Treatment of pacemaker-induced superior vena cava syndrome by balloon angioplasty and stenting.

Superior vena cava (SVC) syndrome is a rare but serious complication after pacemaker implantation. This report describes three cases of SVC syndrome treated with venoplasty and venous stenting, with an average follow-up of 30.7 (±3.1) months. These cases illustrate that the definitive diagnosis, and the extent and location of venous obstruction, can only be determined by venography.

Peak longitudinal strain delay is superior to TDI in the selection of patients for resynchronisation therapy.

BACKGROUND: Mechanical dyssynchrony has proven to be superior to QRS duration in predicting response to cardiac resynchronisation therapy (CRT). Whether time to peak longitudinal strain delay between the mid-septum and mid-lateral left ventricular wall better predicts CRT response than tissue Doppler imaging (TDI) is unclear. This study compares the value of the two methods for the assessment of mechanical dyssynchrony and prediction of CRT responders. METHODS: 66 clinical responders and 17 nonresponders to CRT with severe systolic heart failure (LVEF <35%), New York Heart Association classification III or IV and a wide QRS >130 ms with left bundle branch block were evaluated by peak longitudinal strain and TDI. Doppler echocardiograms and electromechanical time delay (EMD) intervals were acquired before and after pacemaker implantation. RESULTS: In all responders EMD measured by peak longitudinal strain was >60 ms before implantation, compared with 76% of the patients measured by TDI. Nonresponders had EMD <60 ms measured by both techniques. Only peak longitudinal strain delay showed shortened values in every responder postimplantation and demonstrated the most significant reduction and could predict responders to CRT. However, EMD measured by TDI did not diminish in 30% of the positive clinical responders. Nonresponders showed worsening of the EMD with peak longitudinal strain, but not with TDI. CONCLUSIONS: Responders to CRT can be excellently predicted if EMD before implantation determined by peak longitudinal strain delay is >60 ms. Peak longitudinal strain delay appears to be superior to TDI to predict the response to CRT. (Neth Heart J 2010;18:574-82.).

DDDR pacing for symptomatic patients with hypertrophic obstructive cardiomyopathy: The first experience in the Netherlands with pacing in HOCM.

BACKGROUND: Hypertrophic obstructive cardiomyopathy (HOCM) is a primary cardiac disorder with a heterogeneous expression. When medical therapy fails in patients with symptomatic HOCM, three additional therapeutic strategies exist: ventricular septal myectomy, alcohol-induced percutaneous transluminal septal myocardial ablation (PTSMA) of the first septal branch of the anterior descending artery and pacemaker implantation. In this paper we present the results of seven patients in whom a dual-chamber pacemaker was implanted to reduce the gradient in the left ventricular outflow tract (LVOT) and to relieve their symptoms. METHODS: In patients with drug refractory symptomatic HOCM, not eligible for surgery, pacemaker therapy was recommended. Symptomatic HOCM was defined as symptoms of angina and dyspnoea, functional class NYHA 3-4 and a resting LVOT gradient during Doppler echocardiography of more than 2.75 m/s (30 mmHg). In these patients, a dual-chamber pacemaker was implanted with a right ventricular lead positioned in the right ventricular apex and an atrial lead positioned in the right atrial appendage. In all patients the AV setting was programmed between 50 and 100 ms, using Doppler echocardiography to determine the optimal filling and to ensure ventricular capture. RESULTS: A statistically significant reduction of the LVOT gradient was observed in all patients. The pre-implantation gradient in the LVOT measured by Doppler echocardiography varied from 3-5.8 m/s with a mean of 4.7±1.1 m/s. The post-implantation gradient varied from 1.4-2.6 m/s with a mean of 1.9±0.4 m/s (p<0.001). Symptomatic improvement was present in all patients. NYHA functional class went from 3-4 (mean 3.1±0.5) pre-implantation to 1-2 mean (1.3±0.4) after implantation (p<0.001). During a mean follow-up of 2.3±1.1 years, the improvement in functional class was maintained. CONCLUSION: Our preliminary results demonstrate that dual-chamber pacing is an effective and safe treatment for symptomatic patients with HOCM.

Cardiac tamponade secondary to chest tube placement.

A 69-year-old woman was hospitalized because of a left-sided pneumothorax due to chronic obstructive pulmonary disease. During chest tube placement she developed hypotension and a decrease in peripheral oxygen saturation. A diagnosis of heart tamponade was made and the patient was treated successfully with pericardiocentesis and placement of a pericardial drain. Cardiac tamponade following chest tube placement is a rare and serious complication. When the clinical condition deteriorates following chest tube insertion, cardiac tamponade should be considered.

Non-bacterial thrombotic (marantic) endocarditis associated with giant-cell arteritis.

A patient with giant-cell arteritis and non-bacterial thrombotic (marantic) endocarditis of the mitral valve is described. To our knowledge, this is the first case reported. The importance of revising the diagnosis of infective endocarditis when no pathogen can be demonstrated is emphasized.

Bisoprolol reduces cardiac death and myocardial infarction in high-risk patients as long as 2 years after successful major vascular surgery.

AIM: To assess the long-term cardioprotective effect of bisoprolol in a randomized high-risk population after successful major vascular surgery. High-risk patients were defined by the presence of one or more cardiac risk factor(s) and a dobutamine echocardiography test positive for ischaemia. METHODS: 1351 patients were screened prior to surgery, 846 patients had one or more risk factor(s), and 173 of these patients also had ischaemia during dobutamine echocardiography. One hundred and twelve patients could be randomized for additional bisoprolol therapy or standard care. Eleven patients died in the peri-operative period (up to 1 month after surgery). Randomized patients continued bisoprolol or standard care after surgery. During follow-up of 101 survivors (median 22 months, range 11-30) cardiac death or myocardial infarction was noted. No patient was lost during follow-up. Results The incidence of cardiac events during follow-up in the bisoprolol group was 12% vs 32% in the standard care group (P=0.025). Cardiac death occurred in 15 patients, nine patients in the standard care and in six in the bisoprolol group; myocardial infarction occurred in six patients, five in the standard care and one in the bisoprolol group. The odds ratio for cardiac death or myocardial infarction after surgery in high-risk patients with additional bisoprolol therapy was 0.30 (0.11-0.83). CONCLUSIONS: Bisoprolol significantly reduced long-term cardiac death and myocardial infarction in high-risk patients after successful major cardiac vascular surgery.

Clinical value of exercise testing in elderly patients.

Between 1978 and 1983, 1391 exercise tests were performed by 1083 males and 308 females over 64 years of age. This represents 17% of the total number of 8213 exercise tests. A history of myocardial infarction was present in 53% of the males and 30% of the females, while 12% of patients had previous heart surgery. Exercise was performed on a bicycle ergometer with stepwise workload increments of 10 or 20 W min-1. In 10% of patients the physician stopped the test because of serious arrhythmias or abnormal blood pressure response. The test was terminated because of fatigue (40%), angina (12%), dyspnea (18%) or tired legs and claudicatio (18%). Peak workload averaged 115 W in males and 85 W in females, which corresponds to 120% of the predicted normal values. Heart rate increased on average to 130 beats min-1 and systolic blood pressure increased to 180 mmHg. ECG changes compatible with myocardial ischaemia were observed in 42% of patients. Although elderly patients constitute a small fraction of the population referred for exercise testing, these findings indicate that the clinical value of the test when performed is similar to that in younger patients. The observation that most patients achieved higher than 'normal' maximum workloads may be due to unreliability of the reference values.

Cardiovascular actions after intravenous and intracoronary administration of the slow channel blocker bepridil.

The effects of 1-[3-isobutoxy-2-(benzylphenyl)amino]propyl pyrrolidine hydrochloride (bepridil), a new calcium channel blocker, on the systemic and coronary circulation were studied in intact anesthetized domestic pigs. Intravenous administration (0.125-0.500 mg X kg-1 X min-1 over 5 min) caused dose-dependent decreases in systemic (8-26%) and coronary vascular resistance (10-41%), but had only a minor effect on cardiac output and myocardial contractility. Myocardial O2-consumption decreased slightly (1-15%). After administration of 0.5 mg X kg-1 X min-1 there was a slight decrease in heart rate. Intracoronary (i.c.) administration (500-1500 micrograms) had only a slight effect on global hemodynamics and regional myocardial wall function but caused large increases in coronary blood flow (100%) and coronary venous O2-content (140-170%), while myocardial O2-consumption decreased by 40-60%. This decrease in O2-consumption after bepridil i.c. in the absence of significant hemodynamic changes is discussed in terms of a more efficient O2-energy metabolism. The severe hypotension after intravenous administration will enhance catecholamine release and may mask this beneficial effect of bepridil on myocardial O2-consumption during the latter mode of administration.

Significance of haemodynamic variables in coronary care unit for prediction of survival after acute myocardial infarction.

In order to assess the value of haemodynamic monitoring in the coronary care unit for long term prognosis after recovery of an acute myocardial infarction, the records of two groups of consecutive patients were reviewed retrospectively. From 254 patients, 32 (13%) died in the hospital and nine patients had to be excluded from subsequent follow-up for various reasons. Four year mortality among the 213 patients who were discharged from the hospital and could be followed up was 26%. Of the haemodynamic variables measured on admission a high pulmonary capillary wedge pressure, exceeding 18 mmHg, and a low mixed venous oxygen saturation, less than 60%, were not only associated with a high hospital but also with a high four year mortality, whereas a low systolic blood pressure (less than 100 mmHg), an important prognosticator during admission to hospital, was only of minor significance thereafter. A negative value on admission of a specific index 0.24 X systolic blood pressure (mmHg) -0.217 X pulmonary capillary wedge pressure (mmHg)+0.234 X mixed venous oxygen saturation (%)-13.1 developed for the prediction of short term survival was also associated with a much higher four year mortality than a positive value. Low cardiac index on admission could be correlated with high mortality during the first two years after discharge, whereas only 9% of patients with a higher cardiac index died. Haemodynamic monitoring in the coronary care unit is thus not only relevant for the immediate prognosis, but a high mortality risk during hospital stay persists for several years after discharge.

Cardiovascular actions of the calmodulin inhibitor felodipine.

The cardiovascular effects of intravenous (1.5-10 nmol X kg-1) and intracoronary (50 nmol) administration of felodipine, 4-(2,3-dichlorophenyl)-1,4-dihydro-2, 6-dimethyl-3-ethoxycarbonyl-5-methoxycarbonylpyridine, were studied in anaesthetized pigs. Following intravenous administration dose-dependent decreases were observed in left ventricular systolic blood pressure (up to 30%) and in the resistances of the systemic (up to 40%) and coronary vascular beds (up to 45%), whereas heart rate, cardiac output, myocardial contractility (regional and global), and left ventricular end-diastolic pressure were minimally affected. Myocardial blood flow increased independently of the dose (20%), while the coronary venous O2-content more than doubled. The concomitant decrease in myocardial O2-consumption (up to 30%) was dose-dependent in the range from 1.5-6.75 nmol X kg-1. Intracoronary administration of 50 nmol had only minor effects on global and regional myocardial performance but produced a doubling of the coronary blood flow which was accompanied by a 70% decrease in myocardial O2-extraction. O2-consumption decreased considerably more (35%) than after intravenous administration in spite of the minimal decrease in O2-demand (7%). We conclude that felodipine dilates both systemic and coronary blood vessels. Although the reduction in myocardial O2-consumption is primarily caused by the reduction in afterload, a direct effect on myocardial metabolism can also be involved.

Decreased incidence of ventricular fibrillation after an acute coronary artery ligation in exercised pigs.

Evidence has been presented that regular physical activity may be associated with a decreased incidence of sudden cardiac death. It has been suggested that self-selection of those engaging in regular exercise rather than the physical activity itself is a major factor in explaining these results. We therefore studied the effects of a two-month exercise program on the incidence of ventricular fibrillation after an acute ligation of the left anterior descending (LAD) coronary artery in domestic Yorkshire pigs. At the end of the exercise program, the exercised group (EG, n = 17) had a lower heart rate (10%), a 5 times higher maximum exercise capacity, a 10% larger left ventricular mass and a thicker myocardial wall during end-diastole than a sedentary group (SG, n = 13). After the animals were anesthetized, the LAD artery was occluded at one third of its distal end. Ventricular fibrillation (VF) occurred in 92% of the SG (12 out of 13) against only 30% of the EG (5 out of 17) within 1 hour after occlusion. Percentage of the area at risk was the same (9-10% of total left ventricular mass) in both the EG and SG. Transmural myocardial perfusion after coronary artery ligation was slightly larger in EG than in SG (30 vs 21 ml . min-1 . 100 g-1, p less than 0.05). Although the improvement in perfusion of the ischemic zone of the EG may have contributed to the reduced occurrence of ventricular fibrillation, other mechanisms cannot be excluded.

Intracoronary infusion of small doses of nifedipine lowers regional myocardial O2-consumption without altering regional myocardial function.

Intracoronary infusion of low doses (0.1-0.3 microgram X kg-1) of nifedipine caused dose-dependent decreases in regional myocardial O2-consumption, without significant changes in any of its major global hemodynamic determinants: heart rate, left ventricular systolic and end-diastolic pressure and maxLVdP/dt. Furthermore, regional myocardial function was unaltered. It is suggested that nifedipine decreased myocardial O2-consumption by a direct effect on myocardial metabolism. Some of the possible mechanisms involved are discussed.