Authors: João André dos Santos Ferreira, Célia Marques Domingues, Susana Isabel Monteiro Dias da Costa, Maria Fátima Franco Silva, Lino Manuel Martins Gonçalves
Categories: Case Report, Cardiac pacing, cardiac transplant, defibrillator, echocardiography, patent foramen ovale
Source: Journal of Cardiovascular Echography
Implantable cardiac defibrillators (ICDs) are a popular and effective option in heart failure with left ventricular systolic dysfunction patients. Although frequently underdiagnosed, inadvertent malposition can lead to endocardial damage and thrombotic events. As ICD implants tend to increase in the following years, the recognition of their complications is critical. The authors present a case of a 64-year-old female with advanced heart failure and ICD malposition. This accidental discovery was denounced by the presence of a right bundle branch block (RBBB) pattern and later confirmed by echocardiography which showed the lead tip in contact with the midsegment of the left ventricular anterolateral wall. As the patient's hospitalization was complicated with refractory ascites and cardiogenic shock, she underwent cardiac transplantation, with no recurrence of heart failure symptoms. An electrocardiogram showing a RBBB pattern during VVI pacing should arise the suspicion of inadvertent incorrect placement of a pacing/ICD lead. The many facets of echocardiography should be used for the diagnosis of this complication, as they were paramount in this case, as highlighted.
Keywords: Cardiac pacing, cardiac transplant, defibrillator, echocardiography, patent foramen ovale
Implantable cardiac defibrillators (ICDs) are a well-established treatment of heart failure patients with left ventricular systolic dysfunction who are at risk for life-threatening ventricular arrhythmias. As indications for its placement widen, the number of ICD implants also increases and complications arise. The inadvertent malposition of an ICD lead in the left ventricle is a rare complication and may remain undiagnosed for many years. As this lead position may end up in endocardial damage and thrombotic events, its recognition should be prompt. Here, we present a challenging case of a patient with a previous ICD implant who arrived at our department with an electrocardiogram (ECG) showing a right bundle branch block (RBBB) pattern during VVI pacing. The many facets of echocardiography were paramount to the diagnosis of the complication, as highlighted in this case.
A 64-year-old female, with multiple previous hospitalizations for acute heart failure, was admitted for shortness of breath, peripheral edema, and increasing abdominal size in her local hospital emergency department with subsequent hospitalization. She had a history of idiopathic dilated cardiomyopathy with severe biventricular systolic dysfunction, secondary severe mitral and tricuspid regurgitation, and permanent atrial fibrillation. As part of the sequence of heart failure therapies, the patient also had a previous implant of an ICD for primary prevention 5 years before.
During hospitalization, the patient developed diverse infectious complications which contributed to a slow resolution of acute heart failure, with the need of many days of inotropic and vasopressor support and subsequent suboptimization of heart failure therapy. As the patient was recognized as having criteria for advanced heart failure, she was referred and transferred to our advanced heart failure center.
Following admission to our hospital, an ECG was performed, showing ventricular paced rhythm with RBBB pattern in V1 through V5 leads and extreme right axis displacement of the mean QRS in the frontal plane clearly indicating an electrical activation from the left ventricle [Figure 1], which raised suspicion of ICD lead malposition. Chest radiography was performed also showing an abnormal lead path, suggestive of implantation of the lead in the left ventricle [Figure 2]. To confirm our suspicion, our patient then performed a transthoracic echocardiogram, which showed biventricular dilatation with moderate systolic dysfunction, severe mitral and tricuspid regurgitation, and signs of right ventricular pressure overload with plethoric inferior vena cava and abnormal septal motion with systolic “flattening” toward the left ventricle. Peak systolic gradient between the right ventricle and the right atrium was normal, probably underestimated because of right ventricular dysfunction and severe enlargement of the right atrium. However, the implanted ICD appeared to pass through the interatrial septum, with its lead tip in contact with the midsegment of the left ventricular anterolateral wall [Figure 3a-d]. Our patient also underwent a transesophageal echocardiogram to better clarify valvular regurgitations and the behavior of the ICD lead at the level of the interatrial septum [Figure 4a-d].
Figure 1 Electrocardiogram showing underlying atrial fibrillation with ventricular pacing resulting in right bundle branch block morphology of the paced QRS complex
Figure 2 Posteroanterior chest radiograph suggesting an abnormal course of the implantable cardiac defibrillators lead
Figure 3 Transthoracic echocardiography findings. (a) Four-chamber apical view showing lead course through interatrial septum, mitral valve, and tip placed at the anterolateral wall. (b) Dilated right ventricle with tricuspid valve coaptation defect. (c) Severe tricuspid and mitral regurgitation. (d) Systolic “flattening” of the interventricular septum suggesting right ventricular pressure overload. ICD, implantable cardioverter-defibrillator, IVS = Interventricular septum, LA = Left atrium, LV = Left ventricle, MV = Mitral valve, RA = Right atrium, RV = Right ventricle, TV = Tricuspid valve, ICD = Implantable cardioverter-defibrillator
Figure 4 Transesophageal echocardiography findings. (a) Bicaval view showing lead course through the interatrial septum. (b) Mid-esophageal two-chamber view showing severe mitral regurgitation. (c) Modified mid-esophageal aortic valve short-axis view showing a small left-right shunt suggestive of patent foramen ovale. (d) Transgastric two-chamber view showing lead tip at the anterolateral wall. AV = aortic valve, AW = anterior wall, IAS = interatrial septum, ICD = implantable cardioverter-defibrillator, IW = inferior wall, LA = left atrium, LV = left ventricle, MV = mitral valve; RA = right atrium, RV = right ventricle
Initially, our patient registered an important decrease in body weight and improvement in symptoms; however, after many days of stay, her hospitalization was complicated with refractory ascites and cardiogenic shock, with fast progression in INTERMACS classification. As our patient reached INTERMACS Level 2, we launched a desperate appeal for cardiac transplantation, as neither extracorporeal membrane oxygenation nor left ventricular assist devices were available at our center at the time. After a couple of days, we got contacted as there was an available heart, and our patient was promptly transferred to our cardiac surgery unit where she underwent successful orthotopic heart transplantation. Analysis of the explanted heart confirmed the presence in the left ventricle of the ICD catheter. Immediate postoperative course was favorable with extubation after 24 h, requiring inotropic support with dobutamine for 2 days with no need for mechanical support. The patient was discharged after 72 days after transplantation, and to this day remains symptom-free with no further hospitalizations.
Cardiac implantable electronic devices are a safe and effective way of treating arrhythmias. As indications for its use widen, there is an increase in the number of implants and a subsequent increase in generator replacements.[1] ICD and pacemaker leads are conventionally placed in the right ventricle and right atrium with the leads coursing the subclavian vein and superior vena cava. However, in some cases, there can occur lead malposition, which remains underdiagnosed as patients can be asymptomatic and fluoroscopic guidance during implantation can be misleading.[2,3,4] Furthermore, lead thresholds are not always helpful in the diagnosis, as they can be perfectly normal during patient follow-up,[3,4,5,6] which was the case of our patient. As the ICD lead is expected to be implanted in the right ventricular apex, pacing is expected to produce a left bundle branch block pattern. As in the case of our patient, the presence of a paced RBBB pattern must rise suspicion of lead malposition. Sites reported to be associated with the pattern are left ventricular malposition, coronary sinus implantation, lead perforation, and pseudo-RBBB even in the right ventricular lead placement.[7,8] Chest radiography is routinely performed after lead placement, generally to rule out pneumothorax and malposition of the lead. A correctly implanted lead is expected to a right lateral course through the right atrium in the posteroanterior view, with the lateral view showing anterior location of the lead tip. In our patient, radiography revealed more superior and to the left positioning on posteroanterior view, with lateral view showing a more posterior location of lead tip, suggesting lead malposition in the left ventricle. Two-dimensional transthoracic echocardiography is the imaging test of choice to confirm lead malposition, as it is a readily available exam quickly performed at bedside. Transesophageal echocardiography, as performed in our case, can also accurately delineate the course of the lead, especially at the level of the interatrial septum, elucidating if we are in the presence of a patent foramen ovale or other types of atrial septal defect.
Complications of the left ventricular lead position include valvular damage and thromboembolic events.[9] A recent trial, ALternate Site Cardiac ResYNChronization study, aimed to evaluate the feasibility and safety of left ventricular endocardial pacing (LVEP) using a pacing lead implanted through pectoral access by an atrial transeptal lead delivery system.[10] LVEP was successful in 118 cases, and all patients received effective anticoagulation with warfarin, with target international normalized ratio (INR) range 2.5–3.5. A total of five patients had a postprocedure stroke; however, none of the events led to permanent disability as defined by Rankin Class 3 or greater. However, thromboembolic episodes may occur in up to 40% of affected patients, at any time after the procedure.[2] Factors such as timing of implantation, adherent thrombus, and age of patients can influence the management of these cases. If the diagnosis is made shortly after implantation, percutaneous lead extraction can reduce embolic events and need of lifelong anticoagulation; however, the procedure carries some risk of systemic embolization from lead manipulation, especially with laser sheaths.[11] In the patients where diagnosis is delayed, warfarin seems a reasonable option, as thromboembolic events were rare or absent in patients with INR in the range of 2.5–3.5.[3,10] However, it does not address the problem of valvular trauma and increased lifelong anticoagulation complications. As such, percutaneous extraction may be considered because it is a definitive solution for the problem. Surgical lead extraction is also an option, especially if cardiac surgery is warranted.
In our case, as the patient underwent cardiac transplantation for reasons not related to lead malposition, lead extraction did not constitute a problem for the patient management. However, if we had to extract the lead, it would probably prove problematic as the lead was implanted 5 years before.
When a paced RBBB pattern is seen in a patient with previous ICD implantation, lead malposition in the left ventricle should be suspected. ECG is a very useful diagnostic tool and should be performed while under pacing, if necessary forcing it with a magnet, to clarify the position of cardiac stimulation, paramount for clinical suspicion in our case. Furthermore, the Klein maneuver (placement of precordial leads V1 and V2 one interspace lower than the standard location) can help verify true catheter malposition as it can eliminate RBBB pattern occurring with right ventricular pacing.[12] Chest radiography with posteroanterior and lateral views can also help with the diagnosis, showing an abnormal lead path. However, it can be insufficient because the left ventricular position can be mistaken for coronary sinus position. Therefore, echocardiography is crucial to diagnose lead malposition and its complications, as a readily available diagnosis tool capable of locating lead position and following its course. Computed tomography scan may be needed when other exams fail to diagnose lead malposition and suspicion remains high.[13]
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Nil.
There are no conflicts of interest.