Warning Symptoms Precede Sudden Cardiac Arrest in most cases.

Warning symptoms, notably chest pain and dyspnea, occur during the 4 weeks preceding sudden cardiac arrest (SCA) in at least half of cases involving middle-aged adults, suggests a new study. The warnings are usually ignored, observe researchers, with few patients phoning 911 in response to what is almost always a fatal event.

The analysis is based on the Oregon Sudden Unexpected Death (SUD) cohort which was published online December 22, 2015 in the Annals of Internal Medicine.

It suggests that sudden death may not be as sudden as we have been thinking till now. There were people who had their symptoms not only in the 24 hours that preceded the arrest, but also in the 4 weeks that preceded their event.


The Oregon SUD study is a large, prospective, community-based study of deceased and surviving patients who had an SCA in the Portland, Oregon metropolitan area. The analysis included 839 patients between 35 and 65 years of age with SCA whose prodromal symptoms could be comprehensively assessed.

Of the 839 patients, 430 patients or 51% of the cohort experienced at least one symptom within the 4 weeks preceding their arrest. Men and women experienced prodromal symptoms with equal frequency at 50% vs 53%, respectively.

Symptoms also started more than an hour before SCA onset in 80% of patients; but in 147 of these patients, symptom onset occurred more than 24 hours before their arrest. Among this subgroup of patients, 93% had recurrent new episodes of symptoms during the 24 hours preceding their arrest.

The main symptom was chest pain, documented in 199 patients,” or 46%, Marijon observed. Of those, 76% had “intermittent typical angina,” he said.

Another 18% of patients had dyspnea as their apparent prodromal symptom; about one-third of this group had established congestive heart failure or a pulmonary condition.


What Can Be Done

An early call to 911 was associated with better survival odds in the current study suggesting that there is a potential to enhance short-term prevention of SCA by targeting public awareness of SCA.

Source: Warning Symptoms Can Often Precede Sudden Cardiac Arrest

Using AEDs (Automated External Defibrillators).

Using AEDs.

Automated external defibrillators (AEDs) are portable devices that shock a person’s heart back into rhythm after suffering sudden cardiac arrest, greatly increasing chances of survival. But not all public places have these life-saving devices and some may need them more than others, according to a recent study: http://ht.ly/nRsp5 Do you know how to use an AED? Share this infographic with your friends and family!

via CardioSmart.

Study Shows Obstructive Sleep Apnea Increases Risk of Sudden Cardiac Death.


Obstructive sleep apnea (OSA)  is a novel risk factor for sudden cardiac death (SCD), according to a study published June 11 in the Journal of the American College of Cardiology JACC.


The study looked at 10,701 adults referred for polysomnography (sleep study) and followed them for an average of 5.3 years for incidents of resuscitated or fatal SCD.


Results showed that 142 patients experienced SCD, with the most common predictors being a patient aged 60 years or above , having 20 apnea episodes an hour and having a lowest nocturnal oxygen saturation level of below 78 percent.

 Results showed that the severity of nocturnal hypoxemia strongly predicts SCD independently of other risk factors. In the lowest nocturnal oxygen saturation, a drop to below 78 percent increases a patient’s risk of SCD by 81 percent.

“People at risk for OSA ought to be screened with a sleep study, and potentially then being treated for sleep apnea might reduce the risk of dying suddenly,” says Deepak Bhatt, MD, MPH, FACC, in a CardioSource Video News interview on the study’s findings.

It is well known that sleep apnea is seen in obese individuals and can lead to high blood pressure and heart beat problems in the long run.

Prompt recognition and Early treatment of OSA in obese individuals is recommended. 

via CardioSource – Study Shows Obstructive Sleep Apnea Increases Risk of Sudden Cardiac Death.

Tests we perform


Cardiac Electrophysiology is a subspeciality of Cardiology and deals with the diagnosis and management of arrhythmias. It is estimated that approximately 1 million patients in India suffer from abnormal tachycardias which can be cured by a procedure called Ablation.


Hinduja hospital has recently acquired the state of the art St. Jude Medical EP Workmate which is the recording and mapping system used for treatment of arrhythmias. Also, it’s the first hospital to acquire the 3D-Mapping system called Ensite Velocity from St. Jude Medical in the whole of Western India. Also with the joining of Full time Cardiac Electrophysiologists, the hospital provides the full range of diagnostic and therapeutic services necessary for cardiac electrophysiology.


These services can be categorized into the following:

  1. Diagnostic services for patients with Syncope
  2. Diagnostic/ Therapeutic services for patients with Tachycardias (Fast heart rates)
  3. Diagnostic Services for evaluating the risk for Sudden Cardiac Arrest
  4. Diagnostic/ Therapeutic services for patients with Bradycardias (slow heart rates)
  5. Device therapy for patients with Heart Failure



A. Diagnostic services for patients with Syncope:

Syncope is a common symptom presenting in the emergency department or as an outpatient problem. These patients need careful evaluation of their history in order to differentiate them from seizure and also to risk stratify them. The following tests have been provided in this hospital for them

  1. ECG (Electrocardiogram): needed to rule out cardiac disorders like ischemic heart disease, arrhythmias and genetic disorders like long QT syndrome.
  2. Holter recording: ECG is recorded for 24 hours to detect and rule out arrhythmic causes of syncope.
  3. Tilt-table testing: Herein, the patient is made to lie on the tilt bed and then the bed tilted 70 degrees with monitoring of heart rate and blood pressure. Subsequently a provocative phase is carried out by giving drugs. This is an extremely useful test for patients with vasovagal syncope.
  4. External Event recorder: This is a device like a Holter which is rented to the patients on a long term basis (weekly) to as to record the ECG during syncopal episodes. It records the ECG 30 seconds before the syncope episode thereby pinpointing any cardiac arrhythmias.
  5. Internal Event recorder: This is small device implanted in the chest to record syncope which are infrequent, and can be kept in the patient for 2-3 years.


B. Diagnostic/ Therapeutic services for patients with Tachycardias (Fast heart rates)

1. Electrophysiology (EP) Study:  An electrophysiology (EP) study is a specialized procedure conducted by the Electrophysiologist who has gained special expertise in these procedures. These are carried out in patients with arrhythmias and patients with bypass tracts. Three thin flexible wires/ catheters are inserted and placed in different locations within the heart to record the electrical activity. With the help of the catheter, the electrical system of your heart is studied and problems diagnosed.

2. Ablation: The sources of abnormal heart beats or abnormal connections are then burnt off/ blocked by delivering radiofrequency (RF) energy with the help of a fine catheter. This is called Ablation. This gives complete relief to the patient by curing him permanently of the arrhythmia.

3. 3D-Mapping study: Here in a state of the art 3D-mapping system (Ensite velocity) is used to map the electrical activity of the heart. This is the first and the only hospital in Western India to acquire this technology. This is used in specialized procedures for patients with complex arrhythmias like atrial fibrillation, ventricular fibrillation, atrial tachycardias and flutters.


C.  Diagnostic Services for evaluating the risk for Sudden Cardiac Arrest (SCA):  

SCA kills approximately 4-5 million Indians every year (2 per1000 persons). SCA stops the heart thereby leading to death within minutes. Patients with prior heart attacks and reduced heart function (ejection fraction less than 35%) face the highest risk of SCA. These tests evaluate the risk of developing SCA by non-invasive electrocardiology tests. Hinduja hospital is the only hospital in the country to provide all the below mentioned electrocardiography tests under one roof.

  1. Signal averaged ECG with Late Potentials: This is a specialized ECG test where the electrodes are connected on your chest and limbs and a high definition ECG is recorded with a special machine. This machine amplifies your ECG and gives a value for the Late Potentials. Presence of late potential warns of higher risk of sudden cardiac arrest
  2. T wave Alternans: In this test, the patient is made to walk on a treadmill. At the end of the test, the software calculates  a value for T-Wave Alternans which is a very sensitive marker for sudden cardiac arrest
  3. Heart Rate Variability: The Heart Rate Variability value is derived from the 24 hour Holter recording with the help of a special software. Decrease heart rate variability may be an indicator of increased risk of sudden cardiac arrest.


D.  Diagnostic/ Therapeutic services for patients with Bradycardias (slow heart rates)

  1. Electrophysiology (EP) Study: These are carried out to study the function of the sinus node and the AV node.

2.  Pacemaker implantation: Artificial pacemakers are small coin shaped devices (1-2 inches in diameter) which generates electrical current. They are placed just below one’s collar bone and the current is transmitted to the heart with the help of one or two wires (leads) positioned in the right side of the heart. They carry out the normal electrical function of the heart and thus cure the patient of his symptoms due to bradycardia. Pacemaker outpatients clinics are held every Friday from 2 to 5 pm where in patients with pacemakers are followed up and their devices checked.


E. Device therapy for patients with Heart Failure (Ejection fraction < 35%)

Heart Failure (HF) continues to be a major heart problem and an important cause of hospitalization in India. In 2006, the prevalence of heart failure patients was estimated to be around 18.8 million (which is 1.7% of the population) with the annual incidence of 1.57 million per year.

There are 2 devices which can be used in HF treatments (1) Cardiac Resynchronization Therapy and (2) Implantable Cardiac Defibrillator

1.  Cardiac Resynchronization Therapy:

The  synchronized contraction (Synchrony) is lost between the various chambers of the heart in patients with heart failure.
CRT is designed to correct this dys-synchrony between chambers of the heart and thereby improve the heart function. In this procedure, a pacemaker  is implanted in the upper chest region and 3 wires (leads) are inserted into the heart to deliver electrical therapy. This results in a more coordinated and effective heart beat improving the heart function.

2.  Implantable Cardiac Defibrillators (ICD)

ICD is a device designed to shock the heart out of a dangerous life threatening rhythm. It is implanted below the skin in the upper chest and is then connected to a wire (lead) which monitors the heart rhythm 24 hours. Whenever it detects a dangerous heart rhythm, it delivers an internal shock to the heart and Patients most at risk from sudden cardiac arrest benefit from these devices


Hinduja hospital has for the first time in the country provided the entire gamut of diagnostic and therapeutic services in the field of cardiac electrophysiology. We hope to provide relief and specialized care to the patients suffering from arrhythmias as these disorders can be very difficult to detect and treat.

Devices for Heart Failure

Devices for Heart Failure:


There are 2 devices which can be used in HF treatments (1) Cardiac Resynchronization Therapy and (2) Implantable Cardiac Defibrillator


(I) Cardiac Resynchronization Therapy:

The heart is made of 2 upper chambers called atria and 2 lower chambers called ventricles. An electrical system controls the synchronized pumping action of these chambers. The atria contract first followed by the 2 ventricles. The 2 ventricles contracts simultaneously to as to ensure optimal pumping of blood to the body and lungs. However this synchronized contraction (Synchrony) is lost between the atria and the ventricles and also between the 2 ventricles. This dys-synchrony leads to further less effective contraction of the heart thereby reducing thereby aggravating the heart failure. This Dys-synchrony can be easily diagnosed by the Physician with the help of the electrocardiogram and the echocardiogram.
CRT is designed to correct this dys-synchrony between the upper and lower chambers of the heart and also between the 2 lower chambers. This ensures simultaneous contraction of the 2 lower chambers thereby improving the contractions. In this procedure, a pacemaker (the size of a pager) is implanted just below the skin in the upper chest region and 3 wires (leads) are inserted into the heart to deliver electrical therapy. The 3 leads are positioned in the right upper, right lower chambers and the left lower chambers. The CRT device simultaneously stimulates the left and right ventricles and restores a coordinated, or “synchronous,” squeezing pattern. This reduces the electrical delay and results in a more coordinated and effective heart beat.

Who needs the CRT?
According to the Heart Rhythm Society, the ideal candidate for a CRT device is someone with:

  1. Moderate to severe heart failure symptoms, despite lifestyle changes and medication
  2. A weakened and enlarged heart muscle
  3. A significant electrical delay in the lower pumping chambers.

How effective is CRT?

There have been around 8-9 clinical trials involving around 5000 patients. Clinical studies demonstrate modest improvements in exercise tolerance, heart failure severity, and quality of life in most patients. Almost two-third of the patients implanted with the device benefit in their symptomatic status and also have decrease in the number of hospitalizations over the next few years. Improvement may happen quickly, but sometimes it can take several months.

(II). Implantable Cardiac Defibrillators (ICD)

ICD is a device designed to shock the heart out of a dangerous life threatening rhythm. The device is similar to the pacemaker and is the size of a pager. It is implanted below the skin in the upper chest and is then connected to a wire (lead) which monitors the heart rhythm 24 hours. Whenever it detects a dangerous heart rhythm, it delivers an internal shock to the heart and restores the normal rhythm.

Who needs ICD? Who is at risk of developing dangerous heart rhythm?

Dangerous heart rhythms can cause Sudden Cardiac Arrest which can cause instant death. Patients most at risk are those with compromised heart function (Ejection fraction < 35%). These patients if symptomatic need to undergo an ICD implantation so as to reduce their risk of dying from sudden cardiac arrests.

How effective is ICD?

There have been around 6 clinical trials involving around 3000 patients. Clinical studies demonstrate modest reduction in the death rates due to sudden cardiac arrest and have been life-saving in the majority of the patients.


Patients with heart failure are at risk of dying from progressive heart failure and sudden cardiac arrest. This can be now corrected and treated effectively by implanting devices (namely CRT and ICD respectively). However, these patients need to be carefully evaluated and selected by the cardiologist before undergoing these procedures so as to ensure maximum benefit.

Sudden Cardiac Arrest

Image Courtesy: Heart Rhythm Society

October is SCA Awareness Month!

Assess Your Risk of SCA (Sudden cardiac arrest) with the Heart Rhythm Society’s online quiz 

What is the difference between Sudden Cardiac Arrest (SCA) and Heart Attack?

ANS:  Heart attack damages the heart while SCA stops the heart.

Heart attack is caused by blockages in the blood supply (coronary arteries) of the heart. The patient complains of acute severe chest pain at rest. In some patients, it may be associated with vomiting, fatigue, breathlessness, sweating and also pain in the arms.

Sudden Cardiac Arrest is caused by sudden electrical disturbance of the heart. This is mostly caused by ventricular tachyarrhythmias, (wherein the lower chambers of the heart beat so fast that there is no effective output of blood from the heart) or by cardiac standstill (no effective heart rhythm). This causes loss of consciousness with brain death ensuing in the next 4 minutes, causing eventual death.

         Who is at risk of SCA?

ANS: Patients with prior heart attacks are the most at risk of SCA. 80-85% of the patients who have SCA have coronary artery disease. Majority of the patients have poor heart pumping function which is called as ejection fraction. The ejection fraction of the heart gives an idea about the output of the heart. Normally ejection fraction is in the range of 55 to 70%, however, patients with most risk of SCA have ejection fraction less than 35%.

Other patients who are more at risk of developing SCA are patients with dilated hearts and electrical disturbances of the heart.

         How to respond to SCA?

ANS:  Death can ensue within minutes of SCA and so prompt CPR (cardiopulmonary resuscitation) is absolutely necessary. Along with it, the patients needs to be electrically shocked (defibrillated) with the help of AED (Automatic External Defibrillator). AED are installed in most of the public utility buildings in most of the western countries and also available with all the ambulance services. The AED promptly detects the abnormal rhythm of the heart and can shock the patient out of it. However, in India, due to the dearth of trained ambulance personel, lack of AED in public places and also not much of awareness about CPR, the outlook for these patients is dismal. Only 5% of the patients are revived successfully and taken to the hospital. A practical step would be to call a doctor or an ambulance immediately.

         How to prevent SCA?

ANS: Patients with prior heart attacks are the most prone for SCA. Though the patient may have undergone angioplasty or bypass grafting to restore the blood supply to their hearts, they are still at risk if the ejection fraction is less than 35%. These patients need to be evaluated by a Cardiologist, preferably a Cardiac Electrophysiologist, to ascertain their risk to develop SCA. Patients with history of prior syncope (loss of consciousness) and history of early deaths due to SCA may need thorough testing.

The basic investigation required is the 2D-echocardiography to ascertain one’s ejection fraction. Patients with low ejection fraction need to be started on medications to reduce their risks of SCA. Some patients need an electrophysiology study (EP study) to study their risk of develop SCA. EP study is a simple procedure in which 3 to 4 wires are placed in the heart via the groin to study the susceptibility to develop SCA. ICDs (implantable cardiac cardioverter defibrillators) are implanted in patients with high risk of SCA. ICDs are small devices which are implanted in the chest. These devices monitor one’s heart rhythm all the time and deliver a small shock in case the dangerous rhythm develops. ICDs are life saving devices, but cost around 4 to 8 lacs depending on the type of device used. They are proven to treat these dangerous rhythms successfully and reduce chances of dying due to SCA by 25 to 35%. There are also non-invasive electrocardiography investigations like 24 hours ECG recording, Treadmill test and ECGs with special markers to detect T-wave alternans, Heart rate variability and Late potentials. All of these investigations are now available at Hinduja Hospital.