Novel pacemakers MRI compatible

In the summer of 2006, Vikas Saxena (34) fainted in his kitchen. Over the next two months, Vikas had three such unexplained fainting episodes. Vikas was diagnosed with bradycardia, a condition in which the heartbeat becomes slower than normal. After much diagnostic investigation and deliberation with colleagues his cardiologist decided that he needed a pacemaker to normalise the heartbeat.

A pacemaker is a small device inserted under the skin close to the heart. It consists of two parts: a pulse generator (containing the battery) and electrical leads (thin insulated wires inserted in the heart muscle). The implanted pacemaker generates electrical impulses and enables the heart to maintain a normal beating rate. Patients are prescribed pacemakers for conditions such as heart blocks (abnormal conduction of electricity in the heart), bradycardia (abnormally slow heartbeat) and supraventricular tachycardia (abnormally fast heartbeat).  
Pacemaker implantation is usually a safe procedure with a low risk of complications. The surgery is quick, most patients are discharged within a day and the recovery time is minimal. Pacemaker implantation procedures are on the rise in India because a pacemaker saves lives and improves the quality of life for patients.

Vikas lived comfortably with his pacemaker for four years. Then he developed severe pain in his lower back. He needed an MRI scan to diagnose the reason for this and to rule out any internal bleeding, injury, infection or tumour. The problem here was that most people with pacemakers were generally denied MRI scans because its powerful magnetic fields and radio waves  could damage the pacemaker. Hospitals also sometimes refuse to do an MRI scan as this could injure patients and damage the pacemaker system.

Such patients could only rely on x-rays and these were not as precise as MRI scans. Moreover, the 1.5 Tesla MRI machines takes  longer time to scan the patient. The team of cardiologists and radiologists treating Vikas had to establish the compatibility of Vikas’ pacemaker with this machine, then re-programme it to MRI-safe settings before doing the scan. During the procedure, the electrocardiogram was continuously monitored so that the pacemaker malfunction can be detected early. Following the MRI, the pacemaker had to be reset to the original setting.

Today, there have been technological advancements in both MRI machines and pacemakers. Most hospitals have 3.0 Tesla MRI scanners that are superior with a shorter scan time and better image quality, which is a major advantage in the diagnosis of soft tissue cancers.

New-gen pacemakers
Today, we also have new-generation pacemakers that are compatible with the new 3.0 Tesla and 1.5 Tesla MRI machines. These revolutionary innovative pacemakers are a huge leap in medical innovation and come with a host of benefits for patients as well as physicians.
The new pacemakers are equipped with enhanced automation so the system changes required before scanning can be programmed to automatically finish after a certain time, thereby giving patients more flexibility. With no restriction on the part of body to be scanned, these new generation pacemakers can be implanted to anybody who might need a MRI scan in future.

The 3.0 Tesla MRI compatible pacemakers offer the options of automatic daily monit-oring and advanced diagnostics which help physicians identify arrhythmias (abnormalities in heart beat) sooner, enabling them to initiate patient anti-coagulation therapy to reduce the risk of stroke. Additionally, the-se pacemakers have a longer life of over 12 years compared to the previous generation devices, which means they don’t need to be replaced as often.

Most of the large and reputed hospital chains in India have moved from the 1.5 Tesla MRI to the 3.0 Tesla scanners, so it is in the best interest of the patient to get a pacemaker that is compatible with these new age MRI machines. It is estimated that in India, about 20,000 pacemaker implants take place annually and this figure is likely to increase in the future.
This is why I advise that patients speak with their doctors, account for this ahead of time and get an MRI compatible pacemaker in the first place. And if you already have a conventional pacemaker implanted and you have a condition that might require an MRI scan in the future, speak to your cardiologist about upgrading it to the more advanced 3.0 Tesla MRI compatible one.

(The writer is Senior Consultant, Interventional Cardiology & Electro physiology, Apollo Hospitals, Bengaluru)