Whenever we hear the term “heart failure”, immediately left ventricle comes into mind. However, in about 2% of patients who present with “clinical features of heart failure”, the primary pathology originates from the right side of the heart (right ventricle, right atrium, and tricuspid valve) without the involvement of the left heart. Some of these pathologies include Right Ventricle (RV) dysfunction due to ischemia, arrhythmia or cardiomyopathy, pulmonary hypertension, congenital abnormalities, pulmonary embolism and tricuspid valve dysfunction. It is imperative to remember that Right Heart Failure (RHF) is not a synonym for right ventricle impairment. RV impairment is one of the pathologies which can cause RHF, i.e. reduced stroke volume.
Treating patients with Right Heart Failure can be challenging as they are usually elderly with many co-morbidities. Any invasive therapy in this cohort carries considerable risk. Therefore, before committing the patient to an invasive procedure, there should be confidence in the exact pathology and likely outcomes.
Clinical features of congestive heart failure and differentiating right from left heart failure:
Depending on which side of the heart is involved, different symptoms and signs may be present. In most heart failure cases, the left heart is involved, which results in significant fatigue and shortness of breath, first with exertion and eventually at rest, with the progression of the disease.
Paroxysmal Nocturnal Dyspnea and orthopnea are the two hallmarks of Left Heart Failure (LHF).
Orthopnea is the sensation of breathlessness in the recumbent position, which is usually relieved by sitting or standing. Paroxysmal Nocturnal Dyspnea (PND) is a sensation of shortness of breath that awakens the patient, usually 1 or 2 hours after sleep, and improves in the upright position. As the LHF progresses, the filling (resting or diastolic) pressures increase in the left ventricle and left atrium. Increasingly, this pressure gets transmitted back towards the lungs, resulting in pulmonary congestion that causes PND, orthopnea and pulmonary edema in severe cases. With further progression of the LHF, eventually, the right heart becomes overwhelmed and fails. Hence, the most common cause of Right Heart Failure is Left Heart Failure.
As mentioned previously, in about 2% of the patients presenting with heart failure signs and symptoms, the primary pathology can only reside on the right side, i.e. RHF. Here, the main symptoms are fatigue, abdominal fullness, loss of appetite and dyspnea on exertion due to reduced RV stroke volume and lung perfusion. Essential physical findings (signs) of RHF include distended neck veins (Raised Jugular Venous Pressure or JVP) and peripheral pitting edema, especially in the lower limbs. The crucial features differentiating RHF from LHF are the lack of frequent PND, orthopnea, and episodes of pulmonary edema, at least initially.
Right Heart Failure and reduced stroke volume in tricuspid valve regurgitation:
RHF is a clinical syndrome arising from the “impaired function of the right side of the heart”, culminating in “reduced effective stroke volume“, i.e., the blood volume that leaves the right ventricle with each heartbeat via pulmonary artery “towards the lungs”. Here, the phrase “towards the lungs” is crucial in defining the effectiveness of the stroke volume.
As an example, in tricuspid regurgitation (TR), blood leaves the right ventricle towards the right atrium in the wrong direction. In this scenario, the RV function appears to be preserved on echocardiogram. However, the effectiveness of the contraction is reduced as a large portion of the blood is ejected in the wrong direction, resulting in reduced stroke volume—the more severe the TR, the worse the stroke volume and right heart failure. Consequently, the patient will have signs and symptoms of the RHF in the presence of a seemingly preserved RV function. Rheumatic fever or endocarditis involving TV or damage caused by implantation of Cardiac Implantable Electronic Devices (CIED) are some pathologies that can create this clinical picture.
Severe TR and RHF with a seemingly preserved RV function, is an important clue that the primary pathology is intrinsic to the tricuspid valve and creates a window of opportunity to treat the patient’s symptoms by targeting the tricuspid valve.
Mechanisms of CIED-related Tricuspid Valve Regurgitation:
CIED-related tricuspid valve regurgitation (TR), has been defined in many publications and case series. Proposed mechanisms for CIED-related TR include implantation-related, pacing-related or device-mediated.
Implantation-related: Depending on the operator’s technique to implant the device, the risk of TR and damage to the tricuspid valve might differ. There is some evidence, although not robust, that some techniques could cause more damage to the valve than others. Examples are the “prolapsing” technique versus direct crossing of the tricuspid valve, with the latter presumed to be riskier.
Pacing-related: A number of studies have associated RV pacing with a worsening degree of tricuspid valve regurgitation. Alteration in RV geometry due to pacing has been suggested as a likely mechanism. The data in this regard is not as strong as what has been observed with worsening of mitral regurgitation with pacing.
Device (lead)-mediated: Pacemaker or defibrillator leads can interfere with tricuspid valve function by a few different mechanisms, including Impinging, Adhering, Entrapment, Entangling and Perforation, as shown in Table-1.
The terminology used to describe the different lead problems can be highly confusing. Chronologically, impingement, adhering, and entrapment occur along a continuum. The lead initially impinges (rests loosely without adhesion) on a leaflet and, over time, adheres to the leaflet firmly. Over time, fibrotic tissue gradually encroaches over the lead, burying the lead deep inside the tissue, entrapping the lead. Entangling and Perforation are mostly self-explanatory.
An 81-year-old man was referred (2019) with “dyspnea on exertion” and fatigue, progressively increasing during the past three years. He did not have dyspnea at rest, but his exercise tolerance had declined significantly (NYHA class III), especially during the previous year. He denied any symptoms indicative of Paroxysmal Nocturnal Dyspnea (PND) or Orthopnea and had no presentation to the hospital with an acute episode of dyspnea (a clue for predominant RHF). He used to be a professional race walker and could easily race-walk 15 Km up to 5 years ago, but now he could hardly carry a few bags from the shops to his car.
His only medication was warfarin for long-standing Atrial Fibrillation (AF), diagnosed in 2000. He had a Pacemaker inserted for Complete Heart Block in 2005. In 2012 he had a box change and a new ventricular lead insertion. It was unclear why he required a “new ventricular lead” from the available medical records. An Echocardiogram in 2011 had shown low-normal left ventricle function and only trivial to mild tricuspid regurgitation with a mildly dilated left atrium.
In 2013, one year after the box change and insertion of the new lead, he had reported to his Cardiologist that “his general health has gone downhill“; however, he could not give more specific clues. At this point, his echocardiogram showed mild tricuspid regurgitation with mild-to-moderate pulmonary hypertension and moderately dilated atria.
Unfortunately, due to an extended overseas trip, he was lost to follow-up for nearly five years until 2019. His symptoms were worsening gradually over this period, and initially, they used to be dismissed as “age-related complaints” by his family and primary healthcare providers.
He was living with his partner and still independent for activities of daily living. He did not have diabetes, hypertension, or other significant comorbidities and never smoked. His renal function was normal.
On presentation (2019), His blood pressure was 130/70 mmHg, and his pulse was 70 bpm. Lungs were relatively clear to auscultation, and there was only mild pitting edema at the ankles. A prominent feature in his physical exam, visible from across the room, was a distended and pulsatile Jugular Vein, shown video-1.
Video-1: Severely raised JVP with V waves while sitting, 90 degrees
ECG and Chest X-Ray:
ECG and Chest X-Ray are shown below. Rhythm is paced with underlying Atrial Fibrillation. Atrial lead is capped. In apical CXR, RV lead is fixed to the inferior border of the right ventricle and in the lateral CXR, the lead is the posterior aspect of the right ventricle. Overall, the CXR is indicative of an infero-posterior position of the lead.
His echocardiogram showed grossly dilated atria. Left ventricular function was about 50%, mostly due to dys-synchronous septal wall motion. There was mild Mitral Regurgitation. The right ventricle was moderate to severely dilated but RV function was relatively preserved. There was severe, eccentric tricuspid regurgitation that originated from the postero-septal aspect (commisure) of the tricuspid valve where the pacemaker lead is visible. Looking at the images, we see that the pacemaker lead is fixated on the posterior wall with very little movement.
Video-2: Low-normal and dyssynchronous LV function (Paced). RV dilated.
Video-3: Mild MR, sclerotic AV with satisfactory function and reasonable RV function.
Video-4: RV inflow view: with septal (S) and Anterior (A) leaflets in view.
Video-5: TR jet originating close to the septal leaflet and posteriorly directed.
Video-6: Short axis view showing reasonable LV function and dilated RV
Video-7: Apical view showing mild-moderate MR
Video-8: RV outflow view showing septal and posterior leaflets.
Video-9: Significant TR originating from the postero-septal leaflets juncture
Video-10: Apical view showing grossly dilated atria and dilated RV. Lead slack can be seen attached to the RA wall.
Video-11: TR jet starting slightly above the coaptation line. This is usually a hint in favour of lead-induced TR.
Video-12: as the probe tilted more, the TR jet becomes more prominent with the CS in view, indicating the involvement of the posterior and inferior part of the TV
Video-13: probe tilted posteriorly with the CS in view. S and P leaflets are visible. jet originates posteriorly, near the postero-septal commissure, well above coaptation line.
Video-14: Subcostal view showing that the lead is fixated and has minimal movements which mimic the movement of the right ventricle.
Video-15: Origin of the eccentric TR jet, next to the lead (lead-hugging) in subcostal view.
Video-16: Severely dilated IVC with no respiratory collapse, which explains the raised JVP.
The challenge: is the TR just due to AF and dilated atria, or CIED-lead is involved ?
If there was no device-lead present, in this case, the TR could be attributed to the dilated tricuspid annulus, which is a common finding in patients with long-standing atrial fibrillation and severely dilated atria. However, a crucial question arises when a device lead is present; is the lead responsible for the regurgitation’s “presence” or “severity”? Answering this question has obvious clinical and management implications, especially in a patient with signs and symptoms of right heart failure.
Several clues can guide us to answer this question. It is essential to review the imaging studies before the device implantation. If there has been significant TR in these studies, the likelihood of CIED lead-related TR is much less.
The characteristics of TR jet and lead in echocardiographic images can help immensely. CIED lead-related TR jet is usually eccentric and tends to hug the lead and the jet can start well above the leaflet’s coaptation line (Figure-3).
The lead is usually off-centred, fixed to a leaflet, and has minimal motion (video-14). An entrapped lead is closely associated with a leaflet and moves in concert; leaflet puppeteers the lead. Based on these pictures and the characteristics of the TR jet, it could be assumed that the likely cause of the pathology is either an “entrapped lead” or a “perforated leaflet“.
Tricuspid valve leaflet localisation on 2D echocardiogram:
TV has a complex structure with huge variability. It usually comprises three leaflets, but the valve can have two, three, four or even five leaflets. The Septal (S) leaflet is the longest; the Anterior (A) leaflet is the largest, and the posterior (P) leaflet is the smallest. Tricuspid valve should be thoroughly interrogated in every available view to localise the affected leaflets. However, the three most important views on 2D echocardiography are RV inflow, short-axis and 4-chamber views.
We can see septal and anterior leaflets in the RV inflow view (video-4). If “LVOT” is visible in apical pictures, the visible leaflets are septal and anterior, and if the Coronary Sinus (CS) is visible, the leaflets are septal and posterior (Figure-4). We usually see the anterior leaflet in the short-axis view (SAX), the largest TV leaflet, but if two leaflets are in view, they are usually septal and anterior (video-8).
CT coronary angiogram and CIED-induced tricuspid regurgitation.
Another imaging modality that can be incredibly valuable in determining the course of a device lead and localising the pathology is CT Coronary Angiogram (CTCA), an adjunctive imaging tool. With the advance in transcatheter TV device implantations, CTCA has proven to be of exceptional value in interrogating the tricuspid valve and the adjacent structures. This video depicts how CT can help localise the CIED-lead position compared to the tricuspid valve.