocarditis mimicking myocardial infarction

Spontaneous coronary artery dissection (SCAD) still is a rare cause of acute coronary syndrome. SCAD has been observed in three groups of patients: those with coronary atherosclerosis, peripartal women and idiopathic group. SCAD may be associated with some conditions. We report an unusual association: SCAD and pulmonary thromboembolism.     

The ischemia-modified albumin in relation to pacemaker and defibrillator implantation

BACKGROUND: Ischemia-modified albumin (IMA) is considered a marker of myocardial ischemia whereas cardiac enzymes are released when cardiac necrosis occurs. It has previously been shown that permanent pacemaker-defibrillator insertion is associated with myocardial injury expressed as cardiac enzyme rise. OBJECTIVE: We assessed whether pacemaker-defibrillator implantation also induces changes in IMA plasma levels and whether, therefore, myocardial ischemia precedes necrosis. METHODS: We studied 64 consecutive patients undergoing pacemaker or defibrillator implantation; 43 were men and 21 women and their age was 70 +/- 11 years (range 23-84 years). Blood samples were collected at baseline, six hours and 48 hours following the procedure. IMA measured by the albumin cobalt binding test (ACB, Integra 800 analyzer), as well as creatine kinase (CK), the MB isoenzyme of creatine kinase (CK-MB) and cardiac troponin I (Tn-I) were evaluated. RESULTS: Data analysis showed that compared to baseline measurements, IMA increased at six hours (P = 0.015) and at 48 hours (P = 0.003)[97.6 +/- 10.2 vs 101.4 +/- 10.7 vs 102.1 +/- 9.2 U/mL at baseline, six hours and 48 hours, respectively]; similarly, CK increased at six hours (P = 0.0001) and remained high at 48 hours (P = 0.0001) [74.9 +/- 49.9 vs 136.1+/-186.7 vs 115.2 +/- 63.9 mIU/mL], while CK-MB increased at six hours (P = 0.0001), but returned to baseline values at 48 hours (P = 0.05) [0.90 +/- 0.89 vs 1.27 +/- 134 vs 0.71 +/- 0.63 ng/mL] and Tn-I increased at six hours (P = 0.0001) and returned to baseline levels at 48 hours (P = 0.32) [0.057 +/- 0.23 vs 0.16 +/- 0.36 vs 0.03 +/- 0.045 ng/mL]. CONCLUSION: Permanent pacemaker-defibrillator insertion is associated with myocardial ischemia and necrosis.