Dr. Nishi Patel Breaks Down How Better Detection and Device Therapy Are Reshaping Sudden Cardiac Arrest Care
Sudden cardiac arrest can happen with very little warning. Someone may feel relatively well in the days or even hours beforehand, which is part of what makes identifying at-risk people so difficult. By the time a dangerous rhythm causes someone to collapse, the window for intervention is already extremely small.
That’s why so much of the work in cardiology happens before an emergency ever occurs. Physicians are getting better at identifying signs that a patient may be vulnerable to a dangerous arrhythmia, monitoring people longer, and using imaging and genetic information to understand risks that may not be obvious during a routine exam.
Treatment options have changed as well. Implantable defibrillators remain an important part of preventing sudden cardiac death in high-risk patients. Still, physicians now have more choices in how they implant, program, and combine those devices with other treatments.
For Dr. Nishi Patel, a cardiologist whose work includes advanced cardiac imaging and caring for critically ill heart patients, those options make patient selection increasingly important. The question isn’t simply which technology is available. It’s which combination of monitoring, imaging, treatment, and follow-up makes sense for the individual patient.
Some arrhythmias carry much greater risk than others.
An abnormal heart rhythm doesn’t automatically mean someone is at risk for sudden cardiac arrest.
Atrial fibrillation, for example, is the most common sustained arrhythmia and can substantially increase the risk of stroke, but it doesn’t typically cause cardiac arrest on its own. The rhythms most closely associated with sudden cardiac death originate in the ventricles, including sustained ventricular tachycardia and ventricular fibrillation. Severe bradycardia and complete heart block can also become life-threatening.
Understanding why those rhythms develop is another part of assessing risk.
A patient who has had a large heart attack may be left with scar tissue that changes the way electrical signals travel through the heart. That scar can create conditions that allow ventricular tachycardia to develop.
Other patients have inherited electrical disorders such as long QT syndrome or catecholaminergic polymorphic ventricular tachycardia. Their hearts may appear structurally normal, but abnormalities in how cardiac cells handle electrical signals can still put them at risk for dangerous rhythms.
Patients may reach the same outcome through very different mechanisms, which is why identifying the underlying cause matters when deciding how to monitor and treat someone.
Ejection Fraction Doesn’t Tell the Whole Story
Left ventricular ejection fraction has long played an important role in determining which patients may benefit from an implantable cardioverter defibrillator, or ICD. An ejection fraction of 35 percent has traditionally been an important threshold in primary-prevention decisions for certain patients with heart failure.
It’s a useful measurement, but it doesn’t capture every aspect of sudden cardiac death risk.
Some patients with significantly reduced ejection fractions may never experience a life-threatening ventricular arrhythmia. At the same time, cardiac arrest can occur in people whose ejection fraction remains above the traditional threshold.
That’s where additional information can help physicians build a more complete picture.
Cardiac MRI with late gadolinium enhancement can show areas of scar within the heart muscle and provide information about the way that scar is distributed. Depending on the patient’s condition, genetic testing can identify inherited variants associated with arrhythmia risk. Family history, unexplained fainting, ventricular ectopy, functional status, and other clinical findings can add important context as well.
Patel has discussed the value of considering advanced imaging and genetic information together when evaluating patients whose risk may not be obvious from a single measurement. In some cases, that additional information can change how a patient who initially appeared relatively low-risk is evaluated.
Risk assessment, then, becomes less about finding one number that provides the answer and more about understanding how several pieces of information fit together.
Heart Monitoring No Longer Has to Stop After 24 Hours
For years, ambulatory heart monitoring often meant wearing a Holter monitor for a day or two. That works well if the abnormal rhythm happens during the monitoring period. If someone’s symptoms occur once every few weeks, the monitor may not capture anything.
Longer monitoring options have changed that.
Patch monitors can record for days or weeks. Mobile cardiac telemetry can transmit rhythm information remotely, allowing clinicians to identify certain abnormalities much sooner. Implantable loop recorders can remain in place for years, allowing physicians to capture infrequent arrhythmias that shorter monitoring periods might miss.
Consumer devices have added another source of information. Some smartwatches can identify irregular rhythms or record a single-lead ECG, which may prompt someone to seek medical evaluation when they otherwise wouldn’t have known anything was wrong.
These devices have limitations. They aren’t designed to diagnose every type of arrhythmia, and false positives can lead to unnecessary concern and additional testing. Their usefulness depends in part on knowing which findings warrant further evaluation.
Artificial intelligence may eventually add another layer to that process. Researchers have developed models that can find patterns in standard 12-lead ECGs that may be associated with reduced ejection fraction, structural heart disease, or future cardiovascular risk, even when those patterns aren’t obvious during routine interpretation.
That doesn’t make an algorithm a substitute for a cardiologist. It may, however, give clinicians another way to identify patients who should be evaluated more closely using a test that’s already widely available.
Choosing a Device Has Become More Individualized
For patients at sufficiently high risk, an implantable cardioverter defibrillator can detect a dangerous ventricular rhythm and deliver therapy to restore a more normal one.
The range of devices and treatment approaches has changed.
Traditional ICDs use leads that travel through the veins and into the heart. Subcutaneous ICDs avoid placing leads inside the heart and blood vessels, making them useful for patients who need defibrillation but don’t require pacing.
Leadless pacemakers provide another option for selected patients who need pacing without a conventional transvenous lead. Wearable cardioverter defibrillators may be used temporarily in certain situations when a patient’s risk is still being evaluated or when physicians are waiting to see whether heart function improves before considering a permanent device.
Cardiac resynchronization therapy addresses another problem by helping the ventricles contract more coordinately in appropriately selected patients with heart failure and electrical conduction abnormalities. Conduction system pacing, including His bundle and left bundle branch area pacing, has also expanded options for physicians trying to preserve or restore a more physiologic pattern of electrical activation.
How a device is programmed matters, too. Adjusting detection intervals and rate thresholds can help reduce unnecessary or inappropriate shocks in appropriately selected patients.
With more options available, the decision becomes increasingly specific to the person receiving the device. Anatomy, age, underlying disease, pacing needs, infection risk, comorbidities, and the likelihood of future procedures can all influence the choice.
That is also why Patel spends time translating evidence surrounding cardiac devices for clinical audiences. Knowing that a device works is only part of the decision. Physicians still have to determine when its benefits outweigh its risks for the patient in front of them.
Catheter ablation can be part of that plan, too. In patients with recurrent scar-related ventricular tachycardia, ablation can reduce the burden of arrhythmia and the number of ICD therapies a patient experiences. These more complicated cases may involve electrophysiologists, heart failure specialists, and cardiac imaging physicians working together to decide how the different treatments should fit into the patient’s care.
Better Technology Doesn’t Automatically Mean Better Access
The ability to detect and treat dangerous arrhythmias has improved considerably, but those advances aren’t equally available everywhere.
A patient living near a major medical center may have relatively easy access to cardiac MRI, advanced imaging specialists, electrophysiologists, and dedicated heart failure programs. Someone in a rural community may have to travel hours for the same evaluation.
Telemedicine can help close some of that distance. Cardiovascular specialists elsewhere can interpret images acquired at a community or rural hospital, allowing local clinicians to access expertise that isn’t available on-site. Remote monitoring of implanted cardiac devices can also identify arrhythmias and changes in device function without requiring the patient to travel to a clinic for every check.
This is an important part of Patel’s work as National Director of Cardiac Imaging for a telemedicine organization. His role includes extending cardiac diagnostic expertise to rural hospitals, where access to subspecialty cardiovascular care may otherwise be limited.
The technology for finding cardiac problems has advanced quickly. Making sure patients can actually benefit from those advances remains a separate challenge.
About Dr. Nishi Patel
Nishi Patel, MD, is a cardiologist whose clinical work includes advanced heart failure, cardiac critical care, and multimodality cardiac imaging, including echocardiography, cardiac CT, and nuclear cardiology. He also cares for critically ill cardiac patients who require mechanical circulatory support, including ECMO, Impella, and left ventricular assist devices.
As National Director of Cardiac Imaging for a telemedicine organization, Patel works to expand access to cardiovascular diagnostics in hospitals that lack the on-site specialty resources available at larger medical centers. He also holds a faculty appointment in medical education and has been recognized for his teaching.
His published and ongoing work includes ventricular assist device outcomes and cardiac genetics, and he speaks to clinical audiences about cardiac imaging, device selection, and the challenges of providing specialty cardiovascular care across different healthcare settings.
Taken together, these areas of cardiology point to the same shift in sudden cardiac arrest care. Physicians have more ways to identify risk before an emergency, monitor patients over time, and choose treatment options once that risk becomes clear. The challenge now is using those tools selectively and making them available to the patients most likely to benefit.
