A case report-facing blues in cardiac amyloidosis: no more a zebra.

Background: Cardiac amyloidosis presentation in an affected individual can be varied. We describe a patient who had the entire spectrum of involvement in his life time. Initially presented as an ischaemic heart disease and later developed complete heart block (CHB) and frank cardiomyopathy. Increased load of amyloid caused lead-tissue interface disruption resulting in high pacing thresholds with difficulty in capture during permanent pacemaker implantation requiring a novel strategy of management.

Case Summary: A 65-year-old male presented with two episodes of syncope with a history of gradually progressive dyspnoea of 6 months duration along with lower limb swelling for last 1-2 months. He had a history of drug-eluting stent implantation for stable ischaemic heart disease 4 years back. Now he presented with a CHB and a transthoracic echocardiogram hinted towards a restrictive physiology and an infiltrative disease. Cardiac magnetic resonance imaging could not be done in view of the incompatible temporary pacemaker on which the patient was dependent. Abdominal fat pad biopsy was positive for amyloid. He was taken up for permanent pacemaker implantation; however, multiple attempts could not achieve desired threshold and capture amplitudes in the right ventricular apex, septum, or outflow region. The lead was placed in the coronary sinus and a stent was placed proximally to trap the lead behind the deployed stent. Threshold and impedance were satisfactory. Cardiac biopsy subsequently confirmed aTTR amyloidosis.

Discussion: The patient had an ischaemic heart disease, conduction disease, and cardiomyopathy as the manifestation of cardiac amyloidosis. While two-dimensional echo is the screening tool of choice, cardiac biopsy remains the gold standard of diagnosis for amyloidosis. Cardiac pacing comes with its own unique set of challenges in patients with advanced amyloid cardiomyopathy and have to be overcome for symptomatic benefit of the patient. Coronary sinus may be utilized in such patients for single-site ventricular pacing and placing a stent may help to anchor the lead when placed within it.