多层螺旋CT无创显示心脏冠状静脉系统

目的研究多层螺旋CT(MSCT)显示冠状静脉窦及其属支的CT解剖特征。方法利用MSCT冠状动脉造影进行118例患者的冠状静脉成像,观测冠状静脉窦及其属支的形态、位置、数目、直径及角度。结果所有患者均可见冠状静脉窦、心大静脉及心中静脉,大多数患者可见2~3支左室后静脉,心小静脉及左房斜静脉显示率分别为11.0%(13/118),7.6%(9/118)。心中静脉及左室后静脉多成直角汇入冠状静脉窦。心中静脉、心小静脉及左室后静脉的直径分别为(5.2±1.3)mm,(2.6±0.6)mm,(3.8±1.1)mm。冠状静脉窦口上下径为(13.8±4.1)mm,前后径为(10.4±2.9)mm。结论MSCT可以作为无创显示冠状静脉窦及其属支的方法,可为心脏起搏器的置入提供有价值的信息。     

Contrast-enhanced whole-heart coronary MRA at 3.0T for the evaluation of cardiac venous anatomy

This study was designed to evaluate the value of contrast-enhanced whole-heart coronary MRA (CMRA) at 3.0T in depicting the cardiac venous anatomy. In cardiac resynchronization therapy (CRT), left ventricular (LV) pacing is achieved by positioning the LV lead in one of the tributaries of the coronary sinus (CS). Pre-implantation knowledge of the venous anatomy may help determine whether transvenous LV lead placement for CRT is feasible. Images of 51 subjects undergoing contrast-enhanced whole-heart CMRA at 3.0T were retrospectively analyzed. Data acquisition was performed using electrocardiography-triggered, navigator-gated, inversion-recovery prepared, segmented gradient-echo sequence. A 32-element cardiac coil was used for data acquisition. The visibility of the cardiac veins was graded visually using a 4-point scale (1: poor-4: excellent). The paired Student t test was used to evaluate differences in diameters of the ostium of the CS in anteroposterior and superoinferior direction. The cardiac veins were finally evaluated in 48 subjects with three anatomic variations. The diameter of the CS ostium in the superoinferior direction (1.13?±?0.26?cm) was larger than in the anteroposterior direction (0.82?±?0.19?cm) (P?相似文献   

Permanent Left Ventricular Pacing With Transvenous Leads Inserted Into The Coronary Veins

This paper describes a preliminary experiment - conducted jointly by 2 centers - of permanent left ventricular pacing using leads inserted by the transvenous route and through the coronary sinus into the cardiac veins of the left ventricle free wall. The aim was to obtain permanent biventricular pacing in a totally endocavitary configuration in pattents with severe LV dysfunction and drug-refractory heart failure. Two types of leads were used: nonspecific unipolar leads at the beginning of the experiment, followed by leads specifically designed to be used in the coronary sinus in a second step. The electrode could be fitted in an adequate location in 35 of the 47 patients (75.4%), with a 1.15±0.7 V acute pactng threshold and 11.8±5.7 mV R wave amplitude. The success rate was significantly higher with the specific electrodes (81.8% vs 53,3%, p < 0.001). The pacing and sensing thresholds upon implantation were not influenced by the type of lead or by the localization of the cardiac vein that was catheterized (great cardiac vein, lateral vein, postero-lateral or posterior vein, mid cardiac vein). In contrast, the pacing threshold was significantly lower (0.8 ± 0.2 vs L8 ± 0.8 V; p = 0.002) and the R wave amplitude tended to be greater (13.1 ± 4.5 mV vs 9.3 ± 6.5 mV; p = 0.07) when the tip electrode could be inserted distally into the vein, by comparison with a proximal site near the ostium. At the end of follow-up (10.2 ± 8.7 months), 34 out of the 35 leads were still fully functional, with a chronic pacing threshold of 1.8 ± 0.7 V and a R wave amplitude of 10.7 ± 6 mV. To conclude, permanent LV pacing via the transvenous route is possible in most patients, with excellent safety and long-term results.     

Biventricular Pacing via a Persistent Left Superior Vena Cava: Report of Four Cases

GASPARINI, M., et al .: Biventricular Pacing via a Persistent Left Superior Vena Cava: Report of Four Cases. Persistence of left superior vena cava (LSVC) is an uncommon finding during pacemaker implantation, which may be particularly relevant in performing LV transvenous pacing. Rarely, it is further complicated by the presence of atresia of the coronary sinus ostium (CSO). This article reports the authors experience with biventricular pacing (Biv-P) in this unusual clinical setting. From October 1999 to April 2002, 158 patients underwent biventricular pacing. In four of them (mean age 62.2 years), the presence of a persistent LSVC draining into the coronary sinus (CS) was detected at implantation, associated with atresia of the CSO in two patients. A common characteristic was the angiographic finding of a large CS with few tributaries. The LV leads were successfully positioned in the middle cardiac vein in three patients and in a posterolateral vein in one patient. All vessels were large and their cannulation via downstream CS catheterization required the lead to be manipulated through sharp angles. Mean fluoroscopic exposure and procedural times were not significantly different from the overall Biv-P population. In all patients, at a mean follow-up of 11 months, sensing and capture threshold remained stable and a significant decrease in NYHA functional class and increase in LVEF were noted. The direct lead placement in large CS tributaries in the presence of persistent LSVC was feasible and safe. The leads remained stable up to a mean follow-up of nearly 1 year. (PACE 2003; 26[Pt. II]:192–196)     

Permanent Left Atrial Pacing with a Specifically Designed Coronary Sinus Lead

This article reports the original use of a specifically designed coronary sinus (CS) lead for permanent left atrial (LA) pacing. The device is characterized by its distal end shape featuring a double 45° angulation. which ensures very close contact with the CS upper wall. The device was successfully implanted in 39 out of 40 patients (97.5%). The tip electrode was eventually positioned in the distal CS in 9 patients, in the middle CS in 21 patients, and close to the ostium in the proximal CS in 9 patients. The mean acute pacing threshold voltage was 0.9 ± 0.5 V with a mean impedance of 578 ± 144 Ω as measured in unipolar distal configuration at 0.5 ms pulse width (PW). The mean A wave amplitude was 3.5 ± 2.1 mV. Early lead dislodgment occurred only once (3%) when the tip electrode was placed in the distal or middle CS, but more often (4/9 cases) when it was placed in the proximal CS. After a mean follow-up duration of 14 ± 8.5 months, 35 of the 39 successfully implanted leads (89.7%) were still functional in terms of LA pacing and sensing. The mean chronic pacing threshold voltage was 1.5 ± 0.8 V and the mean A wave amplitude was 2.7 ± 1.6 mV. There were no lead related complications. In conclusion, the device proved to be safe and highly effective for permanent LA pacing, provided the distal tip could be positioned in the distal or middle part of the CS.     

Mapping the Coronary Sinus and Great Cardiac Vein

GIUDICI, M., et al. : Mapping the Coronary Sinus and Great Cardiac Vein. The purpose of this study was to develop a better understanding of the pacing and sensing characteristics of electrodes placed in the proximal cardiac veins. A detailed mapping of the coronary sinus (CS) and great cardiac vein (GCV) was done on 25 patients with normal sinus rhythm using a deflectable electrophysiological catheter. Intrinsic bipolar electrograms and atrial and ventricular pacing voltage thresholds were measured. For measurement purposes, the GCV and the CS were each subdivided into distal (D), middle (M), and proximal (P) regions, for a total of six test locations. Within the CS and GCV, the average atrial pacing threshold was always lower (  P < 0.05  ) than the ventricle with an average ventricular to atrial ratio > 5, except for the GCV-D. The average atrial threshold in the CS and GCV ranged from 0.2– to 1.0-V higher than in the atrial appendage. Diaphragmatic pacing was observed in three patients. Atrial signal amplitude was greatest in the CS-M, CS-D, and GCV-P and smaller in the CS-P, GCV-M, and GCV-D. Electrode spacing did not significantly affect P wave amplitude, while narrower electrode spacing attenuated R wave amplitude. The average P:R ratio was highest with 5-mm-spaced electrodes compared to wider spaced pairs. The P:R ratio in the CS was higher (P < 0.05) than in all positions of the GVC. It is possible to pace the atrium independent of the ventricle at reasonably low thresholds and to detect atrial depolarization without undue cross-talk or noise using closely spaced bipolar electrode pairs. The areas of the proximal, middle, and distal CS produced the best combination of pacing and sensing parameters.     

Anatomical variations of the coronary sinus ostium area of the human heart

Classic anatomical dissection of 150 heart specimens from adults aged 18 - 80 years was performed. The Thebesian valve was absent in 20% of cases and, in these, 4% had a large ostial valve of the middle cardiac vein in front of the coronary sinus ostium. Fibres of Chiari were found in 10% of cases. Ostia of the middle cardiac vein, posterior veins of the left ventricle, small cardiac vein and deep cardiac veins were present in the distal 10 mm of the coronary sinus. Some samples had ostial and/or parietal valves or antivalves that sometimes contained muscular fibres. Distal accessory parietal valves (2%) and antivalves (1%) of the coronary sinus wall were found at a distance of 4 - 7 mm from its ostium. The frequency and variability of anatomical structures in the area of the coronary sinus ostium probably influence the haemodynamics of this area. Knowledge of and being able to identify these anatomical variations may help in identifying and overcoming potential difficulties in treating arrythmias and in cardiosurgery.     

Left Atrial- and Left Ventricular-Based Single Lead DDD Pacing

DE COCK, C.C., et al. : Left Atrial- and Left Ventricular-Based Single Lead DDD Pacing. Single lead physiological pacing with right ventricular apex stimulation is feasible in patients with normal sinus node function and is associated with lower costs and a reduced complication rate. Left ventricular or biventricular pacing using the tributaries of the coronary sinus was reported to improve functional status and quality-of-life in patients with advanced congestive heart failure and intraventricular conduction delays. In addition, the proximal part of the coronary sinus has been successfully used for left atrial stimulation. The feasibility and pacing characteristics of left atrial- and left ventricular-based temporary pacing using a conventional single pass lead were studied. The tip of the lead was advanced in a distal position of the lateral or posterolateral branches of the coronary sinus, providing a stable position of the middle and proximal electrode pair in the first 2–7 cm of the coronary sinus. A successful stable position was achieved in 13 of 21 consecutive attempts. Using overlapping biphasic (OLBI) stimulation, left atrial and left ventricular pacing threshold were  2.3 ± 0.6 and 2.5 ± 0.5 V  , respectively. Acceptable sensing values were measured for P waves (  4.1 ± 0.7 mV  ) and R waves (  9.7 ± 3.9 mV  ). There was a good correlation between the diameter of the coronary sinus as assessed by quantitative coronary angiography at the level of the middle and proximal rings and atrial pacing threshold (  r = 0.92, P < 0.0001  ). Thus, single lead left atrialand left ventricular-based pacing is feasible although further development is necessary to increase the success rate for stable stimulation at both sites.     

Emergency guide wire pacing: new methods for rapid conversion of a cardiac catheter into a pacemaker

We developed a new electrode to convert rapidly a previously inserted pulmonary artery or left ventricular catheter into a pacemaker. One method of doing this is by withdrawal of the pulmonary artery catheter from the pulmonary artery to the right ventricle by pressure control, and a Teflon-coated guide wire, stripped of 5 mm of insulation at its tip, is advanced through the catheter to contact the endocardium. In the second method, the pacing electrode is advanced through the distal lumen of the catheter while it is positioned within the pulmonary artery and withdrawn into the right ventricle while pacing. Finally, a third Method involves advancement of the guide wire electrode into the left ventricle through a pigtail catheter. To pace, the guide wire electrode is connected to the cathode of a pacemaker referenced to a skin electrode. We paced 10 of 10 right heart cardiac catheterization, intra- and postoperative surgery patients by methods 1 and 2, and 4 of 4 left heart catheterization patients by method 3. Thresholds (mean ± SEM) for guide wire pacing were: right ventricle 1.52 ± 0.4 mA; left ventricle 1.33 ± 0.1 mA. Guide wire pacing is rapid, reliable, and requires little operator skill. Our indications for guide wire pacing are: 1) emergency right ventricular pacing in operative or intensive care unit patients with unexpected bradyarrhythmias who have an indwelling pulmonary artery catheter; and 2) emergency left ventricular pacing in left heart cardiac catheterization patients with contrast-induced bradyarrhythmias.     

Biventricular Pacing Exclusively Via a Persistent Left-Sided Superior Vena Cava:

LANE, R.E., et al .: Biventricular Pacing Exclusively Via a Persistent Left-Sided Superior Vena Cava: Case Report. Biventricular pacing in association with a persistent left-sided superior vena cava is technically challenging. The presence of an associated innominate vein enables a conventional approach via the right atrium for coronary sinus intubation and left ventricular lead placement. In its absence, the coronary sinus lead must be positioned exclusively via the left-sided superior vena cava. The acute angulation of the branch ostia encountered when catheterizing the coronary sinus "downstream" makes this difficult, but with the use of preshaped cardiac catheters and over-the-wire pacing leads selective intubation of a left ventricular vein is possible. (PACE 2003; 26[Pt. I]:640–642)