Temporary external DDD pacing after cardiac operations

Temporary atrial and ventricular pacing in the DVI, VVI, and AOO modes using atrioventricular sequential DVI devices is routinely used in cardiac operations. This study evaluated a new temporary external DDD pacemaker (Medtronic 5345 External Pulse Generator) capable of ten pacing modes. Thirty-nine devices have been applied to 38 adult patients (27 male, 11 female) after a variety of open heart procedures. Group 1 had atrial pacing wires placed 1.5 to 2.0 cm apart superiorly on the right atrium, group 2 had atrial wires placed 1.0 to 1.5 cm apart on the right atrial free wall, and group 3 had atrial wires placed on the right atrial free wall 0.8 cm apart, using a Silastic ring for fixation. Ventricular wires were placed on the free wall (group 1) or the diaphragmatic surface (groups 2 and 3) of the right ventricle. Postoperative atrial and ventricular sensing and pacing thresholds were obtained on return to the intensive care unit; analysis of variance demonstrated a significantly greater atrial sensing threshold in group 3. Four patients in group 1 permanently lost atrial sensing, 1 patient in group 2 intermittently lost atrial sensing at 24 hours with return at 36 hours postoperatively, and 1 patient in group 1 lost ventricular sensing capability. All other patients had adequate atrial and ventricular sensing capability documented until elective pacemaker removal (mean, 166 hours; range, 17 to 667.5 hours). Nineteen patients required some form of temporary pacing postoperatively; 11 patients demonstrated hemodynamic benefit from a pacing mode that is not available on the currently used DVI devices, and 7 of these required true DDD pacing capability. Six patients benefited from atrial pacing with adequate atrial sensing and simultaneous ventricular backup. Burst pacing with the device was used successfully to treat postoperative atrial flutter in 2 patients. We conclude that temporary external DDD pacing is feasible and effective in postoperative cardiac surgical patients. Atrial sensing is possible in most patients but electrode positioning is important for adequate thresholds. In some patients, hemodynamic as well as electrophysiologic improvement can be demonstrated with universal DDD pacing capability as compared with standard DVI pacing.     

Right paracardiac mass due to organized pericardial hematoma around retained epicardial pacing wires following aortic valve replacement

The use of temporary epicardial pacing wires during cardiac surgery is a routine procedure and has been associated with low morbidity. We describe a rare case of right paracardiac mass due to organized pericardial hematoma with right atrial compression around the epicardial pacing wires left in-situ, presenting three months following aortic valve replacement surgery. The case highlights the fact that such delayed complications can rarely occur around retained epicardial pacing wires following open heart surgery especially in patients on oral anticoagulants. The clinician should be alert to such an occurrence and during follow-up echocardiography always pay attention not only to the valve and ventricular function, but also to the pericardial and extra-pericardial space.     

Salvage transvenous rapid atrial pacing to terminate atrial flutter after cardiac operations.

Atrial flutter occurring after cardiac operations normally responds well to atrial overdrive pacing through epicardial atrial pacing wires and medication. When this fails, transvenous atrial overpacing offers an attractive alternative. We performed the procedure 29 times in 25 patients. Sinus rhythm returned acutely after 25 procedures in 21 patients and persisted with medication in 20 patients at follow-up. The procedure was well tolerated by all.     

Is use of temporary pacing wires following coronary bypass surgery really necessary?

AIM: Temporary epicardial pacing wires (TEPW) which are routinely used after coronary bypass grafting may result in significant complications. We sought to identify variables that predict TEPW implantation and thereby limit their use. METHODS: This prospective study enrolled 564 patients (296 underwent coronary artery bypass grafting with cardiopulmonary bypass [ONCAB] and 268 underwent off-pump coronary artery bypass grafting, OPCAB). TEPW were placed in patients with the intraoperative presence of one or more of the following criteria: sinus bradycardia, sinus arrest, nodal/junctional rhythms, atrioventricular block, bundle branch block, ventricular tachycardia, or onset of atrial fibrillation. RESULTS: Only 31 (5.5%) patients [ONCAB: 20 (6.8%) (ventricular: 14, bichamber: 6); OPCAB: 11 (4.1%) (ventricular: 9, bichamber: 2)] had temporary epicardial pacing wires implanted intraoperatively. Indications for using temporary epicardial pacing wires for ONCAB were sinus bradycardia (8), nodal/junctional rhythms (3), atrioventricular block (3), atrial fibrillation (4), and bundle branch block (2), and for OPCAB were sinus bradycardia (8), nodal/junctional rhythms (2), and atrioventricular block (1). Mean duration for pacing was 22.4 h for the ONCAB group and 11.3 h for the OPCAB group. There were no temporary epicardial pacing wires associated complications. One paced OPCAB patient required a permanent pacemaker and 2 non-paced OPCAB patients required transvenous pacing wires. Univariate and multivariate analyses were also conducted to determine risk factors for TEPW. CONCLUSION: TEPW implantation is overused in cardiac surgery and by identifying independent predictors for pacing we conclude that TEPW use should be limited to a select few.     

Prevention of atrial fibrillation after cardiac valvular surgery by epicardial, biatrial synchronous pacing.

OBJECTIVE: Postoperative atrial fibrillation (AF) after cardiac surgery is a frequent complication after valvular surgery (30-60%). The purpose of this prospective, randomized study was to determine if biatrial synchronous pacing reduces postoperative AF after cardiac valvular surgery as compared to conventional therapy. METHODS: Eighty patients subjected to valvular surgery (52 men, age 66 +/- 10 years) were randomized to one of two groups: one group was treated with biatrial, synchronous pacing (BAP) for 72 h postoperatively (n=40) the other group received no atrial pacing (controls; n=40). All patients had one pair of epicardial wires attached to the right atrium. An additional electrode was placed to the left atrium in the BAP group. These patients were continuously paced at a rate of 10 beats per minute higher than the intrinsic rate starting immediately after surgery. All patients were monitored with full disclosure telemetry or Holter monitors to identify onset of AF. RESULTS: Eighteen of the 40 patients in the control group (45%) developed AF within the first 3 days postoperatively as compared to eight patients (20%) in the BAP group (P=0.02). No complications occurred associated with the placement, maintenance and removal of the atrial pacing electrodes. CONCLUSIONS: Temporary, biatrial synchronous pacing during the first 3 postoperative days is safe and has a significant rhythm-stabilizing effect in patients undergoing valvular cardiac surgery.     

Epicardial atrial defibrillation: successful treatment of postoperative atrial fibrillation

BACKGROUND: Atrial fibrillation is the most common complication after cardiac surgery. Current medical treatment using antiarrhythmics and anticoagulants has a significant morbidity. The goal of this study was to determine if epicardial atrial defibrillation can be safely performed and return patients to sinus rhythm. METHODS: A prospective analysis of patients undergoing cardiac surgery was performed. Patients with a prior pacemaker/defibrillator, history of arrhythmia, preoperative antiarrhythmic, age greater than 85 years, history of stroke, or intraaortic balloon pump were excluded. Temporary epicardial atrial cardioversion wires were placed on the right and left atrium. Bipolar atrial and ventricular pacing wires were also placed. The wires were tested in the operating room. Patients who went into postoperative arial fibrillation were cardioverted with 3 J, 6 J, or 9 J. RESULTS: There were 45 patients enrolled. Sixteen patients (35%) went into postoperative arial fibrillation during their hospital stay. Mean time to onset of arial fibrillation was 2.6 +/- 1.4 days after surgery. Fifteen patients were successfully cardioverted to sinus rhythm on the primary cardioversion, with mean of 5.7 +/- 2.4 J. One patient was cardioverted at 6 hours after onset of arial fibrillation, at 6 J. Recurrent arial fibrillation occurred in 4 patients during their hospital stay. All 4 of these patients were cardioverted with a mean of 6.4 +/- 2.6 J. All wires were removed the day before patients were discharged. There were no complications with wire insertion or removal. There were no adverse neurologic events. The mean hospital stay was 5.1 +/- 2.2 days. All patients were in sinus rhythm at 1 month follow-up. CONCLUSIONS: The use of a temporary atrial defibrillator to resynchronize patients in postoperative arial fibrillation is safe and effective.     

Temporary A-V sequential pacing using transluminal pacing electrodes

A case is presented which describes the initiation of atrialventricular (A-V) sequential pacing using atrial epicardial wires and an in situ transluminal ventricular pacing probe. A 68year-old female with a permanent A-V sequential pacemaker was scheduled for elective aortocoronary bypass. Following sternotomy, pacing function was converted to ventricular pacing (WI) with the use of electrocautery. A Chandler® V-pacing probe was introduced through a Paceport® (American Edwards) pulmonary artery catheter and with a paced increase in ventricular rate, the cardiac output increased from 2.8 to 3.2 L · min^-1. At the conclusion of cardiopulmonary bypass the patient was in sinus rhythm at a rate of 67 · min^-1 and was paced to a faster rate using bipolar atrial epicardial wires. The patient subsequently developed intermittent heart block so temporary A-V sequential pacing was established using atrial epicardial wires and the in situ ventricular pacing probe. Pacing was achieved at routine generator output settings of seven milliamps (mA) for both atrium and ventricle and at an A-V interval of 0.120 sec. This resulted in an immediate increase in cardiac output from 3.3 to 4.1L- min^-1. The compatability of these two pacing systems offers an increased margin of safety in cardiac surgery patients requiring atrial pacing, who are at risk for developing postoperative heart block.     

Influence of atrioventricular synchrony on hemodynamics in patients with normal and low ejection fractions following open heart surgery

The authors wished to test the hypothesis that atrioventricular synchrony has a relatively greater effect on hemodynamic parameters in postoperative patients with low ejection fractions compared to those with normal ejection fractions. Temporary pacing wires were placed on the right atrium and right ventricle of patients undergoing open heart surgery. Duplicate thermodilution cardiac outputs were determined during atrial pacing and ventricular pacing at 100 beats/min. Mean left atrial and systemic blood pressures were monitored. Thirteen patients with ejection fractions of 45 per cent or less (range 24 to 45%, mean 37.3%) were included in the low ejection fraction group, and 27 patients with ejection fractions of 59 per cent or greater (range 59 to 80%, mean 66.8%) were considered in the normal ejection fraction group. All hemodynamic parameters improved significantly when changing from ventricular pacing to atrial pacing in both the normal ejection fraction group and low ejection fraction group (P less than 0.05). The magnitude of change between the groups showed no significant difference for all parameters except left atrial pressure, which decreased by a greater percentage in the low ejection fraction group with atrial pacing (P less than 0.001). The atrial contribution to hemodynamic enhancement is important in patients with normal and low ejection fraction following open heart surgery. Patients with low ejection fractions do not sustain a relatively greater reduction in cardiac output, stroke volume index, or systemic blood pressure with loss of atrioventricular synchrony when compared to patients with normal ejection fractions.     

Optimal positioning of temporary epicardial atrial pacing leads after cardiac surgery

OBJECTIVES: Atrial pacing plays an important role in preventing low output syndrome and arrhythmia after cardiac surgery. We studied the optimal positioning for temporary epicardiac atrial pacing. METHODS: The performance of temporary epicardiac atrial pacing leads was examined after 13 cases of elective coronary artery bypass grafting between October 1999 and January 2000. Two bipolar electrode leads were used--1 on the cephalic atrial wall between the left and right atrial appendages, where the Bachmann bundle indwells (site A), and the other on the interatrial groove (site B). To assess pacing performance on postoperative days 1, 2, and 7, we measured 3 pacing patterns--bipolar use of sites A and B leads, and combined use of the 2 with the site A lead acting as the negative electrode and the site B lead as the ground. The pacing threshold was measured at a 0.5 ms pulse width, using the P wave amplitude and slew rate as indicators of sensing performance. RESULTS: Bipolar pacing both at sites A and A-B was superior to that at site B in pacing threshold and sensing parameters. CONCLUSIONS: The negative electrode at site A is mandatory for high atrial pacing and sensing performance.     

Tempor?re Schrittmachertherapie bei herzchirurgischen Operationen

Bradycardia during and after cardiac surgery requiring temporary pacing is observed in roughly 50% of patients. Complete heart block as well as bradycardia associated with a sinus node dysfunction or permanent atrial fibrillation are the most common types of perioperative bradycardia; however, in some cases even a heart rate below 80 beats/min can be associated with hemodynamic problems. Finally, the occurrence of bradycardia in the immediate postoperative period after cardiac surgery cannot be predicted with reasonable accuracy. Thus, implantation of temporary epimyocardial stimulation leads in every patient undergoing cardiac surgery is common practice. The versatility of temporary pacing in cardiac surgery is unique, as all parts of the heart can be accessed during the operation. Thereby it allows temporary atrial, AV-sequential, P-wave synchronized or biventricular pacing in addition to ventricular pacing, the only pacing mode available for temporary pacing outside cardiac surgery. This results in desirable and substantial hemodynamic advantages compared to single chamber ventricular pacing for cardiac surgery patients in the perioperative period. This article summarizes the key elements of temporary pacing after cardiac surgery and adds some practical points.     

A critical look at temporary ventricular pacing following cardiac surgery.

The effect of atrial, ventricular, and atrioventricular (A-V) sequential pacing on cardiac output (CO) was evaluated in patients within 24 hours after cardiac surgery. In patients with normal sinus rhythm, ventricular pacing reduced CO by as much as 42% (average, 14%), whereas atrial and A-V sequential pacing at the same rate increased CO by averages of 13% and 19%, respectively. In patients with junctional rhythm, increase of the heart rate by ventricular pacing produced an increase in CO, however, and an additional 25% increase in CO could be obtained by atrial or A-V sequential pacing at the same rate. Atrial or A-V sequential pacing was superior to ventricular pacing at the same rate and they are the preferred methods for temporary carciac pacing in the postoperative period. In suitable cases elective A-V sequential pacing is an effective method for increasing CO after cardiac surgery.     

Ventricular tachycardia associated with transmyocardial migration of an epicardial pacing wire

A 66-year-old man who had undergone a three-vessel coronary artery bypass grafting (CABG) procedure 3 years previously presented with ventricular tachycardia (VT) and cardiac arrest. Echocardiography demonstrated a wire coursing through the right ventricle into the pulmonary artery. The wire was removed with a snare and confirmed to be an epicardial temporary pacing wire placed during the CABG operation. We suspect that the epicardial pacing wire eroded through the right atrium and migrated into the right ventricle, contributing to the VT. Complications due to temporary epicardial pacing wires placed during CABG are discussed.     

Biventricular pacing in a patient with severe congestive heart failure

We report a case of dilated cardiomyopathy with severe congestive heart failure (ejection fraction: 19%) and complete left bundle branch block (QRS duration: 240 ms) 13 years after aortic valve replacement. Permanent biventricular pacing was implanted by inserting a left ventricular lead thorough a small left thoracotomy following intravenous insertion of right atrial and ventricular endocardial leads. Biventricular pacing increased hemodynamic parameters such as blood pressure, cardiac output and decreased mitral regurgitation. Symptoms and exercise tolerance improved dramatically. Left ventricular epicardial lead insertion via a small thoracotomy is thus useful in selected patients.     

Use of temporary atrial pacing in management of patients after cardiac surgery

The authors' clinical experience with temporary atrial pacing to evaluate its use in the management of patients after cardiac surgery was reviewed. A total of 339 patients undergoing cardiac surgery were studied with regard to postoperative pacing therapy. Postoperative pacing was performed in 186 of 339 patients to treat supraventricular bradycardia or tachyarrhythmias. Rapid atrial pacing was performed to interrupt re-entrant supraventricular tachyarrhythmias. In bradycardic patients, haemodynamics could be improved as the result of significant increase of blood pressure and oxygen saturation in the pulmonary artery (Svo₂) caused by atrial pacing. Premature beats could be suppressed in 63% and supraventricular tachyarrhythmias could be interrupted in 66% of the patients only by atrial pacing. Temporary atrial pacing is safe, rapid and effective as the treatment of choice; it is believed that the technique should be applied in preference to pharmacological treatment in the management of patients after cardiac surgery. Copyright © 1996 The International Society for Cardiovascular Surgery.     

Acute Hemodynamic Effects of Cardiac Resynchronization Therapy in Patients with Poor Left Ventricular Function During Cardiac Surgery

Abstract   Background: Cardiac resynchronization therapy improves systolic function in patients with heart failure and left ventricular (LV) dyssynchrony. However, the effect of biventricular (BiV) pacing on perioperative hemodynamics in cardiac surgery is not well known. We investigated the acute hemodynamic response using LVdP/dt_max in patients with depressed LV function and conduction disturbances undergoing cardiac surgery. Methods: Patients with LV ejection fraction of ≤35%, QRS duration of >130 ms, and left bundle branch block undergoing aortocoronary bypass and valve surgery were included. Temporary atrial and left and right ventricular pacing wires were applied, and LVdP/dt_max was measured with a high fidelity pressure wire in the left ventricle at the end of cardiopulmonary bypass. Responders had a ≥10% increase in LVdP/dt_max. Results: Eleven patients (age 63 ± 11 years, eight males) with a LV ejection fraction 0.29 ± 0.06% were included. Compared with right ventricular pacing (782 ± 153 mmHg/sec), there was a significant improvement in the mean LVdP/dt_max during simultaneous BiV pacing (849 ± 174 mmHg/sec; p = 0.034) and sequential BiV pacing with the LV 40 ms advanced (880 ± 157 mmHg/sec; p = 0.003). Improvement during LV pacing alone was not significant (811 ± 141 mmHg/sec). Six patients were responders with simultaneous and nine with sequential BiV pacing. Only sequential BiV pacing had a significant improvement in LV systolic pressure (p = 0.02). Conclusions: BiV pacing results in acute hemodynamic improvement of LV function during cardiac surgery. Optimization of the interventricular pacing interval contributes to the effect of the therapy.     

Cardiac arrhythmias in cardiothoracic surgery

Most patients with cardiopulmonary disease are predisposed to develop perioperative arrhythmias with the individual patient risk depending upon the type of operative procedure performed, the risk profile of the patient, and the complexity of the post-operative course. There are several management options that may tend to prevent perioperative arrhythmias that should be considered in certain patient subsets. Most important of these is the use of beta-blocker therapy before and after operation in patients with coronary risks factors undergoing non-cardiac thoracic procedures and in patients having coronary artery bypass grafting. The common supraventricular arrhythmias including atrial fibrillation and flutter, multifocal atrial tachycardia, and paroxysmal supraventricular tachycardia must be properly diagnosed and treated appropriately. Placement of atrial pacing wires for use after open cardiac surgery is of great value both for diagnosis, and in some cases, for treatment of arrhythmias. Fortunately, serious life threatening ventricular arrhythmias occurs less commonly but the clinician must recognize and correct important predisposing factors and know how to treat these when they occur. A specific protocol for arrhythmia management that sets guidelines for drug choice and therapies for each of the common arrhythmias is useful for clinicians and adds predictability to patient care.     

Improved neurohormonal markers of ventricular function after restoring sinus rhythm by the Maze procedure

BACKGROUND: Clinical results of the Maze procedure for treatment of atrial fibrillation (AF) are excellent, suggesting improved ventricular function after restoring sinus rhythm. However, long-term corresponding effects on the release of cardiac natriuretic peptides and other vasoactive hormones are incompletely investigated after isolated Maze surgery. METHODS: Plasma levels of brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP), antidiuretic hormone, aldosterone, and angiotensin II were measured in 15 patients (mean age, 52 +/- 11 years) undergoing isolated surgical Maze (III) procedures for medically refractory AF, preoperatively and 6 months postoperatively. At the time of blood sampling, hemodynamic correlates were obtained at baseline and after 6 and 12 minutes of rapid ventricular pacing at 150 stimulations/minute. RESULTS: All patients were free of AF at 6-month follow-up. The measured plasma levels of BNP, ANP, and angiotensin II were all significantly lower (p = 0.03) late after the isolated Maze procedure. Cardiac output was significantly higher postoperatively (p < 0.01). Other hemodynamic values and left atrial size were unchanged after surgery. Ventricular pacing caused almost identical hemodynamic changes in atrial pressures before and late after surgery, but the associated plasma ANP response was significantly attenuated postoperatively (p < 0.001). CONCLUSIONS: Levels of cardiac natriuretic peptides and angiotensin II as markers of ventricular function are improved in the long term after clinically successful isolated Maze procedures. ANP response to hemodynamic challenge by ventricular pacing was attenuated postoperatively, possibly due to atrial scarring.     

Improved reliability of post-operative ventricular pacing by use of bipolar temporary pacing leads.

The study compared the clinical reliability of using a bipolar epicardial wire (6495, Medtronic) over a unipolar type (FEP15, Ethicon) for post-operative pacing in coronary artery surgery. Atrial and ventricular wires of both types were implanted in 18 patients. Sensitivities and pacing thresholds were tested for 5 consecutive days. Results show that pacing thresholds were better maintained with the bipolar wire in both atria and ventricles. However, sensing failures were frequent in the atrial position (34% vs 9.3% compared with unipolar). By contrast, in the ventricle, no sensing failures occurred (0% vs 17.6% compared with unipolar). Furthermore, sensing magnitude was significantly better (11.13+/-1.32 vs 5.65+/-0.53 mV, P<0.001). We conclude that a single 6495 bipolar wire is effective for temporary ventricular pacing, whilst double unipolar wires remain a useful strategy for securing atrial sensing and pacing.     

Anesthetic management of an AAI pacemaker patient with paroxysmal atrial fibrillation during colorectal surgery

Perioperative management of patients with cardiac pacemakers may be challenging because of the increasing sophistication of these devices. We report a case of a patient with paroxysmal atrial fibrillation (PAF) and with a permanent AAIR (bipolar atrial-inhibited adaptive rate) pacemaker who suffered life-threatening episodes of arrhythmias during operation. The first episode was vagally induced PAF during bowel manipulation; the second, induced by the increased pacing threshold from the external electric cardioversion and hyperkalemia. Transcutaneous pacing provided cardiac pacing and stabilized the patient during the second episode. Thorough preoperative evaluation and prophylactic placement of temporary pacing or at least transcutaneous pacing are important for the avoidance and minimization of intraoperative complications in patients with sick sinus syndrome and with an AAI (atrial inhibited) pacemaker.     

Pacemaker dependent patients with device infection—a modified approach

A modified surgical concept for temporary cardiac pacing in pacemaker dependent patients requiring total removal of infected devices is presented. Proximal to the infected pocket a permanent bipolar pacing lead is placed transcutaneously into the ipsilateral subclavian or jugular vein. The lead is placed in the right ventricle and fixed into the skin using the suture sleeve. Pacing is established by connecting an external pacing generator. Subsequently the infected device can be removed completely. After wound dressing the externalized lead is connected to a permanent VVI-pacemaker allowing for prolonged temporary pacing.