Stiff Left Atrial Syndrome After Multiple Percutaneous Catheter Ablations
Role for Invasive Hemodynamic Exercise Testing
Refractory atrial arrhythmias often require repeat catheter ablations causing decreased atrial compliance. Overtime, dyspnea may develop from secondary elevated pulmonary pressures because of a noncompliant left atrium (LA), referred to as the stiff LA syndrome. We present a case of a patient with a complicated arrhythmia history refractory to antiarrhythmic medications necessitating multiple ablations presenting with dyspnea on exertion. Cardiopulmonary exercise testing (CPET) with invasive hemodynamic measurement supported the diagnosis of stiff LA syndrome noticeable only during exercise.
The patient is a 68-year-old male with a history of atrial arrhythmias refractory to anti-arrhythmic medications and repeat left atrial ablations who presents with exercise intolerance. A transthoracic echocardiogram showed preserved ejection fraction, biatrial enlargement, grade II diastolic dysfunction, and mildly elevated right ventricular systolic pressure, while a nuclear perfusion myocardial scan, cardiac computed tomography angiography, CPET, pulmonary function test, and ventilation-perfusion scan were unremarkable. Diuretics for presumed heart failure with preserved ejection fraction subsequently caused orthostatic symptoms. As such, he was referred for a repeat CPET with the addition of invasive hemodynamic assessment.
The patient underwent a CPET on a cycle ergometer, with hemodynamic results and hemodynamic tracings shown in Table 1 and Figure 1, respectively. Baseline rhythm was atrial fibrillation with ventricular pacing. Baseline hemodynamics revealed normal right- and left-sided filling pressures and cardiac output. Exercise precipitated rapid and sustained increases in right atrial pressure and LA pressure out of proportion to increase in left ventricular (LV) end-diastolic pressure with large V waves ~45 to 50 mm Hg. A low left ventricular transmural pressure, defined as the difference between the left ventricular end diastolic and right atrial pressure, suggested right ventricle pressure overload during exercise contributed to the increases in LV filling pressures. Furthermore, an increase in mean pulmonary artery pressure and transpulmonary gradient suggested concomitant exercise-induced pulmonary hypertension.
In this patient with dyspnea on exertion of unclear cause, invasive hemodynamic CPET unmasked large V waves on LA pressure assessment and pulmonary hypertension only noticeable with exercise, caused by the stiff LA syndrome. First described as a complication after mitral valve surgery, more recently, the stiff LA syndrome has been reported as a potential complication in those who have undergone surgical or catheter ablation for atrial arrhythmias.1,2
Normally, the LA is a compliant chamber that fills via the low resistance pulmonary vasculature throughout systole. In early systole, the atrial pressure is at its lowest, allowing for atrial filling, represented as the x-descent. During late systole, pressure begins to increase with the rise dictated by the pressure–volume relationship. Figure 2 depicts a hypothetical pressure–volume relationship as would be seen in the stiff LA syndrome. As compliance decreases because of atrial scarring, the effect is more pronounced in late systole, causing markedly elevated V waves. In turn, this increased back pressure leads to elevated postcapillary pulmonary pressures and subsequent symptoms of dyspnea on exertion. Over time, persistent elevations in pulmonary venous pressure can lead to pulmonary arterial remodeling and right ventricle dysfunction.
Importantly, in our patient, there was no evidence of pulmonary vein stenosis, a common complication after ablations, or other causes of elevated V waves, such as mitral regurgitation. Furthermore, a low transmural pressure along with the disproportionate rise in estimated LA pressure compared with LV end-diastolic pressure suggests a noncompliant LA as cause for his exertional symptoms arguing against LV diastolic dysfunction as causative of his dyspnea.
There are no proven therapies for stiff LA syndrome. Potential strategies include diuresis or venodilators to decrease preload, negative inotropic agents, or improving ventricular–arterial coupling with the use of afterload reduction, thus, augmenting diastolic suction and, therefore, atrial emptying. As our patient had normal filling pressures at rest, he expectedly developed orthostatic symptoms with diuresis. Phosphodiesterase 5 inhibitors may be considered with the caveat that increasing venous return to a noncompliant LA may precipitate pulmonary edema. Given the low transmural pressure, significant diastolic ventricular interdependence from pericardial constraint may be contributing to exertional symptoms. While pericardial stripping would potentially alleviate biventricular diastolic interaction and improve LV filling and consequently improve cardiac output, this would not affect LA compliance. Finally, atrial septostomy could be considered for palliation after extensive scrutiny, understanding the possibility of precipitating right heart failure.
This case highlights not only the role of individualized invasive hemodynamic cardiac testing, but also the importance of the mechanical properties of the atrium. By increasing awareness of the stiff LA syndrome, more focus could shift toward potential prevention strategies and treatment options.
- Received January 19, 2017.
- Accepted April 10, 2017.
- © 2017 American Heart Association, Inc.
- Gibson DN,
- Di Biase L,
- Mohanty P,
- Patel JD,
- Bai R,
- Sanchez J,
- Burkhardt JD,
- Heywood JT,
- Johnson AD,
- Rubenson DS,
- Horton R,
- Gallinghouse GJ,
- Beheiry S,
- Curtis GP,
- Cohen DN,
- Lee MY,
- Smith MR,
- Gopinath D,
- Lewis WR,
- Natale A