instrument chi cheng 
Chi Cheng ( July 15 , 1970 -- April 13 , 2013 ) was an American musician , best known as the bassist for the American alternative metal band Deftones . His career ended in 2008 , when he was involved in a serious automobile crash in Santa Clara , California . After the crash , he remained in a semi - comatose state for four years before dying of a cardiac arrest in April 2013 . Alternative metal ( also known as alt - metal ) is a rock music genre that infuses heavy metal with influences from alternative rock and other genres not normally associated with metal . Alternative metal bands are often characterized by heavily downtuned , mid - paced ___MASK15___ riffs , a mixture of accessible melodic vocals and harsh vocals and sometimes unconventional sounds within other heavy metal styles . The term has been in use since the 1980s , although it came into prominence in the 1990s . Deftones is an American alternative metal band from Sacramento , California , U . S . Formed in 1988 , the band was founded by Chino Moreno ( lead vocals , rhythm ___MASK15___ ), Stephen Carpenter ( lead ___MASK15___ ), Abe Cunningham ( drums ) and Dominic Garcia ( bass ). During the group ' s first five years , the band ' s lineup changed several times , but stabilized in 1993 when Cunningham rejoined the group after his departure in 1990 . Cunningham replaced John Taylor , who had replaced Garcia after he had switched to drums in 1990 , and the bassist role had been filled by Chi Cheng . The lineup remained stable for fifteen years , with the exception of keyboardist and turntablist Frank Delgado being added in 1999 . In 2008 , Cheng was involved in an automobile accident that ended his stint with Deftones and eventually took his life in 2013 . He has been replaced by Sergio Vega . The band is known as one of the most experimental groups to have come from the alternative metal music scene . The heart is a muscular ___MASK7___ in humans and other animals , which pumps blood through the blood vessels of the circulatory system . Blood provides the body with oxygen and nutrients , as well as assists in the removal of metabolic wastes . The heart is located between the lungs , in the middle compartment of the chest . In humans , other mammals , and birds , the heart is divided into four chambers : upper left and right atria ; and lower left and right ventricles . Commonly the right atrium and ventricle are referred together as the " right heart " and their left counterparts as the " left heart ". Fish in contrast have two chambers , an atrium and a ventricle , while reptiles have three chambers . In a healthy heart blood flows one way through the heart due to heart valves , which prevent backflow . The heart is enclosed in a protective sac , the pericardium , which also contains a small amount of fluid . The wall of the heart is made up of three layers : epicardium , myocardium , and endocardium . The heart pumps blood with a rhythm determined by a group of pacemaking cells in the sinoatrial node . These generate a current that causes contraction of the heart , traveling through the atrioventricular node and along the conduction system of the heart . The heart receives blood low in oxygen from the systemic circulation , which enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle . From here it is pumped into the pulmonary circulation , through the lungs where it receives oxygen and gives off carbon dioxide . Oxygenated blood then returns to the left atrium , passes through the left ventricle and is pumped out through the aorta to the systemic circulation  where the oxygen is used and metabolized to carbon dioxide . The heart beats at a resting rate close to 72 beats per minute . Exercise temporarily increases the rate , but lowers resting heart rate in the long term , and is good for heart health . Cardiovascular diseases ( CVD ) are the most common cause of death globally as of 2008 , accounting for 30 % of deaths . Of these more than three quarters are a result of coronary artery disease and stroke . Risk factors include : smoking , being overweight , little exercise , high cholesterol , high blood pressure , and poorly controlled diabetes , among others . Cardiovascular diseases frequently have no symptoms or may cause chest pain or shortness of breath . Diagnosis of heart disease is often done by the taking of a medical history , listening to the heart - sounds with a stethoscope , ECG , and ultrasound . Specialists who focus on diseases of the heart are called cardiologists , although many specialties of medicine may be involved in treatment . Cardiac arrest is a sudden stop in effective blood flow due to the failure of the heart to contract effectively . Symptoms include loss of consciousness and abnormal or absent breathing . Some people may have chest pain , shortness of breath , or nausea before this occurs . If not treated within minutes , death usually occurs . The most common cause of cardiac arrest is coronary artery disease . Less common causes include major blood loss , lack of oxygen , very low potassium , heart failure , and intense physical exercise . A number of inherited disorders may also increase the risk including long QT syndrome . The initial heart rhythm is most often ventricular fibrillation . The diagnosis is confirmed by finding no pulse . While a cardiac arrest may be caused by heart attack or heart failure these are not the same . Prevention includes not smoking , physical activity , and maintaining a healthy weight . Treatment for cardiac arrest is immediate cardiopulmonary resuscitation ( CPR ) and , if a shockable rhythm is present , defibrillation . Among those who survive targeted temperature management may improve outcomes . An implantable cardiac defibrillator may be placed to reduce the chance of death from recurrence . In the United States , cardiac arrest outside of hospital occurs in about 13 per 10 , 000 people per year ( 326 , 000 cases ). In hospital cardiac arrest occurs in an additional 209 , 000 Cardiac arrest becomes more common with age . It affects males more often than females . The percentage of people who survive with treatment is about 8 %. Many who survive have significant disability . Many U . S . television shows , however , have portrayed unrealistically high survival rates of 67 %.